Adult-Onset IgA Vasculitis With Concurrent Gastrointestinal and Possible Coronary Involvement.

IgA vasculitis, also known as Henoch-Schönlein purpura, is a small-vessel vasculitis that can affect multiple organ systems, most commonly the skin, GI tract, and kidneys. Although it is typically a condition involving the pediatric population, adult cases may follow a more severe, rapidly progressive course with more variable presentations. We present the case of a 50-year-old man with biopsy-proven IgA nephropathy with GI and possible coronary involvement. He initially presented with arthralgia and a purpuric rash, later developing rectal bleeding and eventually abdominal distention, nausea, and vomiting. CT imaging confirmed small bowel inflammation and ruled out mechanical obstruction. Despite treatment with oral and intravenous corticosteroids, his condition deteriorated, prompting escalation to rituximab, after which he initially improved and was discharged. Shortly after discharge, he re-presented with chest pain and was found to have an ST-elevation myocardial infarction (STEMI) requiring critical care admission. Within days, he suffered a ventricular fibrillation arrest and passed away despite resuscitation efforts. This case highlights the aggressive trajectory of adult-onset IgA vasculitis, the potential for severe GI involvement, the considerable diagnostic difficulty in attributing subsequent cardiac events, especially with pre-existing cardiovascular disease, and the urgent need for clearer treatment strategies in severe presentations.