Portal system thrombosis: a complication of long-term residence at extreme altitude.

ABSTRACT

BACKGROUND: With induction of the Indian Army to heights over 5,000 meters above sea level, complications of long-term stay at extreme altitude have come to light. We describe our experience with patients developing portal system thrombosis. METHODS: Clinical data were collected over 2 years on patients hospitalized for thrombotic complications from high-altitude (HAA) and non-high altitude (non-HAA) areas. Site of thrombosis was confirmed by imaging or at surgery. Patients were investigated for conditions that predispose to venous thrombosis. RESULTS: Ten cases of portal system thrombosis were seen during the period; of these, 9 (mean age 28 [SD 3.9] years; all men) were from HAA. Mean duration of residence in HAA was 12.4 (4.9) months; two were smokers and six drank 7-22 g alcohol/day at least 5 times a week. The first symptom was abdominal pain; this was later complicated by gastrointestinal bleeding (n=5), fever (7), vomiting (7), and weight loss (5). Average time between onset of first symptom and reaching a tertiary-care hospital was 9.5 (4.7) days. Clinical examination showed ascites (8 cases), splenomegaly (7), and hepatomegaly (6). Mean hemoglobin level at admission was 15.8 (3.4) g/dL. Ascites was hemorrhagic; five cases also had large splenic hematoma. The site of thrombosis was splenic vein (7 cases), portal vein (6), and superior (4) and inferior (1) mesenteric vein. None of 5 patients investigated had any prothrombotic condition. Endoscopic/ sonographic evidence of development of collaterals appeared as early as 12-20 days after onset of symptoms. CONCLUSION: Residence in HAA for extended periods is a risk factor for development of portal system thrombosis. Persistent pain in abdomen in such individuals should raise the possibility of portal system thrombosis.