Kounis syndrome type I induced by an intramuscular injection of diclofenac: A literature review based on a case report.

Key Clinical Message: The history of any allergy to the medications should be asked by physicians before administration of the medication. The coincidence of allergic and ACS symptoms after a short time of drug administration might be an indicator of Kounis syndrome. Allergic and coronary symptoms should be considered and treated. Abstract: Ischemic heart disease is still the leading cause of death worldwide. Some medications, including NSAIDS and antibiotics, can cause allergic reactions with cardiac manifestations due to spasms of the coronary arteries. In this case, we present a patient with chest pain syndrome due to a hypersensitivity reaction caused by an intramuscular (IM) diclofenac injection. The patient was a 51-year-old male who presented to the emergency department complaining of retrosternal chest pain, breathlessness, and pruritis that started half an hour after an IM diclofenac injection he had because of low back pain. The allergic symptoms subsided with an antihistamine injection, but chest pain and dyspnea remained stable. He was admitted due to the presence of ST-segment depression in leads II, III, and AVF and underwent percutaneous coronary angiography, which was normal. The patient was discharged with the diagnosis of Kounis syndrome, and he had an uneventful follow-up 1 year later. Kounis hypersensitivity-associated acute coronary syndrome, especially type I variant coronary spasm due to endothelial dysfunction is a type of acute myocardial syndrome. The following report describes an uncommon case of anaphylaxis-associated Kounis type I syndrome manifesting ST-segment changes in a male patient following an intramuscular injection of diclofenac.