Cardiomyopathy Secondary to Long-Term Treatment With Lithium: A Case Report and Literature Review

Lithium-Induced Bradycardia and Cardiomyopathy in a Patient With Bipolar Disorder and Paranoid Schizophrenia

Lithium is primarily known to cause neurological and gastrointestinal side effects, however, cardiac effects have been rarely reported. We present a unique case of lithium cardiotoxicity causing bradyarrhythmia and cardiomyopathy. A 68-year-old man with a history of paranoid schizophrenia and bipolar disorder presented with altered mental status. On examination, the patient was lethargic, afebrile, with dry oral mucosa, and a regular pulse of 42 bpm. Labs revealed acute kidney injury and elevated lithium levels. Electrocardiogram (ECG) revealed a junctional escape rhythm with a right bundle morphology. Lithium toxicity was strongly suspected in the setting of raised serum lithium levels, decreased oral intake and acute kidney injury. The patient was found to have lithium-induced junctional bradycardia. Transvenous pacing was not indicated as the patient responded to fluids and atropine and had no severe hemodynamic compromise. As his serum lithium levels decreased, the bradycardia gradually improved. His echocardiogram revealed moderate left ventricular systolic dysfunction. Workup of cardiomyopathies was negative: no obstructive coronary artery disease; viral panel, and autoimmune markers were unremarkable. Thus, his cardiomyopathy was attributed to lithium toxicity. Lithium cardiotoxicity may manifest as arrhythmias and/or cardiomyopathy. Clinicians should have a high index of suspicion for lithium cardiotoxicity due to the narrow therapeutic range of lithium.

[Fatigue, breathlessness and chest pain in a 31-year-old man with schizoaffective disorder]

BACKGROUND

Clozapine is an alternative antipsychotic medication used to control symptoms of schizophrenia and to reduce risks of suicidal behavior in patients who did not adequately respond to standard medication. Due to severe side effects including cardiomyopathy and myocarditis its clinical use is limited.

CASE REPORT

A 31-year-old man of east European descent presented to the emergency medical department with fatigue, shortness of breath and chest pain. Due to a schizoaffective disorder he was treated with clozapine and lithium. Echocardiography revealed severely impaired left ventricular systolic function. After exclusion of coronary artery disease by coronary angiography an endomyocardial biopsy was performed according to the guidelines. This confirmed the clinically suspected toxic cardiomyopathy. Therefore, antipsychotic treatment was immediately changed and state of the art heart failure medication was started resulting in a clear improvement of left ventricular function.

CONCLUSION

In patients treated with clozapine or lithium and clinical signs of heart failure, toxic cardiomyopathy should be considered.

ISMP Adverse Drug Reactions: Lithium-Induced Cardiomyopathy Fixed Drug Eruption Due to Cetirizine, Levocetirizine, and Hydroxyzine Nivolumab-Induced Myasthenia Gravis Nivolumab-Induced Cholangitic Liver Disease Torsade de Pointes Caused by Psychiatric Polypharmacy Trichotillomania Associated With Aripiprazole

The purpose of this feature is to heighten awareness of specific adverse drug reactions (ADRs), discuss methods of prevention, and promote reporting of ADRs to the US Food and Drug Administration's (FDA) MedWatch program (800-FDA-1088). If you have reported an interesting, preventable ADR to MedWatch, please consider sharing the account with our readers. E-mail Dr. Mancano michael.mancano@temple.edu). Your report will be published anonymously unless otherwise requested. This feature is provided by the Institute for Safe Medication Practices (ISMP) in cooperation with the FDA's MedWatch program and Temple University School of Pharmacy. ISMP is an FDA MedWatch partner.