Rubella (MMR) exanthem causes. WinnerzKlub represent.

1. G R O U P : W I N N E R Z K L U B
RUBELLA (GERMAN
MEASLES)

2. RUBELLA, WHAT IS IT?
• It is an acute viral infection of children & adults.
• Characterized by rash, fever, & lymphadenopathy & has a broad
spectrum of other possible manifestations.
• A high percentage of infections are mostly subclinical.
• The illness can resemble a mild attack of measles (rubeola) & can
cause arthritis, especially in adults.
• It causes exanthem in the non-immunised.
• Rubella during pregnancy can lead to a fetal infection with
malformations in high proportion of infected fetuses.

3. RUBELLA RASH:

4. ETIOLOGIC AGENT:
• Rubella virus, a togavirus, is closely related to the
alphavirus.
• Unlike these agents, however, it does not require a
vector for transmission.
• The rubella virion is composed of an inner helical capsid
of RNA & protein that is surrounded by a lipid-containing
envelope.

5. PATHOPHYSIOLOGY:
• Little is known as disease is self-limited.
• Like that of measles, the rash of rubella is immunologically mediated: its onset
coincides with the development of specific antibodies.
• Viremia can be demonstrated for about a week before & ends within a few days
after onset of rash.
• Proposed mechanisms of fetal damage include mitotic arrest of cells, tissue
necrosis without inflammation, and chromosomal damage.
• The growth of the fetus may be retarded.
• Other findings: decreased megakaryocytes in the bone marrow, extramedullary
hematopoiesis, & interstitial pneumonia.

6. CLINICAL FEATURES:
• Rubella is spread by respiratory droplet.
• Infectivity is from 10 days before to 2 weeks after onset of rash.
• The incubation period is 15-20 days.
• In childhood, most cases are subclinical, although c/f may include fever,
maculopapular rash spreading from the face, & lymphadenopathy.
• Complications (rare): thrombocytopenia & hepatitis.
• Encephalitis & haemorrhage are occasionally reported.
• In adults, arthritis involving hands & knees is relatively common, especially in
women.
• In pregnancy, severe congenital disease may result. Even if normal at birth, the
infant has an increased risk of other diseases developing later, e.g. DM.

7. DIAGNOSIS:
• The most commonly used test is an enzyme-linked immunosorbent
assay (ELISA) for IgG & IgM antibodies.
• Diagnosed by the documentation of a ≥four-fold rise in the titer of IgG
antibodies.
• However, false-negative & -positive IgM reactions are sometimes
obtained.
• Congenital rubella is diagnosed by:
• the isolation of rubella virus,
• the detection of IgM antibodies in a single serum sample,
• and/or the documentation of either the persistence of rubella antibodies in serum
beyond 1 year of age
• Or rising antibody titer anytime during infancy in an unvaccinated child.

8. DIFFERENTIALS:
• Other diseases which may mimic rubella:
• Toxoplasmosis
• Scarlet fever
• Modified measles
• Roseola
• Fifth disease (erythema infectiosum due to parvovirus B19)
• And enteroviral infection.

9. RISK OF CONGENITAL
MALFORMATION:
Stage of gestation: Likelihood of malformations:
1-2 months 65-85% chance of illness, multiple
defects /spontaneous abortion
3 months 30-35% chance of illness, usually a
single congenital defect (most
frequently deafness, cataract,
glaucoma, mental retardation or
congenital heart disease, especially
pulmonary stenosis or patent ductus
arteriosus)
4 months 10% risk of congenital defects, most
commonly deafness
> 20 wks Occasional deafness

10. PREVENTION:
• The present vaccination strategy is to immunize all infants at 12-15 months of
age with measles-mumps-rubella (MMR) vaccine (live attenuated).
• And to administer a 2nd dose during childhood (preferentially at 4 years of age).
• Rubella vaccine may also be administered to anyone who is thought to be
susceptible to the infection & is not pregnant.
• It is important that hospital workers of either sex be immune to rubella so that
nosocomial transmission is avoided.
• On occasion, rubella vaccine may cause arthralgia or arthritis, especially in
young women.
• In view of the risks of congenital rubella syndrome, all women of child-bearing
age should also be tested for rubella & vaccinated if seronegative.

11. THE END:
• Sa oji_
• References:
• Davidson’s Principles & Practice of Medicine, 22nd Ed.
• https://thenativeantigencompany.com/products/rubella-virus-
nucleoprotein-strain-f-therien/
• http://clipart-library.com/animated--book.html
• Harrison’s Principles of Internal Medicine, 14th Ed.