Altitude Sickness

Height diseases are caused by the reduced availability of O2 at high altitudes. The acute mountain sickness (AMS, acute mountain sickness), the mildest form of height disease is characterized by headache, as well as from one or more systemic manifestations, it can with hikers and skiers and other traveling at high altitudes, occur. The cerebral edema in height (HACE, high altitude cerebral edema) is an encephalopathy in people with AMS. The pulmonary edema in height (HAPE, high altitude pulmonary edema) is a form of pulmonary edema nichtkardiogenen that causes a severe dyspnea and hypoxemia. The diagnosis is made clinically. The treatment of mild AMS consists of analgesics and acetazolamide. In severe acute mountain sickness (AMS), the descent may be necessary as well as an additional administration of O2 if available. Both HACE and HAPE are potentially life-threatening and require immediate descent. In addition, dexamethasone may be useful in HACE and HAPE at nifedipine or phosphodiesterase. A prevention of AMS is a gradual ascent and the use of acetazolamide.

With increasing height, the atmospheric pressure decreases, while the percentage of O2 in the air remains constant; Therefore, the O2 partial pressure decreases in height and is only at 5800 m, about half of the partial pressure at sea level.

Height diseases are caused by the reduced availability of O2 at high altitudes. The acute mountain sickness (AMS, acute mountain sickness), the mildest form of height disease is characterized by headache, as well as from one or more systemic manifestations, it can with hikers and skiers and other traveling at high altitudes, occur. The cerebral edema in height (HACE, high altitude cerebral edema) is an encephalopathy in people with AMS. The pulmonary edema in height (HAPE, high altitude pulmonary edema) is a form of pulmonary edema nichtkardiogenen that causes a severe dyspnea and hypoxemia. The diagnosis is made clinically. The treatment of mild AMS consists of analgesics and acetazolamide. In severe acute mountain sickness (AMS), the descent may be necessary as well as an additional administration of O2 if available. Both HACE and HAPE are potentially life-threatening and require immediate descent. In addition, dexamethasone may be useful in HACE and HAPE at nifedipine or phosphodiesterase. A prevention of AMS is a gradual ascent and the use of acetazolamide. With increasing height, the atmospheric pressure decreases, while the percentage of O2 in the air remains constant; Therefore, the O2 partial pressure decreases in height and is only at 5800 m, about half of the partial pressure at sea level. Most people can get in one day without any problems to a height of 1500 or 2000 m, but in about 20% of people who are up to 2500 m, and 40% of those who ascend to 3000 m, is developing a form of altitude sickness (AMS, altitude sickness). The speed during the ascent, the highest altitude reached and the height at which the night is spent, affect the probability of the occurrence of the disease. Risk Factors The influence exerted by great heights, in different people can vary widely, but in general, the risk is following increased history of previous AD Living near the sea a fast ascent overexertion sleeping at too high a level young children and adolescents are likely vulnerable. Diseases such as asthma, hypertension, diabetes mellitus, coronary artery disease and mild COPD are not risk factors for AD, but a resultant hypoxia may adversely affect these diseases. Good physical condition will not provide protection. Tips and risks Physical fitness does not protect against altitude sickness. Pathophysiology Acute hypoxia (z. B. the rapid rise to great heights with an airplane without regulated pressure equalization) changed the CNS function within minutes. An AD but is due to the neurohumoral and hemodynamic response of the body to hypoxia; it develops over hours to days. The primary manifestations affecting the CNS and the lungs. It is believed that the pathogenesis of AMS and HACE is similar, HACE represents the extreme of the spectrum of disease. Although it is not certain that the pathogenesis may include mild cerebral edema, possibly related to an increased cerebral blood flow by hypoxia. HAPE is caused by the hypoxia-induced increase in pulmonary artery pressure, which interstitial and alveolar edema caused, which results in impaired oxygenation. An unevenly distributed hypoxic vasoconstriction of small vessels leads to a Überperfusion elevated pressure, damage to the capillary walls and for percolation of the capillary liquid in less konstringierte zones. Other factors such. B. sympathetic overactivity, may also be included. For people who live for a long time in height, a HAPE a phenomenon that is referred to as reentry pulmonary edema may develop, when they come back from a short stay at a low altitude. Acclimatization The acclimatization consists of an integrated set of adaptive responses that tissue oxygenation normalize gradually in individuals at high altitude again. Despite the acclimatization at high altitude but tissue hypoxia occurs in all people. Most people adapt relatively well in a few days at altitudes up to 3000 m. The larger the amount is, the longer the full acclimatization. However, no one can fully acclimate to a long-term residential> 5100 m (> 17,000 ft). Among the signs of acclimatization include a continued hyperventilation, which increases tissue oxygenation, but also causes a respiratory alkalosis. The pH of the blood to normal within a few days once HCO3 is excreted in the urine; if the pH is normalized, the ventilation may continue to increase. Initially, the cardiac output increases; the number of erythrocytes and the tolerance for aerobic work are also increasing. Symptoms and complaints AMS is by far the most common form of altitude sickness. Acute Mountain Sickness (AMS, acute mountain sickness) This disease is unlikely, unless the amount is more than 2,440 meters (8,000 ft), but it can develop in some highly sensitive people at lower elevations. It is believed to be caused by a slight cerebral edema and is characterized by headache, in conjunction with at least one of the following symptoms: fatigue, gastrointestinal complaints (anorexia, nausea, vomiting), prolonged dizziness and insomnia. Exertion aggravates the symptoms. Symptoms usually develop within 6-10 h after the rise and subside after 24-48 h. An AMS usually occurs at ski resorts, write some individuals the symptoms erroneously excessive alcohol consumption (cat) or a viral disease zu.Höhenhirnödem (HACE) A distinctive cerebral edema (HACE, high-altitude cerebral edema) manifests itself in headaches and diffuse encephalopathy with confusion, somnolence, stupor and coma. A gait ataxia is a reliable early warning signs. Epileptic seizures, focal deficits (eg. As cranial nerve palsy, hemiplegia), fever and meningeal signs are rare and should immediately get other diagnoses. It may occur papilledema and retinal hemorrhage, but these are not necessary for diagnosis. Coma and death can usually develops 24-96 hours after a few einstellen.Höhenlungenödem (HAPE) A HAPE (high-altitude pulmonary edema) hours after a rapid rise to> 2500 m and is responsible for most deaths, altitude sickness on a are due. Initially, patients complain of dyspnea on exertion, as well as decreased resilience and dry cough. Later dyspnea is present even at rest. Pink or bloody sputum and respiratory distress are later findings. Cyanosis, tachycardia, tachypnea and mild fever (> 38.5 ° C) are often found in the investigation. Focal or diffuse rales (sometimes without stethoscope audible) are usually present. A HAPE may worsen rapidly, coma and death can auftreten.Andere within hours manifestations Peripheral and facial edema occur at high altitudes before many times. Headache with no other symptoms of AMS are common. Netzhauthämorrhagien can already occur at altitudes of 2700 m and are often at> 5000 m (> 16,000 feet). They are usually asymptomatic if they do not occur in the macular region; they dissolve over weeks without consequences, but if they develop, a descent is necessary and a further rise is contraindicated have solved until the hemorrhage. In individuals in which a radial corneal incision was performed,> 5000 m (> 16,000 feet) can occur in severe visual disturbances heights. These symptoms disappear rapidly after descent. Chronic mountain sickness (Monge’s disease) is a disease that occurs in people who live a long time at high altitude; it is characterized by excessive polycythemia, fatigue, dyspnea, pain, and cyanosis. Often a alveolar hypoventilation shows. Patients should descend to a low level and remain there permanently if this is possible. However, economic factors often prevent them from doing so. Repeated phlebotomy can help in reducing the polycythemia. In some patients, it comes with a long-term treatment with acetazolamide to an improvement. Diagnosis Clinical Evaluation The diagnosis of most forms of altitude sickness occurs clinically, laboratory tests are generally unnecessary. The hypoxemia is often severe in HAPE, wherein the pulse oximetry shows a saturation level of 40-70%, depending on the height at which the sick person. When available, a chest X-ray shows a normal-sized heart and patchy pulmonary edema. HACE can usually from other causes of headaches and coma (eg, infection, hemorrhage, uncontrolled diabetes.) Are distinguished by the history and clinical findings; CT of the head is not performed normally. Treatment In mild to moderate AMS: interruption of the rise and treatment with fluids nichtopioden analgesics and sometimes acetazolamide In severe AMS: Descent In HACE and HAPE: immediate descent and treatment with O2, medicines and relief AMS The patient should stop the rise and efforts so reduce until the symptoms disappear (1, 2). Further treatment includes hydration and nichtopiode analgesics for headaches. If serious symptoms, a decline of 500-1000 m is often rapidly effective. Acetazolamide 250 mg p.o. can 2 times a day relieve symptoms and improve sleep. Dexamethasone p.o. 2 to 4 mg, i.m. or iv every 6 h is also very effective to treat the symptoms of AMS to behandeln.HACE and HAPE Patients should immediately descend to lower altitudes. An evacuation with the helicopter can be lifesaving (1). If the descent is delayed, the patient should keep quiet and be supplied with O2. If the descent is impossible help (To increase the O2 saturation> 90%), thereby gaining time O2 drugs and pressure compensation using a portable hyperbaric bag; a substitute for the descent, however, these measures are not. For HACE (and severe AMS), dexamethasone beginning dexamethasone 8 mg, followed by 4 mg every 6 h, can help. It should p.o. be given, but if this is not possible, dexamethasone can i.m. or iv are given. Acetazolamide 250 mg p.o. can also be given two times a day. For HAPE, nifedipine or a phosphodiesterase inhibitor A nifedipine 30 mg prolonged-release tablet po every 12 hours reduces pulmonary artery pressure and is beneficial, although a systemic hypotension may be a possible complication. A phosphodiesterase inhibitor, such as sildenafil (50 mg p. O. Every 12 h) or tadalafil (10 mg p. O. Every 12 h), can be used instead of nifedipine. Diuretics (. Furosemide, for example) are contraindicated; they have no efficacy and many patients have concurrent volume depletion. In a HAPE cardiac function is normal, therefore, digoxin and afterload with ACE inhibitors are useless. With immediate treatment after the descent, the patient recovers within 24-48 hours from a HAPE. Effort should be avoided during descent. Those who already undergone a HAPE episode, are more vulnerable and should be made aware. Tips and risks diuretics are contraindicated in altitude pulmonary edema. Treatment Note Luks AM, McIntosh SE, Grissom CK, et al. Wilderness Medical Society consensus guidelines for the prevention and treatment of acute altitude illness: 2014 update. Wilderness Environ Med 25 (4S): S4-S14, 2014. Bartsch P, Swenson ER. Acute altitude illness. N Engl J Med 368: 2294-2302, 2013. DOI: 10.1056 / NEJMcp1214870. Sometimes prevention acetazolamide or dexamethasone Although good physical condition in height enables Slower rise to greater efforts, it does not protect against any form of altitude sickness. An adequate fluid intake does not prevent AMS, but protects against drying, whose symptoms are similar to those of AMS. Opioids and heavy drinking, especially just before bedtime should be avoided. Rise The most important measure is a slow rise (1.2). A gradual rise of divided is important for activities in> 2500 m. Above 3000 m (10,000 ft), climbers should not increase their sleeping altitude by more than 500 meters per day, and they should have a rest day (d. E., Sleep at the same level) insert every 3 to 4 days. During their days climbers can take part in physical activity and ascend to higher altitudes, but should return to lower levels for sleep. Since the ability of climbers to ascend without symptoms, is different, a mountain tour should always be tuned to the slowest participant. Acclimatization is gradually lost after a few days at a lower height and climbers who come to this period again back to great heights, should once again the gradual slow rise befolgen.Medikamentöse therapy acetazolamide 125-250 mg po every 12 h decreases the incidence of altitude sickness. Retardkapseln (500 mg / day) are also available. With acetazolamide can be started on the day of the ascent; by inhibition of carbonic anhydrase acetazolamide increased ventilation. 125 mg p.o. at bedtime, the amount of periodic breathing, therefore, reduce (with sleep at high altitudes almost always present) and limits the strong reduction of O2 in the blood. Acetazolamide should not be administered to patients who have an allergy to sulfonamide derivatives. Substances analogous to acetazolamide offer no advantage. Acetazolamide can cause numbness and paresthesia of the fingers; these symptoms are benign, but can be annoying. Carbonated drinks taste stale after taking acetazolamide. Dexamethasone 2 mg p.o. (P.o. or 4 mg every 12 hours) every 6 h is an alternative to acetazolamide. O2 low flow during sleep at high altitudes is effective but impractical and can mean logistical difficulties. Patients who have already undergone a HAPE episode, should additional preventive treatment with 30 mg po Nifedipinlangzeitpräparaten 2 times daily or tadalafil 10 mg p.o. consider two times a day (3). Salmeterol, 125 micrograms of inhaled every 12 hours can be added as a supplement to a pulmonary vasodilator, but should not be used as monotherapy for prevention. . Analgesics (eg, acetaminophen, ibuprofen can height related headaches vorbeugen.Hinweise for prevention Luks AM, McIntosh SE, Grissom CK, et al Wilderness Medical Society consensus guidelines for the prevention and treatment of acute altitude illness. 2014 update Wilderness Environ Med. .% 3 $ s -% 8 $ s% 2 $ s Bartsch P, Swenson ER heights Acute disease N Engl J Med 368: 2294-2302, 2013. DOI: 10.1056 / NEJMcp1214870 Maggiorini M, Brunner…. -La Rocca HP, Peth S, et al Both tadalafil and dexamethasone may reduce the incidence of high-altitude pulmonary edema: a randomized trial Ann Intern Med 3; 145 (7):.. 497-506, 2006. Summary About 20% of people who up to 2500 m and 40% of those who get in a day to 3,000 m, develop an AMS. AMS causes headaches and Müdig ness, gastrointestinal symptoms (anorexia, nausea, vomiting), dizziness and / or sleep. HACE causes ataxia and encephalopathy. HAPE causes shortness of breath, decreased tolerance of exertion, and coughing, which is initially dry. The diagnosis of altitude sickness will be based on clinical criteria. The AMS is treated with liquid supply, analgesics, sometimes acetazolamide, and by interruption of the climb. An immediate descent should be arranged in patients with HACE, HAPE or severe form of AMS. Height diseases can be prevented by gradual rise and taking acetazolamide.

Health Life Media Team

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