Ultra-high altitude environment triggers life-threatening gastrointestinal bleeding in undiagnosed Crohn's disease: a case report.

This case describes a 31-year-old male who presented with acute exacerbation of pre-existing, undiagnosed Crohn's disease (CD) one week after rapid ascent to 4,500 meters. The patient had a long-standing history of recurrent oral ulcers and perianal fistulas. He was initially misdiagnosed with acute appendicitis based on right lower quadrant pain and fever, which resulted in emergency surgery. On postoperative day 9, life-threatening gastrointestinal bleeding (GIB) occurred. Management at the remote high-altitude facility was challenged by diagnostic limitations (lack of advanced imaging and endoscopic equipment), blood supply shortages, and lack of advanced interventions, which hindered the timely identification of the underlying disease and bleeding site. After emergency evacuation to lower altitude, GIB resolved spontaneously. Colonoscopy revealed ileocecal valve ulcers. Two-year follow-up with recurrent GIB and progressive intestinal ulceration further confirmed the diagnosis of CD. This case highlights ultra-high altitude exposure as a potential trigger for acute exacerbation of pre-existing CD, where atypical presentation often leads to misdiagnosis. The importance of recognizing extraintestinal manifestations in acute abdominal conditions is emphasized, alongside the critical challenges in managing complex cases in resource-limited high-altitude settings.