Blood diseases

Types of Blood Disorders

Dozens of different diseases can involve the blood. Blood disorders can affect any of the three main components of blood:

• Red blood cells, which carry oxygen to the body's tissues
• White blood cells, which fight infections
• Platelets, which help blood to clot

Blood disorders can also affect the liquid portion of blood, called plasma.

Treatments and prognosis for blood diseases vary, depending on the blood condition and its severity.

Blood Disorders Affecting Red Blood Cells

Blood disorders that affect red blood cells include:

Anemia : People with anemia have a low number of red blood cells. Mild anemia often causes no symptoms. More severe anemia can cause fatigue, pale skin, and shortness of breath with exertion.

Iron-deficiency anemia: Iron is necessary for the body to make red blood cells. Low iron intake and loss of blood due to menstruation are the most common causes of iron-deficiency anemia. Treatment includes iron pills, or rarely blood transfusion.

Anemia of chronic disease: People with chronic kidney disease or other chronic diseases tend to develop anemia. Anemia of chronic disease does not usually require treatment. Injections of a synthetic hormone (Epogen, Procrit) to stimulate the production of blood cells or blood transfusions may be necessary in some people with this form of anemia.

Pernicious anemia (B12 deficiency): An autoimmune condition that prevents the body from absorbing enough B12 in the diet. Besides anemia, nerve damage (neuropathy) can eventually result. High doses of B12 prevent long-term problems.

Aplastic anemia: In people with aplastic anemia, the bone marrow does not produce enough blood cells, including red blood cells. A viral infection, drug side effect, or an autoimmune condition can cause aplastic anemia. Blood transfusions, and even a bone marrow transplant, may be required to treat aplastic anemia.

Autoimmune hemolytic anemia: In people with this condition, an overactive immune system destroys the body's own red blood cells, causing anemia. Medicines that suppress the immune system, such as prednisone, may be required to stop the process.

Thalassemia: This is a genetic form of anemia that mostly affects people of Mediterranean heritage. Most people have no symptoms and require no treatment. Others may need regular blood transfusions to relieve anemia symptoms.

Sickle cell anemia: A genetic condition that affects mostly African-Americans. Periodically, red blood cells change shape, and block blood flow. Severe pain and organ damage can occur.

Polycythemia vera : The body produces too many blood cells, from an unknown cause. The excess red blood cells usually create no problems, but cause blood clots in some people.

Malaria: A mosquito's bite transmits a parasite into a person's blood, where it infects red blood cells. Periodically, the red blood cells rupture, causing fever, chills, and organ damage. This blood infection is most common in Africa; malaria was eradicated from the U.S. in the 1940s.

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