II. Epidemiology
III. Pathophysiology
- Rubella is the only member of the Genus rubivirus in the Togaviridae family
- Rubella is a pleomorphic RNA Virus that is among the TORCH Viruses (causing serious congenital disease)
-
Togaviridae are otherwise primarily composed of Arboviruses (arthropod-borne), Alphaviruses that cause Encephalitis
- Togaviridae are enveloped, Icosahedral, single stranded RNA Viruses
- Togaviridae are Message Sense RNA Viruses (Positive Stranded, +ssRNA)
- Message sense RNA (+ssRNA) are identical to Messenger RNA (mRNA)
- Like mRNA, +ssRNA may be immediately translated by host ribosomes into Protein
- Rubella 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
IV. Symptoms
- Subclinical in 50% of cases
- Known also as "Three Day Measles" (shorter, more mild course than Measles)
- Viral prodrome precedes the rash (described below)
V. Signs
- Mild Fever
- Significantly tender Lymphadenopathy
- Retroauricular, posterior auricular, Occipital Lymphadenopathy
- Rash
- Red Maculopapular rash with areas of confluence, Flushing
- Distribution and Evolution
- Initially, exanthem may cover Soft Palate and face
- Later, rash begins on face and spreads to cover trunk
- Rash usually clears by Day 3 (hence the name: Three Day Measles)
- Associated findings
- Mild Pruritus
VI. Differential Diagnosis
- See Rash in the Febrile Patient
-
Mononucleosis
- Also causes significant Lymphadenopathy
-
Measles
- Conjunctivitis and Koplik Spots
- More severe course
VII. Complications: Congenital Rubella Syndrome
- Rubella is one of the TORCH Viruses
- Congenital Rubella primarily affects 3 systems
- Cardiovascular
- Patent Ductus Arteriosus
- Interventricular septal defect
- Pulmonary artery stenosis
- Eye
- Congenital Cataracts
- Chorioretinitis
- Neurologic
- Cardiovascular
- 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
VIII. Complications: Miscellaneous
-
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
- Primarily seen in young women
IX. Management: High risk exposure occurs early in pregnancy
- Consider therapeutic abortion
- Give Rubella Immunoglobulin
X. Prevention
-
Primary Series
- MMR Vaccine at Ages 12-15 months, and 4-6 years
-
Preconception Counseling
- Test Rubella Immunity
- Vaccinate women not immune to Rubella