Chronic mountain sickness (CMS) is a disease in which the proportion of blood volume that is occupied by red blood cells increases (polycythaemia) and there is an abnormally low level of oxygen in the blood (hypoxemia). CMS typically develops after extended time living at high altitude (over 2,500 metres (8,200 ft)). It is most common amongst native populations of high altitude nations.[1] The most frequent symptoms of CMS are headache, dizziness, tinnitus, breathlessness, palpitations, sleep disturbance, fatigue, loss of appetite, confusion, cyanosis, and dilation of veins.[2]
CMS was first described in 1925 by Carlos Monge Medrano, a Peruvian doctor who specialised in diseases of high altitude.[3] While acute mountain sickness is experienced shortly after ascent to high altitude, chronic mountain sickness may develop only after many years of living at high altitude. In medicine, high altitude is defined as over 2,500 metres (8,200 ft), but most cases of CMS occur at over 3,000 metres (9,800 ft).
It has recently been correlated with increased expression of the genes ANP32D and SENP1.[4][5]
CMS is characterised by polycythaemia (with subsequent increased haematocrit) and hypoxaemia; raised blood pressure in the lungs (pulmonary hypertension) can develop over time and in some cases progress to heart failure (cor pulmonale).[1] CMS is believed to arise because of an excessive production of red blood cells (erythrocytes) due to the low oxygen levels at altitude, which increases the oxygen carrying capacity of the blood[1]. The increased levels of erythrocytes causes 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.[6]
Consensus for clinical diagnosis of CMS use laboratory values: haemoglobin in Males ≥ 21 g/dL; Females ≥ 19 g/dL, haematocrit > 65%, and arterial oxygen saturation (SaO2) < 85% in both sexes.[1]
Treatmentedit
Migration to low altitude is curative, though not immediate, as the body adapts to the normal oxygen level near sea-level and the haematocrit normalises. Alternatively, bloodletting (phlebotomy) can be performed to lower the haematocrit temporarily; when combined with volume replacement with fluids this can have a longer effect.[1]
Medication with acetazolamide, a carbonic anhydrase inhibitor, has been shown to improve chronic mountain sickness by reducing erythropoietin and the resulting polycythaemia, which results in better arterial oxygenation and a lower heart rate.[7]
Oxygen therapy and training in slow breathing techniques has been shown to reduce symptoms through increasing blood oxygenation.[1]
Epidemiologyedit
Although CMS generally affects people native to altitudes higher than 3,000 metres (9,800 ft), it does not affect populations around the world equally. A 2013 study[8] 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. CMS prevalence rates reported from the study are summarised below:
^ abcdeLeón-Velarde, F; Maggiorini, M; Reeves, JT; Aldashev, A; Asmus, I; et al. (2005). "Consensus statement on chronic and subacute high altitude diseases". High Altitude Medicine & Biology. 6 (2): 147–57. doi:10.1089/ham.2005.6.147. PMID 16060849.
^Wu, TY (20 January 2005). "Chronic mountain sickness on the Qinghai-Tibetan plateau". Chinese Medical Journal. 118 (2): 161–8. PMID 15667803.
^Monge, CC; Whittembury, J (December 1976). "Chronic mountain sickness". The Johns Hopkins Medical Journal. 139 SUPPL: 87–9. PMID 1011412.
^Zhou, D; Udpa, N; Ronen, R; Stobdan, T; Liang, J; et al. (5 September 2013). "Whole-genome sequencing uncovers the genetic basis of chronic mountain sickness in Andean highlanders". American Journal of Human Genetics. 93 (3): 452–62. doi:10.1016/j.ajhg.2013.07.011. PMC3769925. PMID 23954164.
^Cole, AM; Petousi, N; Cavalleri, GL; Robbins, PA (December 2014). "Genetic variation in SENP1 and ANP32D as predictors of chronic mountain sickness". High Altitude Medicine & Biology. 15 (4): 497–9. doi:10.1089/ham.2014.1036. PMC4273201. PMID 25225945.
^Zubieta-Castillo G, Sr; Zubieta-Calleja GR, Jr; Zubieta-Calleja, L (September 2006). "Chronic mountain sickness: the reaction of physical disorders to chronic hypoxia". Journal of Physiology and Pharmacology. 57 (Suppl 4): 431–42. PMID 17072074.
^Richalet, JP; Rivera, M; Bouchet, P; Chirinos, E; Onnen, I; et al. (1 December 2005). "Acetazolamide: a treatment for chronic mountain sickness". American Journal of Respiratory and Critical Care Medicine. 172 (11): 1427–33. doi:10.1164/rccm.200505-807OC. PMID 16126936.
^Sahota, I; Panwar, N (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. PMC4035612. PMID 24872667.
chronic, mountain, sickness, disease, which, proportion, blood, volume, that, occupied, blood, cells, increases, polycythaemia, there, abnormally, level, oxygen, blood, hypoxemia, typically, develops, after, extended, time, living, high, altitude, over, metres. Chronic mountain sickness CMS is a disease in which the proportion of blood volume that is occupied by red blood cells increases polycythaemia and there is an abnormally low level of oxygen in the blood hypoxemia CMS typically develops after extended time living at high altitude over 2 500 metres 8 200 ft It is most common amongst native populations of high altitude nations 1 The most frequent symptoms of CMS are headache dizziness tinnitus breathlessness palpitations sleep disturbance fatigue loss of appetite confusion cyanosis and dilation of veins 2 Chronic mountain sicknessOther namesMonge s diseaseSpecialtyEmergency medicine CMS was first described in 1925 by Carlos Monge Medrano a Peruvian doctor who specialised in diseases of high altitude 3 While acute mountain sickness is experienced shortly after ascent to high altitude chronic mountain sickness may develop only after many years of living at high altitude In medicine high altitude is defined as over 2 500 metres 8 200 ft but most cases of CMS occur at over 3 000 metres 9 800 ft It has recently been correlated with increased expression of the genes ANP32D and SENP1 4 5 Contents 1 Diagnosis 2 Treatment 3 Epidemiology 4 References 5 External linksDiagnosis editCMS is characterised by polycythaemia with subsequent increased haematocrit and hypoxaemia raised blood pressure in the lungs pulmonary hypertension can develop over time and in some cases progress to heart failure cor pulmonale 1 CMS is believed to arise because of an excessive production of red blood cells erythrocytes due to the low oxygen levels at altitude which increases the oxygen carrying capacity of the blood 1 The increased levels of erythrocytes causes 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 6 Consensus for clinical diagnosis of CMS use laboratory values haemoglobin in Males 21 g dL Females 19 g dL haematocrit gt 65 and arterial oxygen saturation SaO2 lt 85 in both sexes 1 Treatment editMigration to low altitude is curative though not immediate as the body adapts to the normal oxygen level near sea level and the haematocrit normalises Alternatively bloodletting phlebotomy can be performed to lower the haematocrit temporarily when combined with volume replacement with fluids this can have a longer effect 1 Medication with acetazolamide a carbonic anhydrase inhibitor has been shown to improve chronic mountain sickness by reducing erythropoietin and the resulting polycythaemia which results in better arterial oxygenation and a lower heart rate 7 Oxygen therapy and training in slow breathing techniques has been shown to reduce symptoms through increasing blood oxygenation 1 Epidemiology editAlthough CMS generally affects people native to altitudes higher than 3 000 metres 9 800 ft it does not affect populations around the world equally A 2013 study 8 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 CMS prevalence rates reported from the study are summarised 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 8 Bolivia 8 10 Cerro de Pasco Peru 4300 m 14 8 18 2 References edit a b c d e Leon Velarde F Maggiorini M Reeves JT Aldashev A Asmus I et al 2005 Consensus statement on chronic and subacute high altitude diseases High Altitude Medicine amp Biology 6 2 147 57 doi 10 1089 ham 2005 6 147 PMID 16060849 Wu TY 20 January 2005 Chronic mountain sickness on the Qinghai Tibetan plateau Chinese Medical Journal 118 2 161 8 PMID 15667803 Monge CC Whittembury J December 1976 Chronic mountain sickness The Johns Hopkins Medical Journal 139 SUPPL 87 9 PMID 1011412 Zhou D Udpa N Ronen R Stobdan T Liang J et al 5 September 2013 Whole genome sequencing uncovers the genetic basis of chronic mountain sickness in Andean highlanders American Journal of Human Genetics 93 3 452 62 doi 10 1016 j ajhg 2013 07 011 PMC 3769925 PMID 23954164 Cole AM Petousi N Cavalleri GL Robbins PA December 2014 Genetic variation in SENP1 and ANP32D as predictors of chronic mountain sickness High Altitude Medicine amp Biology 15 4 497 9 doi 10 1089 ham 2014 1036 PMC 4273201 PMID 25225945 Zubieta Castillo G Sr Zubieta Calleja GR Jr Zubieta Calleja L September 2006 Chronic mountain sickness the reaction of physical disorders to chronic hypoxia Journal of Physiology and Pharmacology 57 Suppl 4 431 42 PMID 17072074 Richalet JP Rivera M Bouchet P Chirinos E Onnen I et al 1 December 2005 Acetazolamide a treatment for chronic mountain sickness American Journal of Respiratory and Critical Care Medicine 172 11 1427 33 doi 10 1164 rccm 200505 807OC PMID 16126936 Sahota I Panwar N 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 External links edit Online calculator illustrating blood oxygen carrying capacity at altitude Retrieved from https en wikipedia org w index php title Chronic mountain sickness amp oldid 1188086646, wikipedia, wiki, book, books, library,
