Measles.ppt

7/29/2019 Measles.ppt

1/23

Measles:

anOverview


2/23

Case 1

7 month female

From East RandPresented on 02/10/2003

Previously well

Not yet immunised against measles5 day history upper respiratory tract infectionsymptoms

Rash for 2 days went to clinic

Referred to JHB Hospital with serological evidenceof measles infection

No known contacts

Also had vomiting, diarrhoea


3/23

On examinationThriving

Colour, hydration adequate

Miserable

Watering eyes, bilateral inflamed tympanic membranes

Rhinitis, nasal discharge

Shotty cervical lymphadenopathy

Cough, but no respiratory distress or chest signsDiffuse maculopapular rash, confluent areas, starting to turnbrown in some areas

Course

Patient admitted to ensure adequate fluid intakeDay 2 less vomiting

Ruptured left tympanic membrane

Discharged on Augmentin, Panado


4/23

Case 2

8 year old boyFrom central JHB

Known HIV positive patient

Recent history cough, fever, malaise, poorappetite, sores on lips

Known TB contact father (on treatment)

Investigated for TB 1 month before

negativeNo known measles contacts

Apparently immunisations up to date


5/23

On examinationToxic, but not marked respiratory distress

Reasonably wellgrown

Pink on nasal prong oxygen

Dry mucous membranes

Generalised lymphadenopathy

Not jaundiced

Diffuse scars/pigmentation from old rashes/folliculitisExcoriated lesion right forearm not from recent PPD

Head and neck

Severe conjunctivitis, no discharge

Unable to open mouth extensive labial sores Herpeslesions

Chest

Evidence of right upper lobe, left lingular pneumonia


6/23

Cardiovascular system Mild cor pulmonale

Abdomen Generally tender, 4cm tender hepatomegaly

Central Nervous System Cooperative

Generalised decreased power

No neck stiffness No focal signs

ManagementTreated for bacterial pneumonia

Lasix for cardiac failure

Investigated for TB


7/23

Course

Deteriorated in wardDay 3 noted to have swollen, red lips, circumoralerythema

Discharging eyes, unable to open them

? new rash on trunk difficult to seeIll-looking, more drowsy, withdrawn but rousable

Lumbar puncture performed, given Vitamin A, measlesserology sent

ResultsDay 6- patient demised; terminal event unknown


8/23

Results

02/10/2003 WCC 10,7

Hb 10,1

Plts 257

CRP 160,3 U&E

128/4,3/96/14/7,9/45

06/10/2003 WCC 8,6

Hb 10,5

Plts 320

CRP 323

CSF no cells, normal,ADA 2,6

Blood cultures negative

Sputum negative Tuberculin skin test -

neg


9/23

Measles(Rubeola)

Measles virus, genus Morbillivirus, familyParamyxoviridae

One serotype, humans only host

Virions spherical structures, 100 250 nmdiameter

Inner capsid composed of coiled RNA helix, 3proteins

Outer envelope matrix protein bearinghaemagglutinin(H) peplomer, fusion(F)protein (NB in cytopathic effects of virus)


10/23

Epidemiology

Important cause of childhood mortality in developingcountriesBefore vaccine developed (1963) epidemics every 2 5 years, winter and springEpidemic - up to half a million cases reportedDeveloping countries mortality rate 1 10%Developed countries 0,3%Much fewer cases since live attenuated virus vaccinedeveloped

Developed countries Measles almost eradicated Outbreaks in older children, young adults, eg. College

campuses


11/23

Developing countries Common, endemic, increases in winter and spring

First year of life, even 6 months of age

Sporadic cases, or outbreaks extensive

Epidemics facilitated by inadequate immunity, overcrowding

More cases complicated

Epidemics occur due to

Failure to immunise Primary vaccine failure (5%)

Waning immunity (rare)

Highly contagious, respiratory secretions

Contagious from 1-2 days before symptoms, 4 days after onset

of rashProdrome most infectious

Quarantine period 1 week after rash appears, longer forcomplicated measles


12/23

Pathogenesis

Portal of entry respiratory tractRegional lymph nodesEnters bloodstream reticuloendothelial system(primary viraemia) target organs (secondaryviraemia)

Target organs epithelial, endothelial cellsEyes, skin, respiratory tract, gastrointestinal tract,including mouthEndothelial cells vasculitis

Koplik spots, rash due to immune responseto virus inendothelial cellsImmunocompromised patients may have norash


13/23

Virus directly invades T lymphocytes lymphopenia

Decreases neutrophil function, chemotaxis

Decreased T helper cells - decreased reactivity toPPD

Fusionprotein causes typical multinucleated giantcells; also aids viral spread from cell to cell

Damage to entire respiratory tract + immuneparesis secondary bacterial infections


14/23

Clinical features

Usually symptomatic

Incubation period (infection to symptoms) : 9-12 daysProdrome : 2-4 days Nonspecific symptoms fever, malaise, anorexia, headache Classical triad cough, coryza, conjunctivitis (with photophobia,

lacrimation)Enanthem: Koplik spots Just before rash appears 1-2 mm, bluish-white, bright red background

Buccal mucosa, opposite 2nd

molars Pathognomonic for measles Disappear soon after rash appears Entire buccal, labial mucosa may be reddened


15/23

Exanthem:

Erythematous, non-pruritic, maculopapular

Hairline, behind ears

trunk

limbs, includingpalms, soles

Confluent, blotchy

Most ill at this time

Day 4 starts to fade (in order of appearance),turns brownish, desquamates

Fever settles after 4-5 days if persists, suspectsecondary infection

Lymphadenopathy, splenomegaly, diarrhoea, vomitingChest Xray may be abnormal, even in uncomplicatedcases

Entire illness 10 days


16/23

Complications

1)Respiratory TractOtitis media most common

Laryngitis, croup, bronchitis due to measles itself

Secondary pneumonia viral,bacterial

Primary giant cell pneumonia due to measles (rare)

immunocompromised, malnourished patientsReactivation of TB

2)Gastrointestinal TractGastroenteritis can be severe, especially in already

malnourished patientsProtein-losing enteropathy

Mouth reactivation of Herpes severe stomatitis

Hepatitis, ileocolitis, appendicitis, mesenteric adenitis


17/23

3)Eye Malnourished especially at risk Keratitis, keratoconjunctivitis Cause of blindness 3rd world Vitamin A preventive role in respect of infection

4)CNS Encephalitis uncommon Fever, headache, drowsiness, coma, seizures Earlier - direct viral effect in CNS Later immune response causing demyelination Significant morbidity, permanent sequelae mental retardation,

epilepsy Rarely transverse myelitis Subacute sclerosing panencephalitis extremely rare, 6-10 years

after infection. Progressive dementia, fatal. Interaction of hostwith defective form of virus

5)Other Glomerulonephritis, myocarditis, postinfective thrombocytopenic

purpura


18/23

Lab findings

FBC, differential lymphopenia, neutropeniaU&E deranged due to dehydrationRaised transaminasesMeasles encephalitis raised protein, lymphocytes inCSF

Virus detection Microscopy of respiratory epithelial cells (throat swab)

giant cells Immunofluorescence detects Measles antigens Culture virus from respiratory secretions/ urine (1-2 weeks)

Serology IgM (1-2 days after onset of rash) IgG (rises after 10 days)


19/23

Differential Diagnosis

Classic Measles Koplik spots, coryza, cough, conjunctivitisKawasaki disease, Scarlet fever, Ebstein Barr virus,Toxoplasmosis, drug reaction, MycoplasmaHistory of immunisation important

IMMUNITY TO MEASLESCell-associated virusProtection antibody-mediatedRecovery cell-mediatedImmunity usually lifelong

Passive maternal transfer of IgG shouldprotect up to 1 yearDeveloping countries higher viral burden + accelerateddegradation of antibodies (malnutrition, HIV, chronic immunestimulation) at risk much earlier


20/23

Rationale for vaccination strategies (developing countries): Higher risk during 1st year BUTlower rates of seroconversion (60%

- 6 months, 80% - 9 months, 95% - 15 months)

1st vaccine at 9 months

2nd at 18 months NOTa booster rather a second chance at seroconversion

Developed countries routine MMR at 15 months, 2nd MMR at 4-5 years, or 12 years

The Vaccine: Live attenuated virus

Schwarz egg most common

Edmonston Zagreb (EZ) human diploid cell culture

Subcutaneous

Side effects occasional fever (5-7 days later), transient rash

Cold chain maintenance NB


21/23

Contraindications

Severehypersensitivity to egg protein give EZ instead

Allergy to Neomycin

Severeimmunosuppression chemotherapy, congenital immunedeficiencies.NOTHIV (unless intercurrent severe febrile illness)

Pregnancy teratogenic

Defer

for 3 months after receiving immune globulin

for 6 weeks after receiving blood products

for 3 months after stopping immunosuppressive treatment

Mustgive HIV patients asymptomatic andsymptomatic, malnourishedpatients, TB patients

Failures

Primary failure 5%

Faulty storage

Pre-existing antibodies (maternally derived)

Simultaneous administration of vaccine and immunoglobulin


22/23

Post-exposureWho is susceptible?

Consider susceptible unless: Proof of receipt of 2 doses of live vaccine, or 1 after 1st birthday

Proof of previous diagnosed measles infection

Laboratory evidence of immunity

Vaccinate within 72 hours of exposure

Immune globulin between 72-96 hours after exposure

Treatment

Supportive, symptom-directed

Antibiotics for otitis media, pneumoniaHigh doses Vitamin A in severe/ potentially severe measles/patients less than 2 years


23/23

Measles in the HIV patient

Lower response to vaccineMay acquire lower titres of antibody from mother,higher rate of degradation of maternally acquiredantibodies

More likely malnourished, more susceptible to severeinfection, complications, higher mortality

May have had TB reactivate

If suspecting TB, PPD beforevaccine (anergy up to 1

month after)Measles may hasten progression of HIV

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