HEALTHNET

What are the symptoms of acute mountain sickness?

At altitude above 3,000 meters, 75% of people will have mild symptoms of acute mountain sickness...

(Posted on 15 March 2007)

Q1. My family will go skiing in Switzerland next month. It is my first time to climb up such high mountains. I am worried that I will suffer from acute mountain sickness. What are the symptoms?

A1. The higher peaks of the Swiss Alps can rise to over 4,000 meters. At altitude above 3,000 meters (10,000 feet), 75% of people will have mild symptoms of acute mountain sickness. As altitude increases, there are fewer oxygen molecules with each breath. Symptoms of acute mountain sickness can arise if our body is not adapted to it. Symptoms tend to be worse at night, when breathing is shallower. There is wide variation in individual susceptibility. Some may experience symptoms at altitudes as low as 2,500 meters (8,000 feet). The rate of ascent is an important factor other than the altitude.

The symptoms of acute mountain sickness usually start 12 to 24 hours after arrival at altitude, which include:

Fatigue
General feeling of malaise
Headache
Nausea & Dizziness
Loss of appetite
Disturbed sleep
Shortness of breath

Your symptoms may be mild, but you should still report them to your friends. They can keep an eye on your condition, and prepare for descend should symptoms get worse. Increasingly severe headache, repeated vomiting, difficulty in breathing, confusion and decreased muscular co-ordination are signs of danger. You should stop ascending and seek immediate medical care. High altitude and lower air pressure can cause the leaking of fluid from capillaries in the brain and the lungs. Severe instances can lead to death if not treated quickly.

Q2. Can any drug prevent acute mountain sickness?

A2. The rate and depth of our respiration is affected by the amount of oxygen present in the blood and the blood's acidity. We would breathe faster when there is not enough oxygen or if our blood is acidic. In high altitude, there are fewer oxygen molecules in each breath. Acidifying the blood may prevent or partly relieve the symptoms of acute mountain sickness by stimulating our respiration.

A drug called acetazolamide (brand name Diamox) is doing just that. The drug works on the kidneys, blocking the action of an enzyme important for the excretion of hydrogen ions. As a result, the urine becomes alkaline while the blood more acidic.

To be effective, the drug needs to be taken one or two days before the trip, and should be continued for three days once the highest altitude has been reached. This drug can cause increased urination. Make sure you would drink plenty of fluids and avoid alcohol. Some patients may experience blurring of vision as a side effect, and some may be allergic to it. For the hobbyists, it is advisable to save the drug for treatment purpose when symptoms have developed.

Q3. My 1-year-old nephew would be with us on this holiday. Is it safe to bring him up to the mountains?

A3. I would advise against bringing along any children for holidays to places where there is a genuine risk of acquiring acute mountain sickness. Compared with adults, young children have lower hemoglobin levels in the blood. The capacity of their red blood cells to carry oxygen is therefore lower. On the other hand, they have a higher level of activity. That's why young children are more susceptible to acute mountain sickness, as verified in various scientific studies. Worst of all, children may not be able to communicate with you even though they are not feeling well. Symptoms such as sleepiness, irritability and loss of appetite are non-specific and can be difficult to interpret.

Taking care of a one year old can be a tiring job even when at home. Kids would find throwing snowballs and building snowman in the valley far more exciting and enjoyable than trekking up the mountains. Remember too, that children have larger surface area to body mass ratio relatively, and are more vulnerable to cold injuries.

Source: Quality HealthCare