Diphenhydramine-Refractory Antipsychotic-Induced Dystonia in an Adolescent Male With Cornelia de Lange Syndrome

Cornelia de Lange Syndrome is a rare genetic disorder that results in distinctive craniofacial deformities, developmental delay, hirsutism, and other physical abnormalities. Case reports suggest some of these patients exhibit sensitivity and paradoxical reactions to certain psychoactive drugs. This report of a 16-year-old male with Cornelia de Lange is the first to describe dystonia from a first-generation antipsychotic that did not respond to conventional treatment with diphenhydramine. The patient initially presented to the Emergency Department for agitation, which progressively worsened after administration of diphenhydramine, olanzapine, and intramuscular haloperidol. The patient returned to the Emergency Department the following day because of altered mental status and lethargy that progressed to periodic lip-smacking movements and contraction of his upper extremities. His symptoms continued despite administration of diphenhydramine and loading doses of 3 antiepileptic drugs. His abnormal labs included an elevated creatine kinase and a prolonged QTc interval on his electrocardiogram. His symptoms were later deemed a probable drug-induced dystonic reaction to haloperidol once seizures were excluded by an unremarkable electroencephalogram. This case supports previous reports suggesting an association between Cornelia de Lange and paradoxical drug reactions, and it is recommended that clinicians strongly weigh the risks of prescribing first-generation antipsychotics for this patient population. These medications should be carefully titrated, with close patient monitoring to prevent adverse drug effects and other iatrogenic complications because antidotes may be rendered ineffective by this condition.