Long term survival in subacute sclerosing panencephalitis: An enigma

Subacute sclerosing panencephalitis (SSPE) usually has a progressive stereotypic downhill course and results in premature death. Long-term stabilization or remission is exceptional. Objective: To analyze the profile of patients with a relatively 'benign' course who survive beyond 3 years. Design: Descriptive analysis of 19 (16 male, 3 females)/307 (6.2%) patients with benign course who were evaluated at NIMHANS between January 1995 and December 2004. Their diagnosis was based on characteristic myoclonic jerks, elevated antibody titers against measles virus in CSF and periodic complexes in EEG. Results: The mean age at onset of symptoms was 11.7±3.9 years and mean duration of follow-up from first symptom was 5.9±3.1 years (3-13.8 years). Their initial symptoms were seizures (7), myoclonus (6), visual disturbances (4), behavioral changes (1) and cognitive impairment (1). These patients had varied clinical course: stabilization in different stages for 6 months to 5 years (13), remissions for 6 months to 9 years and reversal of staging with functional recovery from being bed bound to ambulant (8). Their diagnosis was often delayed. Small sample size did not permit to analyze the influence of possible disease modifying agents used in 10 patients (isoprenosine-3, amantidine-4, oral steroids-4, methylprednisolone-1, intravenous immunoglobulin-1). Conclusions: Our observations suggest that SSPE may have a highly variable clinical course and warrants cautious approach for counseling at initial evaluation and while interpreting beneficial effect of disease modifying agent(s). There is a need to explore prognostic marker(s).