High Altitude Pulmonary Edema

Over the last three decades, increased awareness and education have lessened the instances of high altitude pulmonary edema (HAPE) encountered by otherwise healthy, active sojourners to high altitude. HAPE had been described in Europe as early as the late 1700s and in South America in the late 1800s and 1900s, when it was thought to be pneumonia and/or fluid in the lungs from heart failure. But it was not until the 1950s and 1960s in Peru and the United States that HAPE was recognized as a distinct disease unrelated to infection or heart failure that could afflict otherwise healthy, young and middle-aged individuals. Although not nearly as common as acute mountain sickness (AMS) and occurring more commonly at slightly higher altitudes (3000 meters or above), HAPE, unlike AMS, can be fatal. The purpose of this article will be to review what is known about HAPE and its underly­ ing pathophysiology. We will also provide an update on the latest research and insight into the underlying mechanism of the disease, which results in a potentially fatal leak of fluid into the lungs. References are provided for more exhaustive reviews, but this piece is intended only to tantalize the reader about the current research—research that will one day lead to bet­ ter understanding as well as better prevention and treatment of HAPE.