High altitude cerebral edema (HACE) is a serious condition that can occur when individuals ascend to high altitudes, typically above 8,000 feet (2,400 meters). It results from the swelling of the brain due to a lack of oxygen, leading to symptoms such as headache, confusion, and difficulty walking. HACE is often associated with acute mountain sickness (AMS) and can develop rapidly. If not treated promptly, it can lead to severe complications or even death. The primary treatment involves descending to a lower altitude and administering oxygen or medications to reduce swelling.