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Haemolytic AnaemiaWhat Is Haemolytic Anaemia?Haemolytic anaemia is a rare form of anaemia in which red blood cells are destroyed and removed from the bloodstream before their usual lifespan is up. Healthy red blood cells usually live about 120 days (4 months) in the bloodstream before the body removes them. In haemolytic anaemia, the body breaks down and removes red blood cells faster than it can replace them. The breakdown of red blood cells is called haemolysis. AnaemiaThe term "anaemia" means that the number of red blood cells in a person’s blood is less than normal or the red blood cells don’t contain enough haemoglobin. Haemoglobin is an iron-rich protein in red blood cells that gives blood its red color. Anaemia is also known as having a "low blood count". The most common symptom of anaemia is fatigue (tiredness). Fatigue develops because the tissues of the body don’t receive enough oxygen. The haemoglobin in red blood cells picks up oxygen in the lungs and circulates it to the tissues of the body. If there aren’t enough red blood cells, or not enough haemoglobin in the red blood cells, the blood can’t carry enough oxygen to the rest of the body. Red blood cells also are called RBCs or erythrocytes (eh-RITH-roh-sites). Normal red blood cells are all about the same size and look like tiny doughnuts without holes in the center. Normal red blood cells have an average lifespan of 120 days, after which they die and are removed from the bloodstream. The iron in the haemoglobin is recycled to make new red blood cells. The marrow inside the large bones of the body continually produces new red blood cells to replace the ones that have died. The blood also contains two other types of cells: white blood cells and platelets. White blood cells help fight infection. Platelets help blood to clot. In some kinds of anaemia, there are low amounts of all three types of blood cells. There are three main causes of anaemia: blood loss, lower than normal levels of red blood cell production, or higher than normal rates of red blood cell destruction. More than one of these factors can combine to cause anaemia. Haemolytic AnaemiaHaemolytic anaemia is due to increased haemolysis (destruction) of red blood cells. The bone marrow increases production of red blood cells to replace the haemolysed blood cells, but it can’t produce them fast enough to meet the body’s needs. In some types of haemolytic anaemia, the body makes abnormal red blood cells that break down and haemolyse on their own. In other types of haemolytic anaemia, the body’s immune system, infections, certain drugs, or other agents attack normal red blood cells, causing them to haemolyse. The haemolysis can occur in the bloodstream or in an organ called the spleen. The two main types of haemolytic anaemia are inherited and acquired. In inherited haemolytic anaemia, the condition is passed from parent to child. In acquired haemolytic anaemia, the person develops the condition from some other cause. Haemolytic anaemia can begin rapidly or come on gradually and can range from mild to severe. OutlookHaemolytic anaemia can often be successfully treated or controlled. The course of haemolytic anaemia depends on the cause and the severity of the anaemia. Mild haemolytic anaemia may need no treatment at all. Severe haemolytic anaemia can be life threatening if it’s not treated. If you have an inherited form of haemolytic anaemia, it’s a lifelong condition that requires ongoing treatment. If your anaemia is caused by an infection or use of a particular medicine, the anaemia may go away when the infection is treated or when the medicine is stopped. Types of Haemolytic AnaemiaThere are many types of haemolytic anaemia. Some types are inherited, which means a person is born with them. Other types are acquired, which means they develop in response to some other disease or factor. Inherited Types of Haemolytic AnaemiaIn the inherited haemolytic anaemias, one or more of the genes that control the production of red blood cells are defective, causing the bone marrow to make abnormal cells. The red blood cell abnormality can involve the cell membrane (the outer covering of the cell), the chemistry inside the cell, or the production of abnormal types or amounts of haemoglobin. The abnormal cells may be fragile and break down (haemolyse) on their own while circulating in the bloodstream. Also, the body’s immune system may recognize that the red blood cells are abnormal, and an organ called the spleen may remove the cells from the bloodstream. Sickle Cell AnaemiaIn sickle cell anaemia, the body makes an abnormal type of haemoglobin. This haemoglobin causes the red blood cells to take on an abnormal shape. Instead of their normal shape (a doughnut without a hole) the red blood cells can turn into a sickle (crescent) shape. Sickle cells die and are removed from the bloodstream prematurely. In the United States, sickle cell anaemia occurs most often in African Americans. There also are other types of abnormal haemoglobin that can cause haemolysis. ThalassaemiaThe thalassaemias are a group of anaemias in which the body doesn’t make enough of certain types of haemoglobin. This leads to abnormal red blood cells that die and are removed from the body prematurely. Thalassaemia is most common among people of Mediterranean, African, or Southeast Asian descent. Hereditary SpherocytosisIn hereditary spherocytosis, an abnormality of the surface membrane of red blood cells causes them to take on a spherical (ball) shape. The abnormally shaped blood cells have a short lifespan. Hereditary spherocytosis is the most common cause of haemolytic anaemia among people whose ancestors come from Northern Europe. Hereditary Elliptocytosis (Ovalocytosis)Hereditary elliptocytosis is another condition involving the cell membrane. It’s also known as hereditary ovalocytosis. In this condition, the red blood cells are elliptic (oval) in shape and not as flexible as normal red blood cells. These abnormal red blood cells also have a short lifespan. Glucose-6-Phosphate Dehydrogenase DeficiencyIn glucose-6-phosphate dehydrogenase deficiency (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 prematurely. The haemolysis can be triggered by the person taking sulfa or antimalaria medicines, 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 DeficiencyPyruvate kinase also is an enzyme-deficiency haemolytic anaemia in which the missing enzyme is 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 Types of Haemolytic AnaemiaIn acquired types of haemolytic anaemia, the red blood cells may be normal, but some other disease or factor causes the body to destroy the red blood cells and remove them from the bloodstream. The destruction of the red blood cells can occur in the bloodstream or, more commonly, in the spleen. Immune Haemolytic AnaemiaIn immune haemolytic anaemia, the body’s immune system destroys the body’s red blood cells. There are three main types of immune haemolytic anaemia: autoimmune, alloimmune, and drug-induced. Autoimmune haemolytic anaemia. In autoimmune haemolytic anaemia (AIHA), a person’s immune system mistakenly produces antibodies directed against the person’s own red blood cells. One-half of all cases of haemolytic anaemia are AIHA. The cause of AIHA is unknown. It may come on very quickly and become serious. It’s most common in people over age 40. Having certain diseases or infections can make a person more likely to develop AIHA. These include chronic lymphocytic leukemia, non-Hodgkin’s lymphoma, and other blood cancers; Epstein-Barr virus (which causes infectious mononucleosis); cytomegalovirus (a virus that infects cells); mycoplasma pneumonia (a lung infection); hepatitis; and human immunodeficiency virus (HIV). In some types of AIHA, the antibodies produced by the body are called warm antibodies. This means they are active (that is, they destroy red blood cells) at warm temperatures, such as body temperature. In other types of AIHA, the body produces “cold-reactive antibodies,” which means they become active when exposed to colder temperatures. Cold-reactive antibodies can become active when the body (typically the hands or feet) is exposed to temperatures of less than 32 to 50 degrees Fahrenheit (0 to 10 degrees Celsius). Warm antibody AIHA is more common than cold-reactive antibody AIHA. Alloimmune haemolytic anaemia. In alloimmune haemolytic anaemia, antibodies are produced against the red blood cells a person receives in a blood transfusion. If the blood type used for the tranfusion is different than the recipient’s blood type, the recipient’s immune system can develop antibodies that attack and destroy the transfused blood cells. Alloimmune antibodies also can develop as a result of the mixing of blood between a pregnant woman and her baby at delivery. If the mother’s blood type is Rh-negative and the baby’s is Rh-positive, the mother can produce antibodies against the baby’s blood type. If a mother develops anti-Rh antibodies as a result of one pregnancy, they can cross the placenta during the next pregnancy and harm the fetus. To prevent this, a medicine called RhoGam can be given at the time of delivery to block the mother’s body from developing antibodies against the baby’s blood type. Drug-induced haemolytic anaemia. Certain drugs can cause a reaction that develops into haemolytic anaemia. These drugs include high doses of penicillin and related drugs, acetaminophen, quinine and other drugs to treat malaria, anti-inflammatory drugs, and levodopa. Mechanical Haemolytic AnaemiasPhysical damage to red blood cell membranes can result from microangiopathic (MI-kro-an-jee-o-PA-thik) changes in small blood vessels. An artificial heart valve or other device used in blood vessels also can damage red blood cell membranes. Damage can occur with a heart-lung bypass machine during open-heart surgery. Damage also can occur with preeclampsia or eclampsia (elevated blood pressure and protein in the urine after the 20th week of pregnancy). Blood cell damage may occur in the limbs while participating in marathons or other strenuous activities. Paroxysmal Nocturnal HaemoglobinuriaParoxysmal (par-ok-SIZ-mal) nocturnal haemoglobinuria (PNH) is an acquired genetic disorder in which the red blood cells are abnormal due to a lack of certain proteins. The body destroys these cells more rapidly than normal. The destruction may occur continuously at a low level and flare up at times (paroxysmal). People with 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 CellsInfections and other agents can invade and damage red blood cells. Malaria and “blackwater fever,” tick-borne diseases, snake venom, and toxic chemicals can attack and destroy red blood cells, causing haemolytic anaemia. Other Names for Haemolytic Anaemia
What Causes Haemolytic Anaemia?There are many different types of haemolytic anaemia. The immediate cause of haemolytic anaemia is the early destruction (haemolysis) of red blood cells. The factors that cause early haemolysis can be inherited or acquired. Sometimes, the cause of early haemolysis is not known. Causes of Inherited Haemolytic AnaemiaIn inherited haemolytic anaemias, there is a problem with the genes that control the production of red blood cells. People with an inherited haemolytic anaemia received a defective red blood cell gene from one (or both) of their parents. Different types of defective genes account for the different types of inherited haemolytic anaemias. In each of the types of inherited haemolytic anaemia, the body produces abnormal red blood cells. The red blood cell abnormality can involve the cell membrane (the outer covering of the cell), the chemistry inside the cell, or the production of abnormal haemoglobin. Causes of Acquired Haemolytic AnaemiaIn acquired types of haemolytic anaemia, the body produces normal red blood cells, but some disease or other factor destroys the cells prematurely. The destruction of red blood cells can be caused by an immune disorder, infection, reaction to a medicine, or reaction to a transfusion. The early destruction of cells usually occurs in the spleen or the bloodstream. The spleen is an organ in the upper left part of the abdomen that helps remove abnormal blood cells from the bloodstream. Who Is At Risk for Haemolytic Anaemia?Haemolytic anaemia can affect people of all ages and both genders. Most types of haemolytic anaemia are equally common in men and women and can develop at any age. Autoimmune haemolytic anaemia is slightly more likely in women over age 40. Glucose-6-phosphate dehydrogenase deficiency (G6PD deficiency) is more common among males. People of all races can develop haemolytic anaemia. Some types of haemolytic anaemia are more likely to occur in certain populations than others. In the United States, sickle cell anaemia, one of the most common forms of haemolytic anaemia, occurs primarily among African Americans. G6PD deficiency affects males of African or Mediterranean descent. About 1 in 10 African American men have G6PD deficiency. What Are the Signs and Symptoms of Haemolytic Anaemia?Signs and symptoms of haemolytic anaemia depend on the type of anaemia and its severity. People with mild haemolytic anaemia often have no symptoms. However, if the anaemia is severe, the symptoms increase and become more serious. Many of the signs and symptoms of haemolytic anaemia apply to all anaemias. Signs and Symptoms of AnaemiaThe most common symptom of all types of anaemia, including haemolytic anaemia, is fatigue (tiredness). Fatigue is caused by having too few red blood cells to carry oxygen to the body. This lack of oxygen in the body can cause you to feel weak or dizzy, have a headache, feel short of breath, or even pass out when changing position (for example, standing up). Since the heart must work harder to circulate the reduced amount of oxygen in the blood, signs and symptoms of anaemia may also include a fast or irregular heartbeat or a heart murur. People with anaemia may have pale skin, tongue, gums, and nail beds due to the low levels of haemoglobin. Signs and Symptoms of Haemolytic AnaemiaThe signs and symptoms associated with haemolytic anaemia include:
How Is Haemolytic Anaemia Diagnosed?Haemolytic anaemia is diagnosed using a combination of medical and family history, physical exam, and diagnostic tests. Specialists InvolvedPrimary care doctors, such as a family doctor or pediatrician, may be involved in diagnosing and treating haemolytic anaemia. Other kinds of doctors involved include:
Doctors and clinics that specialize in treating inherited blood disorders, such as sickle cell anaemia and thalassaemia, may be involved. If you have an inherited form of haemolytic anaemia, you may want to consult a genetics counselor. Medical and Family HistoryTo determine the cause and severity of haemolytic anaemia, your doctor may ask detailed questions about your symptoms, personal medical history, and your family medical history. You may be asked whether you or anyone in your family has had problems with anaemia in the past. Your doctor will want to know what illnesses or conditions you have had recently and what medicines you take. You also may be asked whether you have been exposed to any drugs or chemicals or have an artificial heart valve or device that could damage red blood cells. Physical ExamYour doctor will perform a physical exam to determine how severe the anaemia is and to check for possible causes. This exam may include:
Diagnostic Tests and ProceduresYour doctor may perform a number of tests, including the following: Blood TestsComplete blood count. Usually, the first test used to diagnose anaemia is a complete blood count (CBC). The CBC tells a number of things about a person’s blood, including:
The normal range of these levels may be different in certain racial and ethnic populations. Your doctor can explain your individual test results. The CBC also checks:
Additional blood tests. If the CBC results confirm you have anaemia, your doctor may order additional blood tests to determine the type and cause of the anaemia. Some of the tests that can be used in the diagnosis of haemolytic anaemia include:
Bone Marrow TestsIn some cases, the doctor may want to examine the cells of the bone marrow under a microscope. A sample of bone marrow can be obtained with either a bone marrow biopsy or aspiration. A bone marrow biopsy is a minor surgical procedure to remove a small amount of bone marrow tissue. For a bone marrow aspiration, your doctor removes a small amount of bone marrow fluid through a needle. Tests for Other Causes of AnaemiaBecause anaemia has many causes, the doctor may order tests for conditions such as:
How Is Haemolytic Anaemia Treated?Goals of TreatmentThe goals of treating haemolytic anaemia are to reduce or stop the haemolysis of red blood cells, to increase the red blood cell count to normal levels, and to treat the underlying cause. The treatment you receive will depend on the type, cause, and severity of the haemolytic anaemia you have. Your age, overall health, and medical history also will be considered. If you have an inherited form of haemolytic anaemia, it’s a lifelong condition that may require ongoing treatment. If you have an acquired haemolytic anaemia, the anaemia may go away if the underlying cause can be found and corrected. Who Needs TreatmentSevere haemolytic anaemia usually requires ongoing treatment and can be life threatening if left untreated. A person with mild haemolytic anaemia may not need treatment as long as the condition doesn’t get worse. Types of TreatmentTreatments for haemolytic anaemia include blood transfusion, medicines, lifestyle changes, plasmapheresis (treatment to remove antibodies from red blood cells), surgery, and bone marrow or stem cell transplant. Blood TransfusionsBlood transfusions are used to treat severe or life-threatening anaemia. Transfusions are given through a vein and require careful matching of donated blood with the recipient’s blood. The transfused blood must be compatible with the recipient’s blood type (for example, type A, Rh-negative). People who receive blood transfusions on a regular basis must be monitored and treated for a buildup of too much iron in the body. MedicinesSome types of haemolytic anaemia, particularly autoimmune haemolytic anaemia (AIHA), can be improved with medicines. Corticosteroid medicines, such as prednisone, can be used to suppress the immune response against red blood cells. If there is no response to corticosteroids, other drugs that suppress the immune system, such as azathioprine, cyclophosphamide, or danazol, may be prescribed. Intravenous (IV) gamma globulin may also be given to suppress antibody formation if the person does not respond to corticosteroids. Rituximab is being tried experimentally for AIHA. This drug reduces haemolysis by suppressing the immune system cells that produce the antibodies against red blood cells. An experimental medicine called eculizumab is being studied as a treatment for paroxysmal nocturnal haemoglobinuria (PNH). Eculizumab is an antibody directed against part of the immune system that is involved in PNH. PlasmapheresisPlasmapheresis removes antibodies from red blood cells. It may help if other treatments for immune haemolytic anaemia don’t work. SurgeryIn some cases of haemolytic anaemia, it’s necessary to surgically remove the spleen. The spleen is an organ in the upper left part of the abdomen that helps remove abnormal red blood cells from the bloodstream. The spleen also can contribute to some types of haemolytic anaemia. An enlarged or diseased spleen removes more red blood cells than normal, causing anaemia. Removal of the spleen may be necessary to stop or reduce high rates of red blood cell destruction. Bone Marrow or Stem Cell TransplantHaemolytic anaemia that results from the failure of bone marrow to make normal red blood cells (such as in thalassaemia) is sometimes treated with bone marrow or stem cell transplants. Donor marrow is usually taken from a large bone, such as the pelvis. Marrow is given by transfusion through a vein. Stem cells for a transplant can be from matched umbilical cord blood, from bone marrow donated by a family member, or from a matched but unrelated donor. Stem cells in bone marrow develop into mature blood cells. Lifestyle ChangesFor people with AIHA with cold-reactive antibodies, avoiding exposure to cold temperatures can help prevent haemolysis of their red blood cells. It’s especially important to protect the fingers, toes, and ears from the cold. Typical ways to protect from cold include:
People born with glucose-6-phosphate dehydrogenase deficiency can prevent the development of anaemia by avoiding substances that can trigger haemolysis, such as fava beans and certain medicines. How Can Haemolytic Anaemia Be Prevented?Haemolytic anaemia can't be prevented in people who are born with the genes for inherited types of haemolytic anaemia. One exception is glucose-6-phosphate dehydrogenase (G6PD) deficiency. A person born with G6PD deficiency can prevent the development of anaemia by avoiding substances, such as fava beans and certain medicines, which can trigger haemolysis. Transfusion reactions, which can cause haemolytic anaemia, can be prevented by ensuring a match of the blood types between the donor and recipient. When a pregnant woman has Rh-negative type blood and her fetus has Rh-positive type blood, a medicine called RhoGam given at the time of delivery can block the mother’s body from developing antibodies against the baby’s blood type. Living With Haemolytic AnaemiaThe course of haemolytic anaemia depends on the cause and the severity of the anaemia. Mild haemolytic anaemia may need no treatment at all. If you have an inherited form of haemolytic anaemia, it is a lifelong condition that may require ongoing treatment. If the anaemia is caused by a medicine or infection, the anaemia may go away when the medicine is stopped or the infection is cured. Ongoing Health Care NeedsIf you have haemolytic anaemia, taking care of your overall health is important. See your doctor regularly for checkups and follow your treatment plan. Get a flu shot every year, and ask your doctor about the vaccine to prevent pneumoccal pneumonia. Be sure to get plenty of rest. Stay away from cold temperatures if you have cold-reactive antibody autoimmune haemolytic anaemia. During cold weather, wear a hat, scarf, and a warm coat. When taking cold food out of the refrigerator or freezer, wear gloves. Turn down air conditioning or dress warmly while in an air conditioned space, and warm up the car before driving in cold weather. If you have glucose-6-phosphate dehydrogenase deficiency, avoid taking sulfa or antimalaria medicines and eating fava beans. You should also take precautions to avoid infections. Recommended Physical ActivityDiscuss with your doctor the safest types and amounts of physical activity for you. You may need to avoid certain sports or activities that could worsen your condition or lead to complications. Protection From InfectionYour doctor also may discuss ways to reduce your chance of getting an infection. These include staying away from people who are ill and avoiding crowds. Washing your hands thoroughly several times a day and caring for your teeth and gums can reduce the risk of infection. For Parents of Children With Haemolytic AnaemiaParents of children with haemolytic anaemia usually want to learn as much as possible about the illness from the team treating their child. You can be an active partner in caring for your child by speaking with the health care provider team about treatment, diet, and level of physical activity. Learn to watch for signs of worsening anaemia or possible complications so you can contact your child’s doctor. It’s a good idea for parents to educate their family members, friends, and child’s classmates about the illness. You also can inform your child’s teachers or other caregivers so they know about any necessary limitations or restrictions. Family members, friends, teachers, and caregivers can provide a network of support to help your child cope with his or her anaemia. Allow teenagers to have input in decisions about their care. This encourages them to take an active role in their health care. Help them understand about lifestyle restrictions and their medical needs so they can better cope with having anaemia. Haemolytic Anaemia Key Points
Page last modified: September 2006 Source: NHLBI/NIH |
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