Altitude sickness (also known as altitude hypoxia) is negative health effect of high altitude, caused by acute exposure to low amounts of oxygen at high altitude. It can occur as a result of decrease of the oxygen pressure in the mountains, as well as when flying on aircrafts, that are not equipped with sealed cabins (such as paragliders, hang gliders, hot air balloons, gondolas, etc.). People have different susceptibilities to altitude sickness. For some acute altitude sickness can begin to appear at around 2,000 metres above sea level.

Mountain sickness is a type of altitude sickness which is caused by the lack of oxygen, as well as several aggravating factors such as physical fatigue, illness, dehydration, ultraviolet radiation, severe weather conditions (such as downpours), sudden temperature changes during the day (from +30 ° C in the daytime to -20 ° C at night), etc. But the main pathological factor of the mountain sickness is hypoxia.

It is possible to adapt to the high-altitude hypoxia. Athletes specifically train their bodies in order to improve their sports achievements. The maximum possible height for a long-term adaptation to hypoxia (from hours to dozens of hours) is considered the level of around 10,000 meters. A longer stay of a person at such altitudes without breathing through oxygen devices is impossible: it will cause death.

The height at which mountain sickness can occurs varies based on numerous individual and climatic factors. 

The following individual factors influence the occurrence of mountain sickness:

  • Individual resistance of people to the lack of oxygen (e.g. people leaving in highlands have higher resistance to the lack of oxygen);
  • gender (women have higher tolerance to hypoxia);
  • age (younger people have low tolerance to hypoxia);
  • physical, mental and moral state of a person;
  • level of fitness;
  • speed of the climb;
  • degree and duration of the oxygen deprivation;
  • intensity of muscular effort;
  • past “high-altitude” experience.

The following factors provoke development of mountain sickness, and reduce tolerance to high altitudes:

  • Alcohol or caffeine in the blood;
  • Insomnia, overwork;
  • psycho-emotional stress;
  • hypothermia;
  • poor and inefficient nutrition;
  • non-compliance of the water-salt balance regime, dehydration;
  • overweight;
  • respiratory and other chronic diseases (e.g. angina, bronchitis, pneumonia, chronic purulent stomatitis);
  • blood loss.

The following climatic factors contribute to the development and faster progression of mountain sickness.

  • Low temperature. Along with the increasing altitude, the average annual air temperature gradually decreases by 0.5 ° C for every 100 m of height (in winter 0.4 ° C, in summer 0.6 ° C). In winter, at equal heights, morbidity rate is higher than in the summer (for the causes see pathogenesis). Sharp temperature drop also has an adverse effect.
  • At high altitudes, due to low temperature, the partial pressure of water vapour is low. The air humidity at sea level is twice as much as an altitude of 2000 m and above in the same area. At large mountain heights, the air becomes almost dry (the partial pressure of saturated water vapour is negligible). This leads to a loss of fluid in the skin and lungs and, consequently, to dehydration of the body. At large mountain altitudes, air becomes almost dry (partial light and, consequently, dehydration of the body.
  • High in the mountains the wind can reach a hurricane force (over 200 km / h), which overcools the body, exhausts it physically and morally; and makes breathing more difficult.

The above-mentioned factors prove the fact that the height of the mountain sickness is individual, and varies based on a person and conditions. Some begin to suffer from oxygen deficiency already at an altitude of 2000 m, while others do not feel its effect even at 4000 m.

Most of the healthy non-acclimatized residents of lowlands begin to feel the effect of altitude of 2500-3000 m, while with intense physical work it can be felt at lower altitudes. At an altitude of about 4000 m even absolutely healthy people have slight malaise, and acute mountain sickness is registered in 15-20% of the ascent participants. At altitudes of 6,500-7,000 m, complete acclimatization, apparently, is impossible. However, participants in the expeditions to 8,000-meter mountains obtain numerous functional disorders and signs of mountain sickness. In high-altitude mountaineering, there is the term called “lethal zone” or, in other words, “death zone”. The term was brought by the head of the Swiss expedition of 1952 to Everest E. Viss-Dunant, who expressed the opinion that there are boundaries, crossing beyond which is lethal for mountaineers.

At altitudes of more than 8000 m a person can live at the expense of internal reserves no more than 2-3 days, gradually losing resistance to the altitude effect. Nevertheless, the experience of recent Himalayan expeditions, during which many participants did not use oxygen-delivery devices due to successful acclimatization, somewhat broadens our understanding of the limits of adaptation to oxygen deficiency.

The height of the onset of the occurrence of mountain sickness depends on the climate and humidity of the mountains:

In the mountains of humid maritime climate:

  • Kamchatka – 1000-1500 meters
  • Patagonia – 1000-1500 m
  • The Alps – 2500-3000 m
  • Caucasus – 3000-3500 m
  • Andes – 4000 yards

In the mountains of dry continental climate:

  • Tien Shan – 3500 m
  • Pamir – 4500 m
  • The Himalayas – from 5000 m

The human body functions best at the sea level, where the atmospheric pressure is 101.325 Pa (roughly 14.6959 pounds per square inch). The concentration of oxygen (O2) in the air at sea level is 20.9% at a partial pressure of O2 (PO2) of 21.2 Pa. In healthy peoples’ bodies, haemoglobin is saturated with oxygen, which binds to red blood cells. After a person ascends to an altitude of about 2100 meters above the sea level, the body’s saturation with oxy-haemoglobin (a protein of hemoglobin bound to oxygen) begins to fall.

Atmospheric pressure decreases exponentially with increasing altitude, while the proportion of O2 remains unchanged to about 100 km, which means that PO2 also decreases exponentially with increasing altitude. At the height of the base camp on Mount Everest, at 5000 m above sea level, the PO2 pressure is about half of the PO2 pressure at sea level and only a third at the summit of Everest of the PO2 pressure at sea level, at an altitude of 8,848 m. When PO2 falls, the human body responds through its adaptive mechanisms, which is called ‘altitude acclimatization’.

Adaptive reactions aim to maintain the sufficient oxygen supply to organs and tissues, as well as to manage a more economic expenditure of energy and in the conditions of oxygen starvation. Such compensatory reactions include:

  • increased pulmonary ventilation;
  • increase in oxygen capacity of blood due to the release of red blood cells from blood depots – spleen, liver. With prolonged stay in hypoxic conditions, an increase in the amount of haemoglobin is observed;
  • increase in the minute volume of the circulating blood, acceleration of blood flow.

There are also reactions at the tissue level:

  • Capillarity increases;
  • increase of myoglobin;
  • improvement in the regulation of oxidation-reduction processes, etc.

When climbing to an altitude of 2000-4000 m, oxygen deficiency in healthy people is compensated without any (at least visible) harm to health.

Periodic breathing

As a result of hyperventilation of the lungs, the content of carbon dioxide decreases in the blood, as a result of which respiratory alkalosis develops (plasma of blood and body fluids acquire an alkaline reaction). Due to the “washing away” of CO2, the regulation of breathing is disturbed, since the excess of carbon dioxide in the blood excites the respiratory centre. This leads to breathing disorders, due to the suppression of the activity of the respiratory nervous system of the organism at low concentrations of CO2. While a person is awake, his consciousness signals to inhale. In a dream, when consciousness control weakens, a phenomenon called periodic breathing or Cheyne-Stokes breathing occurs: for a few seconds (up to 10-15), breathing stops, and then resumes, at first with redoubled force. The first event is connected with the brain’s reaction to the lack of CO2, the second one: with the reaction to the critically low level of O2. In practice, it looks like a person wakes up because he/she feels suffocated. Climbers describe this feeling as extremely unpleasant.

However, having recovered, the person comes to the senses and can continue to sleep easily. Despite the unpleasant feeling this is a normal reaction of the body to the altitude, and this symptom itself is not a sign of mountain sickness.

Mechanisms of the onset of oedema

With further ascent, hypoxia increases, since the compensatory functions of the body no longer provide sufficient compensation. The lack of oxygen in the air leads to a decrease in the partial pressure of oxygen in the lungs and to a decrease in the saturation of the arterial blood with oxygen, as a result of which there is oedema of the lungs and brain.

Some believe that the basis of clinical manifestations of mountain sickness is the increasing oedema of the brain.

In the human body the most sensitive and vulnerable parts to hypoxia are the brain tissue and the pulmonary alveolar tissue, since the latter receive oxygen directly from the air. It is the insufficient supply of oxygen to these tissues that causes development of oedematous processes in them.

The main sources of pulmonary and brain oedema:

  1. increased pressure in the vessels and capillaries due to their spasm, water retention in the body and stagnation of blood in the venous system;
  2. increase of the permeability of the capillary wall, which leads to the exit of liquid plasma components into the intercellular space;
  3. increase of the permeability of cell membrane: hypoxia disrupts the selective permeability of cell membranes, resulting in equalization of ion concentrations outside and inside the cell, that is, the cell loses K + ions and is overloaded with Na +, Ca + 2 ions;
  4. decrease of the osmotic pressure in blood plasma: Alignment of the concentration of sodium (0.9%) in the body leads to watering of cells and thickens the blood.

There are other mechanisms that join the hypoxic mechanism:

  • Lack of potassium in the myocardium leads to arrhythmia, to a weakening of the pumping function of the heart, which is manifested in the stagnation of venous blood in the small (with pulmonary oedema) or in the large (with oedema of the brain) blood circulatory system;
  • Increased body temperature (fever) – in response to hypothermia, oedema, exacerbation of chronic inflammatory processes, etc., the body temperature rises. This immune stereotype, “useful” under normal conditions, in conditions of lack of oxygen, aggravates hypoxia even more, as the need for oxygen increases with increasing body temperature. It is believed that at 38 ° C the oxygen demand doubles, and at 39.5 ° C it grows 4 times.
  • Due to increased permeability of the walls of the pulmonary capillaries and alveoli, extraneous substances (protein masses, blood elements and microorganisms) enter the pulmonary alveoli;
  • The influence of cold- Cold air has an impact in three ways:
  1. In extreme cold, the cold air must be inhaled in small portions burning the lungs and throat, which increases hypoxia;
  2. In extreme cold, hypoxic oedema is also accompanied by oedema from hypothermia. In the overcooled tissues, the permeability of the cell membranes is also impaired (therefore, frozen tissues swell);
  3. As a result of cold, chronic inflammatory diseases worsen, which accelerate and aggravate the oedema of the lungs.

Therefore, at low temperatures, oedema of the lungs or brain occurs more rapidly – at high altitudes and with a high frost this period can last only 8-12 hours instead of the usual 24 hours.

Oedema of the brain is an excessive accumulation of water in the brain tissues, and the source of water is mainly blood flowing through micro vessels and brain capillaries.

Oedema of the lungs is the accumulation of light blood plasma in the tissues of the lungs, and then in the lumens of the alveoli: when inhaling, the plasma filling the lumens foams, sharply reducing the useful volume of the lungs.

Normally, oedema of the brain and oedema of the lungs develop at night (the peak of the crisis usually occurs at 4 am), which is due to:

  • Increased venous return to the upper half of the trunk when moving from vertical to horizontal position;
  • A decrease in the activity of the central nervous system, which, by superimposing itself on respiratory acidosis, leads to a weakening of the respiratory function (see above);
  • Increase in the tonicity of the valgus nerve, which causes bronchospasm.

This brings us to the conclusion that:

  • the horizontal position of the sick person is unacceptable at any time of the day;
  • The sick person should not use the night for sleeping but for descending. The health of the patient always worsens by the morning.

The death with oedema of the brain is caused by the squeeze of the swollen cortex of the brain with the cranial vault, wedging the cerebellum into the trunk of the spinal cord. The death with pulmonary oedema is caused by massive foaming, which causes asphyxia of the respiratory tract.
The reason for the transience of the lethal outcome is that they develop on the principle of a vicious circle, when the subsequent stages aggravate the original cause, and the original cause – aggravates the consequence (for example, compression of the veins of the brain leads to a stronger oedema and vice versa).

Changes in other bodies and systems

The digestive system

At high altitudes, the appetite significantly changes, the absorption of water and nutrients decreases, the secretion of gastric juice leads to disruption of digestion of food, especially fats. As a result, a person abruptly loses weight (up to 15-22 kg in 6-7 weeks at an altitude of 6000 m). At the height, a person can feel an imaginary feeling of fullness of the stomach, nausea, diarrhoea, not amenable to drug treatment.


At altitudes of about 4500 m, normal visual acuity is possible only at a brightness of 2.5 times as much as the usual for plain conditions. At these altitudes, there is a narrowing of the peripheral field of vision and a visible “blurring” of vision as a whole. At high altitudes, the accuracy of focus and correctness of the distance determination are also reduced. Even in mid-mountain conditions, night vision weakens, and the period of adaptation to darkness is prolonged.

Dehydration of the body

The release of water from the body is known to be carried out mainly by the kidneys (1.5 litters of water per day), skin (1 litter), lungs (about 0.4 litters) and intestines (0.2-0.3 litters), which makes up about 3 litters of water per day. With increased muscular activity, especially in the heat, the release of water through the skin increases sharply (sometimes up to 4-5 litters). Intense muscular work performed in high altitude conditions, due to the lack of oxygen and dry air, dramatically increases pulmonary ventilation and thus also increases the amount of water released through the lungs. All this leads to the fact that the total loss of water among participants in hard high-altitude travel can reach 7-10 litters per day.

Other changes

As the pace of hypoxia decreases, pain sensitivity reduces until to its complete loss.

Mental changes

Many climbers talk about the influence of height on the human psyche. For example, the expeditionary doctor points out a climber, who is mentally stable on a lowland, at the height of a glass that is torn apart. Reinhold Messner (height 8200 m, anoxic single ascent to Everest in 1980) reported an increasing sense of the presence of an invisible companion, up to the point that he shared food with him. The first climber from the Soviet Union to have ascended to Mount Everest, Mikhail Turkevich, reported that Edward Myslovsky, during the descent, refused to go any further after his oxygen ran out, saying that he was well and wanted to stay in the mountains.

The acute form of a mountain sickness occurs with the rapid movement (for several hours) of non-acclimatized people in the highlands, usually at a height of more than 3500 m. Clinical symptoms of it develop rapidly. In subacute form of mountain sickness, they do not develop so quickly and last longer (up to 10 days). The clinical manifestations of both forms of mountain sickness generally coincide.

Acute mountain sickness

Mild degree

Symptoms of a mild degree of mountain sickness appear within 6-12 hours (and sometimes even earlier) after lifting to a new height. At a higher altitude, the symptoms are detected earlier. In many, they are manifested by deterioration of health, a certain lethargy. A newbie in the mountains experiences malaise, rapid heartbeat, mild dizziness, slight dyspnoea with physical exertion, drowsiness and at the same time does not sleep well. 3-4 days later, these symptoms either increase or disappear. There are no clear and objective clinical/neurological symptoms of this form of mountain sickness.

All of the above-mentioned symptoms are not specific and can be a consequence of many other diseases. Nevertheless, it is believed that an un-acclimatized person who has risen to a height of more than 2500 m has an acute mountain sickness, if their head starts to ache and when at least one of the above-mentioned symptoms appears. If the above-mentioned symptoms appear 36 hours after well-being, then you must exclude the presence of another diseases.

Average degree

At the altitudes of 2500-3500 m, some people may have euphoria: good mood, excessive gesticulation and speechlessness, accelerated speech, fun and laughter without any reason.

Later, the euphoric state is replaced by decline in the mood, apathy, melancholy, dull interest in the surrounding.

At altitudes of 4000-5000 m the state of health worsens. One can have a moderate and even severe headache. Sleep becomes restless, anxious, with unpleasant dreams, some fall asleep with difficulty and often wake up from a feeling of suffocation (periodic breathing). With physical effort, breathing and palpitation immediately increase, dizziness occurs. There is a loss of appetite, nausea, which is intense and can end up with vomiting. The affected individual mainly prefers sour, spicy or salty food (which is partly explained by dehydration and violation of the water-salt balance). Dryness in the throat causes thirst. The nose might bleed.

The final degree

At altitudes of 5000-7000 m and above, people rarely feel well, often unsatisfied. There is general weakness, fatigue, heaviness in the whole body. There is a moderate, and sometimes severe pain in the temples; frontal, occipital part of the head. With sudden movements and inclinations or after work, dizziness occurs. A person falls asleep with great difficulty, often awakens, some suffer from insomnia. A mountain-sick person is not able to do physical exercises for a long time due to dyspnoea (“the breath of a stalked dog”) and palpitation, working capacity drops. For example, at an altitude of 8000 m there remains 15-16% of the working capacity at sea level altitude.

Dryness in the throat increases resulting a constant feeling of thirstiness. Many people dry coughs. Appetite normally is either goes down or disappears. The number of cases of nausea and vomiting during food intake increases. Often there are pains in the abdominal area and gastrointestinal tract, there is a feeling of bloating. The rhythm of breathing is disturbed during the night sleep (Cheyne-Stock’s breathing). The skin of the face, especially the lips, become pale, often cyanotic, tint as a result of insufficient oxygenation of the arterial blood, which loses its scarlet colour. The body temperature rises by 1-2 ° C, chills occur. There are frequent incidents of nose, mouth, lungs (haemoptysis), and sometimes gastric bleeding.

Under certain conditions, starting from 4000 m, dangerous forms of mountain sickness can arise due to the failure of adaptation mechanisms and the development of more serious pathologies: pulmonary oedema and cerebral oedema.

High-altitude oedema of the lungs

Along with severe mountain sickness unexpected stagnant phenomena can evolve in the small circle of blood circulation along with pulmonary oedema, as well as acute heartburn.

As a matter of fact, the symptoms of high-altitude oedema of the lungs, appear on 2-3 days of stay at high altitude. The liquid comes out from the capillaries of the lungs and enters the lumen of alveoli, disturbs the with gas exchange. As a result, hypoxia increases and the sickness progresses.

If one does not take measures from the beginning, three hours after the first symptoms occur, they can end up with death. Its development is enhanced by previous diseases of the respiratory and circulatory organs, chronic or acute respiratory tract infections (e.g., angina, bronchitis, pneumonia, chronic purulent dental diseases), excessive physical exertion performed before the onset of sustainable adaptation.

Out of all the mountain-specific diseases high-altitude oedema of the lungs is the most common cause of death. At an altitude of 2,700 m, the incidence of high-altitude pulmonary oedema is 0.0001% and increases to 2% at 4000 m.

Alpine oedema of the lungs has the following three stages of development:

The first stage

  • the patient stands on his feet, but cannot move independently;
  • Lack of urine for more than 8-10 hours;
  • There are symptoms of respiratory centre depression – rapid pulse and breathing, it is difficult to cough, in the breath the nose wings participate, the teeth are compressed;
  • chills, fever;
  • the skin is damp, pale;
  • Cyanosis: bluish nails, lips, nose, ears.

The following symptoms are also characteristic for pulmonary oedema:

  • Dry cough, sore throat;
  • compression below the sternum, chest pains;
  • because of the weakness the patient tries to lie, but because of suffocation he is forced to sit down;
  • The patient has a temperature of 38-39 ° C. If the pulmonary oedema develops without pneumonia, the temperature can be 36-37 ° C.

The second stage

Usually, 8-12 hours after the first symptoms occur, the second stage of pulmonary oedema commences:

  • the patient no longer stands on his feet;
  • cough with frothy sputum;
  • elevated pulse, blood pressure constantly rises;
  • Noisy breathing, rattles are audible while listening;
  • semi-sitting position;

The third stage

It develops after 6-8 hours and 4-8 hours before the death:

  • signs of significant dehydration: thirst is increasing;
  • severe headache;
  • temperature increase;
  • anxiety;
  • rattles audible from a distance;
  • bloody sputum, pink foam from the nose and mouth;
  • suffocation;
  • arrhythmia, the pressure can reach 150-170 / 90-100 mm Hg. Art.

Without proper treatment, there is a drop in the pressure, collapse, coma, cardiac arrest.

High-mountain oedema of the brain

High-altitude oedema of the brain can be considered as an extreme manifestation of acute mountain sickness. A liquid comes out from the capillaries of the brain, the latter increases in volume. In this case, the tissues of the cerebellum are wedged into the trunk of the spinal cord, the vital centres that are in it are destroyed, and death occurs.

A participant in one of the expeditions to Everest, Dale Cruise describes his condition with a brain oedema:

“It felt like I was very drunk. I could not go without stumbling and completely lost the ability to think and speak. I had a few words in my head, but I could not figure out how to say them.”

There are three stages of cerebral oedema:

The first stage

Because of changes in the brain, specific symptoms occur:

  • The head is filled with lead, noise in the head, headaches of a bursting character;
  • Frequent vomiting;
  • Coordination disorder(ataxia): the patient’s behaviour, reminds of the state of alcoholic intoxication, a person cannot walk without staggering in a straight line;
  • lethargy, sleepiness, isolation, apathy;
  • the patient does what is requested and then immediately stops until a being reminded about the tasks;
  • unlike the case of pulmonary oedema, in this case the patient is able to lie.

The second stage

Usually starts in 8-12 hours after the appearance of the first symptoms:

  • increased headaches, insomnia, thirst;
  • Speech disorder;
  • changes in behaviour: a person stops to act like himself, irrational behaviour (aggression, suicide attempt), and the patient may not understand what is happening to him, and actively resist the attempts to let himself go, being in a state of euphoria, tearing up;
  • deafness, inhibition, isolation, apathy;
  • pupils dilate, disappearance of reaction to the light, fixation of vision, asymmetry.

The third stage

Starts 6-8 hours later and 4-8 hours before the death:

Signs of significant dehydration: thirst;

  • the headache is worse;
  • temperature increases;
  • anxiety;
  • more changes appear in the pupils, the veins of the fundus enlarge;
  • numbness of limbs;
  • consciousness falls, deafness, the patient becomes slow, sleepy, answers questions not at once, may be disoriented in the surrounding environment.

At the end of the third stage, there is a loss of consciousness, the breathing and heartbeat stop.

The most acute form of mountain sickness

The most acute form of mountain sickness is hypoxic suffocation, which sometimes occurs right after people land on high altitudes by helicopters, airplanes, motor transport or as they ascend fast.

Suddenly there is a feeling of emptiness when inhaling, strong pain in the whole body, ripples and darkening in the eyes, prostration, there is a fear of death, loss of consciousness (for example, when the cockpit of a plane is depressurized, the pilot loses consciousness after 2 minutes). However, with rapid descent and the provision of necessary medical care, the pilot immediately starts feeling well.

Chronic mountain sickness

Chronic mountain sickness was descovered in 1829 by the famous Peruvian scientist Carlos Monge, which is why it is called Monge’s disease. Chronic mountain sickness is much less common; it affects a small part of mountaineers living at altitudes above 3500-4000 m.

It is characterized by a decrease in physical and mental performance, with prevailing changes in the central nervous system. Because of the increase in hypoxemia (fall of the oxygen content in the blood), there is an increase in the volume of circulating blood, its volume in the lungs, there is an increase in the size of the right side of the heart and liver. The thorax becomes barrel-shaped, it is often possible to observe the thickening of the fingers (“drumsticks”), well-expressed cyanosis.

Patients with chronic mountain sickness often complain about coughing, haemoptysis, dyspnoea, pain in the right hypochondria, bleeding occurs in the food canal. An important diagnostic symptom of Monge’s disease is its almost complete disappearance after the descent into a flat terrain. In severe manifestations of chronic mountain sickness, the same measures and medications are used, as in acute mountain sickness.

There are three “golden rules” for the prevention of mountain sickness:

  1. Never climb up when having symptoms of mountain sickness;
  2. If the symptoms of mountain sickness increase, then you must definitely go down;
  3. If the climber feels bad at an altitude, then in the absence of obvious signs of other diseases, one must assume that the person has an acute mountain sickness, and take appropriate measures of treatment.

To prevent the acute mountain sickness there should be an active step-by-step acclimatization. There should also be a rational selection of climbers who would go through a physical and psychological preparation, have a previous high-altitude experience, and pharmacological prophylaxis.


The basic principles of acclimatization:

  • At above 3000 m, each increase the night-time stay altitude by no more than 300-600 m.
  • Take into account the fact that the acclimatization rate for different people is significantly different.
  • If possible, do not move by a transport (by airplane or car) immediately to a higher altitude.
  • When transporting vehicles to a higher altitude, do not climb even higher for the first 24 hours.
  • “Climb high, sleep low.”
  • The basic acclimatization takes place on the first three days of the journey.
  • If the symptoms of mountain sickness continue, the climbing should be stopped.
  • If the symptoms evolve, start the descent as soon as possible

Pharmacological prophylaxis

Both for the prevention and treatment of acute mountain sickness the same medicines are usually used. When ascending to a height of more than 3000 m, the following medicines are recommended (the recommended daily doses are indicated in brackets):

  • Acetazolamide (Diamox, Diacarb) is a diuretic drug that also reduces the production of cerebrospinal fluid in the intracranial space, which reduces intracranial pressure and allows to reduce or eliminate symptoms arising from mountain sickness, the preventive prescription of the drug is poorly grounded. Presence of bursting headaches, aggravated during straining, inclinations, a feeling of pressure on the eyeballs from inside of the skull, nausea, especially vomiting indicates an increase in intracranial pressure and in most cases, is an indication for the reception of Diacarb. Dosages are individual and for a person who does not usually take Diacarb, can be from 1/4 to 1 tablet. Side effects of acetazolamide are paraesthesia (pins and needles) and increase of diuresis (urination). With the advent of paraesthesia and seizures, it is possible to take drugs that include potassium: Panangin up to 6 tablets per day. Usually, the appointment of Diacarb involves a simultaneous usage of drugs containing salts of potassium and magnesium (Asparcam, Panangin 1-2 tablets: 2-3 times a day, depending on the amount of physical activity, as during the latter a significant amount of salt is goes out as well). The occurrence of above-mentioned symptoms, including the bloating of intestines which are caused by low concentration of potassium salts in the blood and tissues of the body, is an indication that the intake of potassium salts in double dosages is mandatory. Also, it is required to increase the volume of consumed liquid to avoid dehydration and, as a result, blood thickening and deterioration of its fluidity. Acetazolamide is a sulphonamide diuretic, and people with allergy should not use this group of drugs. The drug effects on the body significantly, which is why under no circumstances one should not take Diacarb without serious symptoms (so to say, for other than preventive reasons).
  • Dexamethasone (4 mg every 6 hours) reduces the power and severity of acute mountain sickness during a fast ascent to a height of over 4000 m. Dexamethasone is not the first drug choice for the prevention of mountain sickness due to its side effects. It is only for those who do not tolerate acetazolamide, have the symptoms of mountain sickness, and plan to ascend high rapidly. Dexamethasone stops the symptoms of acute mountain sickness for several hours, but does not contribute to acclimatization.
  • Diabazole – a vasodilator with adaptive features (0.5 tablets of 10 mg).
  • Viagra – a few years ago researches were conducted on the use of Viagra as a preventive means. Viagra improves blood circulation in the peripheries, including the lungs.

Vitamins, microelements and amino acids:

  • Ascorbic acid (vitamin C) – which has antioxidant features, reduces the accumulation of under-oxidized metabolic products that appear during hypoxia. Normally 70-100 mg is enough, and along with acclimatization one can increase the dose several times (up to 500 mg, 2 times a day).
  • Tocopherol (vitamin E) (200 mg, twice daily) and lipoic acid (300 mg, twice daily) also have antioxidant features.
  • Calcium pangamate, which has a distinct anti-hypoxic effect (2 tablets of 50 mg).
  • Calcium pantothenate, which (vitamin B5) normalizes metabolic processes (1 tablet of 100 mg).
  • Potassium orotate, which normalizes the work of the liver and heart, microcirculation in the capillaries (1 tablet).
  • Glutamic acid is an amino acid, a participant in metabolic processes (2 tablets).
  • Methionine – an amino acid that normalizes the work of liver during hypoxia (3 tables).
  • Panangin (asparks) – potassium and magnesium salt of aspartic amino acid, antiarrhythmic agent, sends K +, Mg2 + ions into cells (1-2 tablets).
  • Riboxin – enhances the effect of potassium orotate, has a beneficial effect on the heart and liver (1-2 tablets).

Food recommendations:

Carbohydrates increase the resistance to hypoxia. Thus, to prevent mountain sickness at high altitudes, you need to use more glucose, sugar and other easily digestible carbohydrates, but not more than 300-400 g per day. Canned orange juice, warm lemon juice in powder will do as drinks. Very strong tea is not recommended. It irritated the nervous system and thus causes insomnia.

Coke in the form of tea and chewing leaves, in contrary to widespread prejudice, contains very little cocaine and, in a moderate amount, promotes acclimatization. Therefore, being in the Andes, do not neglect the advice of guides offering to drink it.

The preventive efficacy of the following drugs has not been proven:

  • Ginkgo Biloba extract (Bilobil), tablets, capsules.
  • Analgesics from the group of non-steroidal anti-inflammatory drugs, such as Aspirin, Ibuprofen, Paracetamol, etc. Some researches give a slight privilege to the efficiency of placebo.

The following drugs are ineffective for the prevention of mountain sickness: Spironolactone, Furosemide, Codeine.

Alcohol at a height of more than 3000 m reduces the respiratory rate and increases hypoxia even in small doses. So, the use of alcoholic beverages in the highlands should be prohibited.

Treatment of acute mountain sickness

Light and medium degree

It should be emphasized that the mild degree of mountain sickness, in spite of unpleasant feeling, is usually only a condition that physically restricts a person without any protracted consequences. The basic treatment of mild mountain sickness:

  • Having a rest;
  • Consuming liquids (juices, tea);
  • Weak analgesics (Aspirin, Ibuprofen, Paracetamol);
  • To fight nausea: Aeron, sour fruits (apples, oranges, lemons, apricots) and to fight vomiting (intramuscular injection of metoclopramide;
  • if necessary, consume acetazolamide 125-250 mg twice a day for 3 days.

Normally, the symptoms usually go away after 2-4 days.

Heavy Degree

  • The most effective method of treatment is to take the victim down to a low altitude. If there is any possibility of the independent movement of the victim, without causing apathy, indifference and hypothermia, the patient had better descend himself.
  • In extreme cases, an oxygen mask should be used (preferably mixed with carbon dioxide: O2 + 5-7% CO2). A portable hyperbaric pressure chamber (compression chamber) should be used, which is a sealed bag, into which air is pumped by a hand pump or compressor.
  • Acetazolamide 125-250 mg twice a day for 3 days.
  • Dexamethasone 8 mg through the mouth, then 4 mg every 6 hours for 24 hours.
  • The temperature should be lowered to 37 ° C by fever-reducing medications.
  • Do not use narcotic analgesics (Promedol, morphine) and alcohol.

Treatment of pulmonary oedema

  • The most important method of combating pulmonary oedema is immediate descent. A descent of even a few hundred meters can lead to better conditions.
  • The use of a portable hyperbaric chamber is effective. In extreme cases, use an oxygen mask.
  • The victim should take a semi-sitting position.
  • If the systolic (“upper”) blood pressure is more than 90 mm Hg., then 2-3 ampoules of furosemide should be taken intramuscularly.
  • Nifedipine is effective in preventing and treating alpine oedema of the lungs (initially 10 mg orally, followed by 20 mg of Nifedipine every 12 hours)
  • Place the Nitroglycerin tablet under the tongue (with systolic blood pressure more than 90 mm Hg). Nitroglycerin can be taken after 20 minutes continuously no more than 3 times.
  • Place a venous tourniquet on the hips in such a way that the pulse on the arteries is probed below the place of their application. This will create a depot of blood in the lower limbs and prevent it from moving to the heart. However, this method should be used only during the rapid descent of the victim to gain a little time. After an hour and a half, the tourniquet will have to be removed, and the rapid flow of blood to the hypoxia-induced heart can cause acute heart failure.
  • If possible, intravenously inject aminophylline (10 ml 2.4% in 100 ml isotonic solution).
  • If the patient clearly has a pink foamy sputum, it is better to breathe through alcohol-soaked gauze to reduce foaming in the pulmonary alveoli.
  • Under steady-state conditions, when preservation of consciousness does not play a role, morphine should be used, as it reduces pressure in the pulmonary artery.

It is important to know that no drug manipulation should serve as a excuse for the descent.

Oedema of the lungs can very quickly cause a development of inflammatory diseases of the respiratory tract (sore throats, pneumonia), so when these signs occur, it is necessary to descend and take medicine based on the symptoms.

Treatment of cerebral oedema

  • If the symptoms of high-altitude cerebral oedema appear, start descending immediately. Any delay can lead to the death. If the symptoms appear in the evening, you one must not wait to descend in the morning. The victim must be evacuated at least to the height at which the he last felt well, and preferably up to 2500 m. As a rule, if you start descending in time, the symptoms quickly and completely disappear.
  • Artificial intake of oxygen.

The Medications for oedema of the brain play a rather auxiliary role, but, nevertheless, they should not be neglected. To reduce the symptoms and facilitate evacuation, Dexamethasone is used (at first 8 mg, then 4 mg every 6 hours inside or parenterally).

Vasodilators (Nitroglycerin, Nifedipine, Trental), and medicine increasing the pressure (caffeine, adrenaline) shall not be used when having as oedema of the brain. Any increase in pressure or vasodilation will enhance the oedema of the brain. Now also do not recommend using diuretics.

The symptoms do not immediately after the descent, and the patient must be transferred under the supervision of medical workers.