Chronic mountain sickness

Chronic mountain sickness
Classification and external resources
Specialty	emergency medicine
ICD-10	T70.2
ICD-9-CM	E902.0
DiseasesDB	29615

Chronic mountain sickness (CMS or Monge's disease) is a disease in which the proportion of blood volume that is occupied by red blood cells increases (polycythemia) and there is an abnormally low level of oxygen in the blood (hypoxemia). CMS can develop during extended time living at a high altitude. The most frequent symptoms of CMS are headache, dizziness, tinnitus, breathlessness, palpitations, sleep disturbance, fatigue, anorexia, mental confusion, cyanosis, and dilation of veins.

CMS was first described in 1925 by Carlos Monge. While acute mountain sickness is experienced shortly after ascent to high altitude, chronic mountain sickness may develop after many years of living at high altitude. In medicine, high altitude is defined as over 2500 metres (8200 ft), but most cases of CMS occur at over 3000 m (10000 ft). Recently it has been correlated with increased expression of the genes ANP32D and SENP1.^[1]^[2]

Prevalence

Although CMS generally affects people native to altitudes higher than 3000 m, it does not affect populations around the world equally. A recent study by Sahota and Panwar (2013)^[3] reviewed CMS prevalence rates around the world and found the highest rates were found in Andean countries of South America and the lowest rates in people native to the East African Mountains of Ethiopia. Third party CMS prevalence rates reported from the study are summarized below:

Ethiopia [3600–4100 m]: 0%
Tibetan Plateau (Tibetans): 0.91–1.2%
Indian Himalayas [3000–4200 m]: 4–7%
Kyrgyzstan [3000–4200 m]: 4.6%
Tibetan Plateau (Han Chinese): 5.6%
La Paz, Bolivia [3600 m]: 6% to 8%
Bolivia: 8–10%
Cerro de Pasco, Peru [4300 m]: 14.8–18.2%

Diagnosis

CMS is characterised by polycythemia (with subsequent increased hematocrit) and hypoxemia, which both improve on descent from altitude. CMS is believed to arise because of an excessive production of red blood cells, which increases the oxygen carrying capacity of the blood but may cause increased blood viscosity and uneven blood flow through the lungs (V/Q mismatch). However, CMS is also considered an adaptation of pulmonary and heart disease to life under chronic hypoxia at altitude.

Clinical diagnosis by laboratory indicators have ranges of Hb > 200 g/L, Hct > 65%, and arterial oxygen saturation (SaO2) < 85% in both genders.

Treatment

Treatment involves descent from altitude, where the symptoms will diminish and the hematocrit return to normal slowly. Acute treatment at altitude involves bleeding (phlebotomy), removal of circulating blood, to reduce the hematocrit; however this is not ideal for extended periods. Carbonic anhydrase inhibitors have been shown to improve chronic mountain sickness by reducing erythropoietin and the resulting polycytemia, which resulted in better arterial O₂ and lower heart rate.^[4]

↑ Zhou D, Udpa N, Ronen R, Stobdan T, Liang J, Appenzeller O, Zhao HW, Yin Y, Du Y, Guo L, Cao R, Wang Y, Jin X, Huang C, Jia W, Cao D, Guo G, Gamboa JL, Villafuerte F, Callacondo D, Xue J, Liu S, Frazer KA, Li Y, Bafna V, Haddad GG. Whole-genome sequencing uncovers the genetic basis of chronic mountain sickness in Andean highlanders. Am J Hum Genet. 2013 Sep 5;93(3):452-62. doi:10.1016/j.ajhg.2013.07.011. Epub 2013 Aug 15. PMID 23954164
↑ Cole, Amy M.; Nayia Petousi; Gianpiero L. Cavalleri; Peter A. Robbins (2014). "Genetic Variation in SENP1 and ANP32D as Predictors of Chronic Mountain Sickness". High Altitude Medicine & Biology. 15 (4): 497–499. doi:10.1089/ham.2014.1036. ISSN 1557-8682. PMC 4273201. PMID 25225945.
↑ Sahota, Inderjeet; Nidhi Panwar (September 2013). "Prevalence of Chronic Mountain Sickness in high altitude districts of Himachal Pradesh". Indian Journal of Occupational and Environmental Medicine. 17 (3): 94–100. doi:10.4103/0019-5278.130839. PMC 4035612. PMID 24872667.
↑ Richalet, Jean-Paul; Maria Rivera; Patrick Bouchet; Eduardo Chirinos; Igor Onnen; Olivier Petitjean; Annick Bienvenu; Francçoise Lasne; Stéphane Moutereau; Fabiola León-Velarde (2005). "Acetazolamide: a treatment for chronic mountain sickness". American Journal of Respiratory and Critical Care Medicine. 172 (11): 1427–1433. doi:10.1164/rccm.200505-807OC. ISSN 1073-449X. PMID 16126936.

^ Monge CC, Whittembury J. "Chronic mountain sickness". The Johns Hopkins Medical Journal 1976 Dec;139 SUPPL:87–9. PMID 1011412
^ Online calculator explaining blood oxygen content
^ Zubieta-Castillo G Sr, Zubieta-Calleja GR Jr, Zubieta-Calleja L. "Chronic mountain sickness": the reaction of physical disorders to chronic hypoxia. Journal of Physiology and Pharmacology. 2006 Sep;57(Suppl 4):431–42.
^ Wu TY. "Chronic mountain sickness on the Qinghai-Tibetan plateau". Chinese Medical Journal (Engl). 2005 Jan 20;118(2):161–8. PMID 15667803
^ "Recommendation for the classification and diagnostic criteria of high altitude disease in China". Chin High Alt Med J (in Chinese). Chinese Medical Association for High Altitude Medicine (6): 2–5. 1996.

Consequences of external causes (T66–T78, 990–995)

Temperature/radiation	elevated temperature Hyperthermia Heat syncope reduced temperature Hypothermia Immersion foot syndromes Trench foot Tropical immersion foot Warm water immersion foot Chilblains Frostbite Aerosol burn Cold intolerance Acrocyanosis Erythrocyanosis crurum radiation Radiation poisoning Radiation burn Chronic radiation keratosis Eosinophilic, polymorphic, and pruritic eruption associated with radiotherapy Radiation acne Radiation cancer Radiation recall reaction Radiation-induced erythema multiforme Radiation-induced hypertrophic scar Radiation-induced keloid Radiation-induced morphea

Air	Hypoxia/Asphyxia Barotrauma Aerosinusitis Decompression sickness High altitude Altitude sickness Chronic mountain sickness HAPE HACE

Food	Starvation

Maltreatment	Physical abuse Sexual abuse Psychological abuse

Travel	Motion sickness Seasickness Airsickness Space adaptation syndrome

Adverse effect	Hypersensitivity Anaphylaxis Angioedema Allergy Arthus reaction Adverse drug reaction

Other	Electric shock Drowning Lightning injury

Ungrouped skin conditions resulting from physical factors	Dermatosis neglecta Pinch mark Pseudoverrucous papules and nodules Sclerosing lymphangiitis Tropical anhidrotic asthenia UV-sensitive syndrome environmental skin conditions Electrical burn frictional/traumatic/sports Black heel and palm Equestrian perniosis Jogger's nipple Pulling boat hands Runner's rump Surfer's knots Tennis toe Vibration white finger Weathering nodule of ear Wrestler's ear Coral cut Painful fat herniation Uranium dermatosis iv use Skin pop scar Skin track Slap mark Pseudoacanthosis nigricans Narcotic dermopathy

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