Question

Child presents with myoclonus jerk, decrease performance in school. There is history of fever at the age of 1 year with rash. It is suggestive of-

• A. Subacute sclerosing panencephalitis
• B. Mesial temporal sclerosis
• C. Polio
• D. Measles

Hint:

Think about which progressive CNS disease is linked to measles infection in infancy after a long latent period.

Answer 1

The Correct Option is A

Step 1: Identify the key clinical features.
The child has myoclonic jerks, declining school performance (cognitive deterioration), and a prior history of fever with rash at 1 year of age -- highly suggestive of measles infection in early childhood.

Step 2: Pathophysiology of SSPE.
Subacute Sclerosing Panencephalitis (SSPE) is a progressive, fatal neurological disorder caused by a persistent defective measles virus that remains latent in CNS neurons. It typically appears 6-8 years after the initial measles infection, especially when measles occurred before age 2.

Step 3: Stages of SSPE.
Stage I -- Subtle behavioural changes, memory loss, poor school performance. Stage II -- Involuntary myoclonic jerks (periodic, stereotyped), seizures; EEG shows Radermecker complexes. Stage III -- Rigidity, decerebrate posturing. Stage IV -- Coma and death.

Step 4: Eliminate distractors.
Mesial temporal sclerosis causes temporal lobe epilepsy but not myoclonic jerks post-measles. Polio causes flaccid paralysis without cognitive decline. Measles itself is an acute illness and does not present years later with this picture. SSPE is the only entity linking early measles to a latent progressive CNS disease with myoclonus.