CARDIOVASCULAR JOURNAL OF AFRICA • Volume 34, No 4, September/October 2023 258 AFRICA Elective percutaneous coronary intervention (PCI) on day 12 showed 90% stenosis of the mid-right coronary artery (RCA) with a normal left anterior descending artery (LAD) and circumflex artery (Fig. 3). One drug-eluting stent was placed in the RCA and the patient had an uneventful recovery. Repeat TTE showed improved LV ejection fraction to 55%. The patient was discharged three days post PCI with a prescription of dual antiplatelet therapy (aspirin + clopidogrel), atorvastatin, metoprolol, nifedipine and basal-bolus insulin therapy. Discussion Kounis syndrome is the occurrence of ACS after an allergic insult, the latter of which can be hypersensitivity, anaphylactic or anaphylactoid conditions. The underlying mechanism has been attributed to mast cell (histamine) and platelet (platelet-activating factor) activation and interaction with other inflammatory cells such as macrophages and T lymphocytes, with involvement of a range of cytokine cascades, such as activation of the complement system (C3a, C5a).3 The end effect is coronary artery spasm and/or atheromatous plaque erosion or rupture. To date, three variants have been proposed, coronary spasm, acute myocardial infarction and stent thrombosis. Since its description, the list of allergic triggers for Kounis has been ever expanding. Medications, especially antibiotics, represent the most common iatrogenic trigger overall. In contrast, non-steroidal anti-inflammatory drugs were the most frequent trigger drugs for cases in the USA.4 Other trigger factors include various food and environmental exposures such as pollen and insect bites (bee sting).5 Given the ubiquitous presence of triggers, Kounis syndrome might not be a rare disease. However, there is a paucity of data on its prevalence and incidence, as the most relevant literature is case reports only. One study estimated the incidence of Kounis syndrome in the ED among all allergy patients in that study year to be 3.4%.3 When it comes to China, the country with the largest population, the number of case reports is surprisingly low. For Chinese patients, the triggers that have been reported include, but are not limited to, drug‑eluting stents,6 antibiotics,7 hormone pills,8 oral traditional Chinese medicines (TCM),9 intravenous cervus and cucumis polypeptides,9 intramuscular anisodamine,10 as well autoimmune conditions.11-13 This low number of cases reported in the Chinese population is in sharp contrast with the fact that most Kounis syndrome cases have been reported in southern Europe.3 This difference could well be attributed to increased awareness of physicians of the existence of Kounis syndrome in that geographic area, in addition to other factors such as differences in the prevalence of environmental triggers, medication prescription/consumption behaviour and genetic predisposition to an allergic response. One unique aspect of medical practice in China is the prescription of herbal TCM, both in oral and intravenous form, especially in the vast rural and regional areas. TCM injections have been associated with various adverse drug reactions, including hypersensitivity and anaphylactic shock.14-16 Besides, there have also been inappropriate antibiotic prescriptions, especially in Chinese primary healthcare facilities.17 Sadly, there is a recent case report of Kounis syndrome induced by inactivated SARS-COV-2 vaccine (inactivated CoronaVac from China) in Turkey,18 which would raise concern due to the national vaccine roll-out plan in China with reported delivery of more than 3.34 billion doses of SARS-COV-2 vaccine (inactivated virus vaccines) by the time of writing this report.19 These facts pose a higher risk of iatrogenic medication-related allergic reactions for Chinese patients. Therefore, the discrepancy between the existence of risk factors and very low incidence reports in China is likely to be explained, at least in part, by a missed, unrecognised and/or undiagnosed condition. Take our case, for example. The diagnosis could easily have been missed if we hadn’t probed into the history of a bee sting (which happened three days before presentation to the ED) and neglected its association with cardiac symptomatology in someone with high cardiac risk factors. Also, due to the relatively late onset of cardiac-type chest pain (34 hours after the sting) and late presentation for medical attention (36 hours after onset of chest pain), the patient was given a provisional diagnosis of aortic dissection in the local hospital. In our ED the initial diagnosis was allergic myocarditis after a negative CT aortogram, due to the unawareness of this condition. Luckily, medical management of ACS was not delayed, in concurrence with treatment of the allergic reaction. An elective PCI was organised when a diagnosis of Kounis syndrome was suspected after admission into the cardiology ward, which allows for clear delineation of the coronary anatomy and a potentially lifesaving stent placement. Not surprisingly, given the low incidence, there is a lack of guidelines for the treatment of ACS in the form of Kounis syndrome. The common practice involves therapies to cover Fig. 3. A, B: PCI showed 90% stenosis of the mid-RCA with a normal LAD and circumflex artery. C: One drug-eluting stent was placed in the RCA with satisfactory revascularisation. A C B
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