Kounis Syndrome: Alternative Terminology
Kounis syndrome is also known as "allergic acute coronary syndrome" or "allergic myocardial infarction." 1, 2, 3
Definition and Core Concept
Kounis syndrome represents the coincidental occurrence of acute coronary syndrome (ACS) with hypersensitivity, allergic, anaphylactic, or anaphylactoid reactions following exposure to an allergen. 1, 2, 4 The condition combines allergic reactions with acute coronary events including vasospastic angina, acute myocardial infarction, and stent thrombosis. 2, 5
Pathophysiological Basis for the Terminology
The syndrome results from mast cell degranulation with subsequent release of inflammatory mediators, leading to:
- Coronary artery vasospasm in patients without pre-existing coronary disease 1, 2
- Atheromatous plaque erosion or rupture during the allergic reaction in patients with underlying coronary disease 2, 4
- Stent thrombosis with occluding thrombus in patients with previous coronary interventions 2, 5
Clinical Recognition
The diagnosis is fundamentally clinical and based on the temporal relationship between the allergic/anaphylactic event and the onset of acute coronary syndrome symptoms. 4 The syndrome manifests when chest pain, ECG changes consistent with myocardial ischemia or infarction, and cardiac biomarker elevation occur in conjunction with signs of allergic reaction (urticaria, pruritus, angioedema, bronchospasm, or anaphylaxis). 1, 2
Important Clinical Context
The heart and coronary arteries appear to be the primary target organs in severe anaphylaxis when it manifests as Kounis syndrome. 5 This underscores why "allergic acute coronary syndrome" accurately captures the dual pathophysiology—it is simultaneously an allergic emergency and a cardiac emergency requiring management of both components. 2
The syndrome affects patients of any age and involves numerous continuously increasing causes including medications (particularly antibiotics like ceftriaxone and cefuroxime), contrast media, foods, and environmental exposures. 1, 2, 5