Differential Diagnosis

Treatment of HAPE

• Rapid descent of even a few thousand feet may result in rapid improvement and may be lifesaving. Rapid descent is the most important and usually most easily available method of treatment.
• Bed rest - in some high altitude situations, bed rest with oxygen may be enough for mild HAPE (symptoms only on strenuous activity) if frequent observations are made to ensure that clinical improvement is occurring.
• Oxygen - High-flow oxygen by plastic facemask or nasal cannulae will result in rapid improvement of symptoms and physical signs.
• Hyperbaric bag (Gamow bag) - This can be used successfully to treat HAPE, but, in a similar way to AMS, it is best used to improve symptoms so that descent can be facilitated
• Medications play only a small secondary role in the management of HAPE, because of the effective results of descent and treatment with oxygen. Drug therapy should only be considered as an adjunct to these two modalities and not as a replacement.

• Nifedipine - This vasodilator has been proven to be a useful adjunct to the treatment of HAPE. It has been shown to decrease pulmonary artery pressure and increase arterial oxygen saturation. Nifedipine probably acts by reversing hypoxic pulmonary vasoconstriction. No significant side effects were observed.

• Other medications suggested include nitric oxide, frusemide, steroids and morphine. However, there is little good clinical evidence to support or dismiss these treatments.
• PREVENTION OF HAPE

Prevention of HAPE

Taking preventative measures is particularly important for those individuals who have experienced HAPE in the past. Such measures include:-

• Slow ascent over 2450m
• Acclimatisation for several days at an intermediate altitude.
• Nifedipine - In one randomised controlled clinical trial, nifedipine prevented HAPE in subjects with a history of repeated episodes who rapidly ascended (within 22 hours) from a low altitude to 4559m. By taking the drug in this manner, potentially harmful side effects such as hypotension, headache, nausea, vomiting, and fatigue, restrict its use to those with a known susceptibility to HAPE.
  
  Pathophysiology                     Differential Diagnosis                     Treatment