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 / 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

Subacute sclerosing panencephalitis• 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

Thank you

The greatest obstacle to

discovery is not ignorance -- it is the illusion of knowledge."

~ Daniel Boorstin