Immune checkpoint inhibitor-induced acute fulminant myocarditis: A case report and review of literature

Immune checkpoint inhibitor (ICI)-induced myocarditis is a rare but fatal cardiotoxicity of ICIs. It is an early toxicity of ICIs, occurring within the first 30–40 days of starting the therapy. The exact mechanism is unknown but is postulated to be due to the activation of the CD4+ and CD8+ T-lymphocytes in the myocytes. Patients may have subtle changes in the electrocardiogram (ECG) and echocardiography during therapy with some patients presenting with acute left ventricular failure after the first or second dose of the ICI. We present a case of hepatocellular carcinoma developing severe fulminant ICI-induced myocarditis after 2 doses of the ICI. A high index of suspicion is needed to detect the toxicity early on and the treatment protocol should include an ECG and troponin levels at each cycle in the initial phases of treatment. The mainstay of treatment is high doses of steroids and other cardiac support measures.