D1.289 - The buzz that nearly broke a heart: A case of Kounis Syndrome following a Hymenoptera sting

Amongst the spectrum of clinical presentations associated with hypersensitivity reactions, Kounis Syndrome represents a distinct entity, characterised by vasospastic allergic angina, allergic myocardial infarction or stent thrombosis occurring in the context of a hypersensitivity reaction.

We present the case of a 50-year-old male patient with no significant past medical history. Consent to collect retrospective patient data was obtained in accordance with ethical regulations.

He was initially stung by a honeybee and, minutes later, developed urticaria, dyspnoea, chest pain, nausea, dizziness and syncope. He received emergency care and was monitored for six hours. However, no medical records are available.

A year later, he was stung by a bumblebee and experienced chest pain, dyspnoea, nausea, dizziness and syncope. He received emergency care and was hospitalised due to persistent chest pain. Paraclinical explorations were consistent with myocardial infarction. Coronary angiography excluded pre-existing atheromatous plaques and confirmed coronary vasospasm. The diagnosis of Kounis syndrome was established.

Two months later, following a wasp sting, he developed mild chest pain, dyspnoea, and nausea, which resolved within 30 minutes after self-administered intramuscular corticosteroids.

He was prescribed a complete emergency kit. 

Specific IgEs (sIgEs) have been identified for honeybee venom at 13,29 kU/L, Api m 1 at 10,52 kU/L and Api m 10 at 1.99 kU/L. The sIgEs for venom extract of Vespula spp and Polistes spp was negative, but the sIgEs for antigen 5 were positive for both, at 0.41 kU/L and 0.43 kU/L respectively. Baseline tryptase was normal.

Sensitisation to honeybee venom and cross-reactivity to bumblebee venom accounts for the first two reactions.

The milder clinical reaction following a wasp sting, and the low levels of sIgE to Ves v5 suggest relevant co-sensitisation.

Specific allergen immunotherapy for honeybee and wasp venom can be discussed, but only a limited number of cases have been reported in the literature. The decision will be made once the cardiologist confirms cardiovascular stability and the patient gives informed consent.

We report a patient with three anaphylactic reactions following stings from different Hymenoptera, one of which was documented as Kounis syndrome. The allergy work-up is a key step in establishing sensitisation, implementing allergen avoidance strategies and allergen immunotherapy.