High Altitute Sickness

The pleasure of trekking in the world’s highest mountain ranges cannot be loud. Neither can the dangers. Altitude sickness can occurs in some people as low as 8000 feet, But serious symptoms do not usually occurs until over 12,000 feet. Even then it is not the height that is important, rather the speed in which you ascended to that altitude. Acute maintain sickness (AMS) is actually more common to attempt a rapid ascent by racing up the mountain like some imperishable super hero! As a general rule, it is far safer and more enjoyable to avoid altitude sickness by planning a sensible itinerary that allows for gradual acclimatization to altitude as you ascend ( you can come back down as fast as you like)

High Altitude Sickness

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 weakness. Some people get it and some people don’t because some people are more weakness than others. Most people can ascend to 25oom with little or no effect. if you have been at that altitude before with no problem, you can probably return to that altitude without problems as long as you are properly acclimatized. if you haven’t been to high altitude before, you should exercise caution when doing so.

The Causes of Altitude Sickness The percentage of oxygen in the atmosphere at sea level is about 21% and the barometric pressure is around 760mmHg. As altitude increases, the percentage remains the same but the number of oxygen molecules per breath is reduced. At 3600m the barometric pressure is only about 480 mmHg, so there are roughly 40% fewer oxygen molecules per breath so the body must adjust to having less oxygen. In addition, high altitude and lower air pressure causes fluid to leak from the capillaries in both the lungs and the brain which can lead to fluid build-up. Continuing on to higher altitude without proper acclimatization can lead to the potentially serious, even life-threatening altitude sickness.

Severe AMS Severe AMS result in an increase in the severity of the aforementioned symptoms including: Shortness of breath at rest. Inability to walk , Decreasing mental status, Fluid buildup in the lings, Severe AMS requires immediate descent of around 600m to the lower altitude. There are two serous 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 liquid through the capillary walls into either thelungs or the brain.

High Altitude Pulmonary Edema(HAPE) HAPE result from liquid 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:

In case of HAPE, immediate descent of around 600m is necessary life- saving measure. Anyone suffering from HAPE must also 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:-

It generally occurs after a weak or more at high altitude. Severe instances can lead to death if not treated quickly. Immediate descent of around 600m is a necessary lifesaving measure.

Acclimatization The main cause of altitude sickness is going too high too quickly. Given enough time, you 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, e.g. if you climb to 3000m and spend several days at that altitude. your body will acclimatize to 3000m. if you then climb to 5000 m your body has to acclimatize once again, 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.

Prevention of Altitude Sickness This involves proper acclimatization and the possible use of medications.

Preventative Medications Acetazomide ( Diamox);  This is the most tried and tasted drug for altitude sickness prevention and treatment. Unlike dexamethasone ( below) this drug does not mask the symptoms but actually treats the problem. It seems to works by increasing the amount of alkali (bicarbonate) excreted in the urine, making the blood more acidic. Acidifying the blood drives the ventilation, which is the cornerstone of acclimatization. For prevention, 125 to 250mg twice daily starting one or two days before and continuing for three days once the highest altitude is reached is effective. Blood concentration of acetazolamide peak between one to four hours after administration of the tablets. Studies have shown that prophylactic administration of acetazolamide at a dose of 250mg every  eight to twelve hours before and during rapid ascent to altitude results in fewer and / or less severe symptoms (such as headache, nausea, shortness of breath, dizziness, and fatique) of acute mountain sickness( AMS). pulmonary function is greater both in subjects with mild AMS and asymptomatic subject. The treated trekkers also had less difficulty in sleeping. Gradual ascent is always desirable to try to avoid acute mountain sickness but if rapid ascent is undertaken and actazolamide is used. it should be noted that such use does not obviate the need for a prompt descent id severe forms of high altitude sickness occurs, I.e.  Pulmonary or cerebral edema. Side effects of acetazolamide include: an uncomfortable tingling of the fingers, toes and face carbonated drinks tasting flat; excessive urination; and rarely, blurring of vision. On most treks, gradual ascent is possible and prophylaxis tends to be discouraged. Certainly if trekkers do develop headache and nausea or the other symptoms of AMS, then treatment with acetazolamide is fine. The treatment dosage is 250mg twice a day for about three days. A trial course is recommended before going to a remote location where a severe allergic reaction could prove difficult to treat if it occurred. Dexamethasone: ( a stwroid) is a drug that decreases brain and other swelling reversing the effects of AMS. The does is typically 4 mg twice a day for a few days starting with the ascent . This prevents most of the symptoms of altitude illness from developing.

Warning: Dexamethasone is a powerful drug and should be used with caution and only on the advice of a physician and should only be used to aid acclimatization by sufficiently qualified persons or those with the necessary experience of its use.

Temporary treatment of AMS

The only cure for mountain sickness is either acclimatization or descent. symptoms of easygoing AMS can be treated with pain killers for headache. Acetazolamide and dexamethasone: These help to reduce the severity of the symptoms, but remember, reducing the symptoms is not curing the problem and could even exacerbate the problem by masking other symptoms. Acetazolamide : allows you to breathe faster so that you metabolize more oxygen, thereby minimizing the symptoms caused by poor oxygen which is especially helpful at night when the respiratory drive is decreased. Dexamethasone: This powerful steroid drug can be life saving in people with HACE, and works by decreasing swelling and reducing the pressure in the skull. The dosage is 4 mg three times per day, and obvious improvement usually occurs within about six hours. This drug” buys time” especially at night when it may be problematic to descend. Descent should be carried out the next day. It is unwise to ascend while taking dexamethasone: Unlike diamox this drug onlu masks the symptoms. Dexamethasone can be highly effective: many people who are lethargic or even in coma will improve significantly after tablets or an injection, and may even be able to descend with following a rapid rate of ascent, and respond remarkably well to dexamethasone. Trekkers also sometimes carry this drug to prevent or treat AMS. It needs to be used cautiously, because it can cause stomach irritation, euphoria or depression. It may be a good idea to pack this drug for high altitude trek for emergency usage in the event of HACE in people allergic to sulpha drugs( and therefore unable to take diamox) dexamethasone can also be used for prevention: 4 mg twice a day for about three days may be sufficient.

Other Medicines used for treating Altitude Sickness include:- Ibuprofen which is effective in relieving altitude induced headache( 600mg three times a day). Nifedipine: This drug is  usually used to treat high blood pressure. It rapidly decreases pulmonary artery pressure and also seems able to decrease the narrowing in the pulmonary artery caused by low oxygen levels, thereby improving oxygen transfer. It can therefore be used to treat HAPE, though unfortunately its effectiveness is not anywhere as dramatic that of dexamethasone in HACE. The dosage is 20mg of long acting Nifedipine, six to eight hourly. Nifedipine can cause a sudden lowering of blood pressure so the patient has to be warned to get up slowly from a sitting or reclining position. It has also been used in the same dosage to prevent HAPE in people with a past history of this disease. Frusemide may clear the lungs of water in HAPE and reverse the suppression of urine brought on by already dehydrated. Treatment dosage is 120mg daily.

Breathing: 100% oxygen also reduces the effects of altitude sickness.

The Gamow Bag This clever invention has revolutionized field treatment of altitude sickness. The bag is composed of a sealed chamber with a pump. The  casualty is placed inside the bag and it is inflated by pumping it full of air effectively increasing the concentration of oxygen and there simulating a descent to lower altitude. In as little as 10 minutes the bag can create an ” atmosphere” that corresponds to that at 900 to 1500m lower. 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 lower to a lower altitude and allow for further acclimatization. The bag and pump together weight about 6.5 kilos( 15 pounds) and are now carried on most major high altitude trekking, peak climbing and expeditions. Bags can be rented for short term treks or expeditions.

Some basic guidelines for the prevention of AMS

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