Clozapine-Induced Myocarditis in Huntington's Disease: Case Report

Huntington’s disease (HD) is an autosomal dominant neurodegenerative disease. Its clinical presentation is primarily characterized by motor dysfunction, cognitive decline, and a broad spectrum of neuropsychiatric symptoms. Common psychiatric manifestations of HD include mood and anxiety disorders as well as behavioral and personality changes. Psychosis is relatively rare. Clozapine may be used for HD with psychosis because of its low extrapyramidal side effect profile. However, clozapine administration has been associated with rare but potentially fatal adverse effects, such as agranulocytosis and myocarditis. Clozapine-induced myocarditis is a severe complication that typically emerges within the first weeks of treatment and can lead to cardiovascular collapse if not recognized early. Although cardiac autonomic dysregulation and basal cardiac stress induced by mutant huntingtin (mHTT) protein accumulation are recognized in patients with Huntington’s disease (HD), data regarding clozapine toxicity within this specific context remain limited. This case report presents a 51-year-old male patient who developed acute myocarditis during clozapine treatment initiated for psychotic symptoms arising in the context of HD. Following the discontinuation of clozapine, the patient was referred for cardiological monitoring. Throughout this paper, we will discuss the diagnostic process of myocarditis—a rare but potentially life-threatening complication of clozapine—and potential contributing factors. This case highlights the vital importance of early cardiac monitoring during clozapine use, particularly in psychiatric conditions accompanied by neurodegenerative processes.