Subacute sclerosing pan encephalitis in a tertiary care centre in North India

Abstract

Background: Subacute sclerosing pan encephalitis (SSPE) is caused by persistent, aberrant measles virus infection presenting as rapid neurocognitive decline, associated with myoclonus. Diagnosis is by distinctive clinical presentation, characteristic EEG changes and measles serology. Methods and materials: Retrospective study from a tertiary care hospital SGPGI, Lucknow – a total of non-replicate 89 paired CSF and blood samples from patients presenting to OPD with clinical features suggestive of SSPE (i.e. dementia, myoclonic jerks and/or ataxia in a previously healthy individual) were analyzed from 2015 to 2018. Total IgG and measles-specific IgG levels for CSF and value of relative CSF/serum quotient ≥ 1.5 was accepted indicative for intrathecal measles antibody synthesis. History of previous attack of measles, immunization status, EEG pattern were recorded. Results: Presenting symptoms included myoclonus, behavioural changes, seizures, and cognitive, visual, and extrapyramidal disturbance. A total of 52.08% (47/89) patients had a high cerebrospinal fluid: serum anti-measles antibody ratio showing male preponderance. Age at onset of SSPE ranged from 6 years to 34 years, showing an increase in mean age at onset of SSPE. A sizable percentage of the patients were ≥18 years old and considered to have adult onset SSPE. A definitive history of measles could be elicited in 20% cases. Previous complete immunization history was present in about 40% and partial could be elicited in 35%. Characteristic EEG findings were present in about 80%. All patients received symptomatic therapy; 20% also received disease modifying agents with poor compliance. Demographic details showed more frequent clustering in some neighboring districts of UP. Conclusion: WHO and Indian association of Pediatrics recommends two doses of vaccine. High SSPE cases could be attributed either to referral bias, decrease in the potency of the vaccine at the receiving end/inefficient cold chain system, improper vaccine coverage, poor quality of vaccine and possible circulation of atypical measles virus strain cannot be ruled out.