title: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Army Hospital R & R, Delhi Cantt, New Delhi.
authors.forename: A C
authors.initials: AC
authors.lastname: Anand
authors.forename: A
authors.initials: A
authors.lastname: Saha
authors.forename: S K
authors.initials: SK
authors.lastname: Jha
authors.forename: R
authors.initials: R
authors.lastname: Kumar
authors.forename: V
authors.initials: V
authors.lastname: Sharma
authors.forename: C M
authors.initials: CM
authors.lastname: Adya
mesh_terms: D000328:Adult; D000531:Altitude; D006502:Budd-Chiari Syndrome / Q000175:diagnosis* / Q000453:epidemiology*; D016022:Case-Control Studies; D003287:Contrast Media; D006801:Humans; D015994:Incidence; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D011446:Prospective Studies; D012016:Reference Values; D018570:Risk Assessment; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D018608:Ultrasonography, Doppler
chemical_list: D003287:Contrast Media