Aspirin, acetaminophen, and ibuprofen will help relieve headaches, and most symptoms of mild altitude sickness will fade in a couple of days. However, if symptoms do not disappear, or if you notice a companion staggering, acting irrationally, or refusing to eat or drink, immediately return to a lower elevation. And keep a close eye on children, who are more susceptible to altitude sickness than adults. Two potentially fatal forms of altitude sickness-high-altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE)-can also fell fit men and women at Western hunting altitudes. Drowsiness, shortness of breath, fatigue, and dry cough are early signs of HAPE, which is caused by an accumulation of fluid in the lungs; later warning signs include blue lips, a high resting heart rate (above 90 beats per minute), and a cough with white (later pink) phlegm. HACE, caused by pressure on the brain, manifests itself in symptoms associated with AMS-headache, difficulty speaking, hallucinations. HACE victims often cannot pass the "drunk test" of placing one foot in front of the other and walking a straight line. Any of these symptoms warrants immediate descent and medical attention.