This week, our hypothetical patient is a 30-year-old female who traveled from her home in the Black Hills to hike around Denali National Park and Preserve in Alaska. While there, she decided to hike the centerpiece of the park, Denali (formerly known as Mount McKinley). This is the highest mountain peak in North America with a summit at 20,310 ft above sea level. As she made her ascent, she started to experience increasingly severe headaches. She had trouble sleeping along the way and started feeling nauseous, which led to her eating less and less as she traveled. When she reached 14,000 ft, she stopped at the medical camp on the mountain to see a doctor about her symptoms. Upon physical examination, her lungs were clear to auscultation, her neurological exam was normal, and her oxygen saturation was at 84% while breathing ambient air (which is normal). The doctor recommended for her to consider descending, but she refused. She agreed to stay at the camp overnight and was given acetaminophen for her headaches and anti-emetics for her nausea. The doctor also gave her diamox to take twice a day to help her acclimatize. After a few days, she was forced to stop at the 17,000 ft medical camp because she was having trouble walking and her headache was worse despite the medication. She also reports having vomited a few times before stopping at the camp. The doctor at the 17,000 ft medical camp gave her dexamethasone and ordered her to descend and to be admitted to the hospital.Today, we reveal that our hypothetical patient was diagnosed as having:
Acute Mountain Sickness that progressed to High Altitude Cerebral Edema
Acute Mountain Sickness (AMS) is a common form of altitude sickness that often manifests as dizziness, headaches, muscle aches, and nausea. The can come from ascending too quickly, which doesn't allow your body to acclimatize appropriately to the new environment at higher elevations. Fast ascent can cause hypoxia and related conditions as gas exchange rates between your lungs and your blood becomes less efficient. Younger people and people who live at lower elevations are more likely to experience altitude sickness when climbing mountains. Symptoms typically don't arise until a day or two after you have been exposed to new elevations. In some cases, AMS can be treated with medications to help your body adjust to these changes and to subdue headaches/nausea. Allowing more time for acclimatization can also be helpful. In more severe forms of AMS, patients should get to a lower elevation before the altitude sickness progresses to a more serious form, such as High Altitude Pulmonary Edema (HAPE) or High Altitude Cerebral Edema (HACE). AMS is diagnosed using a variety of scoring systems.
High Altitude Cerebral Edema (HACE) is a severe form of altitude sickness that occurs due to fluid in the brain. This is a life-threatening condition that requires immediate medical attention. It is typically treated with the steroid dexamethason and patients who develop HACE must descend to an elevation below 4,000 ft above sea level. Supplemental oxygen is often provided during descent. If not treated immediately, HACE can be fatal within 24 hours, so patients with HACE are usually assisted in making a rapid descent. Some patients enter into comas without treatment. Most patients who are treated and taken to a lower elevation quickly recover in a few days, but some may need weeks to recover. MRI and CT scans are used to monitor patient progress.
AMS and more severe forms of altitude sickness, like HACE and HAPE, can be prevented by using medications to help with acclimatization and ascending slowly to allow for the body's systems to adjust to the changes in elevation. Some cultures, such as the indigenous peoples who live in the Andes, have chewed coca leaves (the plant used in cocaine production) to alleviate the symptoms of altitude sickness.
Thanks for joining us for this week's Mystery Case and we hope to see you next week!
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