Hemolytic anemia

Overview

Hemolytic anemia is a term used for a variety of anemias characterized by a low count of red blood cells, coupled with more rapid destruction of red blood cells. Red blood cells are produced in the bone marrow and mainly recycled in the spleen when they wear out (usually in 120 days). The red blood cells contain hemoglobin, a protein that carries oxygen and delivers oxygen throughout the body by traveling through the bloodstream. Hemolytic anemia occurs when red blood cells have an abnormally short life span and are destroyed faster than bone marrow can produce them.

There are more than a dozen conditions characterized by hemolytic anemia. Some are inherited, or "congenital," such as sickle cell anemia or thalessemia. Others are acquired and can be triggered by certain drugs, infections or other environmental exposures or a malfunctioning immune system.

Congenital hemolytic anemia

In congenital hemolytic anemias, the destruction of red blood cells is caused by a defect within the red blood cells themselves. These anemias often are inherited, such as sickle cell anemia and thalassemia, and produce red blood cells that do not live as long as normal red blood cells.

Acquired hemolytic anemia

In acquired hemolytic anemias, also called autoimmune hemolytic anemias or Coombs positive hemolytic anemias, the red blood cells are produced as healthy cells but later destroyed after being trapped in the spleen, by infection or by drugs. These forms of anemia are frequently associated with other medical conditions, such as an autoimmune disorder — a disease that causes the immune system to mistakenly attack itself, targeting the cells, tissues and organs of your child's body. But acquired anemias can also occur by themselves.

Some of the common causes of these anemias include:

• Infections, such as hepatitis, cytomegalovirus (CMV), Epstein-Barr virus (EBV), typhoid fever, E. coli or streptococcus
• Drugs such as penicillin, antimalaria medications, sulfa medications or acetaminophen
• Leukemia or lymphoma
• Autoimmune disorders, such as systemic lupus erythematous (SLE, or lupus), rheumatoid arthritis, Wiskott-Aldrich syndrome, or ulcerative colitis
• Tumors

Some types of acquired hemolytic anemia are temporary and resolve over several months. Other types can become chronic, with periods of remissions and recurrence.

Signs & symptoms

Symptoms of hemolytic anemia may vary with each child. The following are some of the most common symptoms:

• Abnormally pale skin as well as jaundice (yellowing) of skin and eyes
• Confusion
• Dark colored urine
• Dizziness, weakness or intolerance to physical activity
• Enlarged spleen and liver
• Fever
• Heart murmur
• Increased heart rate

The symptoms may be similar to other blood conditions and medical problems. Your child's doctors will conduct several tests to diagnose the disease.

Diagnosis

Your child's doctor will take a medical history and perform a physical examination of your child. The doctor may also order the following diagnostic tests:

• Blood Tests — These tests are conducted to measure hemoglobin and reticulocyte count, which reveals how many new red blood cells are being produced; check liver function; and the presence of certain antibodies.
• Urine Tests — These tests are conducted to measure hemoglobin in urine.
• Bone Marrow Aspiration and Biopsy — Bone marrow aspiration or biopsy may be performed under local anesthesia to remove marrow for testing. In the aspiration, a fluid specimen is removed from your child's bone marrow. In the biopsy, a thin sliver of the marrow itself, rather than fluid, is removed. These methods are often used together.

Treatment

Treatment for hemolytic anemia is determined by several factors, including your child's age, overall health and medical history. Other issues that will be considered are the extent and cause of the anemia as well as your child's tolerance for medications, procedures and therapies. Treatment may include:

• Blood transfusions
• Corticosteroid medications, which are synthetic versions of natural hormones produced by the body's adrenal glands
• Intravenous immune globulin to strengthen the immune system

Treatment for Severe Cases

In more severe cases, the following treatments may be necessary and usually require hospitalization:

• Exchange Transfusion — This is similar to a blood transfusion but differs in that your child's blood also is removed. In an exchange transfusion, blood is transferred to your child and an equal amount of your child's hemolyzed blood — the blood in which the red blood cells have been destroyed or impaired — is removed.
• Spleen Removal — Surgical removal of the spleen generally is reserved for children who do not respond to other therapies.
• Immunosuppressive Therapy — This therapy is used to suppress your child's immune system if the anemia is caused by an autoimmune disorder. An autoimmune disorder is a disease that causes the immune system to mistakenly attack itself, targeting the cells, tissues and organs of your child's body.