II. Etiology
- Rubivirus (Togaviridae, pleomorphic RNA virus)
III. Epidemiology
IV. Pathophysiology: Transmission
- Person to person via oral droplets
- Vertical transmission (transplacental) results in congenital Rubella (90% risk in first trimester)
- Up to 60% transmission in susceptible family
V. Symptoms
- Subclinical in 50% of cases
- Known also as "Three Day Measles" for the shorter, more mild course
- Mild Upper Respiratory Infection symptoms
- Fever
- Pharyngitis
- Headache
VI. Signs
- Mild Fever
- Significantly tender Lymphadenopathy
- Retroauricular, posterior auricular, Occipital Lymphadenopathy
- Rash
- Initially, exanthem may cover Soft Palate and face
- Later, rash begins on face and spreads to cover trunk
- Maculopapular rash with areas of confluence, Flushing
- Mild Pruritus
- Rash usually clears by Day 3 (hence the name: Three Day Measles)
VII. Differential Diagnosis
- See Rash in the Febrile Patient
-
Mononucleosis
- Also causes significant Lymphadenopathy
- Measles
VIII. Complications
-
Encephalitis (1 case per 6,000 Rubella infections)
- Mortality from Encephalitis approaches 20%
- Arthritis (immune complex)
- Thrombocytopenia (1 case per 3000 Rubella infections)
- Immune-complex mediated Arthritis
- Congenital Rubella Syndrome
- Rubella is one of the TORCH Viruses
- Pregnant women should avoid Rubella exposure
- Avoid throughout pregnancy (especially early)
- Avoid exposure to infants with congenital Rubella
- Very high risk due to prolonged shedding
IX. Management: High risk exposure occurs early in pregnancy
- Consider therapeutic abortion
- Give Rubella Immunoglobulin
X. Prevention
-
Primary Series
- Immunization at Ages 12-15 months, and 4-6 years
-
Preconception Counseling
- Test Rubella Immunity
- Vaccinate women not immune to Rubella