Altitude sickness

from Wikipedia, the free encyclopedia
Classification according to ICD-10
T70.- Damage from air and water pressure
T70.2 Other and unspecified damage from high altitude, including altitude sickness
ICD-10 online (WHO version 2019)

As altitude sickness (or inaccurate as mountain sickness ) is called a complex of symptoms that occurs in people who go to great heights or live there. Another name is D'Acosta's disease (after José de Acosta ). The altitude at the onset of the first symptoms varies from person to person and is heavily dependent on constitution; altitude sickness can very rarely occur between 2000 and 2500 m.

The main symptom is headache , with loss of appetite , nausea , vomiting , tiredness , weakness, shortness of breath , dizziness , tachycardia , drowsiness up to apathy , tinnitus and sleep disorders .

Altitude sickness can develop into acute and life-threatening high altitude brain edema (HACE), and life-threatening high altitude lung edema (HAPE) can also develop .

Affected

climber

The severity and frequency of altitude sickness for mountain climbers depends primarily on the altitude reached and the speed of the ascent. Mountain climbers who are not acclimatized have 10 to 25 percent signs of altitude sickness after the ascent to 2500 meters, but these are mostly mild and do not restrict activity. Inadequate acclimatization affects 50 to 85 percent of mountaineers at an altitude of 4500 to 5500 meters. The altitude sickness can be significantly more severe and prevent further ascent. In addition to the altitude reached, other strong risk factors for the occurrence of altitude sickness are an ascent of more than 625 meters per day from 2000 meters and a lack of prior acclimatization with less than five days over 3000 meters in the previous two months. Women are more often affected, as are younger people under the age of 46 and people with migraines . A lack of fitness is not a risk factor for altitude sickness, but for general exhaustion.

Residents of high altitudes

In the Andes , where numerous large cities such as La Paz , Cuzco or Quito are located at an altitude of over 3000 meters, altitude sickness, known as "Soroche", is a constant problem for many locals and travelers. Genetically, Tibetans have an increased respiratory rate and increased blood flow, so that - in contrast to the indigenous peoples of South America - they do not get sick as often. The Han Chinese are familiar with subacute mountain sickness in children after births at great heights. A similar syndrome has been described in soldiers who were stationed at altitudes above 6000 m for several months. The chronic mountain sickness ( Monge's disease after their Erstbeschreiber Carlos Monge Medrano , 1925) affects large long-term resident heights; this also leads to polycythemia , pulmonary embolism and symptoms like Pickwick's syndrome .

Causes and course

The reason is that the air pressure decreases with increasing altitude and thus also the oxygen - partial pressure . In addition to the already reduced oxygen uptake, the low oxygen partial pressure leads to a narrowing of the blood vessels in the lungs ( pulmonary vasoconstriction ; see Euler-Liljestrand mechanism ) and thus to a further decrease in the oxygen content in the blood. The body is under-supplied with oxygen ( hypoxia ). The body's own breathing regulation does not counteract this, as it primarily reacts to the carbon dioxide content of the blood. However, this does not increase with decreasing air pressure. High altitude pulmonary edema and high altitude cerebral edema can occur as further complications .

Due to the prevailing lack of oxygen, reflex hyperventilation occurs , which leads to respiratory alkalosis due to increased exhalation of CO 2 (an increase in the pH value in the blood, the blood is deacidified or more alkaline).

This creates headaches, confusion, and hallucinations. The kidneys can partially compensate for this effect through good acclimatization, but above 7000 meters this counterregulation is no longer sufficiently possible. In addition, due to dehydration, there is an acute impairment of kidney performance and the metabolic compensation of alkalosis (metabolic compensation) is no longer necessary .

In the lungs and brain, the blood vessels narrow due to self-regulation. In the brain, the low CO 2 partial pressure, in the lungs, the low O 2 partial pressure is decisive for this vasoconstriction. Cheyne-Stokes breathing is a special form of breathing disorder .

A high systolic blood pressure arises in the large circulation due to the sympathetic activation, which leads to the squeezing of fluid in the brain and life-threatening edema . The only thing that helps here is immediate transport to lower altitudes, oxygen ventilation and possibly a pressure chamber treatment. For this purpose, large expeditions often carry a Gamow sack with them, which offers a mobile pressure chamber functionality within limits.

High elevation pulmonary edema is characterized by increasing shortness of breath and fluid leakage into the alveoli, possibly with foamy or bloody sputum.

Countermeasures

If the symptoms are mild to moderate, you should take a day off. The headache should be treated with a non-steroidal anti-inflammatory drug , e.g. B. ibuprofen, treated. A remedy for nausea (anti- emetic ) and acetazolamide for better acclimatization are recommended. If the symptoms do not improve after a day, a descent of 500 to 1000 m is recommended.

In the case of severe symptoms, an immediate and as far as possible descent must take place. Oxygen should be given as well as dexamethasone (initially 8 mg intramuscularly, intravenously or orally and another 4 mg every six hours). A great danger is the development of high altitude brain edema.

A return to the ascent should only be undertaken if the altitude sickness has completely disappeared without the use of medication (except for acetazolamide). Then it is recommended to take acetazolamide for prophylaxis when climbing again.

In the Andes, tea made from leaves of the coca bush is drunk as a remedy for altitude sickness (also preventive) or these are chewed with lime. In Tibet , the locals praise butter tea (salted tea with lots of butter) as a precaution. There are no studies that prove effectiveness for either.

prevention

The body can adapt to this situation to a certain extent within a few days by producing more red blood cells . This adjustment is known as acclimatization . For mountain tours over 4500 m, it is recommended to spend a week in advance at an altitude between 2000 and 3000 m and to do day tours at higher altitudes. This measure reduces the likelihood and severity of altitude sickness by 50%. Guidelines for tours over 3000 m also recommend a daily ascent of no more than 300 to 500 m and a day break every three to four days. The handbook of the Swiss Alpine Club recommends that you spend the first night at a maximum of 2500 m and the next few nights at most 500 m higher. If you have ascended faster, you should spend the night at least twice at the same height.

If there is a moderate risk of altitude sickness, acetazolamide can be used in a low dose (125 mg twice a day), in a higher risk in a higher dose (250 mg two to three times a day). Since this drug in the higher dose already causes nausea and tiredness in one in four at low altitudes, a. Acroparaesthesia , taste disorders and polyuria often occur, you should try to take it before the tour. In the event of intolerance or contraindication, guidelines recommend the use of dexamethasone 4 mg twice a day at moderate risk and three times a day at higher risk.

If altitude sickness has already occurred, the first choice for prophylaxis is nifedipine (30 mg retard twice a day). Salbutamol inhalations appear less effective and are associated with a higher risk of tremor and tachycardia .

The use of theophylline to improve oxygen uptake is considered obsolete. For tours at very high altitudes (over 4000 m), it is advisable to bring oxygen and a mobile hyperbaric chamber for acute emergencies .

See also

literature

  • John R. Sutton, Norman L. Jones, Charles S. Houston: Hypoxia: Man at Altitude. Thieme-Stratton et al. a., New York 1982, ISBN 3-13-622901-0 .
  • Kai Schommer, Peter Bärtsch: Basic knowledge for advice on altitude medicine . In: Deutsches Ärzteblatt International . tape 49 , no. 108 , 2011, p. 839-848 ( review ).

Web links

Wiktionary: Altitude sickness  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ↑ Fritz Lange: "Textbook of diseases of the heart and the blood flow path", Ferdinand Enke Verlag, Stuttgart 1953, page 451.
  2. ↑ Federal Foreign Office, altitude sickness leaflet. (PDF; 44 kB) Retrieved July 6, 2011 .
  3. ↑ High blood flow strengthens altitude resistance of Tibetans Spektrum.de, accessed on June 26, 2020
  4. ↑ Michael Lange: Natural gene doping in Tibet - the Tibetan genetic makeup has adapted to the oxygen-poor air. In: WDR 5 , Leonardo - Wissenschaft und mehr, broadcast on May 14, 2010. Archived from the original on December 8, 2015 ; accessed on July 28, 2010 : "Geneticists from the USA and China have discovered two gene variants that enable Tibetans to live in thin mountain air" .
  5. ^ "The MSD Manual", 6th German edition, Urban & Fischer , Munich and Jena 2000, ISBN 3-437-21750-X , ISBN 3-437-21760-7 , page 2966.
  6. ^ A b Peter Bärtsch, Erik R. Swenson: Acute High-Altitude Illnesses . The New England Journal of Medicine , 2013, Volume 368, Issue 24, June 13, 2013, pages 2294-2302, doi: 10.1056 / NEJMcp1214870 .
  7. ↑ Winkler, Brehm and Haltmeier: Mountain sports summer - technology, tactics, safety . 3. Edition. SAC-Verlag, 2010, ISBN 978-3-85902-342-0 .