Acute necrotizing encephalopathy presenting as a basal ganglia syndrome

Acute necrotizing encephalopathy is a relatively new disease. The character istic clinical findings are of febrile illness followed by rapid deteriorat ion in mental status and seizures. The hallmark of the disease is multifoca l bilateral symmetric lesions affecting the thalamus, hypothalamus, brainst em tegmentum, cerebral white matter, and cerebellum. The etiology is unknow n, but immune-mediated mechanism was suggested. We present. a 12-year-old p reviously healthy girl who developed increased sleepiness progressing to st upor and coma. Magnetic resonance imaging (MRI) of the brain showed the cha racteristic findings previously described in acute necrotizing encephalopat hy. Her mental status improved dramatically with steroid treatment, and the MRI findings resolved completely within 6 months. Following the acute illn ess, she developed a complex neuropsychiatric disorder consistent with basa l ganglia syndrome.