High Altitude Medicine in Nepal: Part 1

Carlo Canepa, MD

Fellow in Wilderness Medicine at the Massachusetts General Hospital

PGY-6

High Altitude Medicine in Nepal: Part 1

 

I first considered volunteering with the Himalayan Rescue Association (HRA) when I was a fourth-year medical student, hiking in the Khumbu valley with my future wife and my best friend. The three of us decided to hike the Everest Base Camp trek, a world-famous 2-week hike that reaches very high altitudes. Along the way there is a small clinic run by volunteer physicians who take care of the local Nepalese, as well as porters, guides, climbers, and foreign trekkers. We stopped in the clinic for the afternoon lecture and I decided that I would return. Six years later, after an emergency medicine residency and an ultrasound fellowship, I returned as a wilderness medicine fellow at the Massachusetts General Hospital.

Although I had prepared both physically and mentally for the high-altitude experience, the greatest hurdle to my 3-month stay would be paperwork in Kathmandu. The other volunteer physicians and I spent 20 days shuttling between different ministries and government offices getting credentialed to work. We finally received clearance to work and flew to Lukla, a tiny village known for having the world’s most dangerous airport perched on a mountainside. Over the next 4 days we slowly ascended to our clinic in Pheriche at an altitude of 14,340 feet. For reference, that’s about as high as the highest point in the continental United States, Mount Whitney (14,505 feet).

Working at a clinic at this altitude is unique. There are very few places on Earth where one can work as a physician at such a high altitude. In most other places outside of the Himalayas this clinic would be right at the top of a mountain. But here, in Nepal, we’re only about half-way up the route to the summit of Mount Everest (29,029 feet). Being so high up does mean that we get to take care of patients with disease processes found in very few places on Earth, like high altitude headache (HAH), acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). It also affords me the opportunity to conduct research on a unique population.

There are three physicians at the clinic (myself and two Scottish general practitioners) as well as three Nepali staff that help run the clinic. We share responsibilities by each running clinic for two days, then giving an afternoon public lecture to trekkers for two days and covering the overnight shifts in clinic. Then we each get two days off to trek to other parts of the valley. It’s been about 1 month since we opened the clinic and we have seen close to 300 patients. 70% of the patients are Nepali, either locals who live and work in the valley, or guides, porters, and other expedition staff. The other 30% of patients are international trekkers from all over the world. While working the clinic we’ll see about 15 patients per day during the peak hiking and climbing season.

For many Nepali patients, the clinic offers an opportunity for primary care and urgent care, with the most common chief complaints being sore throat, gastritis, cough, skin problems, and minor trauma. For most the foreign trekkers the chief complaints are diseases of high altitude like AMS, HAPE, and HACE. These diseases are caused by a lack of oxygen, which has varying effects on the lungs and the brain. In the lungs, the blood vessels constrict causing areas of shunting and ultimately pulmonary hypertension, which leads to capillary leak and pulmonary edema. In the brain, the hypoxia will lead to vasodilation, increased cerebral blood flow, and ultimately cerebral edema. A common oxygen saturation at this altitude is between 80% and 90%. The most well acclimatized will have oxygen saturations in the low 90s, whereas someone who is sick with HAPE will have saturations in the 50s or 60s. We’ve even had patients in the 30s a couple of times.

Another unique aspect of this clinic is that we have no back-up. It’s just the three physicians and the local staff. We have no consult services available here. We have no CT scanner, no MRI, and no X-ray machine. We have one portable ultrasound device, which we use often, and an EKG machine which we rarely use. We have no laboratory capability beyond a blood glucose level. Otherwise everything we do is based on history and physical exam. If we think someone needs further evaluation or management, then we have a couple of options: either the patient is walking 3-4 days back down to Lukla to catch a flight to Kathmandu or we’re calling in a helicopter evacuation.

Thus far we’ve had about 10 helicopter evacuations during this month. The vast majority are for cases of HAPE and HACE that improved overnight with treatment, but not sufficiently to be able to walk out of the valley on their own strength. For HAPE the treatment of choice is acetazolamide 250mg BID, nifedipine 20mg TID, and oxygen 10L/min. For the HACE we will add dexamethasone 8mg for a loading dose and 4mg every 6 hours. Most patients respond really well to our interventions, but it’s the patients who aren’t able to get to our clinic who we worry about the most. Many trekkers find themselves feeling unwell, but continue to push themselves up the valley, hoping to make it Everest Base Camp (17,600 feet) and Kala Patthar (18,519 feet, and the most guided mountain on Earth). The human body, for the most part, hasn’t evolved to survive at such high altitudes. Even with excellent acclimatization schedules, many people will feel ill when they reach these heights. And every season there are trekkers, mountaineers, and Nepali staff who pass away due to preventable altitude illnesses.

 

The field of wilderness medicine is a quickly growing one. Research on how the human body responds to the oxygen-poor environment of high altitude has been ongoing for almost 50 years. Nonetheless there is always more to discover. In addition to my clinical duties, I am also conducting a research project on high altitude pulmonary edema. I, along with a few research assistants, are screening hikers throughout the valley at different altitudes for evidence of sub-clinical HAPE using lung ultrasound. We use a Samsung Galaxy tablet and a Philips Lumify linear probe to scan the anterior chest walls of participants. Our hypothesis is that high altitude pulmonary edema is a common response to the hypoxia of altitude, not just a disease process. The research is ongoing and we are about halfway toward reaching our sample size.

I have another month left here in Pheriche. The clinic stays open through the spring Everest climbing and hiking season and we close our doors when the monsoons start.