- Published on
KembaraXtra - Medical Terms - ablation
Ablation refers to the removal or destruction of body tissue or abnormal growths using methods such as surgery, heat, hormones, or medications. It is commonly used in the treatment of various conditions, including cancers. For example, hormonal therapy may be used as an alternative to surgical removal in certain cases of breast cancer when surgery is not suitable. In dentistry, hard tooth tissue can be removed using erbium laser ablation, sometimes combined with a water spray. Other forms include endometrial ablation, radiofrequency ablation, and radioiodine ablation.
Ablation refers to the removal or destruction of body tissue or abnormal growths using methods such as surgery, heat, hormones, or medications. It is commonly used in the treatment of various conditions, including cancers. For example, hormonal therapy may be used as an alternative to surgical removal in certain cases of breast cancer when surgery is not suitable. In dentistry, hard tooth tissue can be removed using erbium laser ablation, sometimes combined with a water spray. Other forms include endometrial ablation, radiofrequency ablation, and radioiodine ablation.
- Published on
Infectious Disease and Microbiology – Cholecystitis and Cholangitis
Cholecystitis refers to acute or chronic inflammation of the gallbladder. Cholangitis is a clinical syndrome characterized by systemic infection originating in the biliary tract, usually due to obstruction. Emphysematous cholecystitis is a severe form of gallbladder inflammation in which gas forms within the gallbladder lumen, wall, or surrounding tissues.
Acute cholecystitis accounts for 3–10% of patients presenting with abdominal pain, increasing to approximately 20% among individuals older than 50 years. Among patients with gallstones (cholelithiasis), 1–4% annually develop biliary colic, and if untreated, about 20% of symptomatic individuals may later develop acute cholecystitis.
In 90–95% of cases, acute cholecystitis results from gallstone obstruction. Risk factors for gallstone formation include obesity, rapid weight loss, hemolytic diseases (such as sickle cell disease and G6PD deficiency), and certain ethnic backgrounds (e.g., Pima Indians). Gallstones are more than twice as common in women as in men, although cholecystitis tends to be more severe in men.
Acalculous cholecystitis occurs without gallstones and is associated with serious medical conditions such as diabetes mellitus, sepsis, ischemia, trauma, burns, prolonged total parenteral nutrition, vasculitis, collagen vascular diseases, sarcoidosis, HIV/AIDS, and certain infections (e.g., tuberculosis and parasitic infections). It is slightly more common in men and is associated with higher complication rates. Emphysematous cholecystitis is more frequent in elderly patients and those with diabetes.
Acute calculous cholecystitis results from obstruction of the cystic duct by gallstones. Acalculous cholecystitis develops due to gallbladder stasis and bile stagnation. Acute cholangitis occurs when obstruction of the common bile duct leads to increased biliary pressure, facilitating bacterial translocation into the bloodstream and resulting in systemic infection.
Common pathogens in biliary infections are polymicrobial and include Escherichia coli, Klebsiella species, Enterococcus species, Enterobacter species, and Pseudomonas species. Anaerobes are more common in elderly patients, diabetics, and those with prior biliary surgery. Obstructive causes of cholangitis include choledocholithiasis, malignant strictures, iatrogenic bile duct injury, primary sclerosing cholangitis, congenital biliary abnormalities, and parasitic infections such as Clonorchis, Opisthorchis, and Ascaris.
Clinically, biliary disease often presents with right upper quadrant abdominal pain that may radiate to the right scapular or infrascapular area. Acute cholecystitis typically begins with biliary colic and fever that progressively worsen. Unlike biliary colic, the pain is continuous. Approximately 60–70% of patients report prior self-limited episodes. Acalculous cholecystitis may present with unexplained fever or vague abdominal discomfort, particularly in critically ill patients.
Acute cholangitis classically presents with Charcot’s triad: fever with chills, jaundice, and right upper quadrant pain. However, only 50–70% of patients exhibit all three features. Severe cases may present with Reynolds’ pentad, which includes hypotension and altered mental status in addition to Charcot’s triad, indicating sepsis and possible organ failure.
On physical examination, right upper quadrant tenderness is highly sensitive for biliary tract disease. A positive Murphy’s sign—pain during inspiration while palpating the right upper quadrant—is suggestive of acute cholecystitis.
Laboratory findings in acute cholecystitis often include fever and leukocytosis. A temperature above 38.5°C or white blood cell count greater than 12,500/mm³ suggests infection. Mild elevations in serum bilirubin and aminotransferases are common. Elevated amylase may indicate concomitant gallstone pancreatitis. Abnormal renal function, thrombocytopenia, or coagulopathy suggest more severe disease. Bile cultures are frequently positive in cases of obstruction and jaundice.
Ultrasonography is the primary imaging modality for diagnosing cholecystitis. Findings include gallbladder wall thickening (>2 mm), pericholecystic fluid, intramural gas, ductal dilation, and a sonographic Murphy’s sign. Hepatobiliary scintigraphy may be used if ultrasound is inconclusive; failure of gallbladder filling suggests cystic duct obstruction. CT scanning can identify bile duct dilation, pneumobilia, or complications and may assist in diagnosing cholangitis.
Management includes prompt administration of antibiotics targeting Enterobacteriaceae. For mild-to-moderate community-acquired acute cholecystitis, recommended regimens include cefazolin, cefuroxime, or ceftriaxone. In severe cases, elderly or immunocompromised patients, or in acute cholangitis, broad-spectrum therapy such as piperacillin–tazobactam, carbapenems, cefepime plus metronidazole, or fluoroquinolones plus metronidazole is indicated. Vancomycin may be added in healthcare-associated infections. Anti-enterococcal coverage is generally not required in uncomplicated community-acquired infections.
Supportive care includes bowel rest, intravenous fluids, correction of electrolyte imbalances, and analgesia. Antibiotics are typically initiated within one hour before cholecystectomy and discontinued within 24 hours postoperatively if infection is confined to the gallbladder.
Early laparoscopic cholecystectomy is preferred over delayed surgery due to lower complication rates and shorter recovery. In severe cases or when surgery is contraindicated, biliary decompression may be achieved through percutaneous drainage or endoscopic retrograde cholangiopancreatography (ERCP). Acute cholangitis often requires urgent biliary drainage in addition to antibiotics.
Prognosis for acute cholecystitis is generally favorable with timely treatment, although recurrence is common if the gallbladder is not removed. Acute cholangitis carries a mortality rate of 10–30%, especially in elderly patients or those with severe sepsis.
Complications include chronic cholecystitis, empyema of the gallbladder, perforation, fistula formation, hepatic abscess, sepsis, and recurrent biliary obstruction. Severe acute cholangitis may result in shock, organ failure, and disseminated infection if not promptly treated.
- Published on
Infectious Disease and Microbiology – Chickenpox (Varicella)
Chickenpox is a highly contagious febrile illness of childhood caused by primary infection with the varicella zoster virus (VZV). It is characterized by a generalized pruritic rash in which lesions at different stages of development—macules, papules, vesicles, pustules, and crusts—are present simultaneously.
The disease occurs worldwide and shows seasonal peaks in late winter and early spring. Before widespread vaccination, the primary attack rate in susceptible individuals was approximately 90%, with household secondary attack rates of 70–90%. Since implementation of routine vaccination programs, incidence, hospitalizations, complications, and deaths have declined dramatically. Both sexes are equally affected. Most cases occur in young children, although an increasing proportion of cases now occur in adolescents and adults in partially vaccinated populations.
Risk factors include close contact with an infected individual (varicella or herpes zoster), lack of immunity, and increasing age at exposure. Approximately 90% of individuals aged 15 years or older are immune, but 10% remain susceptible. Adults, pregnant women, and immunocompromised individuals are at higher risk for severe disease and complications.
Varicella zoster virus is a DNA virus (human herpesvirus 3) in the Herpesviridae family. Humans are the only known reservoir. Transmission occurs via respiratory droplets or direct contact with vesicular fluid. The virus enters through the respiratory mucosa, replicates in regional lymph nodes, and spreads through primary viremia. A secondary viremia disseminates the virus to the skin and other organs. After primary infection, the virus remains latent in sensory ganglia and may reactivate later in life as herpes zoster.
The incubation period is typically 10–14 days (range 10–21 days). Patients are infectious from approximately 48 hours before rash onset until all lesions have crusted. In immunocompetent children, mild prodromal symptoms such as malaise and low-grade fever may precede the rash by 1–2 days. The rash begins on the face and trunk and spreads centrifugally, sometimes involving mucous membranes. Lesions evolve rapidly from macules to papules and then to clear vesicles on an erythematous base. Vesicular fluid becomes turbid, crusting follows, and new crops of lesions appear over 2–4 days. Crusts fall off within 1–2 weeks and usually do not scar unless secondarily infected.
In immunocompromised patients, lesions are more numerous, may have hemorrhagic bases, and heal more slowly. Visceral complications occur in 30–50% of severe cases and can be fatal. Adults typically experience more severe illness and have a higher risk of complications. Pregnant women are at increased risk of varicella pneumonia and may transmit infection to the fetus. Perinatal varicella (maternal infection 5 days before to 2 days after delivery) can result in severe neonatal disease with high mortality. Congenital varicella syndrome, occurring when infection develops in the first two trimesters, may cause limb hypoplasia, skin scarring, ocular abnormalities, and central nervous system impairment.
Diagnosis is primarily clinical, based on the characteristic rash. Laboratory confirmation can be obtained by PCR detection of VZV DNA from lesion specimens, which is the most reliable method. Viral culture, direct immunofluorescence staining, Tzanck smear (showing multinucleated giant cells), and serologic testing may also be used. Chest radiographs may show nodular or interstitial infiltrates in cases of varicella pneumonia.
Differential diagnosis includes disseminated herpes simplex infection, enteroviral rashes, scabies, dermatitis herpetiformis, folliculitis, atypical measles, and rickettsialpox.
Oral acyclovir is recommended within 24 hours of rash onset to reduce disease severity. In immunocompetent children aged ≥2 years and weighing ≤40 kg, the dose is 80 mg/kg/day divided into four doses (maximum 3200 mg/day) for 5 days. Older children and adults may receive 3200 mg/day in four divided doses for 5 days. Adequate hydration is important. Valacyclovir and famciclovir are alternatives for older children and adults. Supportive care includes bathing, antipruritic agents, trimmed fingernails to prevent excoriation, and acetaminophen for fever. Aspirin should be avoided due to the risk of Reye’s syndrome.
Passive immunization with varicella zoster immunoglobulin is recommended for high-risk susceptible individuals after exposure, including immunocompromised persons, pregnant women, certain premature infants, and newborns exposed perinatally. It should be administered ideally within 72 hours and no later than 96 hours after exposure.
Active immunization with the live attenuated varicella vaccine is part of routine childhood vaccination schedules. Two doses are recommended, beginning at 12–15 months of age, with a second dose at 4–6 years. Unvaccinated adolescents and adults without evidence of immunity should receive two doses separated by at least 28 days. Vaccination is contraindicated during pregnancy.
Prognosis in healthy children is excellent, and infection usually confers lifelong immunity. However, severe disease may occur in adults, immunocompromised patients, pregnant women, and neonates. The virus remains latent and may later reactivate as herpes zoster.
Complications include secondary bacterial skin infections (commonly due to staphylococci or group A streptococci), varicella pneumonia (particularly in adults and pregnant women), cerebellar ataxia, encephalitis, meningitis, transverse myelitis, myocarditis, nephritis, hepatitis, bleeding disorders, and Reye’s syndrome. Mortality is low in the post-vaccination era but remains significant in high-risk groups.
Chickenpox is a highly contagious febrile illness of childhood caused by primary infection with the varicella zoster virus (VZV). It is characterized by a generalized pruritic rash in which lesions at different stages of development—macules, papules, vesicles, pustules, and crusts—are present simultaneously.
The disease occurs worldwide and shows seasonal peaks in late winter and early spring. Before widespread vaccination, the primary attack rate in susceptible individuals was approximately 90%, with household secondary attack rates of 70–90%. Since implementation of routine vaccination programs, incidence, hospitalizations, complications, and deaths have declined dramatically. Both sexes are equally affected. Most cases occur in young children, although an increasing proportion of cases now occur in adolescents and adults in partially vaccinated populations.
Risk factors include close contact with an infected individual (varicella or herpes zoster), lack of immunity, and increasing age at exposure. Approximately 90% of individuals aged 15 years or older are immune, but 10% remain susceptible. Adults, pregnant women, and immunocompromised individuals are at higher risk for severe disease and complications.
Varicella zoster virus is a DNA virus (human herpesvirus 3) in the Herpesviridae family. Humans are the only known reservoir. Transmission occurs via respiratory droplets or direct contact with vesicular fluid. The virus enters through the respiratory mucosa, replicates in regional lymph nodes, and spreads through primary viremia. A secondary viremia disseminates the virus to the skin and other organs. After primary infection, the virus remains latent in sensory ganglia and may reactivate later in life as herpes zoster.
The incubation period is typically 10–14 days (range 10–21 days). Patients are infectious from approximately 48 hours before rash onset until all lesions have crusted. In immunocompetent children, mild prodromal symptoms such as malaise and low-grade fever may precede the rash by 1–2 days. The rash begins on the face and trunk and spreads centrifugally, sometimes involving mucous membranes. Lesions evolve rapidly from macules to papules and then to clear vesicles on an erythematous base. Vesicular fluid becomes turbid, crusting follows, and new crops of lesions appear over 2–4 days. Crusts fall off within 1–2 weeks and usually do not scar unless secondarily infected.
In immunocompromised patients, lesions are more numerous, may have hemorrhagic bases, and heal more slowly. Visceral complications occur in 30–50% of severe cases and can be fatal. Adults typically experience more severe illness and have a higher risk of complications. Pregnant women are at increased risk of varicella pneumonia and may transmit infection to the fetus. Perinatal varicella (maternal infection 5 days before to 2 days after delivery) can result in severe neonatal disease with high mortality. Congenital varicella syndrome, occurring when infection develops in the first two trimesters, may cause limb hypoplasia, skin scarring, ocular abnormalities, and central nervous system impairment.
Diagnosis is primarily clinical, based on the characteristic rash. Laboratory confirmation can be obtained by PCR detection of VZV DNA from lesion specimens, which is the most reliable method. Viral culture, direct immunofluorescence staining, Tzanck smear (showing multinucleated giant cells), and serologic testing may also be used. Chest radiographs may show nodular or interstitial infiltrates in cases of varicella pneumonia.
Differential diagnosis includes disseminated herpes simplex infection, enteroviral rashes, scabies, dermatitis herpetiformis, folliculitis, atypical measles, and rickettsialpox.
Oral acyclovir is recommended within 24 hours of rash onset to reduce disease severity. In immunocompetent children aged ≥2 years and weighing ≤40 kg, the dose is 80 mg/kg/day divided into four doses (maximum 3200 mg/day) for 5 days. Older children and adults may receive 3200 mg/day in four divided doses for 5 days. Adequate hydration is important. Valacyclovir and famciclovir are alternatives for older children and adults. Supportive care includes bathing, antipruritic agents, trimmed fingernails to prevent excoriation, and acetaminophen for fever. Aspirin should be avoided due to the risk of Reye’s syndrome.
Passive immunization with varicella zoster immunoglobulin is recommended for high-risk susceptible individuals after exposure, including immunocompromised persons, pregnant women, certain premature infants, and newborns exposed perinatally. It should be administered ideally within 72 hours and no later than 96 hours after exposure.
Active immunization with the live attenuated varicella vaccine is part of routine childhood vaccination schedules. Two doses are recommended, beginning at 12–15 months of age, with a second dose at 4–6 years. Unvaccinated adolescents and adults without evidence of immunity should receive two doses separated by at least 28 days. Vaccination is contraindicated during pregnancy.
Prognosis in healthy children is excellent, and infection usually confers lifelong immunity. However, severe disease may occur in adults, immunocompromised patients, pregnant women, and neonates. The virus remains latent and may later reactivate as herpes zoster.
Complications include secondary bacterial skin infections (commonly due to staphylococci or group A streptococci), varicella pneumonia (particularly in adults and pregnant women), cerebellar ataxia, encephalitis, meningitis, transverse myelitis, myocarditis, nephritis, hepatitis, bleeding disorders, and Reye’s syndrome. Mortality is low in the post-vaccination era but remains significant in high-risk groups.
- Published on
Infectious Disease and Microbiology – Chancroid
Chancroid is a sexually transmitted infection characterized by painful genital lesions that may progress to ulceration. The primary lesion typically begins as a tender papule or pustule measuring 2–20 mm in diameter, which rapidly becomes an excavated ulcer with undermined, ragged, or irregular edges.
In the United States, chancroid is rare and usually occurs in localized outbreaks. Only a small number of cases are reported annually, although underdiagnosis is possible. Globally, the disease remains prevalent in parts of Africa, Asia, and Latin America, and in lower socioeconomic populations in the United States.
Risk factors include multiple sexual partners, sexual contact with an infected partner, and travel to or sexual contact with persons from endemic regions. Chancroid increases both transmission of and susceptibility to HIV infection. Approximately 10% of individuals with chancroid acquired in the United States are coinfected with Treponema pallidum (syphilis) or herpes simplex virus (HSV).
The causative agent is Haemophilus ducreyi, a small, fastidious gram-negative rod. The incubation period ranges from 1 to 14 days.
Clinically, tender papules develop at the site of inoculation and become pustular, eroded, and ulcerated within 1–2 days. Multiple lesions may coalesce to form a large ulcer exceeding 2 cm in diameter. Approximately 40% of patients develop tender inguinal lymphadenopathy (“buboes”), which may suppurate and rupture spontaneously. The combination of painful genital ulcers and suppurative inguinal lymphadenopathy is characteristic.
Diagnosis is often based on clinical and epidemiologic features, but misdiagnosis is common; laboratory confirmation is important. Definitive diagnosis requires isolation of H. ducreyi on specialized culture media, which are not widely available. Culture has approximately 80% sensitivity. Polymerase chain reaction (PCR) testing has higher sensitivity (about 95%) but is not widely available and is not FDA approved in many settings. Diagnosis also requires exclusion of syphilis (negative dark-field examination or serology performed more than 7 days after ulcer onset) and genital herpes (negative clinical and laboratory findings). All patients should be tested for HIV at diagnosis.
For specimen collection, the lesion may be gently abraded to obtain exudate, which can be applied to slides for microscopy when indicated. Histopathologic examination typically shows superficial purulent exudate and mononuclear cell infiltrates in the dermis; neutrophil infiltration may be reduced in HIV-infected patients.
The differential diagnosis includes genital herpes, syphilis, acute HIV infection, lymphogranuloma venereum, granuloma inguinale (donovanosis), mycobacterial or fungal infections, parasitic infections, venereal warts, scabies, molluscum contagiosum, folliculitis, and plague. Noninfectious causes such as malignancy, trauma, fixed drug eruptions, Behçet syndrome, and dermatitis herpetiformis should also be considered.
First-line treatment options include azithromycin 1 g orally as a single dose or ceftriaxone 250 mg intramuscularly as a single dose. Alternative regimens include ciprofloxacin 500 mg orally twice daily for 3 days or erythromycin base 500 mg orally four times daily for 7 days. Ciprofloxacin is contraindicated in pregnancy and lactation. Some isolates with intermediate resistance to ciprofloxacin or erythromycin have been reported. Sexual partners within 10 days preceding symptom onset should be evaluated and treated with the same regimen.
Fluctuant buboes may require needle aspiration through intact skin or incision and drainage; incision and drainage may reduce the need for repeated procedures.
Patients should be reexamined within 3–7 days to assess clinical improvement. Complete healing depends on ulcer size; larger ulcers may require more than two weeks to resolve. Healing may be slower in uncircumcised men with subpreputial ulcers. Failure to improve may indicate incorrect diagnosis, coinfection (e.g., syphilis), reinfection, antimicrobial resistance, noncompliance, or HIV infection. Patients with initial negative HIV or syphilis tests should be retested approximately three months later.
Complications include secondary ulcers, draining fistulas following lymph node rupture, and increased risk of HIV transmission. Education on safe-sex practices is essential to prevent recurrence and transmission.
Chancroid is a sexually transmitted infection characterized by painful genital lesions that may progress to ulceration. The primary lesion typically begins as a tender papule or pustule measuring 2–20 mm in diameter, which rapidly becomes an excavated ulcer with undermined, ragged, or irregular edges.
In the United States, chancroid is rare and usually occurs in localized outbreaks. Only a small number of cases are reported annually, although underdiagnosis is possible. Globally, the disease remains prevalent in parts of Africa, Asia, and Latin America, and in lower socioeconomic populations in the United States.
Risk factors include multiple sexual partners, sexual contact with an infected partner, and travel to or sexual contact with persons from endemic regions. Chancroid increases both transmission of and susceptibility to HIV infection. Approximately 10% of individuals with chancroid acquired in the United States are coinfected with Treponema pallidum (syphilis) or herpes simplex virus (HSV).
The causative agent is Haemophilus ducreyi, a small, fastidious gram-negative rod. The incubation period ranges from 1 to 14 days.
Clinically, tender papules develop at the site of inoculation and become pustular, eroded, and ulcerated within 1–2 days. Multiple lesions may coalesce to form a large ulcer exceeding 2 cm in diameter. Approximately 40% of patients develop tender inguinal lymphadenopathy (“buboes”), which may suppurate and rupture spontaneously. The combination of painful genital ulcers and suppurative inguinal lymphadenopathy is characteristic.
Diagnosis is often based on clinical and epidemiologic features, but misdiagnosis is common; laboratory confirmation is important. Definitive diagnosis requires isolation of H. ducreyi on specialized culture media, which are not widely available. Culture has approximately 80% sensitivity. Polymerase chain reaction (PCR) testing has higher sensitivity (about 95%) but is not widely available and is not FDA approved in many settings. Diagnosis also requires exclusion of syphilis (negative dark-field examination or serology performed more than 7 days after ulcer onset) and genital herpes (negative clinical and laboratory findings). All patients should be tested for HIV at diagnosis.
For specimen collection, the lesion may be gently abraded to obtain exudate, which can be applied to slides for microscopy when indicated. Histopathologic examination typically shows superficial purulent exudate and mononuclear cell infiltrates in the dermis; neutrophil infiltration may be reduced in HIV-infected patients.
The differential diagnosis includes genital herpes, syphilis, acute HIV infection, lymphogranuloma venereum, granuloma inguinale (donovanosis), mycobacterial or fungal infections, parasitic infections, venereal warts, scabies, molluscum contagiosum, folliculitis, and plague. Noninfectious causes such as malignancy, trauma, fixed drug eruptions, Behçet syndrome, and dermatitis herpetiformis should also be considered.
First-line treatment options include azithromycin 1 g orally as a single dose or ceftriaxone 250 mg intramuscularly as a single dose. Alternative regimens include ciprofloxacin 500 mg orally twice daily for 3 days or erythromycin base 500 mg orally four times daily for 7 days. Ciprofloxacin is contraindicated in pregnancy and lactation. Some isolates with intermediate resistance to ciprofloxacin or erythromycin have been reported. Sexual partners within 10 days preceding symptom onset should be evaluated and treated with the same regimen.
Fluctuant buboes may require needle aspiration through intact skin or incision and drainage; incision and drainage may reduce the need for repeated procedures.
Patients should be reexamined within 3–7 days to assess clinical improvement. Complete healing depends on ulcer size; larger ulcers may require more than two weeks to resolve. Healing may be slower in uncircumcised men with subpreputial ulcers. Failure to improve may indicate incorrect diagnosis, coinfection (e.g., syphilis), reinfection, antimicrobial resistance, noncompliance, or HIV infection. Patients with initial negative HIV or syphilis tests should be retested approximately three months later.
Complications include secondary ulcers, draining fistulas following lymph node rupture, and increased risk of HIV transmission. Education on safe-sex practices is essential to prevent recurrence and transmission.
- Published on
Infectious Disease and Microbiology – Cervicitis
Cervicitis is a sexually transmitted infection characterized by inflammation of the endocervix and/or ectocervix. It is frequently encountered in sexually active adolescents and young adults, particularly women under 25 years of age.
Cervicitis is common among sexually active adolescent girls under 20 years and young adults aged 20–24 years. In a large U.S. cohort study of individuals aged 18–26 years, the prevalence of chlamydial infection was approximately 4.2%, with higher rates among women than men. Gonorrhea was less common, with a prevalence of 0.4%, and coinfection with both pathogens was rare.
Major risk factors include a new sexual partner within the past 3 months, multiple sexual partners within 6 months, a partner with multiple partners, and inconsistent use of barrier contraception. Preventive strategies emphasize safe sex practices, evaluation and treatment of sexual partners, and annual screening for Chlamydia trachomatis in sexually active women aged 25 years or younger and older women with risk factors. Presumptive treatment is recommended when local prevalence of chlamydia or gonorrhea is high or when follow-up is uncertain.
The most common etiologic agents are Chlamydia trachomatis and Neisseria gonorrhoeae. Other organisms include Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, and herpes simplex virus. In many cases, no pathogen is identified. Vaginal infections such as Trichomonas vaginalis or Candida albicans may extend to involve the ectocervix. Rarely, cytomegalovirus is implicated.
Cervicitis is frequently asymptomatic. When present, symptoms include abnormal vaginal discharge, postcoital bleeding, dysuria, urinary frequency, and dyspareunia. On physical examination, a yellow mucopurulent discharge may be visible in the endocervical canal, and the cervix may be friable and bleed easily on contact.
Diagnostic evaluation includes culture of cervical discharge and nucleic acid amplification testing (NAAT) for C. trachomatis and N. gonorrhoeae, which can be performed on endocervical swabs, vaginal swabs, or urine samples. Gram stain may detect gram-negative intracellular diplococci, which are highly specific for gonococcal infection but less sensitive in cervicitis than in male urethritis. Microscopic examination of vaginal fluid may show leukorrhea (>10 white blood cells per high-power field), which is associated with chlamydial and gonococcal infection. Women with cervicitis should also be evaluated for bacterial vaginosis, trichomoniasis, and pelvic inflammatory disease. If cervical ulcers are present, testing for herpes simplex virus is indicated.
Management includes appropriate treatment of the patient and sexual partners. Patients and partners should abstain from sexual activity until therapy is completed (7 days after single-dose therapy or after completion of a 7-day regimen). In HIV-infected women, treatment reduces cervical viral shedding and transmission risk. In pre-adolescent children, sexually transmitted pathogens warrant evaluation for possible sexual abuse.
Empiric therapy is appropriate when follow-up is uncertain or prevalence of infection is high. For chlamydial infection, first-line treatment includes azithromycin 1 g orally as a single dose or doxycycline 100 mg orally twice daily for 7 days. For gonococcal infection, ceftriaxone 250 mg intramuscularly as a single dose is recommended. Alternative regimens for chlamydia include ofloxacin, levofloxacin, or erythromycin. For gonorrhea, oral cephalosporins such as cefixime or cefpodoxime may be used, although they may be less effective than ceftriaxone. Fluoroquinolones are not recommended because of increasing resistance.
In pregnancy, azithromycin or amoxicillin is recommended for chlamydial infection. Doxycycline and fluoroquinolones are contraindicated. Gonorrhea in pregnancy is treated with ceftriaxone. Erythromycin formulations may be used as alternatives, though erythromycin estolate is contraindicated due to risk of hepatotoxicity.
Test-of-cure for chlamydia is recommended only when adherence is uncertain, symptoms persist, reinfection is suspected, or in pregnancy. NAAT testing should not be performed within 3 weeks of treatment due to possible false-positive results from nonviable organisms. Routine test-of-cure is not required for uncomplicated gonorrhea treated appropriately unless symptoms persist. Repeat screening within 3–4 months is recommended due to high reinfection rates, especially in adolescents.
Complications of untreated cervicitis include pelvic inflammatory disease, infertility, ectopic pregnancy, chorioamnionitis, premature rupture of membranes, and puerperal infections. Early detection, treatment, and partner management are essential to reduce long-term reproductive morbidity.
Cervicitis is a sexually transmitted infection characterized by inflammation of the endocervix and/or ectocervix. It is frequently encountered in sexually active adolescents and young adults, particularly women under 25 years of age.
Cervicitis is common among sexually active adolescent girls under 20 years and young adults aged 20–24 years. In a large U.S. cohort study of individuals aged 18–26 years, the prevalence of chlamydial infection was approximately 4.2%, with higher rates among women than men. Gonorrhea was less common, with a prevalence of 0.4%, and coinfection with both pathogens was rare.
Major risk factors include a new sexual partner within the past 3 months, multiple sexual partners within 6 months, a partner with multiple partners, and inconsistent use of barrier contraception. Preventive strategies emphasize safe sex practices, evaluation and treatment of sexual partners, and annual screening for Chlamydia trachomatis in sexually active women aged 25 years or younger and older women with risk factors. Presumptive treatment is recommended when local prevalence of chlamydia or gonorrhea is high or when follow-up is uncertain.
The most common etiologic agents are Chlamydia trachomatis and Neisseria gonorrhoeae. Other organisms include Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, and herpes simplex virus. In many cases, no pathogen is identified. Vaginal infections such as Trichomonas vaginalis or Candida albicans may extend to involve the ectocervix. Rarely, cytomegalovirus is implicated.
Cervicitis is frequently asymptomatic. When present, symptoms include abnormal vaginal discharge, postcoital bleeding, dysuria, urinary frequency, and dyspareunia. On physical examination, a yellow mucopurulent discharge may be visible in the endocervical canal, and the cervix may be friable and bleed easily on contact.
Diagnostic evaluation includes culture of cervical discharge and nucleic acid amplification testing (NAAT) for C. trachomatis and N. gonorrhoeae, which can be performed on endocervical swabs, vaginal swabs, or urine samples. Gram stain may detect gram-negative intracellular diplococci, which are highly specific for gonococcal infection but less sensitive in cervicitis than in male urethritis. Microscopic examination of vaginal fluid may show leukorrhea (>10 white blood cells per high-power field), which is associated with chlamydial and gonococcal infection. Women with cervicitis should also be evaluated for bacterial vaginosis, trichomoniasis, and pelvic inflammatory disease. If cervical ulcers are present, testing for herpes simplex virus is indicated.
Management includes appropriate treatment of the patient and sexual partners. Patients and partners should abstain from sexual activity until therapy is completed (7 days after single-dose therapy or after completion of a 7-day regimen). In HIV-infected women, treatment reduces cervical viral shedding and transmission risk. In pre-adolescent children, sexually transmitted pathogens warrant evaluation for possible sexual abuse.
Empiric therapy is appropriate when follow-up is uncertain or prevalence of infection is high. For chlamydial infection, first-line treatment includes azithromycin 1 g orally as a single dose or doxycycline 100 mg orally twice daily for 7 days. For gonococcal infection, ceftriaxone 250 mg intramuscularly as a single dose is recommended. Alternative regimens for chlamydia include ofloxacin, levofloxacin, or erythromycin. For gonorrhea, oral cephalosporins such as cefixime or cefpodoxime may be used, although they may be less effective than ceftriaxone. Fluoroquinolones are not recommended because of increasing resistance.
In pregnancy, azithromycin or amoxicillin is recommended for chlamydial infection. Doxycycline and fluoroquinolones are contraindicated. Gonorrhea in pregnancy is treated with ceftriaxone. Erythromycin formulations may be used as alternatives, though erythromycin estolate is contraindicated due to risk of hepatotoxicity.
Test-of-cure for chlamydia is recommended only when adherence is uncertain, symptoms persist, reinfection is suspected, or in pregnancy. NAAT testing should not be performed within 3 weeks of treatment due to possible false-positive results from nonviable organisms. Routine test-of-cure is not required for uncomplicated gonorrhea treated appropriately unless symptoms persist. Repeat screening within 3–4 months is recommended due to high reinfection rates, especially in adolescents.
Complications of untreated cervicitis include pelvic inflammatory disease, infertility, ectopic pregnancy, chorioamnionitis, premature rupture of membranes, and puerperal infections. Early detection, treatment, and partner management are essential to reduce long-term reproductive morbidity.
- Published on
Infectious Disease and Microbiology – Cat-Scratch Disease (Bartonella Infections)
Cat-scratch disease is typically a self-limited acute illness characterized by regional lymphadenopathy with or without fever and constitutional symptoms. It is most commonly caused by Bartonella henselae. In addition to classic lymphadenitis, B. henselae infection may present as fever of unknown origin, hepatosplenic granulomatous disease, neuroretinitis, or encephalopathy. Other medically important Bartonella species include Bartonella quintana, the historical cause of trench fever and a cause of persistent bacteremia, endocarditis, and bacillary angiomatosis, and Bartonella bacilliformis, which causes Oroya fever.
In the United States, the incidence of cat-scratch disease is approximately 10 cases per 100,000 person-years, with an estimated 24,000 recognized cases annually. The disease occurs worldwide and shows seasonal variation in temperate climates, with most cases occurring between August and January. It primarily affects immunocompetent individuals, and about 80% of cases occur in persons younger than 21 years. Most cases are self-limited and present with regional adenopathy. Bartonella quintana is globally endemic and associated with body louse transmission, while Bartonella bacilliformis is transmitted by sand flies and occurs at altitudes above 1 km in the Andes.
Cats, particularly kittens and those infested with fleas, are the natural reservoir of B. henselae. A history of cat exposure is reported in approximately 90% of patients, and about 60% recall a scratch. B. quintana outbreaks are associated with homelessness and poor socioeconomic conditions, where infestation with the human body louse (Pediculus humanus) facilitates transmission. Immunocompromised patients, especially those with advanced HIV infection, are at increased risk of chronic Bartonella infections such as bacillary angiomatosis and bacillary peliosis.
Prevention includes limiting exposure to cat scratches, bites, and licks, especially in immunocompromised individuals. Control of cat fleas may reduce transmission risk.
Bartonella species are fastidious, gram-negative, aerobic rod-shaped bacteria capable of intracellular survival. Infection leads to an inflammatory response and granuloma formation, particularly in lymph nodes. B. henselae accounts for the vast majority of cat-scratch disease cases.
The illness often begins with a small erythematous papule or pustule at the site of inoculation that may persist for weeks. Regional lymph nodes draining the affected area enlarge and become tender. Fever and malaise occur in approximately 30% of patients. Neuroretinitis may present with decreased visual acuity, and encephalopathy may manifest as mental status changes. In HIV-infected individuals, B. henselae bacteremia may cause progressive fatigue, weight loss, recurrent fevers, and hepatomegaly.
Trench fever due to B. quintana typically presents after an incubation period of 3–38 days with sudden onset of chills and fever. Symptoms such as headache, retro-orbital pain, and conjunctival injection are nonspecific. Bacillary angiomatosis presents with red-to-purple papules or nodules that may ulcerate or bleed. Bacillary peliosis involves blood-filled cystic lesions within visceral organs such as the liver or spleen.
On physical examination, regional lymphadenopathy is the most common finding. A primary inoculation lesion may be visible. Parinaud’s oculoglandular syndrome, characterized by conjunctivitis, conjunctival granuloma, and preauricular lymphadenopathy, occurs in approximately 5% of patients. Visceral involvement may produce hepatosplenomegaly.
Laboratory findings may show mild leukocytosis with occasional eosinophilia. Bartonella species can be isolated from blood using specialized culture techniques. Serologic testing with indirect fluorescence assays is widely used; titers greater than 1:256 strongly suggest active infection. If results are equivocal, repeat serology after two weeks may assist diagnosis. Ultrasound of enlarged lymph nodes may help evaluate suppuration and guide aspiration. Histopathology typically shows granuloma formation, and special stains such as Warthin–Starry or tissue PCR may support the diagnosis.
Diagnosis is suggested by compatible clinical findings, history of cat exposure, positive serology, characteristic histopathology, and exclusion of other causes of lymphadenopathy, particularly mycobacterial infections and suppurative adenitis.
Although cat-scratch disease is usually self-limited, antibiotics may hasten resolution. Azithromycin (500 mg orally once, then 250 mg daily for four additional days) is commonly used in adults. Neuroretinitis has been treated with doxycycline plus rifampin, although evidence is limited. Bacillary angiomatosis limited to the skin is treated with erythromycin (500 mg four times daily) or doxycycline (100 mg twice daily) for 8–12 weeks. Bacteremia requires at least four weeks of therapy, and longer courses (2–3 months) are recommended in HIV-infected patients, persistent fever, or endocarditis. Alternative agents include rifampin, ciprofloxacin, and trimethoprim-sulfamethoxazole.
If lymph node suppuration occurs, needle aspiration is preferred over incision and drainage to relieve pain and promote recovery. Valve replacement may be required in Bartonella endocarditis.
Lymphadenopathy usually resolves over several months. One episode appears to confer lifelong immunity. In immunocompetent individuals, fever resolves promptly with or without therapy. In HIV-infected patients, resolution of fever may take longer, although bacteremia typically clears within a week of treatment.
Uncomplicated cat-scratch disease has an excellent prognosis. Complications, including retinitis, encephalopathy, or severe systemic disease, occur in 5–14% of cases. Encephalopathy typically develops weeks after the acute illness and may present with seizures; recovery is usually rapid. Inflammatory organ involvement without angiomatosis or peliosis has been reported in patients with AIDS, affecting the liver, spleen, lymph nodes, heart, and bone marrow.
Cat-scratch disease is typically a self-limited acute illness characterized by regional lymphadenopathy with or without fever and constitutional symptoms. It is most commonly caused by Bartonella henselae. In addition to classic lymphadenitis, B. henselae infection may present as fever of unknown origin, hepatosplenic granulomatous disease, neuroretinitis, or encephalopathy. Other medically important Bartonella species include Bartonella quintana, the historical cause of trench fever and a cause of persistent bacteremia, endocarditis, and bacillary angiomatosis, and Bartonella bacilliformis, which causes Oroya fever.
In the United States, the incidence of cat-scratch disease is approximately 10 cases per 100,000 person-years, with an estimated 24,000 recognized cases annually. The disease occurs worldwide and shows seasonal variation in temperate climates, with most cases occurring between August and January. It primarily affects immunocompetent individuals, and about 80% of cases occur in persons younger than 21 years. Most cases are self-limited and present with regional adenopathy. Bartonella quintana is globally endemic and associated with body louse transmission, while Bartonella bacilliformis is transmitted by sand flies and occurs at altitudes above 1 km in the Andes.
Cats, particularly kittens and those infested with fleas, are the natural reservoir of B. henselae. A history of cat exposure is reported in approximately 90% of patients, and about 60% recall a scratch. B. quintana outbreaks are associated with homelessness and poor socioeconomic conditions, where infestation with the human body louse (Pediculus humanus) facilitates transmission. Immunocompromised patients, especially those with advanced HIV infection, are at increased risk of chronic Bartonella infections such as bacillary angiomatosis and bacillary peliosis.
Prevention includes limiting exposure to cat scratches, bites, and licks, especially in immunocompromised individuals. Control of cat fleas may reduce transmission risk.
Bartonella species are fastidious, gram-negative, aerobic rod-shaped bacteria capable of intracellular survival. Infection leads to an inflammatory response and granuloma formation, particularly in lymph nodes. B. henselae accounts for the vast majority of cat-scratch disease cases.
The illness often begins with a small erythematous papule or pustule at the site of inoculation that may persist for weeks. Regional lymph nodes draining the affected area enlarge and become tender. Fever and malaise occur in approximately 30% of patients. Neuroretinitis may present with decreased visual acuity, and encephalopathy may manifest as mental status changes. In HIV-infected individuals, B. henselae bacteremia may cause progressive fatigue, weight loss, recurrent fevers, and hepatomegaly.
Trench fever due to B. quintana typically presents after an incubation period of 3–38 days with sudden onset of chills and fever. Symptoms such as headache, retro-orbital pain, and conjunctival injection are nonspecific. Bacillary angiomatosis presents with red-to-purple papules or nodules that may ulcerate or bleed. Bacillary peliosis involves blood-filled cystic lesions within visceral organs such as the liver or spleen.
On physical examination, regional lymphadenopathy is the most common finding. A primary inoculation lesion may be visible. Parinaud’s oculoglandular syndrome, characterized by conjunctivitis, conjunctival granuloma, and preauricular lymphadenopathy, occurs in approximately 5% of patients. Visceral involvement may produce hepatosplenomegaly.
Laboratory findings may show mild leukocytosis with occasional eosinophilia. Bartonella species can be isolated from blood using specialized culture techniques. Serologic testing with indirect fluorescence assays is widely used; titers greater than 1:256 strongly suggest active infection. If results are equivocal, repeat serology after two weeks may assist diagnosis. Ultrasound of enlarged lymph nodes may help evaluate suppuration and guide aspiration. Histopathology typically shows granuloma formation, and special stains such as Warthin–Starry or tissue PCR may support the diagnosis.
Diagnosis is suggested by compatible clinical findings, history of cat exposure, positive serology, characteristic histopathology, and exclusion of other causes of lymphadenopathy, particularly mycobacterial infections and suppurative adenitis.
Although cat-scratch disease is usually self-limited, antibiotics may hasten resolution. Azithromycin (500 mg orally once, then 250 mg daily for four additional days) is commonly used in adults. Neuroretinitis has been treated with doxycycline plus rifampin, although evidence is limited. Bacillary angiomatosis limited to the skin is treated with erythromycin (500 mg four times daily) or doxycycline (100 mg twice daily) for 8–12 weeks. Bacteremia requires at least four weeks of therapy, and longer courses (2–3 months) are recommended in HIV-infected patients, persistent fever, or endocarditis. Alternative agents include rifampin, ciprofloxacin, and trimethoprim-sulfamethoxazole.
If lymph node suppuration occurs, needle aspiration is preferred over incision and drainage to relieve pain and promote recovery. Valve replacement may be required in Bartonella endocarditis.
Lymphadenopathy usually resolves over several months. One episode appears to confer lifelong immunity. In immunocompetent individuals, fever resolves promptly with or without therapy. In HIV-infected patients, resolution of fever may take longer, although bacteremia typically clears within a week of treatment.
Uncomplicated cat-scratch disease has an excellent prognosis. Complications, including retinitis, encephalopathy, or severe systemic disease, occur in 5–14% of cases. Encephalopathy typically develops weeks after the acute illness and may present with seizures; recovery is usually rapid. Inflammatory organ involvement without angiomatosis or peliosis has been reported in patients with AIDS, affecting the liver, spleen, lymph nodes, heart, and bone marrow.
- Published on
Infectious Disease and Microbiology – Dengue
Dengue is a mosquito-borne viral illness that causes a severe flu-like disease and, in some cases, progresses to life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS), with a fatality rate of approximately 1–5% in severe cases. It is caused by the dengue virus, a single-stranded RNA virus of the Flaviviridae family, with four antigenically distinct serotypes (types 1–4). Humans and nonhuman primates serve as reservoirs. Transmission occurs through the bite of infected Aedes aegypti and Aedes albopictus, which are predominantly day-biting mosquitoes.
Globally, about 2.5 billion people—nearly two-fifths of the world’s population—are at risk of infection. An estimated 50–100 million infections occur annually, including approximately 500,000 cases of DHF and hundreds of thousands of deaths worldwide. Transmission increases during the rainy season due to mosquito breeding in stagnant water. Dengue is endemic in around 100 countries across Asia, the Pacific, the Americas, Africa, and the Caribbean, primarily in tropical and subtropical urban and suburban areas.
The principal risk factor is travel to or residence in endemic regions. No genetic predisposition has been clearly identified. Prevention focuses on avoiding mosquito bites and vector control. Measures include using insect repellents containing at least 30% DEET, wearing long-sleeved clothing (preferably treated with permethrin), and eliminating mosquito breeding sites such as stagnant water. Indoor insecticide use and larvicidal agents may reduce mosquito populations. Bed nets are of limited value because Aedes mosquitoes bite during the daytime.
After inoculation, the incubation period ranges from 3 to 14 days, most commonly 4–7 days. The virus initially replicates in dendritic cells and then spreads to reticuloendothelial cells, hepatocytes, and endothelial cells. Immune mediators contribute to the acute febrile illness, which typically lasts 5–7 days, with full recovery within 7–10 days in uncomplicated cases. Prior infection with a different serotype increases the risk of DHF and DSS due to immune-mediated mechanisms.
DHF and DSS usually develop between days 3 and 7 of illness, often at the end of the febrile phase. Increased capillary permeability leads to plasma leakage, hemoconcentration, pleural effusions, and ascites. Thrombocytopenia, capillary fragility, and disseminated intravascular coagulation (DIC) can result in hemorrhage ranging from petechiae to life-threatening gastrointestinal bleeding. Liver involvement may cause hepatitis and coagulopathy, which can be fatal in severe cases. Mother-to-child transmission has been documented.
Clinically, patients present with fever, headache, chills, myalgias, bone pain, rash, nausea, vomiting, abdominal pain, and anorexia. Cutaneous hyperesthesia and changes in taste may occur. Hemorrhagic manifestations include bruising, epistaxis, gum bleeding, menorrhagia, and gastrointestinal bleeding. A careful travel history is essential.
On physical examination, fever is common. Rash may appear in two phases: an initial generalized blanching macular rash followed by a morbilliform maculopapular rash that typically spares the palms and soles. Conjunctival and pharyngeal injection are frequent findings. Signs of shock—tachycardia, hypotension, and delayed capillary refill—indicate severe disease. Hepatomegaly, lymphadenopathy, mucosal bleeding, and altered mental status (suggesting encephalopathy or intracranial hemorrhage) may also be present.
Laboratory evaluation often reveals leukopenia, lymphopenia, elevated hematocrit (reflecting hemoconcentration), and thrombocytopenia. Liver transaminases are commonly elevated, and albumin may be low. Electrolyte disturbances such as hyponatremia and metabolic acidosis may occur. Coagulation studies may show prolonged PT and APTT, low fibrinogen, and elevated fibrin degradation products in DIC. Serologic testing (ELISA for IgM and IgG) is commonly used for diagnosis. Imaging may demonstrate pleural or pericardial effusions and ascites. Head CT is indicated in patients with altered consciousness.
The differential diagnosis includes malaria, yellow fever, rickettsial infections, leptospirosis, typhoid fever, viral hepatitis, meningitis, bacterial sepsis, and other viral illnesses such as influenza or chikungunya.
There is no specific antiviral treatment for dengue, DHF, or DSS. Management is supportive. Aspirin and nonsteroidal anti-inflammatory drugs should be avoided due to bleeding risk. Adequate analgesia, antipyretics (such as acetaminophen), and careful fluid management are essential. In severe cases, aggressive fluid resuscitation using isotonic crystalloids or colloids is required to maintain adequate blood pressure and organ perfusion. Advanced life support protocols should be followed in patients with shock. Blood products may be necessary in cases of severe hemorrhage. Close monitoring of fluid balance, urine output, electrolytes, and coagulation status is critical.
Hospital admission is indicated for patients with hemodynamic instability, DHF, DSS, or significant bleeding. Intensive care is required for hypotension, DIC, or organ failure. Discharge is appropriate once the patient is hemodynamically stable and has recovered clinically.
Prognosis is generally excellent for uncomplicated dengue fever, with most patients recovering fully. Those who survive the critical phase of DHF or DSS usually recover without long-term sequelae. However, complications may include neurological manifestations (encephalopathy, seizures, Guillain–Barré syndrome, transverse myelitis), myocarditis, and liver failure. Cases should be reported to public health authorities, and patients should be informed that infection with a different serotype in the future increases the risk of severe disease.
- Published on
Infectious Disease and Microbiology – Cytomegalovirus Infection
Cytomegalovirus (CMV) infection refers to a spectrum of diseases caused by Cytomegalovirus, a DNA virus belonging to the herpesvirus family (Human Herpesvirus 5). Like other herpesviruses, CMV establishes lifelong latency after primary infection and may reactivate during periods of immunosuppression. Infection may be asymptomatic, present as a mononucleosis-like syndrome, or cause severe tissue-invasive disease, particularly in immunocompromised individuals.
CMV is a common pathogen worldwide. In the United States, the incidence among individuals aged 10–49 years is approximately 1.6 infections per 100 susceptible persons per year. About 27,000 new infections occur annually among seronegative pregnant women. Seroprevalence increases with age and is higher among individuals of lower socioeconomic status. Approximately 60% of people older than 6 years in the US are seropositive, and rates exceed 90% in individuals over 80 years of age.
Immunosuppression is the primary risk factor for severe CMV disease. In solid organ transplantation (SOT), the highest risk occurs when a CMV-seronegative recipient receives an organ from a CMV-seropositive donor (CMV D+/R– mismatch). In allogeneic hematopoietic stem cell transplantation, higher risk occurs when a CMV-seropositive recipient receives a graft from a seronegative donor (CMV D–/R+). Lung, small intestine, and pancreas transplant recipients are at particularly high risk, followed by liver and heart transplant recipients, while kidney recipients have lower risk. Additional risk factors include use of lymphocyte-depleting agents (e.g., anti-thymocyte globulin), acute allograft rejection, graft-versus-host disease, and HIV infection with CD4 counts below 50 cells/mm³. CMV is also associated with bone marrow transplantation, AIDS, and hematologic malignancies such as lymphoma and leukemia.
Pathophysiologically, primary infection in transplant recipients occurs through donor transmission (CMV D+/R–), while reactivation occurs when latent virus in a seropositive recipient becomes active during immunosuppression. CMV infection may be asymptomatic (subclinical infection) or symptomatic. Symptomatic infection is classified as CMV syndrome (fever and systemic symptoms without organ involvement) or tissue-invasive disease affecting specific organs. The transplanted organ is particularly vulnerable to tissue-invasive disease.
In immunocompetent individuals, CMV infection is often asymptomatic or presents as a mononucleosis-like illness with fever, malaise, myalgias, lymphadenopathy, splenomegaly, and sometimes rash. In immunosuppressed patients, CMV syndrome presents with fever, malaise, myalgias, and arthralgias. Tissue-invasive disease may involve multiple organs. CMV colitis is common and presents with abdominal pain and diarrhea. CMV gastritis may cause odynophagia, nausea, and vomiting. Pneumonitis presents with fever, cough, and dyspnea and is particularly severe in bone marrow transplant recipients. Hepatitis and myocarditis may occur. CMV retinitis, especially in advanced HIV infection, causes progressive visual loss and characteristic peripheral retinal lesions with yellow-white exudates and hemorrhage. Meningoencephalitis presents with headache, photophobia, and lethargy. Spinal cord involvement (myelitis or polyradiculitis) may cause back pain and ascending weakness, particularly in HIV-infected patients.
Laboratory findings may include anemia, thrombocytopenia, and atypical lymphocytosis. CMV IgG indicates prior exposure and latent infection; IgM may indicate acute infection or reactivation but is often unreliable in immunosuppressed individuals. Because of rapid turnaround time and high sensitivity, nucleic acid amplification testing (real-time PCR) and pp65 antigenemia assays are now preferred diagnostic tools. Antigenemia testing detects CMV pp65 protein in leukocytes but is less useful in neutropenic patients. Viral culture may demonstrate cytopathic effects after several weeks; shell vial assays provide results within 24–48 hours. Drug resistance should be suspected if viral load fails to decline after two weeks of full-dose therapy. Mutations in UL97 are associated with ganciclovir resistance, while UL54 mutations may confer cross-resistance to ganciclovir, foscarnet, and cidofovir.
Imaging findings depend on organ involvement. CMV pneumonitis shows interstitial infiltrates on chest imaging. CMV colitis may show bowel wall thickening on CT. Brain MRI in CMV encephalitis may demonstrate periventricular inflammation or meningeal enhancement. Tissue biopsy reveals characteristic cytopathic changes with large intranuclear inclusions surrounded by a clear halo (“owl’s eye” appearance), sometimes accompanied by cytoplasmic inclusions.
The differential diagnosis varies by presentation and includes infectious mononucleosis, toxoplasmosis, acute HIV infection, human herpesvirus 6 infection, viral hepatitis, viral gastroenteritis, cryptosporidiosis, and Clostridioides difficile infection.
In immunocompetent individuals, CMV syndrome is usually self-limited and does not require treatment. In immunocompromised patients, antiviral therapy is essential. First-line therapy is intravenous ganciclovir (5 mg/kg twice daily, dose-adjusted for renal function). Oral valganciclovir (900 mg twice daily) may be used for mild-to-moderate disease and as step-down therapy. For CMV retinitis in AIDS patients, systemic therapy combined with intraocular ganciclovir implant improves outcomes. Second-line agents for ganciclovir-resistant CMV include foscarnet and cidofovir. High-dose ganciclovir may be considered in low-level resistance. Reduction of immunosuppressive therapy is recommended when possible, and CMV immunoglobulin may be used in severe disease, particularly pneumonitis.
Patients receiving treatment should undergo weekly monitoring of viral load. Therapy typically continues for at least 2–4 weeks and preferably until viremia clears, with additional maintenance therapy in high-risk individuals. Prognosis varies with immune status; severe disease such as pneumonitis or encephalitis carries high mortality. CMV colitis may lead to perforation and peritonitis, myocarditis may cause heart failure, and in HIV-infected patients CMV may cause cauda equina syndrome. In transplant recipients, indirect CMV effects include acute rejection, chronic graft failure, bronchiolitis obliterans, accelerated vasculopathy, vanishing bile duct syndrome, and chronic kidney injury.
Congenital CMV infection is a major cause of congenital anomalies in industrialized countries and may result in fetal loss, neonatal jaundice, anemia, and central nervous system damage. There is currently no available CMV vaccine.
- Published on
Infectious Disease and Microbiology – Cystitis
Cystitis is a lower urinary tract infection (UTI) involving the bladder and occurs in both women and men. It is one of the most common bacterial infections encountered in clinical practice. In the United States, approximately 7 million cases of UTI occur annually. About one-third of women up to 24 years of age will experience at least one episode requiring antibiotic treatment. Furthermore, nearly half of women whose uncomplicated UTIs resolve spontaneously will develop a recurrence within one year. Cystitis is significantly more prevalent in young women than in young men (approximately 20% vs. 0.5% between ages 16–35 years).
Risk factors vary by population. In premenopausal women, risk factors include prior UTI, congenital urinary tract abnormalities, frequent or recent sexual activity, use of spermicides, diaphragm contraception, increasing parity, diabetes mellitus, pregnancy, obesity, neurologic disease, and conditions requiring indwelling or repetitive bladder catheterization. In postmenopausal women, vaginal atrophy, incomplete bladder emptying, pelvic organ prolapse (rectocele, cystocele, urethrocele, uterovaginal prolapse), diabetes, and prior UTIs increase risk. In men, prostatic hypertrophy, urethral obstruction, catheterization, urinary incontinence, and prior urologic surgery are important risk factors.
The most common etiologic agent is Escherichia coli, responsible for more than 80% of cases. Other Enterobacteriaceae include Proteus mirabilis, Klebsiella pneumoniae, Enterobacter species, Citrobacter species, Serratia species, Salmonella species, and Morganella morganii. Non-Enterobacteriaceae such as Pseudomonas aeruginosa may also be involved, particularly in healthcare-associated infections. Among gram-positive organisms, Staphylococcus saprophyticus is a notable cause, especially in young sexually active women. The emergence of extended-spectrum β-lactamase (ESBL)-producing E. coli and other resistant uropathogens is a growing concern in both community and hospital settings.
Clinically, patients typically present with dysuria, urinary frequency, urgency, abrupt onset of symptoms, and sometimes turbid, foul-smelling, or bloody urine. Suprapubic tenderness may be present, and approximately 10% report low back discomfort. Children may present with nonspecific symptoms such as fever, vomiting, or diarrhea. Elderly patients often exhibit minimal or atypical symptoms.
Physical examination may reveal suprapubic tenderness but is otherwise often unremarkable. Diagnosis is supported by laboratory evaluation. Urinary dipstick testing may detect leukocyte esterase and nitrites. Urine microscopy can demonstrate pyuria and bacteriuria. Urine culture confirms the diagnosis and guides antimicrobial therapy. Pregnancy testing should be considered in women of childbearing age. Imaging is generally unnecessary in uncomplicated cases but ultrasonography may be indicated in men, in women who fail to respond to therapy, or in cases of recurrent infection not clearly related to sexual activity.
The differential diagnosis includes infectious conditions such as pyelonephritis (upper UTI), urethritis, vaginitis, and asymptomatic bacteriuria, as well as noninfectious causes including interstitial cystitis, urolithiasis, bladder tumor, and chronic prostatitis or chronic pelvic pain syndrome.
Acute uncomplicated cystitis is treated with short-course antimicrobial therapy. Common regimens include trimethoprim-sulfamethoxazole for three days, trimethoprim alone for three days, fluoroquinolones such as ciprofloxacin or levofloxacin for three days, fosfomycin as a single oral dose, or nitrofurantoin for five to seven days. Selection should be guided by local resistance patterns. In pregnancy, amoxicillin, nitrofurantoin (avoided near term due to risk of neonatal hemolysis), cefpodoxime, or fosfomycin may be used. Recurrent cystitis may be managed with continuous low-dose prophylaxis using agents such as trimethoprim, trimethoprim-sulfamethoxazole, nitrofurantoin, or fluoroquinolones, though this strategy must be individualized due to increasing antimicrobial resistance.
Complementary approaches have been studied. Certain probiotics (e.g., Lactobacillus strains) may reduce recurrence rates. Cranberry products have been suggested to reduce bacterial adherence and may modestly lower recurrence in women with recurrent UTIs. Methenamine salts may be beneficial in short-term prophylaxis in patients without structural urinary abnormalities. Phenazopyridine may relieve dysuria but does not treat infection and carries potential adverse effects such as hemolytic anemia.
The prognosis for acute uncomplicated cystitis is excellent with appropriate antibiotic therapy. However, recurrent episodes are common, especially in patients with underlying risk factors. Complications may include urethritis, progression to pyelonephritis, and psychological distress associated with recurrent infection. Preventive measures include good hygiene, avoidance of spermicides and diaphragms, careful monitoring during pregnancy, and glycemic control in patients with diabetes.
- Published on
Infectious Disease and Microbiology – Cysticercosis
Cysticercosis is a parasitic infection caused by the larval stage of the pork tapeworm, Taenia solium. Humans develop cysticercosis when they ingest tapeworm eggs, which hatch into larvae (oncospheres) that penetrate the intestinal wall and disseminate hematogenously to tissues. The larvae develop into cysticerci—fluid-filled cysts—within various organs. The central nervous system (CNS) is most commonly affected, a condition known as neurocysticercosis. Other commonly involved sites include skeletal muscle, subcutaneous tissue, heart, and eyes. Many infections remain asymptomatic, but symptomatic disease can result in significant neurologic morbidity.
Cysticercosis occurs worldwide and affects more than 50 million people. It is highly prevalent in Central and South America, sub-Saharan Africa, India, Southeast Asia, and parts of Eastern Europe. In endemic villages, 10% or more of the population may be seropositive, and up to 6% may harbor adult intestinal tapeworms at any time. Neurocysticercosis is the most common parasitic infection of the CNS and is the leading cause of seizures in many developing countries. In Mexico, for example, up to 10% of brain CT scans in some institutions show evidence of neurocysticercosis.
Risk factors include consumption of raw or undercooked pork, poor sanitation, close proximity to pigs (particularly where pigs have access to human feces), and inadequate hand hygiene leading to fecal–oral transmission. Humans are the definitive host for the adult intestinal worm, which resides in the small intestine and sheds eggs or gravid proglottids in stool. Pigs serve as intermediate hosts when they ingest eggs, allowing larvae to encyst in muscle tissue. Humans acquire intestinal tapeworm infection by eating undercooked pork containing cysticerci. In contrast, cysticercosis occurs when humans ingest eggs directly—either through contaminated food or water, poor hygiene, or autoinfection in individuals already infected with the adult worm.
In neurocysticercosis, neurologic symptoms primarily result from the inflammatory response that occurs when cysticerci degenerate. Mass effect may also occur when cysts obstruct cerebrospinal fluid flow, leading to hydrocephalus and increased intracranial pressure. Extraneural disease may involve the eyes (commonly vitreous humor or subretinal space), causing visual disturbance or chronic uveitis. Subcutaneous cysts present as firm nodules that may become inflamed. Skeletal muscle involvement is usually asymptomatic but may produce muscular pseudohypertrophy in heavy infestations. Cardiac involvement can lead to conduction abnormalities.
Clinical manifestations vary widely. Patients may present with chronic headache, seizures, focal neurologic deficits, altered mental status, nausea, vomiting, visual disturbances, insomnia, anorexia, or weight loss. Seizures are the most common presentation. Physical examination often reveals absence of fever, nonfocal neurologic findings, papilledema, hyperreflexia, or visual deficits. Intraocular larvae may be visualized on ophthalmoscopy. Subcutaneous nodules resembling sebaceous cysts may be palpable.
Diagnosis relies on imaging and serologic testing. Brain CT and MRI are key diagnostic tools; MRI is especially useful for detecting brainstem or ventricular cysts. Imaging may show viable cysts, ring-enhancing lesions, or calcified granulomas. Soft tissue radiographs may reveal calcified cysts in muscle. Serologic testing includes enzyme-linked immunoelectrotransfer blot (EITB), which has high sensitivity and specificity in patients with multiple cysts, though sensitivity is lower with single lesions. Stool examination may identify ova and parasites if intestinal infection is present. Lumbar puncture findings are nonspecific but may show lymphocytosis, elevated protein, and decreased glucose in cases with significant inflammation. Biopsy of subcutaneous nodules can confirm the diagnosis.
The differential diagnosis of neurocysticercosis includes brain abscess, neoplasms, tuberculosis, toxoplasmosis, encephalitis, stroke, intracranial hemorrhage, meningitis, and other causes of seizures or focal neurologic deficits.
Treatment includes antiparasitic therapy combined with anti-inflammatory management. First-line therapy consists of praziquantel for two weeks along with corticosteroids (prednisone or dexamethasone) to control inflammation. Albendazole is an effective alternative and is commonly used. Anticonvulsant therapy (e.g., phenytoin, phenobarbital, or benzodiazepines for acute seizures) is required for seizure control. Neurosurgical interventions, such as ventricular shunting or burr hole procedures, may be necessary for obstructive hydrocephalus or elevated intracranial pressure. Ophthalmologic or neurosurgical referral is indicated for ocular or severe CNS involvement.
Prognosis is generally excellent with appropriate diagnosis and treatment, although some patients require long-term anticonvulsant therapy due to persistent calcified lesions. Complications include status epilepticus, stroke, intracranial herniation, hydrocephalus requiring shunt placement, shunt-related complications, and permanent vision loss.
Prevention focuses on improved sanitation, hand hygiene, proper cooking of pork, freezing pork to kill cysticerci, strict meat inspection, treatment of infected individuals, and control of infection in pig populations. Education regarding seizure management and avoidance of high-risk activities after seizures is essential for affected patients.
