An Unexpected Complication of Gastroenteritis.

A 37-year-old man, previously healthy, presented to the emergency department with retrosternal chest pain for 24 hours, in the context of watery diarrhea (five to six times a day), abdominal pain, and fever evolving over four days. Following medical assessment, a diagnosis of myopericarditis due to Campylobacter jejuni infection was made. This complication of C. jejuni infection is rare and poorly described, but given its rising incidence, increased vigilance is necessary. The affinity of C. jejuni for the myocardium and pericardium remains unclear. The underlying mechanisms are still under investigation, although several hypotheses are emerging. Its insidious presentation and generally favorable clinical course make it an entity often underdiagnosed and widely unrecognized. This case report aims to highlight the existence of this rare complication (0.4%) to prevent diagnostic errors and iatrogenic complications (potentially harmful coronary angiographies or fibrinolysis) that may result from it.