Anemia - a deficiency of red blood cells or hemoglobin - is a serious and often painful condition in cats with many potential causes, ranging from parasites to immune disease to kidney failure.
Cats with anemia suffer from profound fatigue - even minimal exertion causes breathlessness and distress because their blood cannot efficiently deliver oxygen. The experience is similar to a human with severe blood loss: weakness, dizziness, and the physical suffering of tissue oxygen deprivation. Immune-mediated anemias can deteriorate rapidly, causing cats to crash from apparent wellness to crisis within days. Outdoor cats are at particular risk from parasitic causes. Early detection through routine blood work is essential, as anemia is often a symptom of underlying conditions requiring their own management.