Altitude Sickness Strikes Young Hikers

It’s an extremely rare disease, little understood and capable of killing within hours.

Acute mountain sickness (AMS) is a lethal threat to the thousands who venture each year to the world’s mountain ranges.

“A victim can slip into a fatal coma in a matter of hours after feeling the first symptoms,” said Dr. Charles Clarke, director of the Mountain Medicine Center at St. Bartholomew’s Hospital.

“A person can be feeling queasy at 13,000 feet and be moribund the next morning,” he said.

Most travelers to high altitudes experience some symptoms of AMS--headaches, fatigue, undue breathlessness on exertion, nausea and dizziness.

“There is usually some prelude, but if left untreated AMS can quickly develop into deadly cerebral or pulmonary edema,” Clarke said.

“If you are behaving as if drunk, with a broad rolling gait and slurred speech, you’ve probably got cerebral edema,” he said. “Likewise, over-breathing at rest and an inability to complete sentences are likely signs of pulmonary edema.”

Clarke said the precise pathological mechanism is unknown, but because of a lack of oxygen, the body’s blood flow is increased, causing the capillaries to leak and build up fluid in the brain or lungs.

“There is only one cure, and that is speedy descent to lower altitudes,” Clarke said.

Doctors on mountaineering expeditions now treat AMS by administering steroid drugs that rid the body of fluid. Portable pressure chambers that can simulate lower altitudes are also used.

But these are stopgap measures, and there is no life-saving substitute for speedy descent into a more oxygen-rich environment. Sometimes a descent of only 1,500 feet can make the difference between life and death.

Nobody knows what single factor triggers AMS in an individual, and there is no way of predicting a person’s susceptibility.

Ironically the young and fit are usually the most vulnerable.

“Young and enthusiastic people tend to get it worse,” Clarke said. “They normally overdo it and suffer the consequences.”

He said older people, the inactive and even heavy smokers often escape the worst effects of AMS.

“As one ages, the brain gets smaller and can deal with a bit of swelling from the effects of altitude,” Clarke said.

The danger facing young and even experienced climbers was tragically highlighted last year when Briton Cathy Jessop died on her honeymoon in Nepal. The bride, an accomplished mountaineer with high-altitude experience, collapsed and died of pulmonary edema in the foothills of Mt. Everest. Her husband, Ulric, buried his wife of 18 days and trekked for more than a week to Katmandu to seek help for a proper burial.

Each year, thousands of trekkers, climbers and skiers suffer from some form of AMS, but the number of fatalities is small.

Clarke, an accomplished mountaineer who has climbed to an altitude of 24,000 feet on Everest, says he has only seen a handful of deaths from AMS in his 30-year climbing career.

“This is a tiny statistic, especially when set against a mortality rate of about 5% for high-altitude climbers,” he said. “Unfortunately it is not always possible to know how a climber has met his or her death, and the disease can sometimes rear its head in a most dramatic way.”

Six years ago, 13 climbers were wiped out on K2, the world’s second-highest peak, during a week of savage storms that wore down the resistance of mountaineers huddled in their tents below the 29,028-foot summit.

“It is a myth that experienced people can cope better with AMS,” Clarke said. “The only way to avoid it is by a very gradual ascent to high altitude, and once severe symptoms develop, waste no time in coming down.”