Types of Hemolytic Anemia
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 due to another disease, condition, or factor.
Inherited Hemolytic Anemias
With inherited hemolytic anemias, one or more of the
genes that control red blood cell production are faulty. The defects may
involve 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
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
"C," 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.
Sickle cell anemia mainly affects people of African
descent.
Thalassemias
Thalassemias
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.
Hereditary Spherocytosis
In this condition, a defect in the surface membrane
(the outer covering) of red blood cells causes them to take on 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.
Hereditary Elliptocytosis (Ovalocytosis)
This condition also involves a problem with the cell
membrane. With 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.
Glucose-6-Phosphate Dehydrogenase (G6PD)
Deficiency
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 and die.
A number of 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. It affects about 1 in 10 African American males.
Pyruvate Kinase Deficiency
With this condition, your body is missing an enzyme
called pyruvate 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.
Acquired Hemolytic Anemias
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.
Immune Hemolytic Anemia
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. It's most common in people older than 40.
Having certain diseases or infections can raise your
risk for AIHA. Examples include:
- Autoimmune diseases, such as lupus
- Chronic lymphocytic leukemia
- Non-Hodgkin's lymphoma and other blood
cancers
- Epstein-Barr virus
- Cytomegalovirus
- Mycoplasma
pneumonia
- Hepatitis
- HIV
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, which become active in colder 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-reactive
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 there's a difference in blood type between the mother and the
fetus. For more information, see the Diseases and Conditions Index
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 such medicines include acetaminophen; quinine and
antimalarial medicines; anti-inflammatory medicines; and levodopa.
Mechanical Hemolytic Anemias
Physical damage to red blood cell membranes can
cause them to break down faster than normal. Damage may be due to:
- Changes in the small blood vessels.
- An artificial heart valve or other device used in
blood vessels.
- A heart-lung bypass machine, which may be used
during open-heart
surgery.
- Preeclampsia (pre-e-KLAMP-se-ah) or eclampsia.
Preeclampsia is high blood pressure during pregnancy. Eclampsia, which follows
preeclampsia, is a serious condition that causes seizures in pregnant
women.
Blood cell damage also may occur in the limbs while
participating in marathons or other strenuous activities.
Paroxysmal Nocturnal Hemoglobinuria
Paroxysmal nocturnal hemoglobinuria (PNH) is a
disorder in which the red blood cells are abnormal 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.
Other Causes of Damage to Red Blood Cells
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.
|