Multiple bee stings leading to a delayed fatal coronary event with probable Kounis syndrome: a case report

Kounis syndrome—an acute coronary syndrome occurring in the setting of allergic or hypersensitivity reactions—remains an under-recognised clinical entity. In many cases, the diagnosis is largely probabilistic, particularly in the absence of confirmatory evidence such as mast-cell activation markers or intracoronary imaging. In the present context, while the clinical history of bee sting strongly supports Kounis syndrome as the most likely differential diagnosis, definitive confirmation is limited by the lack of objective mast-cell–related investigations. We report a 72-year-old man with hypertension and diabetes mellitus, a reformed smoker, who presented following multiple (three to four) bee stings localised to the right shoulder. At presentation, he exhibited features limited to a local allergic reaction, with no evidence of systemic involvement or anaphylaxis. He was managed with sting removal, antihistamines, and analgesics, and remained asymptomatic and stable on continuous monitoring during a 12-hour observation period. He was subsequently discharged in stable condition. Approximately one hour post-discharge, he became unresponsive at home, and bystander cardiopulmonary resuscitation (CPR) was initiated. On arrival at the emergency department, he was found to be in asystole. Advanced cardiac life support was continued, and return of spontaneous circulation (ROSC) was achieved. Post-resuscitation electrocardiography revealed inferior ST-elevation myocardial infarction with reciprocal changes. Bedside echocardiography demonstrated inferior wall hypokinesia with a left ventricular ejection fraction of 40%. Coronary angiography showed complete occlusion of the mid-right coronary artery with a non-obstructive left coronary system. A drug-eluting stent was successfully deployed, restoring TIMI 3 flow. However, approximately four to five hours after successful revascularisation, the patient developed refractory ventricular arrhythmias and succumbed despite ongoing resuscitative efforts. This case highlights a temporally plausible, though not definitively established, instance of delayed probable Type II Kounis syndrome following an apparently mild, local Hymenoptera sting reaction. It underscores the need for continued vigilance for delayed coronary events even after seemingly benign allergic presentations, and emphasises the inherent challenge of distinguishing Kounis syndrome from conventional atherosclerotic ST-elevation myocardial infarction in the absence of confirmatory allergic or mechanistic evidence.