Altitude related disorders
There are three main types of altitude related disorders: acute mountain sickness (AMS), which may progress to high altitude pulmonary edema (HAPE) or high altitude cerebral edema (HACE). All three conditions are due to the chronic hypobaric hypoxia which develops at high altitudes
Acute mountain sickness is generally a self-limiting condition. Features of AMS start to occur above 2,500 - 3,000m, developing gradually over 6-12 hours and potentially last a number of days:
Prevention and treatment of AMS
A minority of people above 4,000m go onto develop high altitude pulmonary oedema (HAPE) or high altitude cerebral oedema (HACE), potentially fatal conditions
Management of HACE
Management of HAPE
*the relative merits of these different treatments has only been studied in small trials. All seem to work by reducing systolic pulmonary artery pressure
Acute mountain sickness is generally a self-limiting condition. Features of AMS start to occur above 2,500 - 3,000m, developing gradually over 6-12 hours and potentially last a number of days:
- headache
- nausea
- fatigue
Prevention and treatment of AMS
- the risk of AMS may actually be positively correlated to physical fitness
- gain altitude at no more than 500 m per day
- acetazolamide (a carbonic anhydrase inhibitor) is widely used to prevent AMS and has a supporting evidence base
- treatment: descent
A minority of people above 4,000m go onto develop high altitude pulmonary oedema (HAPE) or high altitude cerebral oedema (HACE), potentially fatal conditions
- HAPE presents with classical pulmonary oedema features
- HACE presents with headache, ataxia, papilloedema
Management of HACE
- descent
- dexamethasone
Management of HAPE
- descent
- nifedipine, dexamethasone, acetazolamide, phosphodiesterase type V inhibitors*
- oxygen if available
*the relative merits of these different treatments has only been studied in small trials. All seem to work by reducing systolic pulmonary artery pressure