Case Study 21

The Answer

Assessment

  • Possible altitude illness with high altitude pulmonary edema (HAPE).
  • Weakness and inability to travel.

The Plan

  • Request a helicopter evacuation.
  • Walk patient with oxygen downhill on trail to a meadow 1/4 mile away for helicopter evacuation.
  • Request backup ground team mobilize with ability to carry the patient to the trailhead.
  • Oxygen started at 4 l/m via cannula. Additional oxygen requested as soon as possible.

Anticipated Problems

  • Altitude illness or lung problem worsens.
  • Helicopter evac not possible and the patient needs to be carried to the trailhead.

Comments

This is based on a real case. Despite what the patient hoped for, fitness and previous altitude experience do not provide immunity from altitude illness.

Risk factors for altitude illness include: rapid ascent, sleeping at an elevation higher than that for which we are acclimatized, and overexertion. This patient had all three of these. There is currently research focusing on identifying genetic predispositions to altitude illness.

The vague symptoms of acute mountain sickness (headache, anorexia, dizziness, nausea, insomnia, lassitude, dyspnea) generate a long differential diagnosis list (dehydration, exhaustion, CO poisoning, viral syndromes, migraine, hypothermia, etc). A high index of suspicion is critical. The setting is an important clue--rapid ascent to an elevation beyond your acclimatization level.

Acute mountain sickness (AMS) is common and unpleasant. High altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE) are uncommon, but life-threatening.

Acute mountain sickness (AMS) is treated by stopping ascent to acclimatize, descending if the symptoms do not resolve, and descending rapidly if HAPE or HACE are suspected.

Ataxia, loss of balance, is an indicator of HACE, along with altered mental status and other neurological signs and symptoms. HACE is treated with immediate descent. 

HAPE, the cause of most deaths from high altitude illness, can be insidious. Be suspicious of a decreased ability to exercise, shortness of breath, unanticipated fatigue, and elevated heart and respiratory rate. Cyanosis, audible wet lung sounds, or frothy sputum are dangerous and obvious signs. HAPE is also treated with immediate descent; oxygen can be helpful.

The Tale Continues

The SAR folks, trained as Wilderness First Responders, considered that this might be a flu-like illness or pneumonia, but the lack of a fever suggested otherwise.  It didn't appear the patient was dehydrated or had CO poisoning.  Considering possible life-threats, and suspicious about the story of the unexpected fatigue, they listened to the lungs and tested for ataxia. 
 
The patient initially wanted to continue to walk, and asked for a horse to help him leave the field; however, he agreed to the helicopter after the WFRs had him listen to his lung sounds. He then insisted on walking to the landing zone, which concerned the WFRs who had been taught that physical exertion with HAPE could make matters much worse. They were able to start him on oxygen at 4 l/m via cannula from a small (D) tank they carried, which they knew would only last an hour at that flow rate.  This helped him to walk, albeit slowly. 

End of the Tale

The patient was able to walk to the meadow and arrived simultaneously with the sound of the rotors. This stoical patient had the flight medics wondering about the urgency of the evacuation until they listened to his lungs and used their pulse oximeter, which registered at 74%. The evacuation was uneventful. In the hospital the patient was diagnosed and treated for HAPE. He was admitted overnight and released in the morning when his lungs were clear of fluid.