Rubella (german measles)

Rubella (german measles)

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  G R OU P : W I N N E R Z K L U B RUBELLA (GERMAN MEASLES)
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  RUBELLA, WHAT ISIT? • 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.
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  RUBELLA RASH:
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  ETIOLOGIC AGENT: • Rubellavirus, 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.
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  PATHOPHYSIOLOGY: • Little isknown 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.
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  CLINICAL FEATURES: • Rubellais 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.
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  DIAGNOSIS: • The mostcommonly 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.
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  DIFFERENTIALS: • Other diseaseswhich may mimic rubella: • Toxoplasmosis • Scarlet fever • Modified measles • Roseola • Fifth disease (erythema infectiosum due to parvovirus B19) • And enteroviral infection.
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  RISK OF CONGENITAL MALFORMATION: Stageof 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
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  PREVENTION: • The presentvaccination 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.
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  THE END: • Saoji_ • 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.