Acute encephalopathy after ingestion of "sugihiratake" mushroom]

An outbreak of acute encephalopathy has occurred among patients with renal dysfunction after ingestion of "sugihiratake" mushroom (angel's wings mushroom) in the northern area of Japan between the end of September and the middle of October in 2004. Most of the patients had varying degree of renal dysfunction. Patients initially presented with asthenia in legs, shaking limbs, and difficulty in ambulation. Several days later, tremor-like involuntary movements or myoclonus developed, which were frequently followed by intractable status epilepticus. Eleven patients were dead. CSF examination showed elevated protein levels without pleocytosis. Brain CT and MRI studies revealed abnormal signal intensities in bilateral external capsule and claustrum, and in the cortical white matter. All of the patients had a history to have ingested sugihiratake in varying quantities and frequencies prior to the onset of the illness. Although no similar patients have been reported in the past, this edible mushroom must have induced acute toxic encephalopathy. The characteristic features of clinical signs and symptoms, and laboratory findings of this encephalopathy were briefly summarized.