Kounis Syndrome (KS) is an acute coronary syndrome that arises as a direct result of mast cell degranulation during an allergic or anaphylactic reaction.
KS usually presents as chest pain during an acute allergic or anaphylactic reaction. There are three recognized variants:
Type I: Patient has no predisposing coronary artery disease.
There are two possible outcomes:
- Coronary artery spasm with no appreciable increase in cardiac enzymes or troponins
- Coronary artery spasm that evolves to acute myocardiac infarction (heart attack) with accompanying increase in cardiac enzymes or troponins
Type II: Patient has history of coronary artery disease. There are two possible outcomes:
- Coronary artery spasm with no appreciable increase in cardiac enzymes or troponins
- Plaque erosion or rupture that evolves to acute myocardiac infarction (heart attack) with accompanying increase in cardiac enzymes or troponins
Type III: Patient has history of coronary artery disease and a drug eluting coronary stent. There are two possible outcomes:
- Coronary artery spasm with no appreciable increase in cardiac enzymes or troponins
- Thrombosis that evolves to acute myocardiac infarction (heart attack) with accompanying increase in cardiac enzymes or troponins
A number of mast cell mediators have effects that can cause coronary spasm or thrombosis. Beyond their direct effects, they also perpetuate an inflammatory cycle that results in activation and infiltration by inflammatory cells
| Mediator | Effect |
| Histamine | Coronary vasoconstriction, activation of platelets, increase expression of tissue factor |
| Chymase | Activation of interstitial collagenase, gelatinase, stromelysin resulting in plaque rupture, generation of angiotensin II, a powerful vasoconstrictor |
| Cathepsin D | Generation of angiotensin II, a powerful vasoconstrictor |
| Leukotrienes (LTC4, LTD4, LTE4) | Powerful vasoconstrictor, levels increased during acute unstable angina |
| Tryptase | Activation of interstitial collagenase, gelatinase, stromelysin resulting in plaque rupture |
| Thromboxane | Platelet aggregation, vasoconstriction |
| PAF | Vasoconstriction, aggregation of platelets |
| Platelets | Vasoconstriction, thrombosis |
References:
Kounis Syndrome (allergic angina and allergic myocardial infarction). Kounis NG, et al. In: Angina Pectoris: Etiology, Pathogenesis and Treatment 2008.
Lippi G, et al. Cardiac troponin I is increased in patients admitted to the emergency department with severe allergic reactions. A case-control study. International Journal of Cardiology 2015, 194: 68-69.
Kounis NG, et al. The heart and coronary arteries as primary target in severe allergic reactions: Cardiac troponins and the Kounis hypersensitivity-associated acute coronary syndrome. International Journal of Cardiology 2015, 198: 83-84.
Fassio F, et al. Kounis syndrome: a concise review with focus on management. European Journal of Internal Medicine 2016; 30:7-10.
Kounis Syndrome: Aspects on pathophysiology and management. European Journal of Internal Medicine 2016.