Superior Mesenteric Vein Thrombosis in a Young Lowlander at High Altitude: A Case of Delayed Diagnosis Due to Isolated Fever

Superior mesenteric vein thrombosis (SMVT) is an uncommon but potentially life-threatening condition, particularly in high-altitude environments where hypoxia induces a prothrombotic state by elevating hematocrit, promoting endothelial dysfunction, and upregulating procoagulant factors, thereby substantially increasing the risk of SMVT and other thrombotic diseases. We report a rare clinical presentation of SMVT in a 30-year-old male military lowlander deployed at 17,000 ft for three months, who initially presented with isolated low-grade fever, leading to a delayed diagnosis (11 days to abdominal pain onset and 20 days to imaging). Contrast-enhanced computed tomography (CECT) confirmed SMVT with mesenteric fat stranding, but no bowel ischemia. This case underscores the importance of maintaining a high index of suspicion for thromboembolic disorders in high-altitude personnel, even with nonspecific symptoms, such as fever.