Anemia causes which type of hypoxia?

• A. Hypoxic hypoxia
• B. Hypemic hypoxia
• C. Stagnant hypoxia
• D. Histotoxic hypoxia

Answer: (B)

Oxygen delivery to tissues depends on how much oxygen your blood can carry, which is determined by hemoglobin. In anemia, there’s less hemoglobin available, so the blood’s oxygen-carrying capacity drops even when breathing and lung function are normal. This means the arterial blood may still have normal oxygen pressure and saturation, but its oxygen content is reduced, leading to tissues receiving less oxygen overall. That situation is called hypemic hypoxia.

To see how this fits, remember the oxygen content of arterial blood is roughly Hb-dependent: more hemoglobin and proper saturation mean more oxygen carried. With less hemoglobin, the same blood can transport far less oxygen, so tissues become hypoxic despite normal ventilation and a normal PaO2.

Other types of hypoxia come from different problems: hypoxic hypoxia is from low arterial oxygen tension (low PaO2) such as at high altitude or with lung disease; stagnant hypoxia is from poor circulation or pooling of blood; histotoxic hypoxia is when cells can’t use oxygen due to toxins like cyanide. In anemia, the issue is the reduced carrying capacity, hence hypemic hypoxia.