Acute Encephalitis Syndrome with an Unusual Diagnosis.

Four-year old boy was admitted with acute onset of fever with seizures and altered sensorium. His mother had history of contact with influenza A H1N1 virus (H1N1) infection. Blood counts, electrolytes, blood sugar and ammonia were normal. Liver enzymes were mildly elevated. CSF study showed elevated protein, normal sugar and no pleocytosis. Cerebrospinal fluid (CSF) viral panel was negative. Magnetic resonance imaging brain was suggestive of acute necrotizing encephalopathy. His throat swab and sputum polymerase chain reaction was positive for H1N1. He was managed with ventilation, intravenous steroids and other supportive measures. At discharge his sensorium improved but had neurological sequelae. We are presenting this case as this is a very rare complication of H1N1 infection with high rate of mortality. Early supportive measures and steroids/intravenous immunoglobulin may save the patient.