CHRONIC MOUNTAIN SICKNESS

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CHRONIC MOUNTAIN SICKNESS
brought to you by

• White, Roy
• Armendariz, Pedro
• Carrasco, Alonso
• Castorena, Felipe
• Cruz de Jesus, Liz
• Lewis, Spencer

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Physiology Objective

• PUL 53. Describe the interaction of hypoxia and
  hypercapnia in the control of alveolar
  ventilation.
• PUL 56. Name five causes of hypoxemia.

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Chronic Mountain Sickness

• Signs and Symptoms
• Physiology
• Maladaption
• Treatment
• Evolutionary/Genetic Adaptation

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SIGNS AND SYMPTOMS

• Millions living above an altitude of 2500 m are
  at risk.
• characterised by polycythaemia (increased
  haematocrit) and hypoxaemia.

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Most Frequent Signs and symptoms

• headache, dizziness, tinnitus, breathlessness,
  palpitations, sleep disturbance, fatigue,
  anorexia, mental confusion, cyanosis, and
  dilation of veins.
• Dimmed vision, hemianopsia, scotomata, and even
  transient blindness have been reported.

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• Retinal hemorrhages may develop at altitudes as
  low as 9000 ft (2700 m).
• Small hemorrhages may also occur under the nails,
  in the kidneys, and in the brain.
• CNS dysfunction is considered a factor in several
  forms of CMS.

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High Altitude Physiology

• ? Altitude ?PO2
• Mechanisms of Adaptation
• ? Pulmonary Ventilation
• ? RBC
• ? Diffusing Capacity of Lung
• ? Vascularity in Tissues
• Enhance Oxygen Use

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CMS Physiology

• ?Erythropoiesis
• ? Viscosity
• ? Resistance
• ? Blood Flow
• Hypoxia
• Pulmonary Arterioles Constrict
• ? Pulmonary Artery Pressure
• Enlargement of Right Side of the Heart
• Congestive Heart Failure

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Mal adaptation
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Diagnosis

• Hemoglobin comparisons
• Oxygen Saturation studies (SaO2)
• Peak Expiratory Flow Rates (PEFR)
• CMS scores (CMSsco)

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Treatment for Chronic Mountain Sickness

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Tx

• Until recently there has been no pharmacologic
  treatment utilized to stop the progressive loss
  of adaptation to chronic hypoxia as seen in CMS
  patients. A few pharmacologic agents, such as
• medroxyprogesterone,
• enalapril,
• almitrine
• They have undergone clinical trials, but none are
  currently used in therapy.

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Tx

• Current treatment of CMS includes removing the
  patients from the high altitude and blood
  letting. If all the patients with CMS were
  removed from these high altitudes the region
  would suffer socially and economically. Beside
  that the families of these patients would
  experience severe consequences.

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Tx

• One of the first treatments discovered for CMS
  that does not have negative side effects is
  Acetazolamide. It is effective and yet is a low
  cost medication making it feasible for many
  living in high altitudes to have the benefit of
  reduced hypoventilation, and blunted
  erythropoiesis.

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Tx

• Acetazolamide (ACZ) an inhibitor of carbonic
  anhydrase,
• Decreases the reabsorption of bicarbonates in the
  proximal tubule of the kidney
• Promotes diuresis,
• Increases cerebral blood flow
• Stimulates ventilation via metabolic acidosis.

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Tx

• ACZ has been shown helpful in reducing central
  apneas in high altitude mountaineers or in
  patients with sleep-related breathing disorders
  at sea level but has never been evaluated.

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Evolutionary Genetic Adaptation
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Sources

• Claydon, V.E., et al. Cardiovascular Responses to
  Orthostatic Stress in Healthy Altitude dwellers,
  and Altitude Residents with Chronic Mountain
  Sickness. Experimental Physiology 90.1, 103-110,
  2004
• Claydon, VE., et al, Orthostatic tolerance and
  blood volumes in Andean High Altitude Dwellers.
  Experimental Physiology, 89.5, 565-571,2004
• Guyton, Arthur C., and John E. Hall. Medical
  Physiology. New York W. B. Saunders Company,
  2000.
• Leon-Velarde F, Arregui A, Vargas M, Huicho Land
  Acosta R. Chronic Mountain Sickness and Chronic
  Lower Respiratory Tract Disorders. Chest, Vol
  106, 151-155, 1994
• Richalet, JP, Rivera M, Bouchet P, Chirinos E, et
  al. Acetazolamide A Treatment for Chronic
  Mountian Sickness. American Journal of
  Respiratory and Critical Care Medicine. Vol. 172,
  Iss. 11, 1427-33, Dec. 1, 2005
• Tierney, LM. Jr, McPhee SJ, and Papadakis MA.
  Current Medical Diagnosis Treatment. New York
  Lange Medical Books, 2004.