Leukemia - Symptoms and causes - Mayo Clinic Overview Leukemia is cancer of the body's blood-forming tissues, including the bone marrow and the lymphatic system Many types of leukemia exist Some forms of leukemia are more common in children Other forms of leukemia occur mostly in adults Leukemia usually involves the white blood cells Your white blood cells are potent infection fighters — they normally grow and divide in an orderly
Stroke - Symptoms and causes - Mayo Clinic An ischemic stroke occurs when the blood supply to part of the brain is blocked or reduced This prevents brain tissue from getting oxygen and nutrients Brain cells begin to die in minutes Another type of stroke is a hemorrhagic stroke It occurs when a blood vessel in the brain leaks or bursts and causes bleeding in the brain The blood increases pressure on brain cells and damages them