Acute mountain sickness : A common problem at high altitude

Hills are the charm and most of the people prefer to go to hills for a good vacation, but there are some who just fall into trouble rather than to enjoy due to sickness caused by high altitude. Some may face a tolerable sickness but some may even have emergencies.

High altitude is above 2700 meters from sea level and there may be low temperature, low oxygen and increased radiation which are the culprit of causing the problem.

The type of problems may be acute mountain sickness to more severe high altitude pulmonary edema and high altitude cerebral edema.

Acute mountain sickness

Acute mountain sickness is a benign and reversible condition occuring in travellers ascending to altitude of 3000 meters. There may be hypoxia which stimulate renin to angitensin to finally aldosterone which releases ADH which results in to fluid retention. Hypoxia may also lead to dilatation of cerebral blood vessels with increased blood flow.

Symptoms of acute mountain sickness

The symptoms develop within 6 to 24 hours of an ascent and vary in severity from trivial to incapacitating. Headache is the prominent presenting symptom and can be over forehead(frontal), it is throbbing and aggravates by any exertion and is more severe in morning. Headache is due to dilatation of cerebral blood vessels.

In a severe cases there may be some other associated symptoms along with headache like anorexia, giddiness, insomnia, nausea and vomiting. Sometimes ataxia and peripheral edema may be present.

In rare instances some may find high altitude intolerable and may suffer with some serious sequelae like high altitude pulmonry edema and high altitude cerebral edema.

Management and prevention of acute mountain sickness

The best way to manage acute mountain sickness is to acclimatize by ascending gradually but as most of the person are tourist and time factor may be important so this may not be feasible to all.

In mild cases, rest and an analgesic and antiemetic are adequate and symptoms resolve after 12 to 48 hours at a stable altitude though may recur with further acsent.

If there is persistent symptom and severe form of illness acetazolamide is given which is a carbonic anhydrase inhibitor. It is given in a dose of 250 mg 8 hourly for 2-3 days. The symptoms of high altitude is probably due to alkalosis and that is why it respond to acetazolamide.

Dexamethasone 8 mg should be given immediately followed by 4mg 8 hourly if symptom persists. Though it is a steroid and should its use should be limited to severe symptoms.

The person should always be alert and if high altitude pulmonary edema or high altitude cerebral edema occurs should report to the doctor immediately.