Villafuerte and Corante have published a review on chronic mountain sickness (CMS) in High Altitude Medicine and Biology (June 2016).

CMS or Monge’s disease is a highly prevalent progressive incapacitating syndrome. More than 140 million people live above 2500 m worldwide, and on average, 5-10% are at risk of developing CMS. It is caused by chronic hypoxic exposure.

CMS is characterized by excessive erythrocytosis and severe hypoxemia. Clinical symptoms of CMS include headache, dizziness, breathlessness and/or palpitations, sleep disturbances, fatigue, localized cyanosis, burning in the palms of hands and soles of feet, dilatation of veins, muscle and joint pain, loss of appetite, lack of mental concentration, and alterations of memory. Clinical signs include excessive erythrocytosis and severe hypoxemia. You could also find pulmonary hypertension, and signs of congestive heart failure.

Given the progressive and incapacitating nature of CMS, yearly check-ups on hemoglobin concentration or hematocrit, and associated comorbidities are necessary. Also, periodic travel to lower altitudes is recommended for those close to or with diagnosed excessive erytrocytosis (the clinical picture of CMS gradually disappears upon descent to low altitudes and reappears after returning to high altitude). Heavy exercise should be avoided, and mild/moderate exercise should be performed only under a supervised controlled regime. Treatment with acetazolamide (250 mg/day) can relief signs and symptoms and is safe up to 6 months. In severe cases the patient should move permanently to a lower altitude or sea level.

Figure 1. CMS patient: cyanosis, vein dilatation and clubbing of vingers.

You can read the full article here, for more information on clinical aspects of the condition, its etiology, epidemiology, risk factors, and treatment strategies of CMS.

Villafuerte FC, Corante N. Chronic Mountain Sickness: Clinical Aspects, Etiology, Management, and Treatment. High Alt Med Biol. 2016;17(2):61-9. doi: 10.1089/ham.2016.0031