Subacute sclerosing panencephalitis

Clinic

• SSPE is a progressive neurological disorder of Children / Young adults.
• Slow, but persistent, viral infection caused by RBOL

Signs and symptoms

• SSPE is characterized by a history of primary measles infection, followed by an asymptomatic period that lasts 7 years on average
• Then progressive neurological deterioration occurs
  • Behavior change
  • Intellectual problems
  • Myoclonic seizures
  • Blindness (Retinitis or Optic neuritis )
  • Ataxia

4 Stages

1. Personality changes, mood swings, or depression.
2. Jerking, muscle spasms, seizures, loss of vision, and dementia.
3. Jerking movements are replaced by twisting movements and rigidity.
4. Progressive loss of consciousness into a persistent vegetative state, which may be preceded by or concomitant with paralysis, occurs in the final stage, during which breathing, heart rate, and blood pressure are affected. Death usually occurs as a result of fever, heart failure, or Autonomic Dysfunction (Heart rate variability)

Symptom prevalence

• The age at presentation is usually 8 -11 years (Average 6 years after RBOL)
• Affected individuals present with poor school performance and progressive intellectual deterioration, personality changes, and behavior abnormalities
• This is followed by steady motor decline, myoclonus, focal paralysis, seizures, autonomic failure, and rigidity, finally leading to death with akinetic mutism.
• These changes are characterized in four stages
  1. Motor regression is eventually seen in 100% of individuals with SSPE
  2. Cognitive decline 86%
  3. Myoclonus 74%
  4. Generalized seizures 16%
  5. Focal seizures 10%

Uncommon symptoms

• Some individuals may present with early visual symptoms that predate cortical signs by up to 2 years, with deficits in visuospatial orientation and early macular damage reported.
• Periodic dystonic myoclonus of abrupt onset
• Behavioural changes concomitant with myoclonus, pyramidal tract signs, and Akinetic rigid syndrome
• Curiously, the left-sided symptoms precede the right-sided ones.
• Cerebellar and brainstem symptoms are not as frequently reported.

Cognitive

• Progressive deterioration in scholastic performance

Motor function

Development of periodic stereotyped myoclonic jerks in Head, Trunk and limbs.

• Myoclonic jerks do not interfere with consciousness
• Agg by excitement
• Disappear during sleep.
• Myoclonus can present as a difficulty in gait, periodic dropping of the head, and falling.
• The myoclonus may not be obvious early in the disease but can be elicited by the patient standing with feet together and arms held forward and then watching for periodic dropping of the head, neck, trunk, or arm
• These are often concomitant with contraction of facial musculature and slow eye blinks.

Pyramidal / Extrapyramidal signs.

• Few patients may develop ataxia, dystonia, and dyskinesia.
• Generalized tonic-clonic seizures and partial seizures may also occur.

• In advanced stages of the disease, patients become quadriparetic, spasticity increases, and myoclonus may decrease or disappear.

Visual

• Ocular and visual manifestations are reported in 10%–50% of patients, which include
  • Optic atrophy
  • Papilloedema
  • Papillitis (Optic Neuritis)
  • Macular or perimacular chorioretinitis.
  • Anton's syndrome (cortical blindness with denial of blindness).

Autonomic failure

• There is autonomic failure with loss of thermoregulation leading to marked temperature fluctuations.
• Decerebrate and decorticate rigidity appear, breathing becomes noisy and irregular. At this stage, patients frequently die due to hyperpyrexia, cardiovascular collapse, or hypothalamic disturbances.

Altered consciousness

• There is progressive deterioration of sensorium to a comatose state and ultimately the patient becomes vegetative.