subacute sclerosing panencephalitis is a progressive, fatal brain disorder caused by a persistent measles virus infection resulting from a mutated, persistent measles virus residing in the central nervous system
Epidemiology
overall prevalence is estimated at 4 to 11 cases per 100,000 people who contract natural measles but risk is much higher the younger the patient when contracting measles:
risk soars dramatically to roughly 1 in 600 for infants who get measles before their first birthday
risk is approximately 1 in 1,700 to 1 in 3,300 when children contract measles between age 1 and 5 years
risk averages out to about 1 in 10,000 to 1 in 25,000 cases across all age groups combined
Clinical features
develops slowly, typically 6 to 8 years after an initial, early childhood measles infection
it is relentlessly progressive and almost always fatal within 1 to 3 years