Travelling safely to places at high altitude - Understanding and preventing altitude illness.

BACKGROUND: Greater numbers of people are travelling to places at high altitude each year. Altitude illness is common in places at high altitude and may be life-threatening. General practitioners (GPs) are best placed to provide evidence-based advice to keep travellers well informed of the possible risks they may encounter in places at high altitude.

OBJECTIVE: The aim of this article is to review knowledge on altitude illness in order to help GPs assist patients to travel safely to places at high altitude.

DISCUSSION: Acclimatisation to high altitude is a complex process and when inadequate leads to the pathological changes of altitude illness, including high-altitude headache, cerebral oedema, pulmonary oedema and acute mountain sickness. Higher ascent, faster rate of ascent and a previous history of altitude illness increase the risk of altitude illness. Acetazolamide and other medications used to prevent altitude illness are discussed in detail, including the finding that inhaled budesonide may prevent altitude illness.