Encephalitis Lethargica in a Twelve-year-old Girl: The Response to Levodopa Therapy

Encephalitis lethargica is an acute encephalopathic illness characterised by sleep disturbance, neuropsychiatric and extrapyramidal symptoms. It is rarely reported in children and the diagnosis is made by exclusion of infective, biochemical, degenerative, autoimmune, toxic or metabolic causes of acute encephalopathy. It is recently postulated to be part of a spectrum of poststreptococcal autoimmune disease. We report a 12-year-old Chinese girl who presented with acute encephalopathic illness with predominant features of rigidity and dystonia. The diagnosis of encephalitis lethargica was contemplated in view of her major presenting neurological features and exclusion of other common causes of acute encephalopathy. She had a prompt and remarkable improvement in both motor and cognitive functions after treatment with levodopa. Encephalitis lethargica, though rare, does occur in children and early dopaminergic therapy not only alleviates symptoms but also heralds the recovery.