Inflammation and altitude can cause low oxygen. Inflammation is commonly caused by viral infections such as colds or influenza, but can occasionally occur with bacterial infections such as strep throat or pneumonia. Low oxygen, or hypoxia, is the result of fluid collecting in the air sacs of the lungs, called pulmonary edema.
There are three types of high altitude pulmonary edema (HAPE).
- Classic HAPE, recognized for over a century. occurs in visitors to altitudes above 8000 ft (2500m) beginning during the first 48 hours after arrival. Symptoms include cough, congestion, trouble breathing, and fatigue, all worse with activity.
- Re-entry HAPE occurs in people who are living at altitude, travel to lower altitude, and develop symptoms during the first 48 hours after returning home
- High Altitude Resident Pulmonary Edema (HARPE) is a recently recognized illness that occurs mostly in children who have an underlying respiratory illness and live at altitude, with no recent history of travel. They have oxygen levels below 89 and lower but do not appear toxic. They are fatigued but rarely have increased work of breathing.
Treatment of HAPE is oxygen. There may also be signs of asthma or pneumonia which are treated with bronchodilators and antibiotics. Most people with pneumonia at altitude do NOT have hypoxia. All three types of HAPE can reoccur, but typically not with every arrival at altitude or viral illness. Many of these patients are told they have pneumonia again and again, or severe asthma, and are treated with inhalers and steroids. Usually, this adds nothing to their recovery.
A chest x-ray may show typical infiltrates seen with pulmonary edema, but in mild or early cases, can look normal. There is no blood test for HAPE. Oxygen should be used continuously at a rate that raises the oxygen saturation into the 90’s. Length of treatment may be as short as 2 days or as long as ten days
Most importantly, owning a pulse oximeter and measuring oxygen levels in anyone at altitude with symptoms of cough, congestion, fatigue and trouble breathing with exertion can keep people out of the ER and ICU. HAPE can rapidly progress to respiratory failure and death if not recognized and treated expediently.