MEASLES

Question 1

Describe the three (3) forms of measles disease in the CNS, with respect to who is affected, the incubation period, the pathogenesis, and disease progression (12)

Answer 1

• Acute measles post-infectious encephalitis – affects immunocompetent people, occurs within days to weeks of acute measles onset, a form of ADEM/PIEM – autoimmune, recovery varies – 15% fatal, 30% permanent neurological damage
• Measles inclusion body encephalitis – affects immunocompromised people, weeks to months after acute measles, virus present and replicating in the brain, uniformly fatal, rapid progression in HIV
• Subacute sclerosing panencephalitis (SSPE) – affects immunocompetent people, occurs years after primary measles infection, partly replication deficient virus in the brain, slowish progression to death in all cases.

Question 2

Briefly describe measles inclusion body encephalitis under the following headings:

a) affected population (2) and
b) clinical progression (3)

Answer 2

• Immune-compromised patients
• Children with leukaemia receiving radiation therapy
• HIV: accelerated process
• Incubation period - a few weeks to 6 months
• Convulsions, usually myoclonic jerks
• Mostly limited to one side
  a. Hemiplegia and/or decreased consciousness
  b. Death within a few months, 100% mortality

Question 3

Name the three (3) forms of encephalitis caused by measles and state their probable outcome (3)

Answer 3

Acute post-infectious measles encephalitis  variable, most recover; measles inclusion body encephalitis, invariably fatal; subacute sclerosing pan-encephalitis, invariably fatal.

Question 4

Name three (3) forms of measles encephalitis and for each state the timing of the onset of encephalitis (3)

Answer 4

• Acute measles post-infectious encephalitis [days-a few weeks after infection],
• measles inclusion body encephalitis [weeks-months],
• Sub-acute Sclerosing PanEncephalitis [years]