Infectious Disease and Microbiology – Rubella (German Measles)

Rubella, also called German measles, is a contagious viral infection caused by an enveloped RNA virus belonging to the togavirus family. In most children and adults the illness is mild, but infection during pregnancy can have devastating effects on the developing fetus.

Rubella has become uncommon in countries with widespread vaccination. Historically, the incidence in the United States fell to approximately 1 case per 100,000 population, with most cases occurring among unvaccinated individuals or people arriving from areas where vaccination coverage is lower. Worldwide incidence has also declined substantially following expansion of immunization programs.

The most important risk factor for rubella is lack of vaccination. Before widespread immunization, the disease occurred predominantly in children between 5 and 14 years of age. In areas where vaccination coverage remains inadequate, infection may also occur frequently among adolescents and young adults.

Prevention depends primarily on vaccination with the live attenuated rubella vaccine, usually administered as part of the measles-mumps-rubella vaccine. Routine childhood immunization includes two doses, traditionally given around 12–15 months of age and again between 4 and 6 years.

Women of childbearing age should have their rubella immune status assessed when appropriate, particularly before pregnancy or during early prenatal care. A nonimmune woman should be vaccinated after delivery rather than during pregnancy because the vaccine contains live attenuated virus. Pregnancy should be avoided for approximately 28 days following vaccination.

If rubella vaccine is inadvertently administered during pregnancy, counseling is appropriate, but vaccination alone is not considered an automatic indication for pregnancy termination. Immunocompromised individuals receiving significant chemotherapy or undergoing bone marrow transplantation generally should not receive live rubella vaccine.

Patients with confirmed rubella should avoid close contact with susceptible individuals and should generally remain isolated for approximately one week after the rash appears. Immunoglobulin has not been considered a reliable method of preventing fetal infection in a susceptible pregnant woman after exposure.

Rubella has an incubation period of approximately 2–3 weeks. Transmission occurs primarily through respiratory droplets and secretions from the upper respiratory tract.

The infection is generally mild in children and adults but is especially important during pregnancy. Maternal infection during the first trimester and early second trimester carries the greatest risk of congenital rubella syndrome. Maternal infection may be mild or even asymptomatic while still causing significant fetal injury.

Infants with congenital rubella may continue shedding virus for many months and, in some cases, for as long as 1–2 years after birth. They can therefore remain infectious for prolonged periods.

Rubella commonly begins with a mild upper respiratory illness characterized by low-grade fever, malaise, and coryza. Some patients may have few or no symptoms before the rash develops.

Physical examination may reveal small red lesions on the soft palate followed by a fine maculopapular or morbilliform rash. The rash usually begins on the face, often around the postauricular region, and spreads downward across the trunk and extremities over the next 1–2 days. The lesions may merge and can occasionally be pruritic.

Tender postauricular and occipital lymphadenopathy is a characteristic early finding. Conjunctivitis may also occur. Adolescents and adults, particularly women, may develop arthralgia or arthritis after the rash, which can persist for several days or occasionally longer.

Congenital rubella syndrome can affect multiple organ systems. Manifestations include fetal death, growth restriction, developmental delay, sensorineural deafness, cataracts, retinopathy, patent ductus arteriosus, pulmonary artery abnormalities, hepatosplenomegaly, diabetes mellitus, and thyroid disorders. Some abnormalities may not become apparent until later childhood.

Laboratory testing may show leukopenia and atypical lymphocytes, although these findings are nonspecific. Serologic testing is commonly used to confirm infection.

Rubella-specific IgM antibodies generally become detectable within several days of illness and may remain present for several weeks. However, false-positive IgM results may occur because of infections such as measles, cytomegalovirus, Epstein-Barr virus, or parvovirus B19, as well as interference from rheumatoid factor.

Rubella IgG testing can demonstrate prior immunity, while IgG avidity testing may help distinguish recent primary infection from past infection or reinfection. When a diagnosis has major implications, particularly during pregnancy, positive serologic findings should be confirmed with additional testing when available.

Polymerase chain reaction testing can detect rubella viral RNA in respiratory secretions, blood, amniotic fluid, or fetal specimens. PCR of oral or nasopharyngeal samples is most useful during the early period after rash onset. Viral culture is available only in specialized laboratories.

The differential diagnosis includes measles, parvovirus B19 infection, enterovirus infection, HIV-associated rash, scarlet fever, and medication-related eruptions.

There is no specific antiviral treatment for uncomplicated rubella or congenital rubella syndrome. Management of acquired rubella is supportive, with rest, adequate hydration, and symptomatic treatment when necessary.

Children with congenital rubella syndrome require long-term multidisciplinary follow-up because hearing impairment, visual abnormalities, developmental problems, endocrine disorders, and cardiovascular defects may require ongoing treatment.

The prognosis of uncomplicated rubella in children and adults is excellent, with most patients recovering completely. Congenital rubella syndrome, however, may cause lifelong disability and significant multisystem disease.

The most important complication is congenital rubella syndrome following maternal infection during pregnancy. Sensorineural hearing loss is among the most frequent permanent manifestations. Other uncommon complications of acquired rubella include thrombocytopenia and acute disseminated encephalomyelitis.

Infectious Disease and Microbiology – Roundworms, Intestinal

Intestinal roundworms are clinically important nematodes that infect humans either after ingestion of eggs from contaminated food, water, or soil, or after infective larvae penetrate the skin. Important intestinal roundworm infections include trichuriasis, enterobiasis, ascariasis, hookworm infection, and strongyloidiasis.

Trichuriasis is caused by Trichuris trichiura, or whipworm, and occurs worldwide, particularly in communities with poor sanitation. Hundreds of millions of people are infected globally. Humans are the principal host, and infection is acquired by ingesting mature eggs from contaminated soil.

After ingestion, whipworm eggs hatch in the intestine, and the larvae migrate to the cecum. Adult worms reside mainly in the cecum and ascending colon and may survive for approximately one year. Diagnosis is made by stool microscopy showing characteristic thick-shelled ova with polar plugs.

Trichuriasis is commonly treated with albendazole 400 mg orally daily for 3 days in mild to moderate infection, with longer courses considered for heavier infection. Mebendazole is another effective option. Heavy worm burdens can cause chronic gastrointestinal symptoms and painful rectal prolapse.

Enterobiasis is caused by Enterobius vermicularis, commonly called pinworm. It occurs worldwide and is especially common among children, households, schools, and other crowded settings. Infection can spread rapidly among family members regardless of socioeconomic status.

Adult pinworms live in the terminal ileum and cecum. At night, female worms migrate to the perianal region to deposit eggs, producing intense itching. Scratching contaminates the hands and fingernails, allowing autoinfection and person-to-person transmission through contaminated clothing, bedding, and surfaces.

Diagnosis of enterobiasis is usually made using the cellophane or Scotch-tape test, which collects the characteristic elongated oval eggs from the perianal region. Stool microscopy is generally less useful because the eggs are deposited outside the intestinal lumen.

Treatment includes a single oral dose of albendazole 400 mg or mebendazole 100 mg, with the dose repeated after 2 weeks to reduce the risk of reinfection. Pyrantel pamoate is an alternative. Household members should generally be treated at the same time, and bedding and clothing should be thoroughly washed.

Complications of enterobiasis include perianal excoriations, secondary bacterial infection, and rarely migration of worms into the female genital tract or abdominal cavity.

Ascariasis is caused by Ascaris lumbricoides and is one of the most common human helminthic infections worldwide. It is especially prevalent in areas with poor sanitation and is commonly seen in children.

Ascaris is the largest human intestinal nematode, with adult worms reaching approximately 35 cm in length. Eggs are passed in feces and become infectious after maturing in soil. They can remain viable in the environment for years.

After infective eggs are swallowed, larvae hatch in the intestine, penetrate the intestinal wall, enter the bloodstream, and migrate to the lungs. They cross into the alveoli, ascend the respiratory tract, are swallowed, and then mature into adult worms in the small intestine. Adult worms may survive for 1–2 years.

Diagnosis is usually established by stool microscopy demonstrating characteristic thick-shelled eggs. Peripheral eosinophilia may develop during the pulmonary migration phase.

Ascariasis is usually treated with albendazole 400 mg orally as a single dose or mebendazole 100 mg twice daily for 3 days. Heavy infection can cause intestinal obstruction, impaired nutrition, and malnutrition, particularly in children.

Hookworm infection is caused predominantly by Necator americanus and Ancylostoma duodenale. It is common in tropical and subtropical regions and affects a substantial proportion of the world’s population.

Infective hookworm larvae in contaminated soil penetrate exposed skin, commonly through bare feet. The larvae enter the bloodstream, migrate to the lungs, penetrate the alveoli, ascend the respiratory tract, and are swallowed. They then attach to the mucosa of the small intestine and feed on blood.

Adult hookworms are approximately 1 cm long and may survive for many years. Chronic intestinal blood loss can result in significant iron deficiency, especially in individuals with poor nutritional reserves.

Diagnosis is made by stool microscopy showing characteristic thin-shelled, colorless eggs. Eosinophilia may occur during larval migration, while chronic disease may produce iron-deficiency anemia.

Treatment generally consists of albendazole 400 mg orally as a single dose or mebendazole for 3 days. Pyrantel pamoate is an alternative. Iron replacement may also be required in patients with significant anemia.

Severe hookworm infection may cause profound iron-deficiency anemia, malabsorption, poor growth, and failure to thrive.

Strongyloidiasis is caused by Strongyloides stercoralis and occurs mainly in tropical and subtropical regions. It is more common in rural communities, institutional settings, and populations with lower socioeconomic conditions.

Infective filariform larvae penetrate the skin following contact with contaminated soil. They enter the circulation, migrate through the lungs, penetrate the alveoli, ascend the respiratory tract, and are swallowed. Adult female worms then live in the upper small intestine.

A distinctive feature of Strongyloides infection is autoinfection. Rhabditiform larvae produced in the intestine can transform into infective filariform larvae before leaving the body. These larvae penetrate the intestinal wall or perianal skin and restart the migration cycle, allowing infection to persist for decades.

Diagnosis is based on demonstration of rhabditiform larvae in stool. Because parasite excretion may be intermittent, repeated stool examinations may be required. Eosinophilia is common in uncomplicated acute and chronic infection. Serologic testing can be useful when stool examinations are negative but clinical suspicion remains high.

Ivermectin is the preferred treatment for strongyloidiasis, usually given at 200 micrograms/kg orally daily for 2 days. A repeat course may be required. Albendazole is an alternative, although generally less effective. Hyperinfection or disseminated strongyloidiasis requires prolonged ivermectin treatment until parasitologic clearance is achieved.

Strongyloides hyperinfection is particularly dangerous in immunocompromised patients, especially those receiving corticosteroids. Large numbers of migrating larvae can cause severe gastrointestinal and pulmonary disease, intestinal microperforation, bacteremia, sepsis, and death.

General prevention of intestinal roundworm infections depends on proper sanitation, safe disposal of human waste, thorough handwashing after defecation and before food preparation, and careful washing, peeling, or cooking of fruits and vegetables. Wearing protective footwear is particularly important for preventing hookworm infection and strongyloidiasis when contact with contaminated soil is possible.

The differential diagnosis includes other intestinal helminthic infections and should be guided by exposure history, clinical manifestations, stool findings, eosinophilia, and geographic risk factors.

Follow-up stool examinations may be useful after treatment to confirm eradication and detect reinfection, particularly in persistent or high-risk infections. Enterobiasis requires attention to household transmission, while strongyloidiasis requires especially careful follow-up in immunocompromised patients.

The overall prognosis is excellent when intestinal roundworm infections are recognized and appropriately treated. However, untreated heavy infection can produce important complications, including rectal prolapse from trichuriasis, intestinal obstruction from ascariasis, severe anemia from hookworm infection, and potentially fatal hyperinfection syndrome from strongyloidiasis.

Infectious Disease and Microbiology – Rocky Mountain Spotted Fever

Rocky Mountain spotted fever (RMSF) is an acute tick-borne infection caused by the intracellular bacterium Rickettsia rickettsii. Despite its name, most cases in the United States occur outside the Rocky Mountain region. The disease can progress rapidly and may be fatal if treatment is delayed.

RMSF is a reportable disease in the United States, with hundreds to a few thousand cases historically reported each year. Although cases have occurred across most states, a large proportion have been concentrated in North Carolina, Oklahoma, Arkansas, Tennessee, and Missouri. RMSF also occurs in Canada, Mexico, Central America, and South America.

The disease is most common during spring and summer, when tick activity is highest. Children younger than 10 years and adults between 40 and 64 years have historically had high incidence rates. Risk increases with residence or activity in wooded areas, tall grass, and places where dogs and ticks are common. Glucose-6-phosphate dehydrogenase deficiency has been associated with more severe disease in some patients.

Prevention depends on reducing tick exposure. People entering wooded or grassy environments should wear protective clothing, perform frequent tick checks, and consider repellents containing DEET on exposed skin and permethrin on clothing where appropriate. Attached ticks should be removed promptly using fine-tipped forceps, grasping the tick close to the skin and pulling steadily upward without twisting.

After a tick bite, R. rickettsii enters vascular endothelial cells and spreads through the vascular system. Infection produces widespread vasculitis, increasing vascular permeability and activating coagulation pathways. The resulting capillary leak, edema, hypovolemia, and tissue ischemia account for many of the systemic manifestations and complications of RMSF.

Rickettsia rickettsii is an obligate intracellular, gram-negative coccobacillus transmitted through the salivary glands of feeding ticks. Important vectors include Dermacentor variabilis, the American dog tick, in much of the eastern United States, and Dermacentor andersoni, the Rocky Mountain wood tick, in western regions. The brown dog tick, Rhipicephalus sanguineus, can transmit infection in parts of Arizona and Mexico, while Amblyomma species have been important vectors in Central and South America.

The incubation period is generally 2–14 days, averaging about 7 days. Illness usually begins abruptly with fever, severe headache, myalgias, and marked malaise. Nausea, vomiting, and abdominal pain are also common. Neurologic involvement may range from mild confusion to seizures and encephalitis. Importantly, many patients do not recall a tick bite.

The classic triad of fever, rash, and known tick exposure is uncommon early in the disease and should not be required for diagnosis. The rash typically appears 2–5 days after fever begins. It usually starts as small blanching erythematous macules on the wrists and ankles, then spreads to the palms, soles, arms, legs, and trunk. As disease progresses, the lesions may become petechial.

The rash may appear late or may never develop. A minority of patients have so-called spotless RMSF. In addition, the rash may be difficult to recognize in people with darker skin tones. Therefore, absence of rash does not exclude the diagnosis.

Ocular abnormalities may include conjunctivitis, retinal vascular changes, hemorrhages, arterial occlusion, and papilledema. Neurologic findings may include lethargy, photophobia, meningismus, transient hearing loss, amnesia, behavioral changes, seizures, or encephalopathy. Hepatomegaly and pulmonary findings resembling pneumonia can also occur.

Diagnosis requires a high degree of clinical suspicion because laboratory confirmation is often unavailable during the early phase when treatment is most important. Antibodies against R. rickettsii are generally not detectable until approximately 7–10 days after illness begins.

Indirect immunofluorescence antibody testing is the traditional reference serologic method. Diagnosis is supported by a fourfold rise in antibody titer between acute and convalescent specimens. A single positive result may be difficult to interpret because antibodies to other spotted-fever rickettsiae may cross-react and background seropositivity can occur.

Thrombocytopenia is one of the most common laboratory abnormalities. The white blood cell count may be normal, decreased, or elevated and is not sufficiently reliable to exclude the disease. Other abnormalities may include hyponatremia, elevated creatinine, azotemia, increased serum transaminases, bilirubin elevation, and increased creatine kinase.

Chest radiographs may demonstrate focal pulmonary infiltrates or interstitial edema. In patients with encephalopathy, CT or MRI may reveal generalized cerebral edema. Cerebrospinal fluid may show a mild lymphocytic pleocytosis. Electrocardiographic abnormalities may range from nonspecific ST-wave changes to atrial arrhythmias.

Direct immunofluorescence staining of a skin biopsy for R. rickettsii antigens can provide early diagnostic evidence, although it is not routinely available and is generally less practical than clinical diagnosis and serology.

The differential diagnosis is broad and includes viral syndromes, bacterial sepsis, meningococcemia, disseminated gonococcal infection, secondary syphilis, typhoid fever, leptospirosis, ehrlichiosis, anaplasmosis, toxic shock syndrome, drug hypersensitivity reactions, idiopathic thrombocytopenic purpura, thrombotic thrombocytopenic purpura, and bacterial or viral meningoencephalitis.

Treatment should begin immediately when RMSF is suspected and must not be delayed while awaiting laboratory confirmation. Doxycycline is the treatment of choice for both adults and children. Adults are generally treated with doxycycline 100 mg twice daily, while children weighing less than 45 kg receive approximately 2.2 mg/kg per dose twice daily.

Therapy is typically continued for at least 5–7 days and for at least 48 hours after the patient becomes afebrile and shows clear clinical improvement. Oral or intravenous therapy may be used depending on severity and the patient’s ability to tolerate oral medications.

Doxycycline is also recommended for young children despite historical concerns about tooth staining because short courses have not shown the same risk associated with prolonged tetracycline exposure, and delayed effective therapy can be life-threatening.

Chloramphenicol has historically been used as an alternative, particularly when tetracyclines were considered contraindicated. However, outcomes have generally been less favorable than with doxycycline, and treatment decisions in pregnancy or other special circumstances require individualized risk-benefit assessment.

Severely ill patients may require hospitalization and intensive supportive care. Intravenous antibiotics are appropriate for patients with persistent vomiting, unstable vital signs, altered mental status, or other signs of severe disease. Shock, renal failure, respiratory compromise, and neurologic deterioration may require intensive care, hemodynamic support, mechanical ventilation, or renal replacement therapy.

Patients with neurologic symptoms, elevated creatinine, significant vomiting, hypotension, or other unstable vital signs should generally be admitted to the hospital. Approximately one-fourth of suspected cases historically required hospitalization.

The prognosis is strongly influenced by how quickly effective treatment is started. Delay beyond the first several days of illness substantially increases the risk of death and severe complications. Older age, neurologic involvement, renal dysfunction, and failure to receive doxycycline are associated with poorer outcomes.

Most survivors recover fully, but severe disease may produce permanent neurologic deficits, hearing impairment, or tissue ischemia severe enough to cause gangrene and require amputation.

Major complications include meningitis, encephalitis, seizures, acute kidney injury, acute respiratory distress syndrome, shock, disseminated vascular injury, myocarditis, tissue necrosis, and multiorgan failure.

Infectious Disease and Microbiology – Rheumatic Fever

Rheumatic fever is an inflammatory clinical syndrome that develops following infection of the pharynx with group A Streptococcus. It can produce a wide range of manifestations, including migratory arthritis, characteristic skin lesions, Sydenham chorea, and pancarditis with cardiac valvular dysfunction.

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Rheumatic fever occurs worldwide but has become relatively uncommon in developed countries because of improved living conditions and appropriate antibiotic treatment of streptococcal pharyngitis. It remains an important cause of acquired heart disease in developing countries, historically accounting for approximately 40% of heart disease in some populations. The estimated incidence in the United States has been approximately 0.5 per 100,000 population, with a prevalence of about 2 per 10,000. It primarily affects children between 6 and 15 years of age.

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Approximately one-third of cases may follow subacute or clinically unrecognized group A streptococcal pharyngitis. Historically, the attack rate after untreated streptococcal pharyngitis has ranged from approximately 0.4–3%. Outbreaks may be influenced by the particular circulating strains of Streptococcus.

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Important risk factors include overcrowded living conditions and a previous history of rheumatic fever. Genetic susceptibility has also been proposed, with associations involving certain HLA types, B-cell alloantigens, and immune-response gene polymorphisms, although the precise genetic contribution remains incompletely understood.

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Prevention begins with appropriate diagnosis and treatment of group A streptococcal pharyngitis. A complete course of penicillin therapy can prevent the development of rheumatic fever even when treatment is initiated several days after the onset of sore throat. Patients with a previous episode of rheumatic fever have a substantial risk of recurrence and therefore require secondary antibiotic prophylaxis. Benzathine penicillin G administered intramuscularly at regular intervals is a commonly used regimen, with oral penicillin or certain alternative antibiotics used when appropriate.

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The pathogenesis of rheumatic fever is primarily immune mediated. Molecular mimicry between antigens of group A Streptococcus and human tissues produces an abnormal immune response in which antibodies and immune cells directed against streptococcal components cross-react with host tissues, particularly structures within the heart.

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Group A streptococcal pharyngitis initiates the disease. Rheumatic fever typically develops approximately 1–5 weeks after the infection, with an average interval historically reported at about 19 days. Certain streptococcal strains have been particularly associated with rheumatic fever. Cross-reacting immune responses against streptococcal antigens and cardiac tissues, especially heart valves, contribute to the development of carditis.

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Patients may present with fever, fatigue, joint pain, skin manifestations, involuntary movements, dyspnea, or peripheral edema. Rheumatic fever is fundamentally a clinical diagnosis. Traditionally, diagnosis is based on the Jones criteria together with evidence of a preceding group A streptococcal infection. The clinical manifestations may persist for several months, particularly when carditis is present.

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The major clinical manifestations include migratory polyarthritis, carditis, Sydenham chorea, subcutaneous nodules, and erythema marginatum. Historically, polyarthritis has occurred in approximately 75% of cases, carditis in about 50%, chorea in approximately 15%, and subcutaneous nodules and erythema marginatum in fewer than 10%.

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Polyarthritis commonly occurs early in the disease and is frequently accompanied by fever. The arthritis predominantly involves large joints, particularly the knees, ankles, elbows, and wrists. Several joints may become involved sequentially, producing the characteristic migratory pattern. Joint manifestations generally resolve without permanent damage.

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Carditis may involve the endocardium, myocardium, and pericardium, producing pancarditis. Some cases are clinically subtle, whereas severe disease may present with congestive heart failure. Acute valvular involvement most commonly produces mitral regurgitation, followed by aortic regurgitation. Persistent valvular damage can eventually result in chronic rheumatic heart disease.

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Sydenham chorea consists of irregular, involuntary, purposeless, dance-like movements involving the face and extremities. It may occur together with arthritis and carditis or occasionally appear as the predominant manifestation of rheumatic fever.

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Subcutaneous nodules are painless lesions that usually develop over tendons or near joints. They may reach approximately 2 cm in diameter and are particularly associated with rheumatic carditis.

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Erythema marginatum is an uncommon, transient rash consisting of irregular erythematous lesions, usually involving the trunk and extremities. Because the lesions are evanescent, the rash may be difficult to detect during examination.

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Minor manifestations include fever and arthralgia without objective arthritis. Laboratory or electrocardiographic abnormalities contributing to the traditional minor criteria include elevated inflammatory markers such as erythrocyte sedimentation rate or C-reactive protein and prolongation of the PR interval on electrocardiography.

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Evidence of a preceding group A streptococcal infection should generally be established. This may include a positive throat culture, positive rapid streptococcal antigen testing, or elevated or rising streptococcal antibody titers such as antistreptolysin O, anti-DNase B, or antihyaluronidase antibodies. Exceptions may occur with manifestations such as Sydenham chorea or indolent carditis, which can appear sufficiently late that evidence of the original infection is difficult to demonstrate.

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Echocardiography is an important component of evaluation because it can detect valvular abnormalities and carditis that may not be obvious on physical examination. Serial echocardiography may be required when cardiac involvement progresses or when monitoring established carditis.

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Pathologically, rheumatic fever produces inflammatory lesions within connective tissues. Characteristic Aschoff bodies may be found in the myocardium. Cardiac inflammation can involve all layers of the heart, resulting in pancarditis.

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The differential diagnosis includes juvenile idiopathic arthritis, systemic lupus erythematosus, Lyme disease, gonococcal arthritis, infective endocarditis, viral infections such as rubella and coxsackievirus infection, medication reactions, sickle cell disease, sarcoidosis, inflammatory bowel disease, leukemia, and other causes of inflammatory arthritis or cardiac disease.

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Treatment is directed toward eradication of group A streptococcal infection, suppression of inflammation, management of cardiac complications, and prevention of recurrent disease. Anti-inflammatory therapy with aspirin or other appropriate anti-inflammatory agents has historically been used for arthritis and other inflammatory manifestations. Corticosteroids may be considered in severe carditis, particularly when significant heart failure is present.

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Older treatment regimens used high-dose aspirin, sometimes beginning at approximately 90–100 mg/kg/day and subsequently reducing the dose after clinical improvement. Corticosteroid therapy has historically been used for severe inflammatory cardiac disease. Because aspirin and corticosteroid regimens require careful consideration of toxicity and current clinical recommendations, treatment should be individualized and supervised appropriately.

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Secondary antibiotic prophylaxis is a central component of long-term management because recurrent streptococcal infections can cause additional episodes of rheumatic fever and progressively worsen valvular disease. The required duration depends on whether the initial episode involved carditis and whether residual valvular disease remains.

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Patients with rheumatic fever accompanied by carditis and persistent valvular disease generally require prolonged prophylaxis, historically for at least 10 years or until approximately 40 years of age, whichever is longer. Some individuals at continued high risk of streptococcal exposure or recurrent disease may require lifelong prophylaxis.

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When carditis occurred but no residual cardiac disease remains, prophylaxis has traditionally been continued for approximately 10 years or until at least 21 years of age, whichever period is longer. In rheumatic fever without carditis, prophylaxis is generally continued for at least 5 years or until approximately 21 years of age, whichever is longer. Sydenham chorea as a manifestation of rheumatic fever also warrants secondary prophylaxis.

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Severe valvular disease that fails medical management may require cardiothoracic surgical evaluation. Rheumatic heart disease remains an important indication for valve surgery in regions where rheumatic fever is common. Procedures may include mitral valve repair, commissurotomy, or valve replacement, depending on the type and severity of valvular damage.

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Hospitalization may be necessary for patients with significant carditis, heart failure, severe Sydenham chorea, or other serious manifestations. Discharge is generally appropriate when symptoms are adequately controlled and there is no evidence of uncontrolled heart failure.

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Patients with carditis require long-term clinical and echocardiographic follow-up, often involving both primary care and cardiology specialists. Education regarding adherence to secondary antibiotic prophylaxis is particularly important because recurrent attacks substantially increase the risk of permanent valvular damage.

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The overall prognosis depends largely on the severity of cardiac involvement and the occurrence of recurrent episodes. Many patients recover from the acute illness, but recurrence can occur following subsequent group A streptococcal infections, particularly when secondary prophylaxis is inadequate.

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The most important long-term complication is chronic rheumatic valvular heart disease. Progressive valve dysfunction can eventually result in refractory heart failure, arrhythmias, pulmonary hypertension, and the need for cardiac surgery. Patients with damaged valves may also have an increased risk of infective endocarditis.

Infectious Disease and Microbiology – Respiratory Syncytial Virus Infection

Respiratory syncytial virus (RSV) is a highly contagious viral infection that causes upper and lower respiratory tract disease in children and adults. It is particularly important in infants, children with congenital heart or chronic lung disease, immunocompromised individuals, and older adults. Acute bronchiolitis is the major clinical manifestation in young children.

RSV is one of the most important causes of lower respiratory tract infection in childhood. In 2005, an estimated 33.8 million episodes of RSV-associated acute lower respiratory tract infection occurred worldwide among children younger than 5 years, with an estimated 66,000–199,000 associated deaths. Severe RSV disease occurs most frequently between 2 and 8 months of age. By 24 months, most children have experienced at least one RSV infection. RSV also causes substantial disease in older adults, with annual attack rates historically estimated at approximately 5–10%.

Important risk factors for severe RSV infection include age younger than 6 months, prematurity, male sex, crowding, lower socioeconomic conditions, exposure to passive cigarette smoke, day-care attendance, older siblings attending day care, and birth during the early part of RSV season. Children with congenital heart disease, chronic lung disease such as bronchopulmonary dysplasia or cystic fibrosis, and individuals who are immunocompromised because of chemotherapy or transplantation are also at increased risk.

Prevention focuses on reducing viral transmission and protecting individuals at high risk of severe disease. Frequent handwashing, avoiding the sharing of contaminated objects, and appropriate infection-control precautions can reduce transmission. Glove and gown precautions are particularly important in healthcare environments. Historically, passive immunization with RSV-specific immunoglobulin and the monoclonal antibody palivizumab has been used for selected high-risk infants. Motavizumab was investigated as a more potent monoclonal antibody against RSV.

RSV spreads from the upper respiratory tract into the lower respiratory tract. Viral infection promotes cell-to-cell fusion, producing characteristic multinucleated structures known as syncytia. Infection and inflammation of the small airways contribute to airway obstruction, mucus production, wheezing, and the characteristic manifestations of bronchiolitis.

Severe RSV bronchiolitis during infancy has been associated with an increased prevalence of recurrent wheezing and asthma later in childhood. Some studies have suggested that RSV prophylaxis may reduce recurrent wheezing in certain nonatopic children, although the relationship between RSV infection, atopy, and subsequent asthma is complex.

The incubation period of RSV is approximately 2–8 days. Transmission occurs through contact with infected respiratory secretions, contaminated hands or surfaces, and respiratory droplets. Infection commonly begins with upper respiratory symptoms and may progress rapidly to cough, coryza, and wheezing. Fever is usually low-grade, although high fever can occur in children.

As the disease progresses, young children may develop a deeper cough, episodes of coughing, wheezing, and manifestations of bronchiolitis. Mild croup may occur, and otitis media is a frequent associated condition. Older adults may develop more significant lower respiratory tract disease, including bronchopneumonia.

Physical examination of infants with RSV lower respiratory tract infection may demonstrate tachypnea, diffuse rales associated with small-airway disease, wheezing, and, in severe cases, cyanosis. Otitis media may also be present. Careful assessment of hydration is particularly important in infants and should include evaluation of skin turgor, capillary refill, and the condition of the mucous membranes.

Laboratory assessment in patients with significant illness may include measurement of oxygen saturation, arterial blood gases, serum electrolytes, and a complete blood count. RSV can be identified from respiratory secretions using rapid diagnostic tests. Other diagnostic techniques include immunofluorescence assays, enzyme-linked immunosorbent assays, and viral culture of nasal washings.

Chest radiographs may demonstrate hyperinflation, focal atelectasis, and pulmonary infiltrates. Expiratory CT imaging may show evidence of small-airway disease, particularly air trapping. Histopathologic examination of lung tissue can demonstrate mononuclear cell and neutrophil infiltration around bronchioles, together with areas of atelectasis and pulmonary infiltrates.

The differential diagnosis includes asthma, acute or chronic bronchitis, bacterial or viral pneumonia, influenza, parainfluenza infection, croup, human metapneumovirus infection, and neonatal sepsis.

Treatment is primarily supportive. Oxygen should be administered when clinically indicated, and adequate hydration should be maintained with oral or intravenous fluids depending on the patient’s condition. Respiratory support, including mechanical ventilation or intubation, may be necessary in severe disease.

Nebulized ribavirin has historically been approved for severe RSV infection. A regimen described is 6 g of lyophilized ribavirin dissolved in 300 mL of distilled water and administered through a small-particle aerosol generator for 12–20 hours per day for 3–7 days. However, evidence supporting substantial clinical benefit has been limited, and concerns include cost and potential occupational exposure of healthcare workers. Its use has therefore generally been reserved for selected severe cases, particularly among profoundly immunocompromised patients.

Various additional approaches have been investigated in high-risk populations. Intravenous palivizumab, alone or in combination with ribavirin, has been studied in severe RSV infection. Combination regimens involving inhaled ribavirin, corticosteroids, intravenous immunoglobulin, and sometimes palivizumab have also been evaluated in transplant recipients. RNA interference therapies have additionally been investigated in lung transplant patients.

Hospitalized patients require careful supportive management. Oxygenation and hydration should be monitored closely, and patients with progressive respiratory failure may require assisted ventilation. Young infants, immunocompromised patients, individuals with significant cardiopulmonary disease, and older adults are at increased risk of severe outcomes.

Most otherwise healthy children hospitalized with RSV infection improve sufficiently for discharge within several days. Follow-up is generally unnecessary after uncomplicated recovery, although patients who subsequently develop persistent or recurrent bronchospasm may require additional evaluation.

The prognosis is generally favorable in healthy children, but RSV can cause substantial morbidity and mortality in young infants, older adults, and individuals with underlying cardiopulmonary disease or immunocompromising conditions. A small but important proportion of infants with RSV infection require intermediate or intensive care.

Potential complications include bacterial pneumonia, otitis media, respiratory failure, and recurrent wheezing. Neurologic complications such as seizures and encephalopathy have also been reported. Severe childhood RSV infection has been associated with subsequent asthma or recurrent wheezing, although the precise causal relationship remains uncertain.

Ophthalmology – Hypertensive Retinopathy

Basics

Description

Hypertensive retinopathy refers to characteristic retinal, choroidal, and optic nerve changes produced by systemic hypertension. The ocular findings may be divided broadly into acute changes, usually associated with severe or rapidly rising blood pressure, and chronic changes, which reflect longstanding vascular damage.

Acute severe hypertension may cause retinal ischemia, hemorrhages, cotton-wool spots, hard exudates, choroidal infarction, serous retinal detachment, and optic disc edema. Chronic hypertension produces progressive retinal arteriolar narrowing, vascular wall thickening, arteriovenous crossing abnormalities, and eventually copper- or silver-wiring of the retinal arteries.

Pregnancy Considerations

In a woman of childbearing age with severe or uncontrolled hypertension, pregnancy status should be established because hypertension may be related to preeclampsia or eclampsia. These conditions can produce marked retinal and choroidal changes and may threaten both maternal and fetal health.

Epidemiology

The frequency of hypertensive retinopathy varies between populations and depends on the definition used.

In the Beaver Dam Eye Study, approximately 6% of patients developed hypertensive retinopathy. Retinal arteriolar narrowing was noted in about 9.9%, while arteriovenous nicking occurred in approximately 6.5%.

Reported prevalence among adults older than 40 years ranges from roughly 2–15%. Some studies have found a higher prevalence among African American populations than among Caucasian populations.

Risk Factors

The principal risk factor is elevated systemic blood pressure, including both systolic and diastolic hypertension.

Diabetes mellitus increases the risk and severity of retinal vascular damage.

Other cardiovascular risk factors, particularly dyslipidemia, smoking, obesity, renal disease, and atherosclerosis, may contribute to the overall vascular burden.

Genetics

There is no single genetic cause of hypertensive retinopathy. Multiple genetic factors contribute to the development of systemic hypertension and therefore indirectly influence susceptibility to hypertensive retinal vascular changes.

General Prevention

Prevention centers on maintaining well-controlled systemic blood pressure.

Regular blood pressure monitoring, adherence to prescribed antihypertensive therapy, control of diabetes and dyslipidemia, appropriate diet, exercise, and management of other cardiovascular risk factors reduce the likelihood of hypertensive end-organ damage.

Pathophysiology

As systemic blood pressure rises, the retinal arterioles initially respond with vasoconstriction. Persistent hypertension eventually causes structural thickening of the arteriolar walls.

With more severe hypertension, the blood-retinal barrier becomes disrupted, allowing leakage of plasma, lipid, and blood into the retina.

Damage to small retinal vessels causes ischemia, producing cotton-wool spots and other manifestations of retinal infarction.

Severe acute hypertension may also compromise the choroidal circulation and optic nerve blood supply, producing choroidal infarcts, retinal pigment epithelial abnormalities, optic nerve ischemia, and optic disc edema.

Etiology

The most common cause is essential hypertension.

Secondary causes include renal disease, renal artery stenosis, endocrine disorders, pregnancy-related hypertension such as preeclampsia/eclampsia, and other systemic conditions capable of producing severe elevations in blood pressure.

Commonly Associated Conditions

Hypertensive retinopathy is associated with systemic and ocular vascular disease, including diabetes mellitus, hyperlipidemia, atherosclerosis, retinal artery macroaneurysm, retinal vein occlusion, retinal artery occlusion, stroke, and cognitive decline.

Longstanding systemic hypertension may also be associated with an increased cardiovascular risk, including coronary artery disease.

Diagnosis

History

Many patients with hypertensive retinopathy are asymptomatic and may not even know that they have hypertension.

Others have a known history of elevated blood pressure and may be receiving antihypertensive medication.

Patients should be asked about headaches, visual changes, neurologic symptoms, chest pain, shortness of breath, renal disease, pregnancy, diabetes, and medication adherence.

In acute severe hypertension, symptoms related to end-organ injury may dominate the presentation.

Physical Examination

A complete ophthalmic examination should include visual acuity, pupils, intraocular pressure when appropriate, slit-lamp examination, and a dilated fundus examination.

The retinal appearance differs substantially between acute severe hypertension and chronic hypertension.

Acute or Malignant Hypertensive Changes

Severe or rapidly developing hypertension can cause fibrinoid necrosis of the retinal and choroidal arterioles, producing ischemic and exudative changes.

Deep yellow-gray retinal pigment epithelial or choroidal lesions may be seen during the acute phase.

Later, areas of choroidal infarction can become hyperpigmented and are called Elschnig spots.

Linear hyperpigmented streaks resulting from choroidal infarction along choroidal arteries are known as Siegrist streaks.

Optic Disc Edema

Optic disc swelling may occur in very severe hypertensive disease.

It reflects significant end-organ involvement and may result from ischemic injury to the optic nerve and disruption of autoregulation.

Historically, optic disc edema was an important feature in definitions of malignant hypertension.

The presence of optic disc edema in a patient with severely elevated blood pressure should be considered a medical emergency requiring urgent systemic evaluation.

Retinal Hemorrhages

Hypertensive retinopathy may produce retinal hemorrhages of varying severity.

These may include:

Flame-shaped hemorrhages in the nerve fiber layer, deeper dot-blot hemorrhages, and occasionally more extensive pre-retinal or subretinal hemorrhage in severe disease.

Cotton-Wool Spots

Cotton-wool spots represent localized infarctions of the retinal nerve fiber layer caused by precapillary arteriolar occlusion.

They indicate significant retinal ischemia and are more likely in severe hypertension.

Hard Exudates

Breakdown of the blood-retinal barrier permits lipid-rich plasma to leak into the retina, producing hard exudates.

When arranged radially around the fovea, they may create a macular star.

Serous Retinal Detachment

Acute severe hypertension, particularly in younger patients or those with pregnancy-associated hypertension, can produce serous retinal detachment because of choroidal ischemia and retinal pigment epithelial dysfunction.

This may cause sudden visual loss.

Chronic Hypertensive Changes

Longstanding hypertension produces structural changes in the retinal arterioles.

Arteriolar Narrowing

Generalized or focal narrowing of the retinal arterioles is common.

The normal artery-to-vein caliber ratio is approximately 2:3. With chronic hypertension, the arterial component becomes progressively narrower.

Copper Wiring

As the arteriolar wall becomes thickened and sclerotic, the central light reflex broadens.

The vessel develops a reddish-brown appearance referred to as copper wiring.

Silver Wiring

With advanced arteriolosclerosis, the arterial wall becomes so thick and opaque that the blood column is difficult or impossible to visualize.

The vessel then appears pale or white, producing silver wiring.

Arteriovenous Nicking

At arteriovenous crossings, the artery and vein share a common adventitial sheath.

A thickened, rigid artery can compress the underlying vein, producing narrowing or interruption of the venous blood column.

This is termed AV nicking, or the Gunn sign.

Salus Sign

The retinal vein may be deflected from its normal course as it passes beneath a sclerotic arteriole.

This is known as the Salus sign.

Microaneurysms

Microaneurysms may develop as a consequence of chronic microvascular damage.

However, their presence should also prompt consideration of diabetes or other retinal vascular disease.

Diagnostic Tests and Interpretation

Blood Pressure Measurement

The most important initial systemic test is accurate blood pressure measurement.

If severe hypertension is found, assessment for acute end-organ damage should follow promptly.

Patients with diabetes should have careful blood pressure control because reduction of systemic hypertension decreases progression of diabetic microvascular complications.

Imaging

Routine ocular imaging is not always necessary in straightforward cases.

However, several modalities may be useful when the diagnosis is uncertain or complications are suspected.

Fundus Photography

Color fundus photography is useful for documenting the severity and progression of retinal vascular changes.

Optical Coherence Tomography

OCT may reveal macular edema, subretinal fluid, retinal thickening, or structural changes associated with severe hypertensive retinopathy.

Fluorescein Angiography

Fluorescein angiography may demonstrate:

Microaneurysms, retinal telangiectasia, retinal or choroidal ischemia, capillary nonperfusion, vascular leakage, and optic disc leakage.

It is generally reserved for cases in which additional information is needed.

Pathological Findings and Grading

A traditional grading system is the Scheie classification.

Grade 0: Normal fundus.

Grade 1: Mild generalized retinal arteriolar narrowing.

Grade 2: More obvious narrowing with focal irregularities.

Grade 3: Grade 2 changes plus retinal hemorrhages, cotton-wool spots, or exudates.

Grade 4: Grade 3 changes plus optic disc edema.

Modern clinical management places more emphasis on the presence of acute end-organ injury than on the grading system alone.

Differential Diagnosis

Important differential diagnoses include diabetic retinopathy, radiation retinopathy, retinal vein occlusion, retinal artery occlusion, retinal vasculitis, juxtafoveal telangiectasia, giant cell arteritis, and other ischemic or inflammatory retinal vascular disorders.

The patient’s systemic history and retinal distribution of lesions help distinguish these conditions.

Treatment

Treatment is directed primarily at the systemic hypertension, not the retinal lesions themselves.

The retinal changes frequently improve as blood pressure is controlled.

Medication

Chronic Hypertension

Patients with chronic hypertension generally require oral antihypertensive therapy chosen according to their overall cardiovascular and renal status.

Medication selection should be managed by the patient’s primary care physician, internist, cardiologist, nephrologist, or other appropriate clinician.

Hypertensive Emergency

Patients with severe hypertension and evidence of acute end-organ damage may require intravenous antihypertensive therapy in a monitored hospital setting.

Blood pressure should generally be lowered in a controlled manner rather than abruptly, because excessive rapid reduction can compromise cerebral, coronary, renal, and ocular perfusion.

Referral

All patients with newly recognized hypertensive retinopathy should have systemic blood pressure evaluation and appropriate medical follow-up.

Patients with severe retinal hemorrhages, cotton-wool spots, optic disc edema, choroidopathy, neurologic symptoms, or other evidence of acute hypertensive end-organ damage require urgent medical assessment.

Inpatient Considerations

Hospital admission is indicated when the patient has a hypertensive emergency, meaning severely elevated blood pressure accompanied by acute target-organ injury.

Ocular evidence of severe hypertensive damage, particularly optic disc edema together with other systemic findings, may form part of the end-organ injury picture.

Management requires controlled blood pressure lowering and evaluation for neurologic, cardiac, renal, and other systemic complications.

Follow-Up

Blood pressure should be monitored closely by the patient’s medical provider.

Ophthalmic follow-up depends on the severity of retinal findings.

Patients with mild chronic changes may be followed during routine dilated eye examinations.

Patients with acute exudative or ischemic changes should be re-examined more closely to document resolution of hemorrhages, cotton-wool spots, retinal edema, subretinal fluid, and optic disc swelling.

Diet

A diet that supports blood pressure control is recommended.

For patients with salt-sensitive hypertension, reduction of dietary sodium can contribute to improved blood pressure control.

Overall cardiovascular dietary measures should also emphasize appropriate calorie intake, fruits, vegetables, whole grains, and management of dyslipidemia and diabetes.

Patient Education

Patients should understand that hypertensive retinopathy is evidence of systemic vascular injury, not merely an isolated eye problem.

Regular blood pressure monitoring, adherence to antihypertensive medication, treatment of diabetes and hyperlipidemia, smoking cessation, and regular medical follow-up are important for preserving both vision and overall cardiovascular health.

Patients with sudden visual loss, severe headache, neurologic symptoms, chest pain, or severe blood pressure elevation should seek urgent medical care.

Prognosis

The visual prognosis is usually excellent when blood pressure is adequately controlled before permanent retinal, choroidal, or optic nerve damage develops.

Many acute retinal changes, including hemorrhages, cotton-wool spots, and edema, can improve substantially after appropriate treatment of systemic hypertension.

Longstanding vascular sclerosis may remain even after blood pressure is controlled.

Severe ischemic injury to the macula or optic nerve may result in permanent visual impairment.

Complications

Complications of systemic hypertension affecting the eye include retinal vein occlusion, retinal arterial occlusion, retinal artery macroaneurysm, optic nerve ischemia, hypertensive optic neuropathy, macular edema, choroidal infarction, and serous retinal detachment.

The presence of significant hypertensive retinopathy also serves as an important marker of increased risk for systemic cardiovascular and cerebrovascular disease.

Ophthalmology – Horner Syndrome

Basics

Description

Horner syndrome (HS) results from interruption of the oculosympathetic pathway supplying the eye and face.

The classic clinical features are:

• Miosis — due to paralysis of the iris dilator muscle
• Mild ptosis — due to denervation of Müller’s superior tarsal muscle
• Anhidrosis — variable, depending on the level of the lesion

Other findings include:

• Dilation lag in darkness
• Mild reverse ptosis of the lower eyelid
• Transient conjunctival hyperemia in acute cases
• Iris heterochromia in congenital or very early-onset Horner syndrome

Horner syndrome may be congenital or acquired.

Clinical priority: New painful Horner syndrome should raise immediate concern for internal carotid artery dissection.

Oculosympathetic Pathway

Understanding the three-neuron sympathetic pathway is essential for localizing Horner syndrome.

First-Order Neuron — Central

The pathway begins in the posterolateral hypothalamus.

Fibers descend ipsilaterally through the:

Hypothalamus → midbrain → pons → medulla → cervical spinal cord

They terminate in the ciliospinal center of Budge, approximately C8–T2.

Causes of First-Order Horner Syndrome

• Brainstem stroke
• Demyelinating disease
• Brainstem tumor
• Syringomyelia
• Cervical spinal cord tumor
• Cervical spinal cord trauma

Associated neurologic findings frequently help localize the lesion.

Second-Order Neuron — Preganglionic

Preganglionic fibers leave the spinal cord, pass over the pulmonary apex, and ascend through the cervical sympathetic chain.

They eventually synapse in the superior cervical ganglion, near the carotid bifurcation.

Causes of Second-Order Horner Syndrome

Think particularly about lesions of the chest and neck:

• Pancoast/apical lung tumor
• Neck tumors
• Mediastinal disease
• Cervical trauma
• Brachial plexus injury
• Neck or thoracic surgery
• Neuroblastoma in children

Because the pathway passes near the lung apex, an otherwise unexplained Horner syndrome may be the presenting manifestation of an apical pulmonary malignancy.

Third-Order Neuron — Postganglionic

Postganglionic fibers leave the superior cervical ganglion and travel with the internal carotid artery into the skull.

They pass through the cavernous sinus, then enter the orbit and ultimately reach:

• Iris dilator muscle
• Müller’s superior tarsal muscle

Causes of Third-Order Horner Syndrome

Important causes include:

• Internal carotid artery dissection
• Internal carotid aneurysm
• Cavernous sinus lesions
• Skull-base lesions
• Cluster headache
• Other trigeminal-autonomic cephalalgias

A cavernous sinus lesion usually causes additional cranial neuropathies rather than an isolated Horner syndrome.

High-Yield Localization

A useful anatomical framework is:

1st order: hypothalamus → brainstem → C8–T2

2nd order: spinal cord → lung apex → cervical sympathetic chain → superior cervical ganglion

3rd order: internal carotid artery → cavernous sinus → orbit

This anatomy determines both the differential diagnosis and the required imaging.

Pathophysiology

Loss of sympathetic innervation produces the characteristic ocular findings.

Miosis

Paralysis of the iris dilator leaves parasympathetic pupillary constriction relatively unopposed.

Ptosis

Denervation of Müller’s muscle causes approximately 1–3 mm of upper-lid ptosis.

Reverse Ptosis

Loss of sympathetic tone to the lower eyelid can produce slight elevation of the lower lid.

Together, upper and lower lid changes create an apparent narrowing of the palpebral fissure.

Anhidrosis

Loss of sympathetic innervation to sweat glands causes reduced sweating.

Its distribution depends strongly on lesion location.

Diagnosis

History

The most common presenting complaint is new unilateral ptosis.

Patients usually do not notice the miosis itself.

The history should establish:

• When the ptosis or anisocoria began
• Whether it was sudden or gradual
• Whether old photographs show the same findings
• Previous head, neck, or chest trauma
• Recent neck manipulation or surgery
• Previous central venous procedures
• Smoking history
• Pulmonary disease
• Previous malignancy
• Neurologic symptoms

Old photographs are particularly valuable for distinguishing a longstanding Horner syndrome from a newly acquired one.

Pain Is a Critical Red Flag

The most important associated symptom in an acute Horner syndrome is:

Head, orbital, facial, or neck pain.

A patient with:

Acute Horner syndrome + ipsilateral head/neck pain

should be considered to have internal carotid artery dissection until appropriately excluded.

The pain may be severe, but it can also be described simply as a dull ache or discomfort.

This presentation requires urgent vascular imaging.

Associated Neurologic Symptoms

Ask specifically about:

• Vertigo
• Ataxia
• Dysarthria
• Dysphagia
• Nystagmus
• Facial sensory abnormalities
• Hemisensory loss
• Limb weakness
• Diplopia

These findings may indicate a central lesion such as a brainstem stroke.

Physical Examination

Ptosis

Upper-eyelid ptosis is generally mild, approximately 1–3 mm.

This is because the major eyelid elevator—the levator palpebrae superioris supplied by CN III—remains functional.

Thus:

Horner ptosis = mild

whereas a complete third-nerve palsy can cause profound ptosis.

Reverse Ptosis

Slight elevation of the lower eyelid may occur from loss of sympathetic innervation to the inferior tarsal muscle.

The combination of:

Upper-lid ptosis + lower-lid reverse ptosis

creates an apparent enophthalmos.

The globe itself is generally not truly enophthalmic.

Miosis and Anisocoria

The affected pupil is smaller.

The key examination principle is:

Anisocoria is greater in darkness.

In bright illumination, both pupils constrict relatively normally.

In darkness, the normal pupil dilates promptly while the Horner pupil cannot dilate normally.

Therefore, the difference between the pupils becomes more obvious.

Dilation Lag

Dilation lag is characteristic of Horner syndrome.

After moving from bright illumination into darkness, the Horner pupil dilates more slowly than the normal pupil.

The anisocoria may therefore be most prominent during the first several seconds of darkness.

Dilation lag supports the diagnosis but its absence does not exclude Horner syndrome.

Pupillary Light Reaction

Because the parasympathetic pathway is intact, the Horner pupil generally has a normal direct and consensual light response.

This is an important distinction from disorders involving the parasympathetic pupillary pathway.

Anhidrosis

Anhidrosis varies according to the anatomical level of the lesion.

Central and preganglionic lesions may produce more extensive facial anhidrosis.

In many postganglionic lesions involving the internal carotid sympathetic plexus, facial sweating is relatively preserved because sudomotor fibers to much of the face travel predominantly with the external carotid artery.

Therefore:

Absence of anhidrosis does not exclude Horner syndrome.

Iris Heterochromia

Congenital or very early-onset sympathetic denervation can interfere with iris melanocyte development.

The affected iris becomes less pigmented and therefore lighter.

Thus:

Congenital Horner syndrome → lighter iris on the affected side

Heterochromia is much less useful in adult-onset disease.

Pharmacologic Confirmation

Apraclonidine Test

Apraclonidine testing is now commonly used to confirm Horner syndrome.

Chronic sympathetic denervation produces denervation supersensitivity of α₁ receptors in the iris dilator.

After apraclonidine:

• Normal pupil → little dilation or slight constriction
• Horner pupil → significant dilation

This produces a characteristic:

Reversal of anisocoria

The previously smaller Horner pupil becomes similar in size to, or larger than, the normal pupil.

The Horner ptosis may also improve temporarily.

Important Limitation in Acute Horner Syndrome

Denervation supersensitivity requires time to develop.

Consequently, very acute Horner syndrome may occasionally produce a false-negative apraclonidine test.

More importantly:

Pharmacologic testing must never delay urgent imaging when carotid dissection or another dangerous cause is suspected.

Apraclonidine in Infants

Apraclonidine requires particular caution in young children because systemic absorption can cause:

• Profound lethargy
• Bradycardia
• Hypotension
• Respiratory depression

It should generally be avoided in very young infants, with pediatric testing protocols determined by the treating specialist.

Cocaine Test

Cocaine blocks norepinephrine reuptake at sympathetic nerve terminals.

Normal Eye

Norepinephrine accumulates → pupil dilates.

Horner Eye

Little norepinephrine reaches the terminal → minimal dilation.

Thus, after cocaine:

Anisocoria increases.

Historically, cocaine was the classic confirmatory test, but practical limitations have made apraclonidine more commonly used in many settings.

Hydroxyamphetamine

Hydroxyamphetamine was historically used to distinguish preganglionic from postganglionic Horner syndrome by stimulating norepinephrine release from intact postganglionic terminals.

However, it is difficult to obtain and has important practical limitations.

Modern imaging has substantially reduced the need for pharmacologic lesion localization.

Laboratory Investigation

Routine laboratory testing is generally not necessary to establish Horner syndrome.

Laboratory studies should instead be directed toward the suspected underlying disease.

The central diagnostic priority is usually appropriate imaging.

Imaging

Imaging is determined by:

• Age
• Acute versus chronic onset
• Pain
• Associated neurologic abnormalities
• Trauma
• Suspected anatomical localization
• Whether a benign cause has already been established

Unexplained acquired Horner syndrome generally requires investigation of the relevant oculosympathetic pathway.

Acute Painful Horner Syndrome

This is the most important emergency presentation.

Suspect: Internal Carotid Artery Dissection

Urgent imaging generally involves:

• CTA head and neck, or
• MRI/MRA head and neck

The carotid arteries must be adequately visualized.

Carotid Doppler ultrasonography alone is insufficient to exclude many dissections, particularly lesions near the skull base.

Suspected Central Horner Syndrome

When associated with:

• Ataxia
• Vertigo
• Dysarthria
• Dysphagia
• Nystagmus
• Sensory abnormalities
• Other focal neurologic deficits

perform appropriate brain and brainstem MRI, often with vascular imaging depending on the presentation.

Suspected Preganglionic Horner Syndrome

Evaluate the:

• Neck
• Cervical sympathetic chain
• Thoracic inlet
• Lung apex

Chest and neck imaging is particularly important when there is:

• Shoulder or arm pain
• Smoking history
• Brachial plexopathy
• Neck mass
• Known malignancy

An apical lung tumor must be excluded when clinically appropriate.

Pediatric Horner Syndrome

The evaluation differs from that in adults.

Possible causes include:

• Birth trauma
• Neck/chest surgery
• Congenital abnormalities
• Neuroblastoma
• Other neck or thoracic masses

When there is no definite benign explanation, investigation for neuroblastoma and other mass lesions may be required.

This can include appropriate imaging of the neck, chest, abdomen, and pelvis and measurement of urinary catecholamine metabolites such as:

• VMA
• HVA

Importantly, normal urinary catecholamine metabolites do not completely exclude neuroblastoma.

Differential Diagnosis

Physiologic Anisocoria

Physiologic anisocoria is common.

Unlike Horner syndrome, there is:

• No characteristic ptosis
• No convincing dilation lag
• No pharmacologic evidence of sympathetic denervation

The degree of physiologic anisocoria is generally relatively similar under different illumination conditions, although some variability can occur.

Third Cranial Nerve Palsy

Both disorders may produce ptosis.

The key pupillary distinction is:

Horner syndrome → abnormal pupil is SMALL

Compressive CN III palsy → abnormal pupil is typically LARGE

Third-nerve palsy may additionally produce:

• Marked ptosis
• Ophthalmoplegia
• “Down-and-out” eye position

Adie Tonic Pupil

In Adie syndrome, the abnormal pupil is usually larger, particularly in bright light.

There may be:

• Poor light reaction
• Better near response
• Segmental iris sphincter palsy
• Slow redilation after near effort

Thus, it represents essentially the opposite anisocoria pattern from Horner syndrome.

Pharmacologic Anisocoria

Consider exposure to:

• Pilocarpine or other miotics
• Anticholinergic agents
• Sympathomimetics
• Scopolamine
• Certain inhaled or nebulized medications

Medication and occupational exposure history can prevent unnecessary investigation.

Treatment

There is no specific treatment required for the miosis itself.

Treatment is directed at the underlying cause.

Examples include management of:

• Carotid artery dissection
• Stroke
• Neoplasm
• Neuroblastoma
• Infection
• Inflammatory disease
• Cervical or thoracic pathology

Management of carotid dissection is individualized according to neurologic and vascular findings and generally involves specialist-directed antithrombotic therapy.

Ptosis Treatment

If the underlying disorder has been appropriately investigated and the ptosis remains cosmetically or functionally significant, surgical correction can be considered.

Options may include procedures targeting Müller’s muscle or other ptosis repair techniques depending on eyelid measurements and function.

Prognosis

The ocular manifestations of Horner syndrome themselves usually do not threaten vision.

Prognosis depends almost entirely on the underlying cause.

For example:

• Congenital or longstanding benign Horner syndrome may remain stable indefinitely.
• Horner syndrome associated with carotid dissection may improve as sympathetic function recovers.
• Tumor-associated Horner syndrome depends on the prognosis of the underlying malignancy.

High-Yield Clinical Pearls

Horner syndrome = mild ptosis + miosis ± anhidrosis.

Anisocoria is greatest in the DARK.

Dilation lag supports Horner syndrome.

The affected pupil retains a normal light reaction because the parasympathetic pathway is intact.

Apraclonidine can reverse the anisocoria because of denervation supersensitivity.

Acute Horner syndrome + ipsilateral head/neck/orbital pain = carotid artery dissection until excluded.

Preganglionic Horner syndrome → think lung apex and neck.

Central Horner syndrome + neurologic deficits → think brainstem/spinal cord disease.

Congenital Horner syndrome can cause ipsilateral iris hypopigmentation.

Unexplained pediatric Horner syndrome warrants consideration of neuroblastoma.

Do not delay urgent vascular imaging merely to obtain pharmacologic confirmation in a clinically suspicious acute painful Horner syndrome.

Ophthalmology – Homocystinuria Basics Description Homocystinuria comprises a group of inherited disorders of methionine metabolism characterized by excessive accumulation of homocysteine in the blood and urine. The classic and most common form is caused by deficiency of cystathionine β-synthase (CBS). Other metabolic defects causing homocystinuria include abnormalities of cobalamin metabolism and methylenetetrahydrofolate reductase (MTHFR) deficiency. Classic homocystinuria is a multisystem disorder affecting primarily the: Eyes Central nervous system Skeletal system Vascular system The hallmark ophthalmic manifestations are progressive high myopia and ectopia lentis. A major systemic danger is arterial and venous thromboembolism, which can cause stroke, pulmonary embolism, and premature death.

Epidemiology Classic homocystinuria is rare, although incidence varies substantially among populations because of founder mutations and consanguinity. Historically, the worldwide incidence has been estimated at approximately 1:200,000–300,000 live births, although biochemical and molecular screening suggests that it may be more common in some populations. Particularly high frequencies have been reported in Qatar and certain European populations.

Genetics Classic homocystinuria has autosomal recessive inheritance. It results from pathogenic variants in the CBS gene, located on chromosome 21q22.3. Many affected patients are compound heterozygotes, possessing two different pathogenic CBS variants. The particular variants and the amount of residual CBS enzyme activity influence disease severity and whether the patient responds to pyridoxine (vitamin B6).

Pathophysiology CBS normally participates in the transsulfuration pathway that converts homocysteine toward cysteine metabolism. CBS deficiency results in accumulation of: Homocysteine → homocystine → methionine with reduced downstream cysteine production. Elevated homocysteine has toxic effects on connective tissue and vascular endothelium. Ocularly, abnormal connective-tissue metabolism weakens the zonular fibers supporting the crystalline lens, eventually producing ectopia lentis. Systemically, increased endothelial dysfunction and platelet activation create a marked thrombotic tendency.

Ocular Manifestations Progressive Myopia Progressive myopia is often one of the earliest ophthalmic manifestations. Increasing lenticular myopia can precede obvious lens dislocation and may therefore provide an early clue to weakening of the zonules. A child developing unexplained rapidly progressive high myopia should be examined carefully for phacodonesis and early ectopia lentis.

Ectopia Lentis Ectopia lentis is the hallmark ocular abnormality of classic homocystinuria. It generally develops after infancy and becomes increasingly common with age. Progressive disruption of the zonular fibers causes the lens to become unstable and eventually subluxated or completely dislocated. Although traditionally described as inferonasal displacement, the lens in homocystinuria can actually dislocate in any direction. This is an important correction to the classic teaching.

Homocystinuria vs Marfan Syndrome Both disorders may produce a marfanoid body habitus and ectopia lentis, making differentiation particularly important. In homocystinuria, the zonular fibers tend to undergo degeneration and disruption, whereas in Marfan syndrome they are characteristically abnormal but may remain elongated. Classically: Homocystinuria → inferonasal lens displacement Marfan syndrome → superotemporal lens displacement However, lens direction alone should not be used to establish the diagnosis because homocystinuric lenses may dislocate in any direction. More useful distinguishing features are the presence in homocystinuria of developmental/intellectual impairment, osteoporosis, and especially thromboembolic disease.

Other Ocular Manifestations Additional ophthalmic abnormalities include: High myopia Irregular astigmatism Phacodonesis Cataract Pupillary-block glaucoma Retinal detachment Optic atrophy Staphyloma Amblyopia

Acute Pupillary-Block Glaucoma A markedly subluxated or dislocated lens may move anteriorly and obstruct aqueous flow through the pupil. This can cause acute pupillary-block glaucoma with: Severe ocular pain Red eye Blurred vision Markedly elevated intraocular pressure Corneal edema Possible nausea and vomiting This constitutes an ophthalmic emergency.

Systemic Manifestations Skeletal Findings Patients frequently develop a marfanoid habitus characterized by: Tall, thin stature Long extremities Scoliosis Pectus excavatum or carinatum Genu valgum Pes cavus High-arched palate Dental crowding Unlike Marfan syndrome, generalized osteoporosis is characteristic of homocystinuria.

Neurologic and Psychiatric Manifestations Neurologic manifestations vary considerably and may include: Developmental delay Intellectual disability Seizures Behavioral abnormalities Psychiatric disorders Importantly, early metabolic treatment can substantially modify neurologic outcome.

Thromboembolic Disease Thromboembolism is the major life-threatening complication of classic homocystinuria. Both arteries and veins may be affected. Complications include: Ischemic stroke Cerebral venous thrombosis Deep-vein thrombosis Pulmonary embolism Peripheral arterial thrombosis Other organ ischemia Thrombosis may occur spontaneously or be precipitated by dehydration, prolonged immobilization, surgery, anesthesia, or other physiologic stresses. This risk is particularly important when planning ocular surgery.

Diagnosis History Important questions include: Birth and Screening History Determine whether newborn metabolic screening was performed and whether abnormalities were detected. Developmental History Ask about: Speech delay Developmental delay Learning difficulties Behavioral or psychiatric abnormalities Family History Important clues include: Consanguinity Similarly affected siblings Unexplained thrombosis Stroke or thromboembolic death at a young age Ocular History Ask about: Progressive myopia Frequent spectacle changes Poor vision Monocular visual preference Ocular pain or redness Previous lens dislocation

Physical Examination General Examination Look for: Marfanoid habitus Scoliosis Pectus deformity Genu valgum Pes cavus High-arched palate Dental crowding Malar flushing Osteoporosis or history of fractures Neurologic and developmental assessment should also be performed. Ophthalmic Examination A comprehensive examination should include: Visual acuity Cycloplegic refraction in children Slit-lamp examination Intraocular pressure Assessment for phacodonesis Lens position Dilated retinal examination Particular attention should be directed toward progressive high myopia and ectopia lentis.

Diagnostic Tests Biochemical Testing Classic CBS deficiency typically produces: Markedly elevated plasma total homocysteine and usually: Elevated plasma methionine Urinary homocystine may also be elevated. Modern diagnosis relies principally on quantitative plasma amino acids, plasma total homocysteine, biochemical enzyme assessment when required, and molecular genetic testing.

Newborn Screening Newborn screening traditionally detects classic homocystinuria through elevated methionine. However, screening can miss affected infants, particularly those whose methionine concentration has not risen sufficiently when the specimen is obtained. Thus, a normal newborn screen does not absolutely exclude homocystinuria when later clinical findings are strongly suggestive.

Molecular Genetic Testing Molecular analysis of the CBS gene can confirm the diagnosis and identify the causative variants. Genetic testing is also valuable for: Family screening Carrier identification Genetic counseling Prenatal or preimplantation genetic testing when familial pathogenic variants are known

Pyridoxine Responsiveness An important component of metabolic evaluation is determining whether the patient responds to pyridoxine (vitamin B6). CBS uses pyridoxal phosphate, derived from vitamin B6, as a cofactor. Some pathogenic variants leave sufficient residual enzyme activity that pharmacologic pyridoxine substantially lowers homocysteine concentrations. Patients are therefore broadly classified as: B6-responsive or B6-nonresponsive. Responsiveness has important implications for both treatment and prognosis. High-dose pyridoxine testing and therapy should be conducted under specialist metabolic supervision because excessive doses can cause serious toxicity.

Imaging and Additional Testing Brain MRI with appropriate vascular/stroke imaging should be obtained when focal neurologic findings suggest cerebrovascular disease. DEXA scanning may be used to assess and monitor osteoporosis. Ocular imaging such as anterior-segment OCT or ultrasound biomicroscopy can occasionally help characterize severe lens displacement, although the diagnosis of ectopia lentis is usually clinical.

Differential Diagnosis Important causes of ectopia lentis include: Marfan syndrome Weill–Marchesani syndrome Familial isolated ectopia lentis Ectopia lentis et pupillae Trauma Aniridia Ocular coloboma Microspherophakia Sulfite oxidase deficiency Molybdenum cofactor deficiency Other metabolic causes of elevated homocysteine, particularly remethylation disorders such as MTHFR and cobalamin-related defects, must also be distinguished from classic CBS deficiency.

Treatment Treatment should be coordinated with a metabolic disease specialist. The principal objective is sustained reduction of plasma homocysteine to decrease the risk of thromboembolic and other systemic complications.

Pyridoxine Patients who demonstrate pyridoxine responsiveness are treated with vitamin B6, with dosage individualized by the metabolic specialist according to biochemical response. Folate and vitamin B12 status should be optimized because deficiencies can further impair homocysteine metabolism.

Dietary Therapy Patients who are insufficiently responsive to pyridoxine generally require a methionine-restricted diet. Specialized amino-acid preparations may be required to maintain adequate nutrition while restricting methionine. Dietary treatment should be managed by a metabolic dietitian because excessive protein restriction can adversely affect growth and development.

Betaine Betaine promotes remethylation of homocysteine to methionine and can substantially reduce plasma homocysteine concentrations. It is particularly useful when pyridoxine and dietary treatment do not achieve adequate biochemical control. Because betaine can increase methionine concentrations, biochemical monitoring remains important.

Ophthalmic Treatment Refractive Correction Myopia and astigmatism should be corrected promptly using: Spectacles Contact lenses when appropriate Children require careful monitoring for anisometropic or deprivation amblyopia. Amblyopia Amblyopia should be treated aggressively during the visual-development period with appropriate optical correction and, when indicated, patching or pharmacologic penalization.

Lens Surgery Lens extraction may be necessary when ectopia lentis causes: Uncorrectable visual impairment Severe progressive refractive error Amblyogenic optical distortion Lens-induced inflammation Pupillary-block glaucoma Complete lens dislocation Other significant complications Modern surgical technique is individualized according to the degree of zonular instability and associated ocular anatomy.

Perioperative Considerations Surgery in a patient with homocystinuria requires special planning because of the marked risk of perioperative thrombosis. Before elective ocular or systemic surgery, coordination with metabolic medicine, anesthesia, hematology, and the surgical team is appropriate. Important measures include: Maintaining adequate hydration Avoiding prolonged immobilization Maintaining metabolic control Assessing individual thrombosis risk Using thromboprophylaxis when indicated by the treating team The thromboembolic risk may be more clinically consequential than the ocular procedure itself.

Ongoing Care Patients require multidisciplinary lifelong follow-up involving: Ophthalmology Metabolic medicine Primary care/pediatrics Nutrition Genetics Hematology when appropriate Neurology when cerebrovascular or neurologic disease is present Ophthalmic monitoring should assess: Refraction Lens stability Intraocular pressure Amblyopia Retinal status Visual function

Patient Education Patients and families should understand the importance of lifelong metabolic treatment, even when the patient feels well. They should recognize symptoms potentially indicating thrombosis or stroke and seek emergency medical evaluation when these occur. Genetic counseling is appropriate because classic CBS-deficiency homocystinuria is autosomal recessive.

Prognosis Prognosis depends strongly on how early the disorder is recognized and how effectively homocysteine concentrations are controlled. Early treatment can markedly reduce systemic complications and may prevent or delay developmental impairment and ectopia lentis. Untreated disease carries a substantial risk of progressive ocular abnormalities, neurologic impairment, osteoporosis, and potentially fatal thromboembolism.

Complications Major complications include: Ectopia lentis Severe myopia Amblyopia Cataract Pupillary-block glaucoma Retinal detachment Optic atrophy Osteoporosis and fractures Developmental and neuropsychiatric impairment Arterial and venous thromboembolism Stroke Pulmonary embolism Premature death

High-Yield Clinical Pearls Homocystinuria + ectopia lentis + marfanoid habitus + developmental abnormalities + thrombosis = classic CBS deficiency until proven otherwise. The most dangerous complication is thromboembolism. The major ophthalmic clue is progressive myopia followed by ectopia lentis. Unlike traditional teaching, the lens in homocystinuria can dislocate in any direction. Homocystinuria vs Marfan: think thrombosis, developmental impairment, osteoporosis, and disrupted zonules in homocystinuria. Early diagnosis and metabolic treatment can prevent major ocular and systemic morbidity.

Ophthalmology – HIV/AIDS-Related Retinopathies

Basics

Description

Ocular disease is common in patients with advanced human immunodeficiency virus (HIV) infection. The two classic retinal manifestations are:

• HIV microvasculopathy (HIV retinopathy) — the most common retinal manifestation.
• Cytomegalovirus (CMV) retinitis — the most important opportunistic retinal infection and a potentially devastating cause of blindness.

Other ocular manifestations include toxoplasma retinochoroiditis, syphilitic retinitis, acute retinal necrosis (ARN), progressive outer retinal necrosis (PORN), cryptococcosis, intraocular lymphoma, Kaposi sarcoma, and ocular surface squamous neoplasia.

CMV retinitis is a full-thickness necrotizing retinal infection. Progressive retinal necrosis can result in retinal breaks and rhegmatogenous retinal detachment.

Modern antiretroviral therapy (ART) has dramatically reduced the incidence of CMV retinitis and other opportunistic ocular infections.

Epidemiology

Before effective combination ART, CMV retinitis occurred in approximately 25–40% of patients with AIDS during their lifetime.

Its incidence has fallen dramatically in the ART era.

HIV microvasculopathy was historically reported in approximately 50–60% of patients with advanced HIV infection.

CMV retinitis remains particularly important in individuals with advanced immunosuppression, including patients who are unaware of their HIV status, are untreated, or have failed ART.

Risk Factors

The major risk factor for CMV retinitis is severe immunosuppression.

The classic setting is:

CD4 count <50 cells/µL

Risk also increases with:

• High HIV viral load
• Lack of effective ART
• Poor adherence to ART
• Treatment failure or antiviral resistance
• Other causes of profound immunosuppression, including transplantation and chemotherapy

Pathophysiology

HIV Retinopathy

HIV-associated retinal microvasculopathy is thought to result from retinal microvascular injury, immune-complex deposition, endothelial dysfunction, and altered retinal perfusion.

The characteristic lesion is the cotton-wool spot, representing focal retinal nerve fiber layer ischemia.

Unlike CMV retinitis, HIV microvasculopathy does not produce progressive full-thickness retinal necrosis.

CMV Retinitis

CMV reaches the retina primarily through hematogenous dissemination during severe immunosuppression.

The virus infects retinal vascular endothelial and retinal cells, producing:

• Full-thickness retinal necrosis
• Retinal hemorrhage
• Occlusive retinal vasculitis
• Variable choroidal inflammation

Because these patients are profoundly immunosuppressed, there is often surprisingly little vitreous inflammation despite extensive retinal destruction.

Histopathologically, infected cells may contain characteristic enlarged cells with intranuclear viral inclusions.

Etiology

Cytomegalovirus is a member of the herpesvirus family.

CMV infection is extremely common in the general population and usually remains latent after primary infection.

In immunocompetent individuals, primary CMV infection is usually asymptomatic or produces a mononucleosis-like illness.

Profound impairment of cell-mediated immunity allows CMV reactivation and dissemination, including infection of the retina.

HIV Microvasculopathy

The most characteristic finding is cotton-wool spots, particularly around the posterior pole.

Other findings may include:

• Intraretinal hemorrhages
• Microaneurysms
• Telangiectatic vascular abnormalities
• Capillary nonperfusion

Cotton-wool spots generally resolve spontaneously over several weeks.

A key distinction from CMV retinitis is that HIV cotton-wool spots are small, superficial, nonprogressive lesions, whereas CMV lesions enlarge progressively without treatment.

Diagnosis

History

CMV retinitis may be asymptomatic, particularly when disease begins in the peripheral retina.

Symptoms include:

• Floaters
• Blurred or decreased vision
• Photopsias
• Scotomas
• Peripheral visual-field loss

Central disease involving the macula or optic nerve can cause profound visual loss.

Because peripheral CMV retinitis can remain asymptomatic, patients with advanced immunosuppression require a high index of suspicion.

Physical Examination

A complete dilated retinal examination is essential.

Classic CMV retinitis consists of yellow-white areas of retinal whitening and necrosis associated with variable retinal hemorrhage.

The disease characteristically progresses along retinal vascular arcades.

The advancing edge of a lesion is the most active component.

Because of severe immunosuppression, vitritis is typically mild or absent.

Classic Patterns of CMV Retinitis

Fulminant or Hemorrhagic Pattern

This consists of dense areas of retinal whitening and necrosis associated with extensive retinal hemorrhage.

The classic descriptive term is:

“Pizza pie” or “cottage cheese and ketchup” retinopathy.

Granular Pattern

This is characterized by granular peripheral retinal whitening with relatively little hemorrhage.

It may appear less dramatic but remains progressive without treatment.

Frosted-Branch Angiitis

Marked translucent white sheathing of retinal vessels produces the appearance of frost-covered tree branches.

This represents severe retinal vasculitis and may occur with CMV infection.

CMV Retinitis vs HIV Cotton-Wool Spots

This distinction is clinically important.

HIV cotton-wool spots are generally small, superficial, and nonprogressive and resolve spontaneously.

CMV lesions are usually larger, deeper, associated with retinal necrosis and/or hemorrhage, and progressively enlarge over days to weeks if untreated.

A suspicious retinal whitening lesion in a severely immunocompromised patient should therefore be followed closely or investigated for infectious retinitis.

Diagnostic Tests

Laboratory Studies

Important systemic investigations include:

CD4 T-cell count and plasma HIV viral load.

Routine CMV antibody testing is usually unhelpful because prior CMV exposure is extremely common.

Ocular Fluid PCR

When the clinical appearance is atypical or the differential diagnosis includes other infectious retinitides, aqueous or vitreous fluid may undergo PCR testing for CMV DNA.

PCR can also test simultaneously for HSV, VZV, and Toxoplasma gondii when appropriate.

Imaging

Fundus Photography

Serial wide-field or conventional fundus photographs are extremely useful for documenting lesion borders and determining whether retinitis is progressing or responding to therapy.

Optical Coherence Tomography

OCT can document retinal structural damage and is particularly useful when the macula is involved or when complications such as cystoid macular edema or epiretinal membrane develop.

Fluorescein Angiography

Fluorescein angiography may demonstrate vascular leakage and nonperfusion but is generally not required to make the diagnosis of typical CMV retinitis.

Differential Diagnosis

Important alternatives include:

• HIV microvasculopathy/cotton-wool spots
• Toxoplasma retinochoroiditis
• Syphilitic retinitis
• Acute retinal necrosis
• Progressive outer retinal necrosis
• Intraocular lymphoma
• Other infectious or inflammatory retinitides

Progressive Outer Retinal Necrosis

PORN is another particularly severe herpetic retinitis occurring in profoundly immunocompromised patients, most often caused by varicella-zoster virus.

It typically causes rapidly progressive multifocal outer retinal whitening with relatively little hemorrhage, vasculitis, or intraocular inflammation.

Disease can progress extremely rapidly and become bilateral.

PORN carries a particularly poor visual prognosis and requires urgent aggressive antiviral therapy.

Toxoplasma Retinochoroiditis

Ocular toxoplasmosis in patients with AIDS may be unusually severe.

Unlike typical toxoplasmosis in immunocompetent individuals, lesions may be:

• Large
• Multifocal
• Bilateral
• Associated with relatively little vitritis
• Unassociated with an old chorioretinal scar

CNS toxoplasmosis should also be considered in patients with ocular disease.

Treatment

Immediate Priorities

CMV retinitis is a vision-threatening opportunistic infection requiring prompt treatment.

Management has two essential components:

anti-CMV therapy + effective systemic ART.

The choice of antiviral regimen depends on lesion location, severity, systemic disease, renal and hematologic status, previous antiviral exposure, and ability to adhere to therapy.

Valganciclovir

For many patients, oral valganciclovir is preferred because systemic treatment simultaneously treats ocular disease and protects the fellow eye and other organs from CMV dissemination.

A commonly used adult induction regimen is:

Valganciclovir 900 mg orally twice daily with food for 14–21 days

followed by maintenance therapy:

900 mg orally once daily.

Dosage must be adjusted for renal impairment.

Major adverse effects include:

• Neutropenia
• Anemia
• Thrombocytopenia
• Other bone-marrow suppression
• Renal toxicity

CBC and renal function require monitoring.

Sight-Threatening CMV Retinitis

Lesions immediately threatening the macula or optic nerve require especially rapid control.

Current NIH guidance recommends systemic therapy plus an intravitreal injection of ganciclovir or foscarnet for immediate local antiviral concentrations when lesions are immediately sight-threatening.

Systemic treatment remains necessary because an intravitreal injection treats only the injected eye and does not protect the fellow eye or prevent extraocular CMV disease.

Alternative Antiviral Therapy

Alternatives include:

Intravenous ganciclovir — useful when oral treatment cannot be used or absorption is unreliable; major toxicity is bone-marrow suppression.

Foscarnet — useful particularly when ganciclovir resistance or intolerance is suspected. Important adverse effects include nephrotoxicity and electrolyte disturbances, which can occasionally precipitate seizures.

Cidofovir has anti-CMV activity but is now used much less commonly because of substantial toxicity, particularly nephrotoxicity and ocular complications such as uveitis and hypotony.

Antiretroviral Therapy

Effective ART is fundamental.

Immune recovery markedly decreases:

• New CMV retinitis
• Progression and recurrence
• Fellow-eye involvement
• Other opportunistic infections
• Overall morbidity and mortality

ART should be coordinated with clinicians experienced in HIV management.

Maintenance Therapy

Following successful induction, maintenance anti-CMV treatment is continued until sufficient immune recovery has occurred.

Current NIH guidance allows discontinuation of maintenance therapy when CMV lesions have been treated for at least 3–6 months, are inactive, and the CD4 count has remained ≥100 cells/mm³ for at least 3–6 months in response to ART, following consultation with an ophthalmologist.

Maintenance treatment should be restarted if immune function subsequently deteriorates substantially.

Follow-Up

During active CMV retinitis, patients require frequent dilated retinal examinations to document regression of the active borders and detect new lesions.

Serial fundus photography is particularly useful.

Even after immune recovery, ophthalmologic monitoring remains important because complications can occur after the infectious retinitis becomes inactive.

Immune Recovery Uveitis

Immune recovery uveitis (IRU) is an inflammatory complication that may occur after ART restores immune function in a patient with previously treated CMV retinitis.

As the recovering immune system reacts to residual CMV antigens within the eye, patients may develop:

• Anterior uveitis
• Vitritis
• Floaters
• Decreased vision
• Cystoid macular edema
• Epiretinal membrane

Additional complications can include posterior subcapsular cataract and proliferative vitreoretinopathy.

This differs fundamentally from recurrent CMV retinitis: IRU represents inflammation associated with immune recovery rather than uncontrolled viral replication.

Retinal Detachment

CMV causes full-thickness retinal destruction.

As necrotic retina heals, it becomes thin and atrophic, predisposing to multiple retinal breaks and rhegmatogenous retinal detachment.

This was a major cause of visual loss in the pre-ART era and remains an important complication of extensive disease.

Retinal detachment requires prompt vitreoretinal evaluation and frequently surgical repair.

Prognosis

The prognosis of HIV-associated ocular disease has improved dramatically with modern ART.

Visual outcome in CMV retinitis depends heavily on:

• Location and extent of retinal involvement
• Macular or optic nerve involvement
• Speed of diagnosis and treatment
• Degree of immune suppression
• Response to ART
• Development of retinal detachment or IRU

Peripheral disease diagnosed and treated early may preserve excellent central vision.

Disease involving the macula or optic nerve can cause irreversible severe visual loss.

Complications

Major complications include:

• Permanent retinal atrophy
• Macular destruction
• Optic nerve involvement
• Retinal breaks
• Rhegmatogenous retinal detachment
• Bilateral CMV retinitis
• Immune recovery uveitis
• Cystoid macular edema
• Epiretinal membrane
• Cataract
• Proliferative vitreoretinopathy
• Permanent visual-field defects
• Severe irreversible visual loss

High-Yield Clinical Pearls

CD4 <50 cells/µL + retinal whitening/hemorrhage → strongly consider CMV retinitis.

CMV retinitis = full-thickness necrotizing retinitis with surprisingly little vitritis in a profoundly immunosuppressed patient.

Cotton-wool spots are common in HIV retinopathy but are small and nonprogressive; CMV lesions enlarge without treatment.

Macula- or optic nerve-threatening CMV → systemic therapy + intravitreal antiviral treatment.

ART is essential for long-term control.

New inflammation after immune recovery does not necessarily mean recurrent CMV—consider immune recovery uveitis.

Retinal detachment is an important late complication of CMV-induced retinal necrosis.

Ophthalmology – Herpes Zoster Ophthalmicus

Basics

Description

Herpes zoster ophthalmicus (HZO) results from reactivation of latent varicella-zoster virus (VZV) within the ophthalmic division of the trigeminal nerve. It classically produces an acute, painful, unilateral vesicular eruption involving the V1 dermatome.

Ocular inflammation may involve the eyelids, conjunctiva, episclera, sclera, cornea, anterior chamber, iris, retina, optic nerve, or ocular motor nerves.

Occasionally, ocular VZV disease occurs without the characteristic skin eruption. This presentation is called zoster sine herpete.

HZO is clinically important because ocular complications can arise during the acute eruption or weeks to months later, and some may cause permanent visual loss.

Epidemiology

The risk of herpes zoster increases substantially with age because of declining VZV-specific cellular immunity.

HZO represents reactivation involving the ophthalmic division of the trigeminal nerve and occurs more often in older adults and immunocompromised individuals.

Risk Factors

The strongest risk factor is increasing age.

Other important risk factors include impaired cellular immunity due to HIV infection, malignancy, organ transplantation, immunosuppressive medication, chemotherapy, or other causes of immunodeficiency.

General Prevention

Vaccination is the principal preventive measure.

Current CDC recommendations use the recombinant zoster vaccine, Shingrix, rather than the older live Zostavax vaccine. Two doses of Shingrix are recommended for immunocompetent adults 50 years and older and for adults 19 years and older who are or will be immunodeficient or immunosuppressed. Previous herpes zoster does not eliminate the indication for vaccination. Zostavax is no longer available in the United States. 

Vaccination is preventive and is not a treatment for an active episode of HZO.

Pathophysiology

After primary varicella infection, VZV establishes latency within sensory ganglia.

HZO occurs when latent virus reactivates in the trigeminal ganglion, particularly along the ophthalmic division of cranial nerve V.

The virus travels along sensory axons toward the skin and ocular structures, producing a combination of direct viral injury, vascular inflammation, and host immune-mediated tissue damage.

Declining VZV-specific cellular immunity with increasing age helps explain the rising incidence of zoster in older adults.

Diagnosis

History

The illness may begin with a prodrome consisting of fever, malaise, headache, fatigue, and neuropathic pain within the affected dermatome.

Pain may precede the rash by several days and can be described as:

burning, aching, stabbing, lancinating, itching, or hypersensitivity to touch.

The characteristic rash is unilateral and respects the midline.

Patients should be questioned about visual blur, photophobia, ocular redness, diplopia, floaters, reduced vision, and severe eye pain.

Skin Findings

The V1 rash evolves from erythematous macules and papules into vesicles, followed by pustules and eventually crusting.

The forehead, scalp, upper eyelid, and periocular skin may be involved.

Lesions involving the tip, side, or root of the nose suggest involvement of the nasociliary branch of V1 and increase concern for ocular involvement. This is traditionally called Hutchinson sign, although ocular disease can still occur when the sign is absent.

Ophthalmic Examination

All patients with HZO should undergo careful ocular assessment, particularly when ocular symptoms are present. Contemporary reviews recommend ophthalmologic evaluation because potentially serious ocular disease may accompany or follow the rash. 

Examination should include visual acuity, pupils, slit-lamp examination, intraocular pressure, corneal sensation, ocular motility, and dilated fundus examination when indicated.

Early Ocular Findings

Eyelids

The eyelids may show edema, erythema, vesicles, crusting, and temporary ptosis.

Marked swelling may occasionally make examination difficult.

Conjunctiva

Conjunctival involvement may cause hyperemia, follicular or papillary reaction, petechial hemorrhages, vesicular lesions, or pseudomembranes.

Episclera and Sclera

Patients may develop episcleritis, scleritis, sclerokeratitis, or posterior scleritis.

Cornea

Early corneal manifestations include punctate epithelial keratitis and pseudodendrites.

Unlike the classic dendrites of herpes simplex, VZV pseudodendrites are typically elevated epithelial lesions and generally do not have the same classic terminal bulbs.

Later stromal involvement may produce nummular keratitis, stromal inflammation, endothelial disease, or disciform edema.

Anterior Uveitis

HZO can cause a granulomatous or nongranulomatous anterior uveitis with anterior chamber cells, keratic precipitates, and elevated intraocular pressure.

A characteristic late finding is sectoral iris atrophy, caused in part by ischemic damage to iris vessels.

Secondary ocular hypertension or glaucoma may result from trabeculitis, chronic inflammation, synechial changes, or corticosteroid treatment.

Late Corneal Disease

Ocular complications may begin or recur after the skin eruption has resolved.

Late manifestations include delayed pseudodendrites, mucous plaque keratitis, neurotrophic keratopathy, persistent epithelial defects, stromal scarring, chronic edema, lipid deposition, band keratopathy, and corneal ulceration.

Reduced corneal sensation is particularly important because it may result in severe epithelial disease with surprisingly little pain.

Neurotrophic Keratopathy

Damage to trigeminal sensory innervation can substantially reduce corneal sensation.

The resulting neurotrophic cornea may develop:

• Persistent epithelial defects
• Sterile ulceration
• Stromal melting
• Secondary infection
• Corneal perforation

Patients with reduced corneal sensation require particularly careful long-term follow-up.

Retina and Optic Nerve

Serious posterior segment complications include retinal vasculitis, optic neuropathy, acute retinal necrosis (ARN), and progressive outer retinal necrosis (PORN).

ARN is a rapidly progressive necrotizing retinitis accompanied by retinal vasculitis and inflammation.

PORN is particularly associated with profound immunosuppression and may progress extremely rapidly with relatively little intraocular inflammation.

Both require urgent retina specialist evaluation and systemic plus local antiviral therapy.

Neuro-Ophthalmic Manifestations

HZO may affect ocular motor nerves and produce transient or persistent diplopia and ophthalmoplegia.

Cranial nerves III, IV, and VI may be involved.

Rarely, multiple cranial neuropathies may occur in association with orbital apex inflammation, vasculitis, or brainstem disease.

Postherpetic Neuralgia

Postherpetic neuralgia (PHN) is persistent neuropathic pain after the acute rash has healed.

Symptoms may include:

• Constant burning or aching
• Sudden electric or lancinating pains
• Allodynia, where light touch causes pain
• Persistent itching or dysesthesia

Risk increases considerably with age.

Diagnostic Tests and Interpretation

Laboratory Testing

Typical HZO with a characteristic dermatomal rash is primarily a clinical diagnosis, and routine laboratory confirmation is unnecessary.

Testing for an underlying immunodeficiency, including HIV, should be considered when disease occurs in an unusually young patient, is severe or disseminated, or when other clinical features suggest immunosuppression.

PCR

When zoster sine herpete is suspected or when the cause of anterior uveitis, retinitis, or other ocular inflammation is uncertain, PCR of aqueous or vitreous fluid for VZV DNA can help establish the diagnosis.

Differential Diagnosis

Important differential diagnoses include herpes simplex infection, orbital cellulitis, contact dermatitis such as poison ivy exposure, bacterial skin infection, other causes of anterior uveitis, and other necrotizing retinitides.

Treatment

Systemic Antiviral Therapy

Systemic antiviral treatment is the cornerstone of HZO management.

Therapy should be initiated as soon as possible, ideally within 72 hours of rash onset. Early treatment reduces viral replication and is associated with faster rash resolution and fewer ocular complications. Because HZO itself carries a high risk of complications, antiviral treatment may still be appropriate when a patient presents after 72 hours, particularly if new lesions are appearing or ocular disease is present. 

Common oral regimens in immunocompetent adults include:

Valacyclovir 1,000 mg three times daily, famciclovir 500 mg three times daily, or acyclovir 800 mg five times daily, generally for approximately 7–10 days depending on clinical circumstances. Renal adjustment is required when appropriate. 

Treatment should not be delayed while awaiting ophthalmology evaluation.

Renal Considerations

Acyclovir, valacyclovir, and famciclovir require dose adjustment in patients with impaired renal function.

Older adults are particularly vulnerable to drug accumulation, acute kidney injury, and neurotoxicity when renal function is reduced or hydration is inadequate.

Skin Care

Crusted or secondarily infected skin lesions may be treated with appropriate local wound care.

Topical antibiotic ointment may be used when there is concern for secondary bacterial infection of open or crusted lesions.

Ocular Surface Treatment

Lubricating artificial tears and ointment may help when ocular surface irritation or dry eye is present.

Patients with reduced corneal sensation require more aggressive lubrication and close observation for epithelial breakdown.

Topical Corticosteroids

Topical corticosteroids may be appropriate for stromal keratitis, endotheliitis, scleritis in selected circumstances, or anterior uveitis, but they should be used under ophthalmologic supervision and generally with adequate systemic antiviral treatment.

Steroids should not be used indiscriminately for epithelial disease.

Patients receiving corticosteroids require monitoring of intraocular pressure.

Cycloplegia

Cycloplegic agents may be used for significant anterior uveitis to reduce ciliary spasm, relieve pain, and prevent posterior synechiae.

Secondary Glaucoma

Elevated intraocular pressure should be treated with appropriate pressure-lowering medication.

Persistent or difficult-to-control glaucoma may require referral to a glaucoma specialist.

Postherpetic Neuralgia Treatment

Management of PHN may involve agents used for neuropathic pain, such as gabapentin or pregabalin, selected antidepressants, topical lidocaine, and other analgesic strategies.

Persistent or severe neuralgia may warrant referral to neurology or a pain specialist.

Neurotrophic Corneal Disease

Management depends on severity and may include preservative-free lubrication, autologous serum tears, protective contact or scleral lenses in selected cases, amniotic membrane, punctal occlusion, tarsorrhaphy, or other ocular surface procedures.

Corneal thinning or melting requires urgent corneal specialist management.

Acute Retinal Necrosis and PORN

Suspected ARN or PORN is an ophthalmic emergency.

Treatment generally requires aggressive systemic antiviral therapy and frequently intravitreal antiviral therapy.

Immediate retina specialist involvement is essential because progression can be rapid and may lead to retinal detachment and profound vision loss.

Surgery and Other Procedures

A tarsorrhaphy may be necessary for persistent neurotrophic epithelial defects or ulceration that fails conservative treatment.

Small corneal perforations may sometimes be managed with tissue adhesive and protective measures.

Amniotic membrane transplantation or conjunctival flap procedures may be considered for persistent epithelial defects, thinning, or neurotrophic ulceration.

Corneal transplantation may eventually be necessary for visually significant scarring or structural failure, although surgery in a severely neurotrophic eye carries increased risk.

Inpatient Considerations

Hospital admission may be necessary for patients with disseminated zoster, severe immunosuppression, inability to take or administer oral medication, serious neurologic complications, severe posterior segment involvement, or need for intravenous antiviral therapy.

Airway, neurologic, systemic, and ocular complications should be addressed according to severity.

Follow-Up

The timing of follow-up depends on ocular involvement.

Patients with active ocular disease frequently require reevaluation within several days, followed by visits determined by corneal, uveitic, retinal, and intraocular pressure findings.

Long-term follow-up may be necessary because keratitis, uveitis, glaucoma, neurotrophic keratopathy, and retinal disease can develop or recur after the cutaneous rash has resolved.

Patient Education

Patients should understand that the skin eruption may improve while ocular complications continue to develop.

They should seek urgent assessment for new blurred vision, photophobia, increasing redness, worsening eye pain, diplopia, floaters, flashes, or sudden loss of vision.

Patients should also be informed about vaccination after the acute illness has resolved. Current CDC guidance recommends Shingrix even for people who have previously had shingles. 

Prognosis

In otherwise healthy individuals, formation of new skin lesions generally stops within several days and the rash subsequently crusts and heals.

The ocular prognosis varies with the structures involved.

Patients with uncomplicated epithelial disease may recover well, while those developing stromal scarring, glaucoma, neurotrophic keratopathy, optic neuropathy, or necrotizing retinitis can sustain permanent visual loss.

Complications

Important ophthalmic complications include corneal scarring, chronic keratitis, neurotrophic ulceration, corneal perforation, secondary bacterial keratitis, cataract, glaucoma, chronic anterior uveitis, retinal necrosis, retinal detachment, optic neuropathy, ocular motor nerve palsies, and permanent visual impairment.

Systemic and neurologic complications include postherpetic neuralgia and an increased risk of cerebrovascular events after herpes zoster.

The combination of early systemic antiviral treatment and appropriate ophthalmic follow-up is central to reducing preventable morbidity.