1. Hypothermia

2. Frostbite

 

An abnormal breathing pattern whilst asleep is a common occurrence at high altitude: short spells of an increased breathing rate alternate with brief periods when breathing slows down seems to stop - the medical term for this is "Cheyne Stokes" respiration. It is only a problem if it makes the sufferer wake up repeatedly, breathless, anxious and unable to sleep. An effective remedy is Diamox 125 mg before dinner, which counteracts the low oxygen dips during sleep that trigger the problem.Sleeping pills should be avoided. 

Many people develop a persistent, bothersome cough and cold-like symptoms in the cold dry air of high altitude. An antihistamine at night like Benadryl 25 mg may help suppress the cough. Antibiotics are sometimes useful, but keeping the head and face covered and breathing through a silk or wool scarf to humidify the air may also help. Many studies have shown that upper respiratory tract infections can predispose to AMS.

There may be swelling around the eyes, fingers, ankles at high altitude, but this may not indicate AMS per se unless accompanied by the symptoms of AMS. These symptoms without AMS usually require no treatment.

This is well known but harmless problem, in which fainting occurs suddenly, usually shortly after arrival. Simple measures like keeping the individual in a reclining position and raising the legs are helpful.

Blood pressure initially increases at high altitude due to the initial stress of low oxygen triggering neurohumoral changes. However people who suffer from high blood pressure can go up to high altitude as long as this is well controlled and they continue to take their medication. 

People with a history of heart attack (myocardial infarction) and even those with coronary artery bypass grafts or angioplasty but with no angina, can trek up to high altitude provided they are fit and able to walk rigorously at low altitude. The high altitude does not seem to add any extra burden to the heart

Although seizures may be provoked by altitude there is no convincing evidence that it is unsafe for well-controlled epileptics travelling to travel to high altitude, though such people should always take their anti seizure medications conscientiously.

Sufferers may possibly have more attacks in the mountains and this may sometimes be difficult to distinguish from AMS. In doubt it is best to descend

Also noteworthy is the limited observation that bronchial asthma does not seem to get exacerbated at high altitude due to the cold and exercise. However it is prudent for asthmatics to carry inhalers and other medications. Obviously people with chronic obstructive lung disease may be more short of breath and travel at high altitude would be inadvisable. 

Diabetics on insulin should have a reliable glucometer to check their blood glucose regularly, but high altitude does not seem to cause additional risks. 

People who have had non laser surgery (radial keratotomy) to correct their short sightedness may run into problems at high altitude due to swelling of their cornea caused by the low oxygen. Such people should carry corrective lenses as well if travelling to high altitude.

Pregnant women should not sleep higher than 12000ft as this may endanger the fetus; a further problem is that high altitude places are generally remote, making emergencies more difficult to deal with. 

Children do not suffer any more from the effects of altitude than adults. However, it is important that a child should be able to communicate any symptoms to a responsible adult, so that prompt descent can be arranged. It may therefore be dangerous to take children to high altitude who are not yet old enough to do this.

Oral contraceptive pills may predispose to abnormal blood clotting ( thrombosis) at high altitude. The hypoxia (low oxygen), the excessive red blood cells( polycythemia) in the blood, and the possible dehydration in this environment may already be other predisposing factors for thrombosis. Hence it is best to use other forms of contraception at high altitude. 

Many high altitude destinations are in developing countries, so it is important to be up to date with vaccinations against diseases like typhoid and hepatitis, to know about travelers' diarrhoea and its treatment, and to understand the other precautions described elsewhere in this website. Malaria is not a risk at altitude - transmission does not take place above 2000 metres. 

Improving medical facilities in countries such as Nepal have made it much easier to distinguish between altitude illness and conditions that can produce similar symptoms, such as bleeding in the brain (subarachnoid haemorrhage), strokes, dehydration and blood viscosity related problems like venous thrombosis.

It is important to be aware that porters may be just as vulnerable to the effects of altitude as tourists; for your own safety, it is also vital to confirm with the trekking agency that your porter has been provided with proper clothing, boots and equipment prior to the start of the trek.

Most of the problems of high altitude are totally preventable. With careful precautions, your experience in the mountains should be safe and rewarding.