Coronary spasm as a manifestation of allergic reaction to contrast material: a case report of Kounis syndrome.

Background: Kounis syndrome is a rare but significant clinical entity that combines hypersensitivity reactions with acute coronary syndromes. It is triggered by various allergens, including contrast media, leading to coronary vasospasm, atheromatous plaque rupture, or stent thrombosis. Despite its clinical relevance, the diagnosis is often challenging due to its multifaceted presentation. Case summary: We report the case of a 60-year-old woman with a history of bronchial adenocarcinoma treated with pembrolizumab, who developed Kounis syndrome Type 1 following the administration of iodinated contrast media during a computed tomography scan. Shortly after receiving the contrast agent, the patient experienced acute thoracic pain, dyspnoea, and ST-segment elevations indicative of inferior ischaemia. Emergency coronary angiography revealed a coronary vasospasm without significant stenosis, which resolved upon administration of intracoronary nitroglycerin. The diagnosis of Kounis syndrome was further supported by delayed hypersensitivity symptoms, including a trunk-accentuated rash. Management included antihistamines, corticosteroids, and vasodilators, resulting in complete resolution of symptoms. Discussion: This case highlights the importance of recognizing Kounis syndrome in patients presenting with simultaneous allergic and cardiac symptoms, particularly following exposure to known triggers like contrast media. Early identification and a multidisciplinary approach are crucial for appropriate management, balancing treatment for both hypersensitivity and acute coronary syndromes.