Acute mountain sickness, more commonly known as altitude sickness, is the single biggest killer on Kilimanjaro. This may surprise a few people who, given the large number of trekkers who climb Kilimanjaro each year, are under the mistaken impression that Africa’s highest mountain is also a safe mountain. Unfortunately, as any mountaineer will tell you, there’s no such thing as a safe mountain, particularly one nearly 6000m tall with extremes of climate near the summit and ferociously carnivorous animals roaming the lower slopes.
Your biggest enemy on Kilimanjaro, however, is likely to be neither the weather nor the wildlife but the altitude. Unsurprisingly, KINAPA are shy about revealing how many trekkers perish on Kili each year but what is known is that, during the millennium celebrations, when the mountain was swamped by more than a thousand trekkers on New Year’s Eve alone, three died and thirty-three more had to be rescued.
The authorities are doing what they can to minimize the number of deaths: guides are given thorough training in what to do if one of their group is showing signs of altitude sickness and trekkers are required to register each night upon arrival at the campsite and have to pay a US$20 ‘rescue fee’ as part of their park fees.
But you too can do your bit, by avoiding AMS in the first place. The pages in this section discuss in detail what AMS actually is, how it is caused, the symptoms and, finally, how to avoid it. Read this section carefully: it may well save your life.
Acute Mountain Sickness (AMS) The percentage of oxygen in the atmosphere at sea level is about 21%. As altitude increases, the percentage remains the same but the number of oxygen molecules per breath is reduced. At 12,000 feet (3,600 m) there are roughly 40% fewer oxygen molecules per breath so the body must adjust to having less oxygen. Altitude sickness, known as AMS, is caused by the failure of the body to adapt quickly enough to the reduced oxygen at increased altitudes. Altitude sickness can occur in some people as low as 8,000 feet, but serious symptoms do not usually occur until over 12,000 feet. Mountain medicine recognizes three altitude categories: High altitude: 4,900 to 11,500 ft (1,500 to 3,500 m) Very high altitude: 11,500 to 18,000 ft (3,500 to 5,500 m) Extreme altitude: 18,000 ft and above (5,500 m and above) In the first category, high altitude, AMS and decreased performance is common. In the second category, very high altitude, AMS and decreased performance are expected. And in extreme altitude, humans can function only for short periods of time, with acclimatization. Mount Kilimanjaro's summit stands at 19,340 feet - in extreme altitude.
There are four factors related to AMS:
Severe AMS results in an increase in the severity of the aforementioned symptoms including: Shortness of breath at rest
Inability to walk
Decreasing mental status
Fluid build-up in the lungs
Severe AMS requires immediate descent of around 2,000 feet (600 m) to a lower altitude. There are two serious conditions associated with severe altitude sickness; High Altitude Cerebral Edema (HACE) and High Altitude Pulmonary Edema (HAPE). Both of these happen less frequently, especially to those who are properly acclimatized.
But, when they do occur, it is usually in people going too high too fast or going very high and staying there. In both cases the lack of oxygen results in leakage of fluid through the capillary walls into either the lungs or the brain.
High Altitude Pulmonary Edema (HAPE)
HAPE results from fluid build up in the lungs. This fluid prevents effective oxygen exchange. As the condition becomes more severe, the level of oxygen in the bloodstream decreases, which leads to cyanosis, impaired cerebral function, and death. Symptoms of HAPE include:
Shortness of breath at rest
Tightness in the chest
Persistent cough bringing up white, watery, or frothy fluid
Marked fatigue and weakness
A feeling of impending suffocation at night
Confusion, and irrational behavior
Confusion, and irrational behavior are signs that insufficient oxygen is reaching the brain. In cases of HAPE, immediate descent of around 2,000 feet (600 m) is a necessary life-saving measure. Anyone suffering from HAPE must be evacuated to a medical facility for proper follow-up treatment.
The Gamow Bag is portable hyperbaric chamber used to treat AMS. The inflatable bag simulates descent to lower altitude. The patient is placed inside the bag and it is inflated with air to increase the concentration of oxygen. A Gamow bag weighs about 12 lbs. Inflated, the bag is about 7 feet long and 2 feet in diameter At 9,800 feet (3,000 m), the Gamow Bag can simulate a descent of 4,800 feet (1,500 m). After two hours in the bag, the person's body chemistry will have "reset" to the lower altitude. This acclimatization lasts for up to 12 hours outside of the bag which should be enough time to get them down to a lower altitude and allow for further acclimatization. Our staff does not carry Gamow bags. Use of a Gamow bag on Mount Kilimanjaro is impractical because descent is the most immediate, accessible treatment.
Diamox (generic name acetazolamide) is an F.D.A. approved drug for the prevention and treatment of AMS. The medication acidifies the blood, which causes an increase in respiration, thus accelerating acclimatization. Diamox does not disguise symptoms of altitude sickness, it prevents it.
Studies have shown that Diamox at a dose of 250 mg every eight to twelve hours before and during rapid ascent to altitude results in fewer and/or less severe symptoms of acute mountain sickness (AMS).
The medicine should be continued until you are below the altitude where symptoms became bothersome. Side effects of acetazolamide include tingling or numbness in the fingers, toes and face, taste alterations, excessive urination; and rarely, blurring of vision. These go away when the medicine is stopped. It is a personal choice of the climber whether or not to take Diamox as a preventative measure against AMS.
Our guides will use a pulse oximeter to measure the oxygen level in your blood and your pulse rate in the morning and evening. The oximeter is placed on a climber's fingertip. The oximeter uses two beams of light that shine into small blood vessels and capillaries in your finger. The sensor reflects the amount of oxygen in the blood. Oxygen saturation is a measurement of how much oxygen your blood is carrying as a percentage of the maximum it could carry. Normal blood oxygen levels at sea level are 95-100%.
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