Involuntary movements in infantile cobalamin deficiency appearing after treatment

Involuntary movements may be a symptom in most infants who present with neu rologic syndrome of infantile cobalamin (vitamin B-12) deficiency. In this report, two infants with cobalamin deficiency are presented. These patients also developed a striking movement disorder that appeared a few days after treatment with intramuscular cobalamin. The movement disorder was characte rized by severe involuntary movements, which were a combination of tremor a nd myoclonus particularly involving tongue, face, pharynx, and legs. The ne urologic symptoms improved within a few days after the administration of cl onazepam. In each patient the mother was also cobalamin deficient and the i nfant was solely breast-fed. The cause of involuntary movements that can ap pear rarely after treatment in infantile cobalamin deficiency is not known. Besides initial neurologic presenting symptoms of cobalamin deficiency, th e occurrence of involuntary movements after treatment should also receive a ttention. This movement disorder may disappear spontaneously, or an additio nal treatment may be an alternative approach if the symptoms are severe. (C ) 2001 by Elsevier Science Inc. All rights reserved.