II. Epidemiology
III. Pathophysiology
- Etiology: Human Parvovirus (B19)
- Single-stranded DNA virus
- Inactivated by heat,detergents (No lipid envelope)
- Targets P Antigen receptor on erythroid progenitors
- Bone Marrow
- Fetal liver and Umbilical Cord
- Peripheral blood
- Transmission modes
- Exposure to infected respiratory droplets or blood
- Vertical transmission from mother to fetus
- Transmission rates
- Living with infected person: 50%
- Teacher, daycare worker of infected children: 20-30%
- Transmission timing
- Not contagious after rash onset
- May Return to School once rash appears
IV. Course
- Incubation: 4-14 days (21 days in some cases)
- Infectivity: Prior to rash onset
V. Symptoms (more severe in adults)
- Children are often asymptomatic
- Prodromal symptoms (precede rash by 2 weeks)
- Low grade fever
- Gastrointestinal Upset
- Coryza
- Headache
- Pharyngitis
- Subsequent symptoms
- Pruritic exanthem in children (see below)
- Myalgia and Arthralgia (see below)
VI. Signs: Rash (more common in children)
- Stage 1 (onset within 2 weeks of prodromal symptoms)
- Cheek erythema ("Slapped Cheek") appearance on face
- Circumoral pallor
- Facial erythema spares the chin and periorbital region
- Stage 2 (follows facial rash by 1-4 days)
- Lacy-reticular maculopapular (blotchy) rash
- Involves trunk and extremities for 1-6 weeks
- Rash is pruritic
- Provocative factors (may result in recurrence)
- Sunlight exposure
- Heat
- Exercise
VII. Signs: Polyarthralgia or Polyarthritis
-
Incidence in Parvovirus infection
- Children: 8%
- Adults: 60% (twice as likely in women than men)
- Rheumatoid-like joint involvement
- Hand involvement (most common in adults, bilateral)
- Metacarpophalangeal joints (MCP joints)
- Proximal interphalangeal joints (PIP joints)
- Wrist involvement
- Leg Involvement (most common in children)
- Knee involvement (82% of children)
- Ankle Joint involvement
- Hand involvement (most common in adults, bilateral)
- Arthralgia and Arthritis course
- Associated conditions
VIII. Differential Diagnosis
- Rubella
- Atypical Rubeola
- Drug-induced rashes
- Other Viral Exanthem
IX. Labs: Adults with persistent Polyarthritis
- Anti-B19 IgM Antibody
- Test Sensitivity: 89%
- Test Specificity: 99%
- Elevated for 2-3 months after acute infection
- Parvovirus DNA by PCR testing
- Similar sensitivity to IgM testing
- Indicated in aplastic crisis or if Immunocompromised
- Persistence suggests chronic Parvovirus infection
-
Peripheral Blood Smear or Bone Marrow findings
- Giant pronormoblasts
- Non-specific finding
- Variably present serologies at low to moderate titer
- Rheumatoid Factor (RF)
- Antinuclear Antibody (ANA)
- Anti-dsDNA
- Anti-ssDNA
- Anti-cardiolipin Antibody
X. Management: Exposure in Pregnancy
- Pregnant women should avoid contact with Parvovirus
- Risk of transmission to fetus: 30%
- Risk of Hydrops fetalis with findings in newborn:
- Severe Anemia
- High output cardiac failure
- Extramedullary hematopoiesis
- Risk of fetal loss (2-6%)
- Risk of congenital infection syndrome
- Rash
- Anemia
- Hepatomegaly
- Cardiomegaly
- Risk per timing of exposure in pregnancy
- Highest risk: Second trimester
- Lowest risk: First trimester
- Child with Erythema Infectiosum does not need isolation
- May attend school and daycare once rash appears
- Hospital isolation is not needed
- Evaluation and mangement post-exposure in pregnancy
- Labs to confirm maternal Parvovirus infection
- Parvovirus B19 IgM or
- Parvovirus B19 IgG seroconversion
- Monitoring pregnancy if testing positive
- Serial Ultrasounds weekly for 10-12 weeks
- Fetal hydrops present by Ultrasound
- Fetal blood sampling
- Fetal transfusion as needed
- Labs to confirm maternal Parvovirus infection
XI. Complications: General
XII. Complications: Parvovirus associated erythrocyte aplasia
-
General
- May be life threatening
- Monitor closely for possible transfusion
- Transient aplastic crisis in chronic Anemia
- Chronic Bone Marrow suppression in Immunocompromised
- Malignancy
- Transplant recipient
- Human Immunodeficiency Virus
- Course
- Typical full recovery within 2 weeks
XIII. References
- Klippel (1997) Primer Rheumatic Diseases, p. 201
- Allmon (2015) Am Fam Physician 92(3): 211-6 [PubMed]
- Katta (2002) Dermatol Clin 20:333-42 [PubMed]
- Naides (1998) Rheum Dis Clin North Am 24(2):375-401 [PubMed]
- Qari (1996) Postgrad Med 100(1):239-52 [PubMed]
- Sabella (1999) Am Fam Physician 60(5): 1455-60 [PubMed]
- Servey (2007) Am Fam Physician 75:373-7 [PubMed]
- Siegel (1996) Am Fam Physician 54(6):2009-15 [PubMed]
- Takahashi (1998) Int Rev Immunol 17(5-6):309-21 [PubMed]
- Young (2004) N Engl J Med 350:586-97 [PubMed]
- Ytterberg (1999) Curr Opin Rheumatol 11:275-80 [PubMed]