Health Encyclopedia

Hemolytic anemia

Definition

Hemolytic anemia is a condition in which there are not enough red blood cells in the blood, due to the premature destruction of red blood cells. There are a number of specific types of hemolytic anemia, which are described individually.

Alternative Names

Anemia - hemolytic

Causes, incidence, and risk factors

Hemolytic anemia occurs when the bone marrow is unable to increase production to make up for the premature destruction of red blood cells. If the bone marrow is able to keep up with the early destruction, anemia does not occur (sometimes called compensated hemolysis).

There are many types of hemolytic anemia, which are classified by the reason for the premature destruction of red blood cells. The defect may be in the red blood cell itself (intrinsic factor), or outside the red blood cell (extrinsic factors).

Intrinsic factors are often present at birth (hereditary). They include:

Abnormalities in the proteins that build normal red blood cells
Differences in the protein inside a red blood cell that carries oxygen (hemoglobin)

Extrinsic factors include:

Abnormal immune system responses
Blood clots in small blood vessels
Certain infections
Side effects from medications

Types of hemolytic anemia include:

Hemoglobin SC disease (similar in symptoms to sickle-cell anemia)
Hemolytic anemia due to G6PD deficiency
Hereditary elliptocytosis
Hereditary ovalocytosis
Hereditary spherocytosis
Idiopathic autoimmune hemolytic anemia
Malaria
Microangiopathic hemolytic anemia (MAHA)
Non-immune hemolytic anemia caused by chemicals or toxins
Paroxysmal nocturnal hemoglobinuria (PNH)
Secondary immune hemolytic anemia
Sickle-cell anemia
Thalassemia
Transfusion of blood from a donor with a different blood type

Symptoms

Signs and tests

These are tests for red blood cell destruction (hemolysis). Specific tests can identify the types of hemolytic anemia. They are usually performed when hemolysis is suspected or has been determined.

Absolute reticulocyte count
Free hemoglobin in the serum or urine
Hemosiderin in the urine
Red blood cell count (RBC) and hemoglobin
Serum haptoglobin levels
Serum indirect bilirubin levels
Serum LDH
Urine and fecal urobilinogen

Directly measuring the red cell life span with radioactive tagging techniques shows a shortened life span.

This disease may also affect the following test results, depending on the specific cause:

Treatment

Treatment depends on the type and cause of the hemolytic anemia. Folic acid, iron replacement, and corticosteroids may be used. In emergencies, a blood transfusion or removal of the spleen (splenectomy) may be necessary.

Expectations (prognosis)

The outcome depends on the type and cause of hemolytic anemia.

Complications

The complications depend on the specific type of hemolytic anemia. Severe anemia can cause cardiovascular collapse. Severe anemias can aggravate heart disease, lung disease, or cerebrovascular disease.

Calling your health care provider

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

Prevention

There is no known prevention for hemolytic anemia.

References

Schwartz RS. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 164.

Review Date:11/23/2008
Reviewed By:David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; 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., Inc.

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