Treating Acute Mountain Sickness

The mainstay of treatment of AMS is rest, fluids, and mild analgesics: acetaminophen (paracetamol), aspirin, or ibuprofen. These medications will not cover up worsening symptoms. The natural progression for AMS is to get better, and often simply resting at the altitude at which you became ill is adequate treatment. Improvement usually occurs in one or two days, but may take as long as three or four days. Descent is also an option, and recovery will be quite rapid.

A frequent question is how to tell if a headache is due to altitude. See Golden Rule I. Altitude headaches are usually nasty, persistent, and frequently there are other symptoms of AMS; they tend to be frontal (but may be anywhere), and may worsen with bending over. However, there are other causes of headaches, and you can try a simple diagnostic/therapeutic test. Dehydration is a common cause of headache at altitude. Drink one liter of fluid, and take some acetaminophen or one of the other analgesics listed above. If the headache resolves quickly and totally (and you have no other symptoms of AMS) it is very unlikely to have been due to AMS.


Acetazolamide

Acetazolamide (Diamox®) is a medication that forces the kidneys to excrete bicarbonate, the base form of carbon dioxide; this re-acidifies the blood, balancing the effects of the hyperventilation that occurs at altitude in an attempt to get oxygen. This re-acidification acts as a respiratory stimulant, particularly at night, reducing or eliminating the periodic breathing pattern common at altitude. Its net effect is to accelerate acclimatization. Acetazolamide isn't a magic bullet, cure of AMS is not immediate. It makes a process that might normally take about 24-48 hours speed up to about 12-24 hours.

Acetazolamide is a sulfonamide medication, and persons allergic to sulfa medicines should not take it. Common side effects include numbness, tingling, or vibrating sensations in hands, feet, and lips. Also, taste alterations, and ringing in the ears. These go away when the medicine is stopped. Since acetazolamide works by forcing a bicarbonate diuresis, you will urinate more on this medication. Uncommon side effects include nausea and headache. A few trekkers have had extreme visual blurring after taking only one or two doses of acetazolamide; fortunately they recovered their normal vision in several days once the medicine was discontinued.

   
 Acetazolamide Use & Dosage: 
   
 For treatment of AMS 
 We recommend a dosage of 250 mg every 12 hours. The medicine can be discontinued once symptoms resolve. Children may take 2.5 mg/kg body weight every 12 hours. 
   
 For Periodic Breathing 
 125 mg about an hour before bedtime. The medicine should be continued until you are below the altitude where symptoms became bothersome. 
   

 

There is a lot of mythology about acetazolamide:

MYTH: acetazolamide hides symptoms

Acetazolamide accelerates acclimatization. As acclimatization occurs, symptoms resolve, directly reflecting improving health. Acetazolamide does not cover up anything - if you are still sick, you will still have symptoms. If you feel well, you are well.

MYTH: acetazolamide will prevent AMS from worsening during ascent

Acetazolamide DOES NOT PROTECT AGAINST WORSENING AMS WITH CONTINUED ASCENT. It does not change Golden Rule II. Plenty of people have developed HAPE and HACE who believed this myth.

MYTH: acetazolamide will prevent AMS during rapid ascent

This is actually not a myth, but rather a misused partial truth. Acetazolamide does lessen the risk of AMS, that's why we recommend it for people on forced ascents. This protection is not absolute, however, and it is foolish to believe that a rapid ascent on acetazolamide is without serious risk. Even on acetazolamide, it is still possible to ascend so rapidly that when illness strikes, it may be sudden, severe, and possibly fatal.

MYTH: If acetazolamide is stopped, symptoms will worsen

There is no rebound effect. If acetazolamide is stopped, acclimatization slows down to your own intrinsic rate. If AMS is still present, it will take somewhat longer to resolve; if not - well, you don't need to accelerate acclimatization if you ARE acclimatized. You won't become ill simply by stopping acetazolamide.


Dexamethasone

Dexamethasone (Decadron®) is a potent steroid used to treat brain edema. Whereas acetazolamide treats the problem (by accelerating acclimatization), dexamethasone treats the symptoms (the distress caused by hypoxia). Dexamethasone can completely remove the symptoms of AMS in a few hours, but it does not help you acclimatize. If you use dexamethasone to treat AMS you should not go higher until the next day, to be sure the medication has worn off and is not hiding a lack of acclimatization.

Side effects include euphoria in some people, trouble sleeping, and an increased blood sugar level in diabetics.

   
 Dexamethasone Use & Dosage: 
   
 For treatment of AMS 
 Two doses of 4 mg, 6 hours apart. This can be given orally, or by an injection if the patient is vomiting. Children may be given 1 mg/kg of body weight, up to 4 mg maximum; a second dose is given in 6 hours. Do not ascend until at least 12 hours after the last dose, and then only if there are no symptoms of AMS. 
   

Oxygen

AMS symptoms resolve very rapidly (minutes) on moderate-flow oxygen (2-4 liters per minute, by nasal cannula). There may be rebound symptoms if the duration of therapy is inadequate - several hours of treatment may be needed. In most high altitude enviroments, oxygen is a precious commodity, and as such is usually reserved for more serious cases of HACE and HAPE.


Hyperbaric Therapy

Treatment in a portable hyperbaric bag is essentially equivalent to descent or treatment with oxygen; the person is inside a pressurized bag breathing an atmosphere equivalent to a much lower altitude. AMS symptoms rapidly resolve (minutes), but may recurr if treatment is too short - at least two hours are needed. Dexamethasone works as well, though not quite as fast, is much cheaper, and far less labor-intensive than hyperbaric therapy. Hyperbaric treatment is usually reserved for more serious cases such as HACE and HAPE.


A Review of the AMS treatment options:

 Descent
   
 ProRapid recovery: trekkers generally improve during descent, recover totally within several hours.
 ConLoss of "progress" toward trek goal; descent may be difficult in bad weather or at night; personnel needed to accompany patient.
   
 Rest at same elevation
   
 ProAcclimatization to current altitude, no loss of upward progress.
 ConIt may take 24-48 hours to become symptom-free.
   
 Rest plus acetazolamide
   
 ProAs with rest alone, plus acclimatization is accelerated, recovery likely within 12-24 hours.
 ConRecovery may take 12-24 hours; side effects of acetazolamide.
   
 Rest plus dexamethasone
   
 ProFaster resolution of symptoms than with acetazolamide (usually in a few hours); minimal side effects; cheap.
 ConCan hide symptoms & thus give a false sense of security to those who want to continue upwards. Does not accelerate acclimatization.
   
 Rest plus dexamethasone & acetazolamide
   
 ProFast resolution of symptoms from the dexamethasone, plus improved acclimatization from the acetazolamide.
 ConSide effects of acetazolamide. Same cautions as above regarding ascent after taking dexamethasone.
   
 Oxygen or Hyperbaric Therapy
   
 ProVery rapid relief of symptoms (minutes).
 ConExpensive; hyperbaric bags are very labor-intensive; rebound symptoms may occur if treatment is too short - several hours are needed.

 

   
 Questioning Your Porters About AMS Symptoms 
   
 If you hire your own porters, please be aware that they are just as susceptible as you to the ravages of AMS. Porters may even be at increased risk of severe forms of altitude illness as they are unlikely to know anything about AMS, are more likely to have a communication barrier to telling you how they feel, and may actively hide their symptoms as they fear losing their job due to illness. For those of you who will be trekking in Nepal, please look at the AMS questionnaire with phonetic Nepali translations (based on the Lake Louise AMS scoring criteria). For more information, also look at the International Porter Protection Group's web site.