SUBACUTE SCLEROSING PANENCEPHALITIS

 

SUBACUTE SCLEROSING PANENCEPHALITIS

 

DEFINITION:

A slow viral infection of the brain characterized by chronic encephalitis caused by a persistent measles viral infection.

EPIDEMIOLOGY:

  • incidence: rare
    • incidence decreased after immunization initiation in 1963
      • risk 8.5/million cases of natural measles infection
      • risk 0.7/million cases after immunization
  • age of onset:
    • 5-15 years in 85% of cases
    • (5-15 years after a natural measles infection or immunization)
  • risk factors:
    • M > F (2:1)
    • urban > rural
    • measles before age 18

PATHOGENESIS:

1. Background

  • pathogenesis involves the accumulation of incomplete measles virus that cannot be cleared by B or T cell mechanisms
  • measles genomes in SSPE are larger and contain multiple mutations
  • begins in cortical grey matter -> subcortical grey & white matter -> lower structures

PATHOLOGY:

1. Intranuclear Inclusion Bodies

  • inflammation, necrosis, gliosis, and repair
  • panencephalitis involves cortical and subcortical grey and white matter and blood vessels with an increasing number of glial cells

CLINICAL FEATURES:

1. Prodrome

  • mild to severe measles with full recovery or immunization
    • mean interval between immunization and SSPE: 8 years
    • mean interval between measles and SSPE : 12 years

2. Clinical Course

1. 1st Clinical Stage - Behavioural Changes

  • insidious onset
  • subtle changes in behaviour and declining school work:
    • aggression
    • withdrawal
  • followed by overtly bizarre behaviour and dementia
  • occasional headaches

2. 2nd Clinical Stage - Neurological Changes

  • seizures
    • myoclonic - symmetrical involving axial muscles
    • generalized tonic-clonic develop later
  • movement disorders
    • cerebellar ataxia, chorea, choreoathetosis, dystonia, progressive bulbar palsy, spasticity
  • optic changes
    • chorioretinitis, macular pigmentation, optic atrophy, papilledema, retinopathy
  • dementia progresses to stupor and coma in either flaccid or spastic decorticate postures
  • few patients live longer than 3 years after diagnosis

INVESTIGATIONS:

1. Serology

  • IgG and IgM to measles virus

2. Cerebral Spinal Fluid

  • elevated IgG and IgM fractions to measles virus on oligoclonal electrophoresis
  • normal cell count
  • normal or elevated total protein

3. EEG

  • 1st Stage - moderate nonspecific slowing
  • 2nd Stage - episodes of "suppression-burst";high amplitude slow and sharp waves recur at intervals of 3-5 sec on a slow background

4. Imaging Studies

1. CT/MRI

  • variable cortical atrophy & ventricular enlargement
  • normal or single or multiple focal low-density lesions in the white matter

MANAGEMENT:

1. Supportive

  • anticonvulsants, physiotherapy, etc.

2. Medications

  • Inosiplex 100 mg/kg/day

 

Pediatric Database - SUBACUTE SCLEROSING PANENCEPHALITIS

Pediatric Organization - Pedbase [at] Gmail.com