Hemolytic anemia

Causes

Hemolytic anemia occurs when the bone marrow is unable to replace the red blood cells that are being destroyed.

Immune hemolytic anemia occurs when the immune system mistakenly sees your own red blood cells as foreign substances. Antibodies then develop against the red blood cells. These antibodies attack the red blood cells and cause them to break down too early.

The body may also destroy red blood cells because of:

• Certain genetic defects that cause the blood cells to take on abnormal shapes (such as sickle cell anemia, thalassemia, and hemolytic anemia due to G6PD deficiency
• Exposure to certain chemicals, drugs, and toxins
• Infections

Other causes are:

• Blood clots in small blood vessels
• Transfusion of blood from a donor with a blood type that does not match yours

Symptoms

You may not have symptoms if the anemia is mild. If the problem develops slowly, the first symptoms may be:

• Feeling grumpy
• Feeling weak or tired more often than usual, or with exercise
• Headaches
• Problems concentrating or thinking

If the anemia gets worse, symptoms may include:

• Blue color to the whites of the eyes
• Brittle nails
• Light-headedness when you stand up
• Pale skin color
• Shortness of breath
• Sore tongue

Exams and Tests

A test called a complete blood count (CBC) can help diagnose anemia and offer some hints to the type and cause of the problem. Important parts of the CBC include red blood cell count (RBC), hemoglobin, and hematocrit (HCT).

These tests can identify the type of hemolytic anemia:

• Absolute reticulocyte count
• Coombs' test, direct
• Coombs' test, indirect
• Donath-Landsteiner test
• Febrile or cold agglutinins
• Free hemoglobin in the serum or urine
• Hemosiderin in the urine
• Platelet count
• Protein electrophoresis - serum
• Serum haptoglobin levels
• Serum LDH
• Urine and fecal urobilinogen

A test that measures how long red blood cells last using radioactive tagging techniques can also help diagnose hemolytic anemia.

Treatment

Treatment depends on the type and cause of the hemolytic anemia. 

• In emergencies, a blood transfusion may be needed.
• For hemolytic anemia caused by an overactive immune system, drugs that suppress the immune system may be used.
• When blood cells are being destroyed at a fast pace, the body may need extra folic acid and iron supplements to replace what is being lost.

Rarely, the spleen may need to be removed, because it acts as a filter, removing abnormal cells from the blood.

Outlook (Prognosis)

The outcome depends on the type and cause of hemolytic anemia. Severe anemia can make heart disease, lung disease, or cerebrovascular disease worse.

When to Contact a Medical Professional

Call for an appointment with your health care provider if you develop symptoms of hemolytic anemia.

Alternative Names

Anemia - hemolytic

References

Schwartz RS. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011: chap 163.

Powers A, Silberstein LE. Autoimmune hemolytic anemia. In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone;2008:chap 47.

Schrier SL, Price EA. Extrinsic nonimmune hemolytic anemias. In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone;2008:chap 48.

Update Date: 2/7/2012

Updated by: Yi-Bin Chen, MD, Leukemia/Bone Marrow Transplant Program, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.