‘Altitude sickness’ is a set of symptoms that occur when people are at a high altitude, i.e. elevations of about 1,500 metres. It occurs acutely in persons who climb high altitudes and are not accustomed to it. Some tourists trekking gorillas at high altitudes tend to develop health problems like breathlessness, palpitations, swelling over the feet, etc. It usually subsides a few days after rest. However, prolonged high-altitude residence can lead to chronic mountain sickness (CMS), or Monge’s disease. Common symptoms of CMS are headache, dizziness, tinnitus, breathlessness, blueish discolouration of the lips and nails, palpitations, nausea, loss of appetite, sleep disturbances, fatigue, and confusion. Genetic factors also work in occurrence of mountain sickness. In hilly terrains, at high altitudes, the atmospheric oxygen levels are reduced. In response to this, the body produces more red blood cells, resulting in increased thickness of blood. As this thickened blood is pumped from the heart and flows through blood vessels, it imposes a burden on the heart, as well as blood vessels. The pressure within pulmonary artery (vessel supplying blood to lungs) is also increased. All these factors add up to stress the heart, resulting in heart failure, earlier and in more severe form. This manifests as swelling over feet and face, breathlessness on exertion, and palpitations. Chest pain may also occur on exertion in some cases. Apart from heart problems, the lungs are also vulnerable to being affected, due to living at high altitude for a long time. Chronic obstructive pulmonary disease (COPD) occurs commonly in people living in hills or mountains. This causes breathlessness on exertion, blueish discolouration of lips and nails, and swelling around the nails. In advanced cases, this causes right-sided heart failure, resulting in swelling over the feet, face and abdomen, enlargement of the liver, blueish discolouration of the lips and nails, prominent, and distended veins over the side of the neck. The gut can be affected, resulting in loss of appetite, nausea, vomiting, and or diarrhoea. One can have headaches, dizziness, fatigue, and cognitive disturbances. In severe cases, there may be lethargy and even disturbance of equilibrium of the body. Burning sensation may occur over the hands and feet. Exposure to low oxygen levels for a long time can affect the reproductive system, resulting in impaired fertility in both men and women. The axis between brain and hormones released from reproductive organs is also disturbed, affecting fertility. If pregnancy occurs, the number of miscarriage or stillbirths is more in women living at a high altitude, as compared to those living in plains or low altitude. The surviving babies in uterus are smaller in size as compared to their gestational age, due to chronic exposure to low oxygen levels. Smokers, people who are chronically exposed to smoke, dust, and fumes due to their work, are more vulnerable to the health issues caused due to chronic mountain sickness. Individuals suffering from obesity, hypertension, diabetes, and or any heart problem, are also more susceptible to developing chronic mountain sickness. Treatment consists of use of oxygen therapy and drugs which are used to treat chronic lung diseases and heart failure. Therapeutic phlebotomy (puncture of a vein to let go some blood), helps in reducing congestion of blood vessels and thus reducing strain on the heart. Acute mountain sickness can be prevented by gradual acclimatisation, i.e. climbing for a comfortable distance and taking a pause for a day or two. Prevention of chronic mountain sickness lies in a healthy lifestyle. Taking a healthy diet is very useful in keeping the heart, lungs, and every part of the body healthy. It is beneficial to take plenty of fresh green vegetables, fruits, whole grains, nuts, healthy milk products, and fish. Avoid excess white salt, white sugar, and fried food. The use of tobacco and alcohol should be avoided. Heavy exercise is not good. Regular breathing exercises help to strengthen the lungs and heart. Dr Rachna Pande is a specialist in internal medicine.
