Arterial Thrombosis at High Altitude Resulting in Loss of Limb

Abstract

Vascular thrombosis is an uncommon but recognized peril of high altitude travel. Traditionally, this has been associated with prolonged exposure to extreme altitudes where dehydration, hemoconcentration, cold, use of constrictive clothing, and enforced stasis due to severe weather have been named as contributing factors. It is widely hypothesized that hypoxia itself alters the coagulation cascade to create a prothrombotic milieu, though evidence thus far is limited and frequently conflicting. Case reports have described venous thrombosis, pulmonary embolism, cerebrovascular accidents, transient ischemic attacks, and thromboses of the portal circulation at altitude. We report a unique case of aortic thrombosis presenting with critical lower extremity ischemia in a previously healthy individual after a brief exposure to altitudes up to 4620 m. None of the frequently invoked risk factors of dehydration, cold, enforced use of constrictive clothing, weather-imposed inactivity, or extreme altitude were present, and no medical predisposition to thrombosis was identified, suggesting hypoxia as the most likely prothrombotic stimulus. We discuss the treatment of this problem and the application of Doppler ultrasonography in a wilderness setting.

Biventricular thrombosis in a structurally normal heart at high altitude

“…The exact underlying mechanism of this is not known but it is postulated to be multifactorial resulting from altered coagulation cascade, haematocrit values and platelet reactivity 1 2. Platelet adhesiveness and aggregation has been shown to be increased at HA.…”

“…Platelet adhesiveness and aggregation has been shown to be increased at HA. In addition, hyperviscosity resulting from hypoxia mediated by increased red cell counts along with dehydration also increases the risk of thrombosis 1 2. Associated hereditary thrombophilic state may compound the above mentioned altered physiological state leading to an increased risk of thrombosis.…”

“…Exposure to high altitude (HA) has been observed to result in a hypercoagulable state, thus predisposing individuals to thromboembolic events 1 2. Environmental conditions at HA such as hypoxia; dehydration; enforced stasis and use of constrictive clothing due to low temperatures predispose individuals to the occurrence of thrombotic events 1 2.…”

“…Environmental conditions at HA such as hypoxia; dehydration; enforced stasis and use of constrictive clothing due to low temperatures predispose individuals to the occurrence of thrombotic events 1 2. The condition gets further compounded in individuals with underlying hereditary thrombophilic disorders which may result in the occurrence of thrombosis at unusual sites 3 4.…”

Ultrasound in Austere Environments

“…Veins that are noncompressible or that lack flow indicate the presence of a venous clot. Fagenholz et al (2007c) reported a case of arterial thrombosis at high altitude. They describe a previously healthy 41-year-old male hiking the Everest Base Camp trek with acute right lower extremity pain and loss of distal pulses.…”