Ceftriaxone-induced Kounis syndrome presenting with arrhythmia: a case report and literature review from a resource-limited setting

Introduction and importance: Kounis syndrome (KS), a rare allergic reaction-induced myocardial injury, can be triggered by various allergens, such as antibiotics (including ceftriaxone). Ceftriaxone carries a higher risk of anaphylactoid reactions compared to other antibiotics. Presentation of case: A 65-year-old female from Ethiopia presented with 3 days of nausea, diarrhea, vomiting, abdominal pain, fever, and fatigue. Examination revealed tachycardia and fever. Initial tests, including electrocardiography (ECG), were normal, except for leukocytosis. Sepsis from a gastrointestinal source was suspected, and she was started on intravenous fluids, metronidazole, and ceftriaxone. Immediately after the first dose of ceftriaxone, she developed signs of anaphylaxis. Repeat ECG revealed diffuse ST-segment elevation and atrial fibrillation. Ceftriaxone-induced KS was suspected. Anti-ischemic treatment and supportive care were initiated with discontinuation of ceftriaxone. After 2 hours, her ECG normalized. Troponin and echo were normal. She improved and was discharged after 5 days. Clinical discussion: Ceftriaxone-induced KS is a rare, potentially fatal manifestation of allergic reactions to ceftriaxone, affecting about 1.1%–3.4% of all allergic reactions. Although the exact mechanism is unknown, this immune-mediated reaction results in significant effects on the cardiovascular system. KS is classified into three types based on the underlying cause and is typically managed by immediate discontinuation of the triggering agent, but it still carries a high in-hospital mortality rate of approximately 7%. Suspicion should be high in allergic drug reactions. Conclusion: Ceftriaxone-induced KS is a rare but dangerous complication of ceftriaxone allergy. Improving outcomes requires a focus on prevention through detailed allergy histories, prompt diagnosis, and better healthcare resources.