Altitude Acclimatization, Acute Mountain Sickness, HACE and HAPE While Climbing Mount Kilimanjaro

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Altitude Acclimatization

Climbing Kilimanjaro is probably one of the most dangerous things you will ever do. In 2006, approximately 1,000 people were evacuated from the mountain. Approximately 10 deaths are reported every year on the mountain. The main cause of death is altitude sickness. Everyone climbing Mount Kilimanjaro should be familiar with the symptoms of altitude sickness.

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. 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. It is not the height that is most troublesome, but the rate of ascension. It is difficult to determine who may be affected by altitude sickness since there are no specific factors such as age, sex, or physical condition that correlate with susceptibility.

At over 10,000 feet (3,000 m), more than 75% of climbers will experience at least some form of mild AMS.

The main cause of altitude sickness is going too high too quickly. Given enough time, your body will adapt to the decrease in oxygen at a specific altitude. This process is known as acclimatization and generally takes one to three days at any given altitude. Several changes take place in the body which enable it to cope with decreased oxygen:

The depth of respiration increases
The body produces more red blood cells to carry oxygen
Pressure in pulmonary capillaries is increased, "forcing" blood into parts of the lung which are not normally used when breathing at sea level
The body produces more of a particular enzyme that causes the release of oxygen from hemoglobin to the body tissues

Again, AMS is very common at high altitude. Many people will experience mild AMS during the acclimatization process. The symptoms usually start 12 to 24 hours after arrival at altitude and will normally disappear within 48 hours. The symptoms of Mild AMS include:

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

Symptoms tend to be worse at night and when respiratory drive is decreased. Mild AMS does not interfere with normal activity and symptoms generally subside as the body acclimatizes. As long as symptoms are mild, and only a nuisance, ascent can continue at a moderate rate.

While hiking, it is essential that you communicate any symptoms of illness immediately to others on your trip.

The signs and symptoms of Moderate AMS include:

Severe headache that is not relieved by medication
Nausea and vomiting, increasing weakness and fatigue
Shortness of breath
Decreased coordination (ataxia)

Normal activity is difficult, although the person may still be able to walk on their own. At this stage, only advanced medications or descent can reverse the problem. It is important to get the person to descend before the ataxia reaches the point where they cannot walk on their own (which would necessitate a stretcher evacuation). Descending only 1,000 feet (300 m) will result in some improvement, and 24 hours at the lower altitude will result in a significant improvement. The person should remain at lower altitude until all the symptoms have subsided. At this point, the person has become acclimatized to that altitude and can begin ascending again.

Continuing on to higher altitude while experiencing moderate AMS can lead to death.

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.

High Altitude Cerebral Edema (HACE)

HACE is the result of the swelling of brain tissue from fluid leakage. Symptoms of HACE include:

Headache
Weakness
Disorientation
Loss of co-ordination
Decreasing levels of consciousness
Loss of memory
Hallucinations & Psychotic behavior
Coma

This condition is rapidly fatal unless the afflicted person experiences immediate descent. Anyone suffering from HACE must be evacuated to a medical facility for follow-up treatment.

Proper Acclimatization Guidelines

The following are a guide to achieving acclimatization:

Eat enough food and drink enough water while on your climb. It is recommended that you drink from four to five liters of fluid per day. Also, eat a high calorie diet while at altitude, even if your appetite is diminished.
Ascend Slowly. Your guides will tell you, "Pole, pole" (go slowly) throughout your climb. Because it takes time to acclimatize, your ascension should be slow. Taking rest days will help. Taking a day increases your chances of getting to the top by up to 30% and increases you chances of actually getting some enjoyment out of the experience by much more than that.
Do not overexert yourself. Mild exercise may help altitude acclimatization, but strenuous activity may promote HAPE.
Climb high, sleep low. Climb to a higher altitude during the day, then sleep at a lower altitude at night. Most routes comply with this principle and additional acclimatization hikes can be incorporated into your itinerary.
Avoid tobacco, alcohol and other depressant drugs including, barbiturates, tranquillizers, sleeping pills and opiates. These further decrease the respiratory drive during sleep resulting in a worsening of altitude sickness.
If you begin to show symptoms of moderate altitude sickness, don't go higher until symptoms decrease. If symptoms increase, descend.

Our guides are all experienced in identifying altitude sickness and dealing with the problems it causes with climbers. He will constantly monitor your well-being on the climb by watching you and speaking with you. It is important that you be open, active and honest with your guide. If you do not feel well, do not try to pretend you are fine and mask your symptoms and say you feel OK. Only with accurate information can your guide best treat you.

In some cases, you may be asked to descend to a lower altitude temporarily to see if the altitude sickness subsides, and if it does, you may continue your climb. Of course, there is always the chance that you will have to abandon your climb. In these situations, the guide will tell you to descend. It is not a request, but an order. Do not try to convince him with words, threats or money to continue your climb. The guide wants you to succeed on your climb, but will not jeopardize your health. Respect the decision of the guide.

Diamox

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.

Ultimate Kilimanjaro neither advocates nor discourages the use of Diamox.

Ibuprofen

Ibuprofen can be used to relieve altitude induced headaches.

Bottled Oxygen

Bottled oxygen may be requested to be carried by our staff for an additional fee. It is for use only in emergency situations. It is NOT used to assist clients who have not adequately acclimatized on their own to climb higher. To administer oxygen in this manner and for this purpose is dangerous because it is a temporary treatment of altitude sickness. Upon the cessation of the use of oxygen, the client will be at an even higher altitude without proper acclimatization.

The most immediate treatment for moderate and serious altitude sickness is descent. With Kilimanjaro's routes, it is always possible to descend, and descend quickly. Therefore, oxygen is used strictly as a supplement to descent, when necessary, to treat those with moderate and severe altitude sickness.

Gamow Bag

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. 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 regularly carry Gamow bags on its climbs because descent is the most immediate, accessible treatment. However, Gamow bags can be rented and carried by our staff upon request for an additional fee.