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Measles. Measles. Highly contagious, acute exanthematous respiratory disease with a typical clinical picture and a characteristic enanthem: Koplik’s spots Family: Paramyxoviridae Genus: Morbillivirus. Classic measles: 1. Incubation. 10-14/7 - enters through resp epithelium /
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Measles • Highly contagious, acute exanthematous respiratory disease with a typical clinical picture and a characteristic enanthem: Koplik’s spots • Family: Paramyxoviridae • Genus: Morbillivirus
Classic measles: 1. Incubation • 10-14/7 - enters through resp epithelium / conjunctiva, replicates locally, spreads to regional lymphatic tissue - disseminates to RES via blood stream
Classic measles: 2. Prodrome • 3 /7 but up to 8/7 - appearance of symptoms : fever, malaise, anorexia and then cough, coryza, conjunctivitis - enanthem – Koplik’s spots
Koplik’s spots • Pathognomonic • “Grains of salt against a red back ground” • Occurs 48hr before rash • Often disappear with appearance of the rash
Classic Measles: 3. Exanthem • Maculopapular, blanching • Cranial-caudal progression • Face – neck, trunk and extremities • 3-4 / 7 later – fade, changes to brownish colour with fine desquamation
Classical measles: 4. Recovery • Clinical improvement after 48hrs • Rash fades after 3 days • No more fever after > 3/7 after rash appeared
Diagnosis of measles • WHO: laboratory diagnosis – IgM • IgM: can be undetectable on the first day of exanthem -- from 3rd day onwards for 30days • IgG: from day 7 of rash – peaks @ 14/7 • False +: Parvo B19
Giant cells with inclusions - conjunctival - nasopharyngeal - buccal epithelial cells - urine
Viral cultures from mononuclear cells resp secretions conjunctival swabs urine • Special facilities, difficult
Complications • Fever > 3/7 after onset of rash = complications • Developing countries – mortality 10% • Poor nutritional status • Pregnant women • Immunocompromised patients
Pneumonia • 2’ bacterial pneumonia Streptococcus pneumonia Streptococcus pyogenes Heamophilus influenza Staphylococcus aureus • Viral pneumonia – giant cell
Neurological complications • Acute disseminated encephalomeningitis • Subacute sclerosing panencephalitis
Acute disseminated encephalomyelitis • Demyelinating • During recovery phase – within 2/52 of exanthem • Post-infectious auto-immune process • Fever, headache, neck stiffness, ataxia, myoclonus, seizures, mental status changes • LP : lymphocytic pleocytosis elevated protein • Residual neurological abnormalities
Subacutesclerosingpanencephalitis • Progressively fatal degenerative CNS disease • 7-10yrs after measles • ? Pathogenesis – persistent CNS measles infection • Stages: stage 1 – soft neurological signs stage 4 – severe deterioration, flaccidity, decorticate rigidity and autonomic dysfunction
Tracheobronchitis • Otitis media • Corneal ulceration and keratitis • Myocarditis • Pericarditis • Mesenteric lymphadenitis • Appendicitis • Diarrhoea
Modified measles • Similar to classic measles, but milder • 17 – 21/7 • Partial immunity - babies: transplacental transfer of AB - live vaccine, with incomplete antibody response - rare: previous measles
Atypical measles • Previously vaccinated with killed vaccine • 7-14/7: fever, headache, cough, pleuritic pain • Rash: from extremities to trunk (vesicular, petechial, purpuric, urticarial) • Can cause severe illness • Not infective • IgM: @ onset of rash: titre< 1:5 day 10: 1:1280 • Broad differential
Immune-supressed patients • @ risk for severe, progressive measles • Atypical presentation: - absence of rash - any rash – purpura / desquamating - giant cell pneumonia - measles inclusion body encephalitis - up to 6/12 later • Deficient antibody synthesis • Biopsies
Isolation • Infective 5/7 before exanthem till 4/7 after it started • Aerosol spread • Strict respiratory isolation • Private room with negative air ventilation • Masks should be worn at all times
Treatment • Supportive • Secondary infections • Vit A 200 000u po as stat dose
Vaccination • Live attenuated vaccine
Contra-indications • HIV with CD4 < 200 • Glucocorticoid therapy >2mg/kg 20mg alternate days - wait 1/12 • Leukaemia in remission – wait 3/12 • Pregnancy • Gelatine allergy • Thrombocytopenia
Post exposure prophylaxis: Immunoglobulin • At risk: Immunocompromised Pregnancy Babies < 1yr • Within 6/7 of exposure • However, if not high risk and < 72hrs after exposure = Vaccinate
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