ST-Segment Elevation Beyond the Coronaries

BACKGROUND: Descending necrotizing mediastinitis (DNM) is a rare, life-threatening infection (mortality 18%-36%) that can extend to the pericardium and produce electrocardiogram changes mimicking ST-segmentelevation myocardial infarction (STEMI). CASE SUMMARY: A young, previously healthy man presented with anterior chest pain. Initial electrocardiogram showed ST-segment elevation prompting STEMI suspicion. Computed tomography angiography of the chest revealed deep neck infection with mediastinal and pericardial extension, diagnosing DNM. Cultures grew Streptococcus constellatus. Management included broad-spectrum intravenous antibiotics and surgical drainage/debridement with intensive care unit care; the patient recovered. DISCUSSION: DNM arises from oropharyngeal or odontogenic infection spreading along cervical fascial planes, with mortality driven by diagnostic delay and inadequate source control. S constellatus is an uncommon cause. This case highlights pericardial involvement as a noncoronary cause of ST elevation. TAKE-HOME MESSAGE: Consider noncoronary causes of ST-segment elevation; early imaging is essential to diagnose DNM and guide lifesaving source control.