SERUM IRON IN CATATONIA AND NEUROLEPTIC MALIGNANT SYNDROME

Background: Preliminary data suggest that decreased serum iron levels predict the progression of catatonia to neuroleptic malignant syndrome (NMS), This study examines the predictive value of low serum iron in this NMS conversion and explores other potential significance of serum iron in catatonia. Methods: Fifty patients with catatonia were prospe ctively identified at two psychiatric intensive care units during a 3- year period [incidence of 5% (39/716) and 13% (11/86) respectively]. S erum iron was measured in 39 episodes. Seventeen episodes (44%) showed low serum iron levels. A retrospective chart review of patients ident ified was conducted, comparing those with law and normal serum iron le vels. Results: Low serum iron levels were associated with malignant ca tatonia, excited catatonia, and poor responses to benzodiazepines. The re were 7 episodes of malignant catatonia. All had low serum iron. Neu roleptics were used in 5 of them, and all 5 evolved into NMS. No such NMS conversion was noted in those with normal serum iron or in nonmali gnant catatonia with low serum iron. Seven episodes (with low serum ir on)failing benzodiazepine therapy responded subsequently lithium-neuro leptic combination therapy. Conclusions: Malignant catatonia, associat ed with low serum iron is at high risk of evolving into NMS. Low serum iron in nonmalignant catatonia does not predict this NMS conversion. Excited catatonia as a catatonic subtype (associated with low serum ir on and unfavorable benzodiazepine responses) deserves more research at tention. There appears to be a possible connection between treatment r esistance to benzodiazepines, favorable responses to lithium-neurolept ic combination, and law serum iron. (C) 1998 Society of Biological Psy chiatry.