Clinical syndrome of myalgias, rhabdomyolysis, and myoglobinuria after consumption of cooked freshwater or brackish water fish and crustaceans due to toxin-mediated effects.

Haff syndrome typically occurs in outbreaks due to heat-stabile toxins, and patients present within 4-10 hours of ingestion. The most common vectors include burbot, pike, freshwater eel, whitefish, Atlantic salmon, bigmouth buffalo fish, and crayfish.

Patients typically present with vomiting, myalgias, diaphoresis, chest pain, and muscle stiffness, and symptoms may be confused with acute myocardial infarction or unstable angina (see acute coronary syndrome). Care is supportive with IV fluid resuscitation for rhabdomyolysis.