Some examples of the pathophysiology of anoxic encephalopathy, or brain damage due to lack of oxygen, are a blood clot or stroke stopping blood and therefore oxygen from reaching the brain, lung disease that reduces the amount of oxygen the brain receives even though the arteries to the brain are healthy, or toxins such as carbon monoxide preventing oxygen from getting to the brain, explains Mount Sinai Hospital.
Other examples of the pathophysiology of anoxic encephalopathy are a person lingering in a place where there is little oxygen, such as the summit of a tall mountain, or suffering an event that deprives him of oxygen, such as drowning, suffocation or choking, notes Mount Sinai Hospital.
Factors that place people at risk of brain damage from lack of oxygen include heart attack, drug use, electrical shock and heart arrhythmias, according to Mount Sinai Hospital. A malfunctioning gas or propane space heater that fills the air with carbon monoxide is also a risk, especially because CO is an odorless and colorless gas. If the lack of oxygen is very severe, the patient can lose consciousness, slip into a coma or a vegetative state, or die. Symptoms that indicate a lack of oxygen are headache, problems concentrating and paying attention, confusion, mood swings, and clumsiness. The person may pass in and out of consciousness and suffer seizures.