hypoxia

hypoxia

Condition in which tissues are starved of oxygen. The extreme is anoxia (absence of oxygen). There are four types: hypoxemic, from low blood oxygen content (e.g., in altitude sickness); anemic, from low blood oxygen-carrying capacity (e.g., in carbon monoxide poisoning); distributive, from low blood flow (e.g., generally in shock or locally in atherosclerosis); and histotoxic, from poisoning (e.g., with cyanide) that keeps cells from using oxygen. If not reversed quickly, hypoxia can lead to necrosis (tissue death), as in heart attack.