Rhabdomyolysis resulting from mushroom poisoning previously has been unrepo
rted in the literature. We present an outbreak of Russula subnigricans pois
oning with rhabdomyolysis. The most severely ill patient presented with rha
bdomyolysis, severe electrolyte disturbance (hyperkalemia, hypocalcemia), r
espiratory failure, acute renal failure, pulmonary edema, ventricular tachy
cardia, and circulatory shock. Mycotoxin may be the cause of rhabdomyolysis
. In areas where mushroom gathering is common, mushroom poisoning should be
included in the differential diagnosis of rhabdomyolysis. (C) 2001 by the
National Kidney Foundation, Inc.