Serum iron and neuroleptic malignant syndrome.

Neuroleptic malignant syndrome (NMS) is a fulminant, life-threatening reaction to neuroleptic medications. The only consistently described biochemical abnormalities are increased creatine kinase and leucocytosis. Because of a possible association between NMS and dopaminergic function and between serum iron and dopaminergic function, we prospectively measured serum iron in 26 episodes of NMS in twenty-three patients. In 25 episodes (96%) serum iron concentration was 10 mumol/l or lower--more than 2 SD below the mean normal value. Serum iron in 11 episodes (36%) was 4 mumol/l or lower. In each episode for which data are available, serum iron returned to normal upon resolution of the NMS. Serum iron may be a helpful adjunct for the diagnosis of the disorder. The pronounced reduction in serum iron suggests that the acute phase reaction may have a role in NMS.