We report a case of
malignant catatonia initially diagnosed as
neuroleptic malignant syndrome (NMS) that responded successfully to
diazepam administration. A 29-year-old man with
mental retardation was admitted to our hospital because of high
fever,
muscle pain, and consciousness disturbance. Fifteen days before admission, he had developed
muscle pain and weakness in his legs. He presented with
fever,
tachycardia,
tachypnea, elevated blood pressure, excessive sweating, and neurological findings of
lethargy and severe
muscle rigidity in the neck and extremities. Laboratory findings included elevated serum
creatine phosphokinase (CPK) level. His clinical features and the laboratory test results fulfilled the diagnostic criteria for NMS. He was treated for NMS with
dantrolene sodium and
bromocriptine mesylate for 2 weeks; however, there was no improvement. Therefore, treatment was changed to
diazepam administration because of suspected
malignant catatonia. One week after initiation of
diazepam administration, his symptoms gradually improved, and the serum CPK level normalized. The diagnosis of
malignant catatonia was confirmed because treatment with
diazepam was dramatically effective, whereas the initial treatment for NMS was not beneficial. The clinical presentation of
malignant catatonia is similar to that of NMS. Indeed, some authors have described NMS as a variant of
malignant catatonia. If treatment is refractory in cases of NMS,
malignant catatonia may be suspected, and changing treatment to
diazepam administration may be useful.