› Pregnancy-specific risks and management
› Susceptibility and transmission risk
› Approximately 35 to 40% of pregnant women are seronegative and susceptible
› Household exposure carries 50% secondary attack rate
› Classroom or occupational exposure carries 20 to 50% infection risk
› Fetal risk by gestational age
› Fetal loss risk 8 to 17% with infection before 20 weeks gestation
› Risk decreases significantly after 20 weeks
› Hydrops fetalis from fetal erythroid suppression causing severe anemia
› Diagnostic approach in pregnancy
› Maternal parvovirus B19 IgM and IgG serology at exposure
› IgG positive alone confirms immunity; no fetal risk
› Parvovirus PCR if serology equivocal or immunocompromised
› Monitoring protocol
› Fetal ultrasound with MCA Doppler every 1 to 2 weeks for 8 to 12 weeks after acute infection
› Maternal-fetal medicine referral for any confirmed acute infection
› Intrauterine transfusion if MCA PSV > 1.5 MoM or hydrops present
› Antiviral and drug safety
› No antiviral therapy available
› Acetaminophen preferred for symptom relief in pregnancy
› Avoid NSAIDs in third trimester due to premature ductal closure risk
› IVIG considered in selected cases in coordination with MFM
› Older adult considerations
› Arthropathy burden
› Symmetric polyarthritis more common and more prolonged in older adults
› May persist months and mimic rheumatoid arthritis
› ANA and rheumatoid factor testing to exclude RA when arthritis persistent
› Immunosenescence
› Blunted antibody response may cause false negative IgM
› PCR preferred if serology inconclusive and clinical suspicion high
› Chronic anemia baseline
› Aplastic crisis superimposed on baseline anemia of chronic disease can be severe
› Lower transfusion threshold appropriate given reduced cardiac reserve
› NSAID safety in older adults
› Renal function assessment before prescribing NSAIDs for arthropathy
› Proton pump inhibitor co-prescription for GI protection
› Avoid NSAIDs in significant renal impairment or active peptic ulcer disease
› Pediatric-specific considerations
› Classic presentation epidemiology
› Peak incidence in school-age children 5 to 15 years
› Most common exanthem in this age group during epidemic periods
› Myocarditis risk in young children
› Median age of myocarditis presentation approximately 32 months in 2024 outbreak
› Higher mortality burden than adult myocarditis from parvovirus B19
› Low threshold for troponin and ECG in febrile young child with tachycardia and rash
› Aplastic crisis in pediatric hemoglobinopathy patients
› Sickle cell disease children most vulnerable
› CBC mandatory; transfusion with sickle cell negative matched blood
› Weight-based transfusion: 10 to 15 ml/kg pRBC over 2 to 4 hours
› Antipyretic dosing
› Acetaminophen 15 mg/kg per dose every 4 to 6 hours; maximum 5 doses per 24 hours
› Ibuprofen 10 mg/kg per dose every 6 to 8 hours in children > 6 months
› Avoid aspirin in children due to Reye syndrome risk
› IVIG in pediatric myocarditis
› IVIG 2 g/kg IV over 10 to 24 hours; evidence from small pediatric series
› Hemodynamic monitoring required during infusion
› School exclusion guidance
› Child is contagious during prodromal phase before rash
› Once rash present, no longer contagious; school attendance generally permitted
› Alert school and daycare to notify pregnant contacts for serological testing
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