Case Report: Rapid altitude transition as an environmental trigger for acute sigmoid volvulus following oxaliplatin-based chemotherapy.

Background: Environmental and lifestyle factors-including rapid altitude transitions and cytotoxic chemotherapy-are increasingly recognized as drivers of gastrointestinal pathology. To our knowledge, the combined effect of recent oxaliplatin-based chemotherapy and abrupt hypobaric transition on acute colonic volvulus has not been previously reported. We describe a case of acute sigmoid volvulus (SV) with full-thickness gangrene that developed within 2 h of high-altitude arrival after commercial air travel, despite upper abdominal CT at sea level less than 48 h earlier showing no bowel dilation, air-fluid levels, or signs of obstruction. Case description: A 33-year-old man with hepatocellular carcinoma (HCC, CNLC stage Ib) underwent transcatheter arterial chemoembolization (TACE) combined with hepatic arterial infusion chemotherapy (HAIC) using a FOLFOX-based regimen (oxaliplatin, 5-fluorouracil, and leucovorin) at a sea-level hospital in Xiamen (63 m). Pre-discharge upper abdominal CT performed less than 48 h before symptom onset showed no bowel dilation, no air-fluid levels, and no obstructive findings. He remained asymptomatic during two commercial flight segments (Xiamen → Chengdu → Lhasa) and a ground-level layover, but within 2 h of disembarking in Lhasa (altitude 3,650 m) developed severe abdominal cramping, profound distension, complete obstipation, and intense tenesmus. On presentation to our emergency department, he exhibited diffuse peritonitis and SpO Conclusion: This case suggests that acute high-altitude hypobaric exposure may have contributed to the onset of sigmoid volvulus. The supporting evidence is distinctive in both timing and imaging: sea-level baseline imaging, an asymptomatic two-leg flight with layover, and an unchanged hepatic tumor serving as an internal anatomical reference. Rapid hypobaric exposure, recent systemic chemotherapy, and colonic redundancy may together precipitate catastrophic mechanical GI emergencies. However, as this is a single case report, the observed association could be explained by chance alone and cannot establish causality. Further cases, case series, and other lines of evidence are required before far-reaching conclusions or changes to clinical care can be made. Acute abdominal symptoms after high-altitude arrival should prompt consideration of acute surgical conditions in addition to acute mountain sickness.