A case of drug-induced hypersensitivity syndrome complicated with fulminant type 1 diabetes and type 2 myocardial infarction.

Drug-induced hypersensitivity syndrome (DiHS)/drug reaction with eosinophilia and systemic symptoms (DRESS) is a type of drug eruption that causes multiorgan disorders after the administration of certain drugs such as anticonvulsants. Herein, we report the case of a 66-year-old man with DiHS/DRESS complicated by fulminant type 1 diabetes (FT1D), shock, and cardiac involvement who was treated conservatively without systemic corticosteroid administration. He had taken carbamazepine for trigeminal neuralgia for 7 weeks until he noticed eruptions on his trunk. Two days after admission, he developed diabetic ketoacidosis, resulting in hypovolemic shock. The patient was diagnosed with FT1D, and insulin was administered. Additionally, the patient had a fever over 38°C, elevated white blood cells (>20 000/μL), liver dysfunction, atypical lymphocytes, and lymphadenopathy, but no evidence of viral reactivation. The lymphocyte transformation test for carbamazepine was positive, and human leukocyte antigen typing revealed the A31:01 haplotype, a risk factor for carbamazepine-induced cutaneous adverse drug reactions. Collectively, a diagnosis of atypical DiHS and a definitive case of DRESS was made. Moreover, myocardial dysfunction wall motion was observed. A close examination revealed mild coronary artery stenosis, leading to a diagnosis of type 2 myocardial infarction due to relative ischemia. The patient was carefully monitored without systemic corticosteroid administration because both clinical findings and laboratory data peaked on the same day. The patient's eruption and general condition improved, and he was discharged 4 weeks later. While most cases of DiHS/DRESS with cardiac involvement present with myocarditis, the possibility of ischemic heart disease should be considered in patients with cardiac involvement under shock.