Altitude sickness

Are you experiencing respiratory shortness, headaches and a rapid heart rate as you are climbing up to a higher altitude? You could be suffering from Altitude sickness, a common disease affecting mountain climbers. Read and find out al about the causes, symptoms, diagnosis and treatment of this disorder.

What is Altitude sickness?

It refers to a condition that affects people in high altitudes who cannot get adequate oxygen from the air that they breathe. Mountain climbers, skiers, hikers or people travelling at regions greatly elevated from the sea level are common sufferers of this disease.

Altitude sickness Synonyms

The condition is referred to by various other names, such as:

Picture of Altitude sickness

Fatigue and labored respiration are common signs of Altitude illness.

Picture 1 – Altitude sickness

  • Acute Mountain Sickness (AMS)
  • Soroche
  • Altitude illness
  • Hypobaropathy

Altitude sickness ICD 9 Code

The ICD 9 Code for this disorder is E902.0.

Types of Altitude sickness

The condition is broadly categorized into three types:

Acute Mountain Sickness (AMS)

It is usually milder than the other forms of the disease. It is a common problem affecting trekkers in the Himalayas or skiers in high altitudes. The condition is marked by symptoms like dizziness, headache, loss of appetite, fatigue and insomnia.


HAPE (High Altitude Pulmonary Edema) arises due to a build-up of fluid in the lungs as a result of reduced air pressure in the surroundings. A person with this condition can be diagnosed by signs like:

  • Respiratory failure
  • Wet cough (with frothy phlegm)
  • Gurgling sounds during breathing
  • Respiratory shortness (even at rest)
  • Possible fever

HAPE can develop gradually or abruptly. The problem typically arises after a person has spent more than one night at a highly elevated region.


HACE or High Altitude Cerebral Edema) is a disorder that can become fatal within anytime between a few hours to a few days. It can arise as a possible complication of Altitude illness. Its onset is usually characterized by confusion. It is a higher form of severe Altitude sickness that is characterized by problems like:

  • Respiratory shortness
  • Impaired walking and coordination
  • Lethargy and possible coma, due to inflammation of brain
  • Unless timely treated, HACE may result in the death of a sufferer.

What Causes Altitude sickness?

The disease typically affects those travelling in regions 2,400 meters or 8,000 feet above the sea level and when a person climbs more than 1,000 feet every day. Altitude illness arises as a result of a combination of lower levels of oxygen and lower air pressure at high altitudes. Those climbing such regions fast are at a greater risk of developing this condition due to a rapid change in air pressure and oxygen levels. The body is unable to cope with this sudden alteration, caused by a rapid ascent to higher regions. This inability of the system manifests in the form of Altitude illness symptoms.

The disorder is usually triggered by factors like:

  • A very rapid ascent
  • Hypothermia
  • Low intake of fluids
  • Overexertion within a day
  • Intake of sedatives or alcohol

Altitude sickness Risk Factors

It is difficult to determine who would be affected by this syndrome as no specific factors that are mutually associated to its development. That said, some people are believed to be more susceptible to this disorder than others. This risk-prone population includes individuals who are:

  • Less than 50 years old
  • Climbing rapidly to high altitudes
  • Past sufferers of Altitude illness

Altitude sickness Symptoms

Altitude illness is manifested by a cluster of nonspecific symptoms. The problems may vary from moderate to fatal and can impact the nervous system, muscles and vital organs like heart and lungs. The moderate symptoms related with the condition include:

  • Headache
  • Difficulties in sleeping
  • Nausea or vomiting
  • Light-headedness or dizziness
  • Respiratory shortness, triggered by exertion
  • Fatigue
  • Rapid pulse
  • Loss of appetite

The acute symptoms include:

  • Congestion or tightness in chest
  • Cough, often accompanied by expulsion of blood
  • Mental confusion
  • Cyanosis or bluish discoloration of skin
  • Pale or gray complexion
  • Respiratory shortness, even during times of rest
  • Inability to walk or to walk in a straight line
  • Reduced consciousness or social withdrawal

Altitude sickness Diagnosis

Doctors generally begin the diagnosis of Altitude illness by asking patients about the symptoms that they experience. This is followed by a physical examination of sufferers. Physicians may ask whether patients have been taking any medicines or drinking alcohol or any other intoxicants to rule out other possible causes of the problems.

If doctors suspect an Altitude illness, they may look for lung sounds. A ratting or crackling sound from the heart can be an indication of the disorder. Other symptoms that physicians may look out for include:

  • Respiratory shortness, even at rest
  • Abnormalities in vital signs, including rapid heart and respiratory rates and low-grade fever
  • Changed mental condition

Doctors may also check the amount of oxygen in the bloodstream of patients through a procedure known as Pulse oximetry. A lower than normal oxygen saturation, for the particular altitude level that the sufferer is in, can be a sign of the disorder.

Altitude sickness Treatment

It is essential to conduct an early diagnosis of the disorder. Detecting Altitude illness in its early stages can help doctors treat the condition much more easily. In most cases, a climb-down is a main requirement for remedying the condition of a sufferer. A descent lessens air pressure and increases oxygen levels for a sufferer, thus curing the symptoms in a natural manner. If you begin to experience the symptoms while climbing, it is important that you stop ascent and go downwards as fast as possible.

Those suffering from acute cases of the disease may require immediate hospitalization to prevent further complications arising due to lack of proper medical support and treatment. If a climb-down fails to remedy the condition, the treatment of Altitude illness can usually involve oxygen therapy and medications. If extra oxygen is available, it should be rendered to a patient as early as can be done. Medicines can be effective in improving the moderate as well as the acute symptoms of Altitude illness.

Nifedipine is a high blood pressure medicine that counters the problems arising in patients due to increased air pressure. Phosphodiesterase inhibitors, like Sildenafil, and beta agonists are useful in curing cases of pulmonary edema (accumulation of fluids in the lungs). Severe pulmonary edema patients may require a breathing apparatus in some cases. If Cerebral edema (inflammation in the brain) occurs due to Altitude illness, Dexamethasone (Decadron) may be useful in remedying the problem.

First Aid for Altitude sickness

If any of your team members is showing signs of Altitude illness, first-aid is very important for instant remedy of the condition. Administer Paracetamol or Aspirin to the sufferer in recommended doses. Ecourage the patient to breathe deeply after every few minutes to help them naturally lower the level of CO2 in bloodstream. Refrain from ascending any longer and stay put exactly where you are. Urge the patient to stop from going up any more. Give diuretics to him or her to promote greater urinary output and reduce the danger of fluid accumulation in the system. If possible, supply oxygen to the affected person from a portable oxygen cylinder.

If the patient exhibits symptoms like headache, nausea, fatigue or tightness in chest, administer Dexamethasone immediately. If the problems continue to persist, start descending at once. The value of life is greater than any achievement. A descent of anywhere from 500 to 1000 meters can help remedy the condition.

Diamox and Altitude sickness

Diamox (Acetazolamide) is a drug that is provided to reduce moderate symptoms and improve respiration. People susceptible to Altitude illness should start taking the oral form of this drug 1-2 days before they begin to climb. It should be orally consumed while climbing and for at least two days after reaching the final region. However, Diamox also increases the output of urine in its users. Due to this reason, patients should take care that they avoid alcohol and take lots of fluids while using this medication.

Some other side-effects of this medication include:

  • Change in taste sensations
  • Mental confusion
  • Drowsiness
  • Loss of appetite
  • Tingling sensations in hands or feet (Parethesias)
  • A feeling of malady, which involves nausea, diarrhea and vomiting

Altitude sickness Complications

The condition may give rise to various complications, such as:

  • Inflammation of the brain
  • Build-up of fluid in the lungs (Pulmonary edema)
  • Coma

Altitude sickness Prognosis

Most cases of this disorder are mild in nature. The symptoms tend to improve soon after a person climbs down to a lower altitude. However, a delay in treatment can complicate the condition and lead to potentially life-threatening problems like Cerebral or pulmonary edema or coma. This can affect the outcome of Altitude illness in a negative way. In worse cases, patients may even die. Fortunately however, the majority of cases of this disease resolve with descent, oxygen therapy and medications.

How to prevent Altitude sickness?

Altitude illness can best be prevented by ascending at a slow pace while climbing higher altitudes. It is best to climb over a span of several days to provide the body with time to cope with changes in oxygen level and air pressure. Restricting physical activities for the first few days after ascension may also be helpful. Enough fluids should be taken to keep the body hydrated. However, alcoholic beverages should be avoided or kept to a bare minimum to keep away from ill-effects. Climbers should have a high-carbohydrate diet and plenty of fluids while ascending.

In case the condition of a patient is found to be abnormally severe, a descent to a lower region is highly recommended.

Altitude illness is a serious issue and should not be neglected. It is better to be ready beforehand than be sorry during times of crisis later. It is essential that you climb with an experienced guide/mountaineer to be well-prepared for the challenges that lie in your way up. Avoid alcohol, cigarettes and sleeping tablets that can act as trigger factors for Altitude illness. You and your team members should also try to follow a high-carbohydrate diet to make your body well-prepared for the challenges in high altitudes.

How to Avoid Altitude sickness medically?

People who are susceptible to Altitude illness are often provided with Dexamethasone (DexPak, Decadron) or Acetazolamide (Diamox), two medications that have been found to be effective in reducing the symptoms of Altitude illness or preventing the occurrence of the condition itself. Remember to pack important medications before you actually begin your journey. Talk to a doctor and preferably also an experienced climber to know which drugs might be needed during ascension.

Image of Altitude sickness

Oxygen support through Hyperbaric chambers can be effective in remedying the condition of Altitude sickness patients.

Picture 2 – Altitude sickness Image

Hikers and mountain climbers can consider taking portable hyperbaric chambers along with them. These equipments allow hikers to simulate environments similar to regions in lower altitude without physically moving away from the location they have climbed to. Such devices are extremely useful in cases where bad weather conditions, broken leg or any other factor makes descent virtually impossible for a person. In remote areas, where immediate evacuation is not possible, Hyperbaric chambers can come in handy for patients.  At sea level, oxygen constitutes 21% of air. These chambers can deliver up to 100% oxygen in pure form and makes use of specially constructed rooms or chambers that can resist high air pressure.

If the symptoms occur, do not continue ascension simply by administering medications or oxygen therapy to a patient. This can have life-threatening consequences for the sufferer. Once the symptoms begin to occur, you should stay put or descend immediately. Begin ascension only when a patient feels much better and after some time has passed.


If you are experiencing the problems while hiking or climbing mountains, get in touch with a medical care provider or call 911 immediately. Timely treatment will help you resolve the problem in time and prevent occurrence of any of its complications. Avoid travelling to high altitudes if you are suffering from heart disorders, lung conditions or anemia.


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