High Altitude Illness and Mountain Sickness - Prevention and Care

High Altitude

One of the interesting and strangely anti-Darwinian aspects of physical conditioning is that it allows subgroups of our species frequently venture into environments for which we have not been engineered to tread. High mountains represent just such an environment. High altitude, because of the incredible severity of its effects on human physiology, can deliver a huge number of interesting afflictions that can prevent you from passing your DNA on to future generations.

Prevention is key to eliminate these potential afflictions. Follow the recommended average-daily-ascension guidelines, drink fluids until you lose all voluntary control of your bladder, and pay attention to any unusual symptoms, such as headache, dizziness, confusion, the sudden urge to sing a duet with Colin Powell, and so on. Remember, you are not the first person to climb K2, or hike to Machu Picchu, or trek the Kumbhu Icefall, or whatever, so who cares if it takes an extra day or two? For that matter, what if you can’t accomplish your goal at all? There really can be a next time. If you fail to respect altitude, however, not only may you really inconvenience your companions (when they have to haul your decomposing carcass back to civilization and notify your next of kin), but you won’t have an opportunity to try again. So, please, respect this entity that you cannot see, feel, hear, taste, or smell. Hmmm… sounds like a religion.

Acute Altitude-Related Illnesses

One prospect for those of you who engage in high-altitude pursuits— that is, mountaineering—is the potential to endure all sorts of ungodly suffering usually grouped under the term “acute altitude-related illnesses.”

There are three broad categories of mayhem here: acute mountain sickness (AMS), high-altitude pulmonary edema (HAPE), and high-altitude cerebral edema (HACE).

AMS has traditionally been described as a few specific symptoms; however, I will include in this category all nastiness that one experiences at high altitudes but not at lower elevations.

A few words about “normal” issues one will likely encounter at higher altitudes. First, breathing—a fun and worthwhile pursuit at any altitude. At high altitude, however, breathing patterns change. Most people experience what is usually called Cheyne-Stokes, or periodic breathing. This unsettling breathing pattern is characterized by 5 to 15 seconds of very rapid breaths followed by a period of no breathing at all (called apnea, for those collecting Cranium points). This apnea usually lasts 5 to15 seconds as well. This pattern becomes more pronounced during sleep and can be very alarming to a tent mate. There do not seem to be any negative effects from acute episodes of periodic breathing. Taking 125 mg of Diamox (acetazolamide) before bedtime can help reduce or eliminate apnea.

Second, when humans other than Sherpas or high-Andes dwellers ascend to the 14,000-foot range and above for long periods of time, they often demonstrate rather impressive swelling of their hands, feet, and face. This is not a permanent condition—just really funny.

Now on to the more serious high-altitude issues.

Acute Mountain Sickness (AMS)

OK, here’s the meaning of life for a mountaineer—headaches. Kind of disappointing, huh? This really is it, though, because the presence or absence of a headache while climbing high mountains can spell the difference between life and death. You’re probably thinking, “What in the heck do you mean by that?” Glad you asked. Headaches represent the sine qua non (medical talk for “really important shit”) of AMS.

Prevention Tip

Have yourself reincarnated as a Sherpa.

More Useful Prevention Tip

The current accepted climbing rate to limit (but not eliminate) the risk of AMS is 1,000 feet (about 300 meters) of vertical gain per day. Obviously, this represents an average. If you find yourself exceeding this pace (most often done by the 20-something testosterone-driven variant of Homo sapiens) and developing a terrible headache— usually behind the eyes, and often accompanied by nausea—you almost certainly have the first symptom of AMS.

If you have prudently abided by the above acclimatization guidelines and still develop a headache, you must identify the underlying problem. The key here is to immediately stop, think, and, yes, sort out the problem. Please don’t just pop some ibuprofen and continue with your current course of action. This really could prove fatal—stay tuned for more info. There have been countless examples (given my math skills anything over five is countless) of trekkers and climbers developing a headache, not deciphering and treating the cause properly, and then developing a more serious condition such as HAPE or HACE.

Treatment

If a headache does appear, immediately stop, rest, and drink a liter of fluid—water, Gatorade, or such, and take some headache medicine. Ibuprofen works best for most people—800 mg—no more, no less. Try Tylenol (acetaminophen) if you can’t take ibuprofen or have found that Tylenol works better for you. If, after hydrating, medicating, and stopping and resting for 30 to 60 minutes, you are no better, you must assume that you have AMS, which is a very serious condition that requires specific and considered action.

First, you absolutely must not ascend farther until the headache has resolved (unless your insurance policy does not contain a specific suicide clause and you have named me the beneficiary— then you may climb again immediately). Depending on your circumstance, you may even consider descending for 1,000 feet or so for the night. This may not be required, but if your headache does not resolve over 12 hours or so, if it worsens, or if you develop any other symptoms (page 40), you must descend. Don’t cry: you can go back up once your symptoms resolve. If your headache does resolve with fluids and medicine, you may continue on your way.

A Word on Diversity of Conditioning

Upon headache, some experienced mountaineers who consume fluids and ibuprofen, and also Diamox and/or Decadron, continue to ascend once the headache and associated symptoms have cleared. I cannot recommend this. However, if you are very experienced, and wish to do so, it is your choice.

What Are Diamox and Decadron?

Diamox (acetazolamide) is a respiratory stimulant that increases your rate of breathing. This usually alleviates the headache caused by AMS. If you would like to engage in a lively discussion of acetazolamide’s biochemical mechanism of action, and why it works the way it does, call me; we’ll have a latte.

Some experienced folks recommend starting Diamox (125 mg, twice per day) several days before beginning an ascent; other experienced folks argue strongly against taking Diamox to prevent AMS. The argument against taking it beforehand is that it may mask the symptoms of evolving AMS. In reality, it is probably OK to take it, as long as you stick to the ascension guidelines, don’t ignore a headache or other sign of AMS, and stay well hydrated. Remember, Diamox, or any other drug for that matter, does not speed the acclimatization process.

Decadron (dexamethasone) works differently. It is a steroid— no, not that kind of steroid, you muscle head—and works by reducing fluid accumulation in the lungs and brain, among other things. Therefore, it also helps alleviate the headache associated with AMS. In addition to treating altitude illnesses, these medicines have also been used to prevent AMS and subsequent HAPE and HACE. Several more familiar drugs are listed below.

Ginkgo Biloba

One small, well-constructed experiment has suggested that Ginkgo biloba (120 mg, twice per day, starting several days before the climb) helps alleviate the major symptoms of AMS, especially headache. As of this writing there does not appear to be any downside to taking it, so go ahead if you feel like it.

Viagra (Sildenafil Citrate)

Even if you can’t mount an assault on the mountain, you can always mount your tent mate. OK, back to serious business. This has been tried with some suggestion of benefit for staving off AMS symptoms,but unlike Ginkgo biloba, Viagra (and similar medications) has some potential for serious side effects—especially on blood pressure (which can suddenly and rapidly drop). Without further extensive study, I would strongly discourage you from using it (unless you want to drop it into your boyfriend’s tea in the event that his rope has been a little slack lately).