There are many types of hemolytic anemia. The condition can be inherited or acquired. "Inherited" means your parents passed the gene for the condition on to you. "Acquired" means you aren't born with the condition, but you develop it.
With inherited hemolytic anemias, one or more of the genes that control red blood cell production are faulty. This can lead to problems with the hemoglobin, cell membrane, or enzymes that maintain healthy red blood cells.
The abnormal cells may be fragile and break down while moving through the bloodstream. If this happens, an organ called the spleen may remove the cell debris from the bloodstream.
Sickle cell anemia is a serious, inherited disease. In this disease, the body makes abnormal hemoglobin. This causes the red blood cells to have a sickle, or crescent, shape.
Sickle cells don't last as long as healthy red blood cells. They usually die after only about 10 to 20 days. The bone marrow can't make new red blood cells fast enough to replace the dying ones.
In the United States, sickle cell anemia mainly affects African Americans.
Thalassemias (thal-a-SE-me-ahs) are inherited blood disorders in which the body doesn't make enough of certain types of hemoglobin. This causes the body to make fewer healthy red blood cells than normal.
Thalassemias most often affect people of Southeast Asian, Indian, Chinese, Filipino, Mediterranean, or African origin or descent.
In this condition, a defect in the surface membrane (the outer covering) of red blood cells causes them to have a sphere, or ball-like, shape. These blood cells have a lifespan that's shorter than normal.
Hereditary spherocytosis (SFER-o-si-to-sis) is the most common cause of hemolytic anemia among people of Northern European descent.
Like hereditary spherocytosis, this condition also involves a problem with the cell membrane. In this condition, the red blood cells are elliptic (oval) in shape. They aren't as flexible as normal red blood cells, and they have a shorter lifespan.
In G6PD deficiency, the red blood cells are missing an important enzyme called G6PD. G6PD is part of the normal chemistry inside red blood cells.
In G6PD deficiency, if red blood cells come into contact with certain substances in the bloodstream, the missing enzyme causes the cells to rupture (burst) and die.
Many factors can trigger the breakdown of the red blood cells. Examples include taking sulfa or antimalarial medicines; being exposed to naphthalene, a substance found in some moth balls; eating fava beans; or having an infection.
G6PD deficiency mostly affects males of African or Mediterranean descent. In the United States, the condition is more common among African Americans than Caucasians.
In this condition, the body is missing an enzyme called pyruvate (PI-ru-vate) kinase. Not having enough of this enzyme causes red blood cells to break down easily.
This disorder is more common among the Amish than other groups.
With acquired hemolytic anemias, your red blood cells may be normal. However, some other disease or factor causes the body to destroy red blood cells and remove them from the bloodstream.
The destruction of the red blood cells occurs in the bloodstream or, more commonly, in the spleen.
In immune hemolytic anemia, your immune system destroys your red blood cells. The three main types of immune hemolytic anemia are autoimmune, alloimmune, and drug-induced.
Autoimmune hemolytic anemia (AIHA). In this condition, your immune system makes antibodies (proteins) that attack your red blood cells. Why this happens isn't known.
AIHA accounts for half of all cases of hemolytic anemia. AIHA may come on very quickly and become serious.
Having certain diseases or infections can raise your risk for AIHA. Examples include:
AIHA also can develop after you have a blood and marrow stem cell transplant.
In some types of AIHA, the antibodies made by the body are called warm antibodies. This means they're active (that is, they destroy red blood cells) at warm temperatures, such as body temperature.
In other types of AIHA, the body makes cold-reactive antibodies. These antibodies are active at cold temperatures.
Cold-reactive antibodies can become active when parts of the body, such as the hands or feet, are exposed to temperatures lower than 32 to 50 degrees Fahrenheit (0 to 10 degrees Celsius).
Warm antibody AIHA is more common than cold antibody AIHA.
Alloimmune hemolytic anemia. This type of hemolytic anemia occurs if your body makes antibodies against red blood cells that you get from a blood transfusion. This can happen if the transfused blood is a different blood type than your blood.
This type of hemolytic anemia also can occur during pregnancy if a woman has
Rh-negative blood and her baby has Rh-positive blood. "Rh-negative" and "Rh-positive" refer to whether your blood has Rh factor. Rh factor is a protein on red blood cells.
For more information, go to the Health Topics Rh Incompatibility article.
Drug-induced hemolytic anemia. Certain medicines can cause a reaction that develops into hemolytic anemia. Some medicines, such as penicillin, bind to red blood cell surfaces and can cause antibodies to develop.
Other medicines cause hemolytic anemia in other ways. Examples of these medicines include chemotherapy, acetaminophen, quinine and antimalarial medicines, anti-inflammatory medicines, and levodopa.
Physical damage to red blood cell membranes can cause them to break down faster than normal. Damage may be due to:
Blood cell damage also may occur in the limbs as a result of doing strenuous activities, such as taking part in marathons.
Paroxysmal nocturnal hemoglobinuria (HE-mo-GLO-bih-NYU-re-ah), or PNH, is a disorder in which the red blood cells are faulty due to a lack of certain proteins. The body destroys these cells more quickly than normal.
People who have PNH are at increased risk for blood clots in the veins and low levels of white blood cells and platelets.
Certain infections and substances also can damage red blood cells and lead to hemolytic anemia. Examples include malaria and blackwater fever, tick-borne diseases, snake venom, and toxic chemicals.
Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Hemolytic Anemia, visit www.clinicaltrials.gov.
November 20, 2013
Gary H. Gibbons
New NHLBI Program Trains Scientists to Bring More Science Out of the Lab and into the Patient Care Marketplace
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.