High altitude retinal hemorrhages in the expeditions to 8,000 meter peaks. A study of 10 cases

BACKGROUND: Retinal haemorrhages are common at high altitude. Their pathogenesis is unknown. It has been suggested that they are less frequent in sherpas, and that possible predisposing factors might be the abscence of previous high-altitude experience, the extent of the high-altitude hypoxic exposure, polycythemia (because of hyperviscosity), history of cough and Valsalva manoeuvres during the expedition, existence of severe forms of mountain sickness (high-altitude pulmonary oedema and high-altitude cerebral oedema) and use of antiinflammatory drugs. The aim of this study is to know the incidence of retinal haemorrhages in the expeditions to mountains higher than 8.000 m and their relationship to the previously referred possible predisposing factors. SUBJECTS AND METHODS: Funduscopy was performed on 17 healthy subjects taking part in expeditions to Cho-Oyu (8.201 m) and to Shisha Pangma (8.046 m) and on six of their Nepali coworkers. RESULTS: Retinal haemorrhages were found in 10 of the European (59%) and in none of the Nepali mountaineers (p = 0.019). Other 2 Spanish climbers had tortuosity and engorgment of the retinal veins. No statistical association was found between retinal haemorrhages and maximal altitude attained prior to the expedition, maximal altitude reached during the present expedition, number of nights spent at extreme altitude, weight loss as an expression of chronic exposure to hypoxia, haemoglobin, history of cough or Valsalva manoeuvres during the expedition, existence of severe forms of mountain sickness or use of drugs. CONCLUSIONS: These results do not allow us to state that the mentioned factors predispose to high-altitude retinal haemorrhages.