Thursday, February 7, 2013

Nepal 2012 Khumbu Cough

Nearly all people who spend time at extreme altitude (over 14,000ft or 4267m) will develop some degree of the Khumbu cough. Some attribute this to a bronchial infection from bacteria borne by the dust. Others believe it to be a lung irritation caused by altitude, dry cold air, and extreme exertion.  

Lung Irritation at High Altitudes
Khumbu Cough may be caused by the low humidity and sub zero temperatures experienced at altitude, and triggered by over exertion. This leads to an increased breathing rate, which exposes the delicate lung lining to excess cold air, resulting in dried membranes and partially damaged bronchi. This causes extreme irritation which manifests itself in the form of a dry, persistent cough which can restrict breathing. Eventually the cough can be so violent and put so much strain on the chest cavity that it causes its victim to tear chest muscles or break ribs.

Bronchial Infections
The Namche Trail has been a major trade route for many generations, for goods being carried between China and Nepal. The trail is usually dusty. With the high altitude and thin air, we can't get enough air through our noses, so we relent and breathe through our mouths.  This dries out the mouth, tongue, and lungs. Breathing the fine dust starts the coughing. But the dust is laden with bacteria from thousands of years of urine, feces, snot, spit, and phlegm from humans, horses, mules, yaks, and jopkeys. The bacteria starts a lung infection. Yak-dung smoke permeates the air, further aggravating the lungs. 

Whatever the cause, we cough incessantly. Day and night. It's hard to sleep. Within a few days the coughing delivers clear phlegm, and over the next few days it turns white, then green, then brown. Some people cough blood (fortunately I didn't). Lungs, throat, and ribs hurt from the violent and frequent coughing. Cough suppressants help us sleep, but inhibit the coughing necessary to clear the lungs. Weeks after descending to lower altitudes and higher humidity, the coughing stops (unclear if the Antibiotics, or the lower altitude, or the higher humidity cured the condition)

We all cough and spit and add our bacteria back to the trail, and as we walk we all stir up the dust.

Trekkers and Porters

Horses and Mules

Yaks and Jopkeys

Those with prior experience with the Khumbu Cough wear buffs to filter the dust. 
Buffs don't prevent the Khumbu Cough ... just delay it, so we spend fewer days caughing on the mountain.

Other measures to delay the Khumbu Cough include
  • avoid over-exertion (this idea caused great laughter, resulting in more coughing fits)
  • keep lungs moist by drinking more fluids and wearing a balaclava

More climbers are stopped by the Khumbu Cough, than by frostbite or altitude sickness or bad weather.

The Khumbu Cough is an inevitable part of trekking and climbing in the high altitudes of Nepal. 
Unpleasant, but part of the adventure.

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1 comment:

  1. Quite the conditions: "Yak-dung smoke permeates the air, further aggravating the lungs." I have a greater appreciation for what you went through. Thanks for sharing.