Kembara Xtra - Medicine - Human Parvovirus B19 Infection The sixth disease, morbus quintus, erythema infectiosum, is brought on by human parvovirus B19. ● Transient aplastic crisis (TAC) is more common in people with high RBC turnover (sickle-cell anemia, spherocytosis, thalassemia). Pure red cell aplasia may cause transfusion-dependent anemia in immunocompromised people. Arthritis and arthralgias are frequent side effects of parvovirus B19 infection in immunocompetent people. ● Hematologic, lymphatic, immune, musculoskeletal, exocrine, cardiovascular, renal, and hepatobiliary systems are among those that are affected. Pregnancy Considerations Acute infection that has been documented during pregnancy should trigger a referral to a specialist in maternal-fetal medicine. Acute maternal infection has a 30% probability of transmitting to the fetus; this risk may rise during epidemic outbreaks. The risk of fetal death is highest before 20 weeks of gestation and is thought to occur in 5–10% of cases of fetal infection. Epidemiology Common in young children; asymptomatic The death rate for erythema infectiosum is quite low. Erythema infectiosum is most common between the ages of 4 and 12. Both men and women are equally impacted. There is no known ethnic preference; women are more prone to develop postinfectious arthritis. Infections frequently happen between late winter and early summer in temperate climates, and local outbreaks can happen every two to five years. Parvovirus B19 DNA has been found in human remains that are more than 6900 years old, and the prevalence of erythema infectiosum decreased as a result of the COVID pandemic's physical and social exclusion (2). Prevalence Serologic research indicates that parvovirus B19 infection is very prevalent. In Western Europe and the United States, 2-15% of children by age 5 have IgG antibodies. By the age of >40, this gradually rises to 70–85% seropositivity. Pathophysiology and Etiology Parvovirus B19, the only parvovirus known to infect humans, was first identified in 1974. It is a tiny (20 to 25 nm), nonenveloped, single-stranded DNA virus belonging to the Erythrovirus genus of the Parvoviridae family. Human infection is spread through respiratory, transfusion-related, and vertical transmission. The natural host of B19 is the human erythroid progenitor. The incubation period typically lasts 4 to 14 days, but it sometimes can go up to 21 days. Coryza, a fever, a headache, and nausea are prodromal symptoms. Infection, however, can not show any symptoms. After the first infection, rashes and joint problems typically appear 2 to 3 weeks later. These are connected to viral clearance (and a lower risk of transmission) and are assumed to be the result of immunological complex development. Patients with parvovirus B19 infection are most contagious 5 to 10 days after exposure, which is well before the usual rash appears. RBC synthesis is decreased by erythroid progenitor cell cytotoxic infection. Genetics People who lack the erythrocyte P antigen (about 1 in 200,000) are immune to infection. RISK ELEMENTS Highest secondary attack rates are for daycare providers and school staff who come into contact with infected children. Secondary attack rates are 20-50% for school-related epidemic and nonimmune household contacts. Spherocytosis, sickle-cell anemia, and thalassemia are diseases that increase RBC turnover and raise the likelihood of a brief aplastic crisis. Pure red cell aplasia and chronic anemia are more common in those with immunodeficiency (congenital, caused by HIV or cancer), which affects up to 40% of pregnant women and has a 1.5% seroconversion rate annually. Prevention Barrier precautions, hand washing, cough/sneeze hygiene, and respiratory spread Droplet precautions are advised for individuals with transitory aplastic crises and those who are immunosuppressed. It is challenging to completely avoid exposure because the peak of contagiousness occurs before the start of the usual rash. If appropriate isolation procedures are taken, there is no appreciable risk of infection based on occupational exposure. Exclusion from the workplace is not advised or necessary. There isn't a preventative vaccine accessible right now. Accompanying Conditions Nondegenerative arthritis - In children, joint complaints are rare and usually affect the knees and ankles (joint involvement may be symmetrical or asymmetrical). - Adults are far more likely to experience joint symptoms, which are typically symmetrical, involve the hands more frequently, and involve bigger joints less frequently. Women have joint symptoms more frequently than men do. Joint problems may last for months or years, although they usually go away in 3 weeks. Women are more likely to experience symptoms that last longer. Regular radiography is not required. Patients with accelerated RBC turnover (sickle cell disease, spherocytosis, thalassemia) or decreased RBC production (iron deficiency anemia) are at risk for transient aplastic crisis. - demonstrates signs of anemia such as fatigue, weakness, lethargy, and pallor; they may also have dyspnea or shortness of breath. - Aplastic events are normally self-limited but can be fatal. In general, reticulocytes return in 7–10 days, and a full recovery takes 2–3 weeks. - Fever is the most prevalent symptom in children with sickle cell hemoglobinopathies and hereditary spherocytosis (73% of the time); rash is less common in these patients. Chronic anemia is a condition that affects people who are immunocompromised due to HIV, cancer, or organ transplants and is characterized by a poor antibody response. Patients may be transfusion dependent. Fetal/neonatal infection (1) - Mothers who are infected have a 30% risk of the virus spreading transplacentally. - Vertical transmission is still possible even if up to 50% of pregnant women with the infection may not show any symptoms. - If a pregnant woman has symptoms that are compatible with parvovirus B19 infection, check her IgM and IgG levels. - Pregnant women who have been exposed to people who have the acute parvovirus B19 should be tested. If IgG is positive and IgM is negative, the patient is thought to be immune and no additional treatment is required. If IgM and IgG testing results are negative, repeat the procedure to check for seroconversion. If IgM is positive, further testing should be done to rule out acute infection (false-positive result). - Infections during pregnancy can cause fetal death in 5–10% of cases, whether or not there is fetal hydrops. - Infection with parvovirus B19 may be the cause of 8–20% of cases of nonimmune fetal hydrops. - The fetal bone marrow is most affected. Shortened RBC survival results in anemia and (perhaps) high-output cardiac failure. Fetal hypoalbuminemia, myocarditis, hepatitis, and placentitis can all have additional side effects. - The risk of fetal loss is highest in the first trimester (19%) and gradually reduces throughout pregnancy (15% between 13 and 20 weeks and 6% beyond 20 weeks). - If fetal hydrops is present, intrauterine fetal red blood cell transfusion can reduce fetal loss rate. - Infants who have received intrauterine transfusions run the risk of experiencing psychomotor development delays. Parvovirus has also been linked to the syndrome of the gloves and socks. - Symmetrical painful erythema and edema of the hands and feet are typically present in younger adults. - Eventually leads to skin sloughing, petechiae, purpura, vesicles, and bullae - May not have any additional symptoms but may experience fevers or arthralgias - Usually goes away without leaving any scars in 1 to 3 weeks Diagnosis: Arthralgias and rash may appear after a prodrome of fever, coryza, pharyngitis, headache, rhinorrhea, and nausea. Arthralgias may linger for many weeks or longer. clinical assessment The nasolabial folds are not affected by the typical "slapped cheek" appearance. After 1 to 4 days, a secondary lacy, reticular rash that may last 1 to 6 weeks appears across the torso, buttocks, and limbs. B19 may present as painful pruritic papules and purpura on the hands and feet (glove and sock distribution). This secondary rash may be pruritic and recurring, made worse by bathing, exercise, sun exposure, heat, or mental stress. Differential diagnosis: Rheumatoid arthritis, Systemic lupus erythematosus, Measles, Rubella, Enteroviral illness, and Drug Reaction Laboratory Results Initial examinations (lab, imaging) There is typically no need for routine lab tests. The sickness is minor and self-limiting, and the diagnosis is clinical. IgG and IgM serology in patients with immunocompetence B19-specific DNA polymerase chain reaction (PCR) testing for prenatal infection (through cord blood or amniotic fluid), as well as for people with persistent infection or those who have weakened immune systems. Anemia and reticulocytopenia are observed in patients with transitory aplastic crisis. IgG antibodies are detectable at the time of clinical recovery, while IgM antibodies are noted by day 3. PCR reveals viremia at high levels. To determine the risk to the fetus, pregnant women exposed to B19 must undergo serologic testing. Tests in the Future & Special Considerations Fetal or newborn infectionFollow IgG serology for the first year of life in newborns with negative B19 IgM results to rule out congenital B19. With hydrops fetalis, maternal serum -fetoprotein may rise. Serial fetal ultrasounds to check for ascites, pericardial effusion, oligohydramnios, cardiomegaly, and placental thickening in cases of acute maternal infection that have been described in the first trimester. It is advised to perform weekly Doppler US peak systolic velocity measurements on the middle cerebral artery to check for fetal anemia, heart failure, and the potential requirement for intrauterine transfusion (>1.5 MoM). A cerebral MRI to examine infected infants with protracted hydrops fetalis or hematocrit levels under 15% for CNS damage. Management No therapy is typically required. Some people can recover from chronic infections after stopping immunosuppressive therapy. Antiretroviral therapy and immunological reconstitution may be able to treat B19-associated anemia in HIV-positive patients. First Line of Medicine Antipyretics for fever and anti-inflammatory drugs for arthritic symptoms Second Line Intravenous immunoglobulin (IVIG) for B19-related refractory anemia or PRAC, especially in immunodeficient conditions, may necessitate RBC transfusions. Intrauterine RBC transfusions decrease mortality in situations of fetal hydrops. Referral A maternal-fetal medicine specialist should be consulted in cases of acute infection during pregnancy. Immunology or infectious disease experts may be able to help patients with chronic or unusual B19 infections. Admission Erythema infectiosum is often managed in an outpatient setting. Aplastic crisis is typically managed in a hospital setting and may call for RBC transfusions. Droplet isolation is appropriate for acute infections, brief periods of aplastic crisis, and chronic infections in immunocompromised patients when they occur in an inpatient setting. Periodic blood counts for anemic patients until they have reticulocyte recovery are part of follow-up patient monitoring It is typically self-limited. Joint symptoms often go away in 3 weeks, although they might continue for months or even years. In 20% of infections, the virus is not completely eliminated and the viremia lasts for several months to years. Complete aplastic crisis recovery takes two to three weeks. Complications Hepatitis may increase the risk of developing acute fulminant hepatic failure in conditions connected to B19 but where causality is unknown. Neurologic symptoms (meningoencephalitis, peripheral nervous system symptoms, myalgic encephalomyelitis/chronic fatigue syndrome), myocarditis, pericarditis, focal segmental glomerulosclerosis, nephrotic syndrome, membrane-proliferative glomerulonephritis Vasculitis, lymphocytic histiocytosis/hemophagocytic syndrome, Henoch-Schönlein purpura, idiopathic thrombocytopenic purpura,
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