[A case of hyperammonemia presented in a patient with multiple myeloma].

Hyperammonemia-induced encephalopathy is a rare complication of untreated multiple myeloma. This case report illustrates a 78-year-old woman with multiple myeloma who developed acute delirium due to elevated level of serum ammonia in the absence of hepatic failure. One should suspect the condition when common management is ineffective. The adequate treatment of underlaying multiple myeloma is necessary.