Blood disorders are common in lupus and can be very important. Hematologists, who are specialists in blood disorders, are often asked to be involved in the evaluation and treatment of patients with systemic lupus erythematosus (SLE).
The principal hematological (blood) issues of interest are:
- Anemia: low hemoglobin or red blood cells
- Thrombosis: excess blood clotting
- Blood transfusion
- Bone marrow testing
The most common blood disorder is anemia, affecting about half of all people with active lupus. Anemia can be measured and discussed in several different ways, including a low red blood cell count, low hemoglobin, or low hematocrit. Each doctor usually has a preference for using a particular term. In the most important sense, anemia means too little hemoglobin. Hemoglobin is the protein inside red cells that carries oxygen from the lungs to all the tissues of the body. Fatigue, a very common lupus symptom, is generally the first and most common symptom of anemia.
Common Causes of Anemia
Normal red blood cells live only 120 days (about four months) and must constantly be produced by the bone marrow. The commonest explanation for anemia is reduced red cell production. This may be due to inflammation; kidney problems (when the kidneys do not produce enough of the hormone, erythropoietin, that stimulates the marrow to make more red cells); iron deficiency (without which hemoglobin cannot be made—iron deficiency may result from menstrual bleeding or from intestinal bleeding due to non-steroidal anti-inflammatory drugs); or direct depression of the bone marrow by certain lupus drugs (such as azathioprine or cyclophosphamide). Intestinal bleeding can be obvious if the stool is red, maroon, or pitch black in color, but often bleeding is so slow and gradual that special stool tests are needed to detect it.$$PAGE$$
Less often, anemia is due to the premature destruction of red cells. This is called hemolytic anemia , or simply hemolysis . Sometimes, patients with hemolysis will appear slightly jaundiced, and in this situation, a yellowish tinge to the skin and eyes does not mean a liver problem. Hemolysis is most commonly due to antibodies that attach to red cells, causing the cells to be eliminated from the circulation. When coupled with thrombocytopenia (a low platelet count), this can mean a condition named thrombotic thrombocytopenic purpura (TTP for short).
Treatment of Anemia
The treatment of anemia in lupus depends on its cause. Inflammation can be reduced with drugs such as prednisone. For iron deficiency, iron given orally, such as ferrous sulfate or ferrous gluconate, is almost always effective. In the case of bleeding, the source should be determined in order to correct the problem. Erythropoietin or darbepoietin may be given to individuals with kidney problems to stimulate the bone marrow to make more red blood cells. The same may be given to patients with anemia who are taking azathioprine or cyclophosphamide. For hemolysis due to antibodies, prednisone and other drugs are often helpful, but sometimes the best treatment is splenectomy. This is an abdominal surgery to remove the spleen (which may be done laparoscopically, that is, with small incisions in the abdominal wall). The treatment of TTP is complex, requiring blood plasma exchange by machine.
Blood platelets are tiny pieces of megakaryocytes, which reside in the bone marrow. A low platelet count is termed thrombocytopenia . As the platelet count falls, bruising, tiny red bleeding points in the skin called petechiae (especially on the lower legs), nosebleeds, or other bleeding may occur. Although there are many possible causes of thrombocytopenia, in lupus it is almost always due to antibodies. A low platelet count may briefly be aggravated by infection. Whereas thrombocytopenia is common in lupus, only occasionally does serious bleeding result. On rare occasions, a person with lupus may have antibodies against both red blood cells and platelets.$$PAGE$$
Treatment of Thrombocytopenia
Most people with lupus who have mild to moderate thrombocytopenia do not need treatment. When necessary, prednisone and intravenous gammaglobulin (called IV Ig) are commonly used. Other drugs, such as azathioprine or rituximab, also can help. As in hemolysis due to antibodies, thrombocytopenia can sometimes be relieved by splenectomy. The doctor will advise whether non-steroidal anti-inflammatory drugs (NSAIDs) can be used safely when thrombocytopenia is present.
Be sure to ask your doctor whether NSAIDs can be used safely when thrombocytopenia is present.
Leukopenia and Neutropenia
White blood cells are actually made up of several different types of cells, including neutrophils (also called granulocytes), lymphocytes, and monocytes. They are involved in a person's defenses against infection. A reduction in the number of white blood cells is called leukopenia ; a particular reduction in granulocytes is called neutropenia (or granulocytopenia ).
Leukopenia and neutropenia are very common in active lupus, but rarely are white cell counts low enough to lead to infection. Counts may be lowered by azathioprine, cyclophosphamide, and some other drugs. Therefore, white cell counts are always monitored during treatment with these agents. If counts go too low, the prescribed drug is usually stopped briefly or the dosage is reduced. When infections occur in lupus, they are more often related to alterations in the body's immune system that are not reflected in routine blood counts.
The body's blood is normally in a liquid state. When a person is injured or has surgery, blood thickens and plugs up the spot that is bleeding in a process called hemostasis , also known as coagulation or clotting . Hemostasis is a normal, vital function of the body.
Sometimes in lupus, however, the processes of hemostasis are too strong, and a blood clot forms where it is not needed—or wanted. This condition is called thrombosis . It may be said that the difference between hemostasis and thrombosis is that the latter is too much of a good thing. If a thrombus , or clot, breaks off and travels elsewhere in the circulation, it is called embolus .$$PAGE$$
Thromboembolism is fortunately not common, but it is always significant. Blood clots may affect the leg veins (sometimes with embolism going to the lungs), or the arteries to the arms, legs, or brain, as well as other places in the body.
During pregnancy, blood clots can lodge in the placenta and disrupt nutrition to the fetus. A baby may be born prematurely with low birth weight, or may not survive to be delivered. Some women lose pregnancies over and over until a proper diagnosis is made and treatment given.
Most thrombosis in lupus is associated with antibodies in the blood called antiphospholipid antibodies . The two blood tests most often used to detect antiphospholipids are the anticardiolipin test and the lupus anticoagulant test . (The lupus anticoagulant has a paradoxical name, since it is not really an anticoagulant in the body—it just looks like one in the laboratory.)
Diagnosis and treatment
The best treatment is anticoagulation (blood thinning) medication, such as warfarin (Coumadin and generics). Warfarin cannot safely be used during pregnancy because of a risk of birth defects in the middle of the first trimester, and a risk of fetal bleeding in the third trimester. Thus a woman who takes warfarin must switch to the injectable anticoagulant heparin or low molecular weight heparin as soon as she is pregnant. These are safe for the fetus.
Aspirin and other anti-inflammatory drugs are not very effective antithrombic treatments when the problem is antiphospholipids. The best management of antiphospholipid pregnancy is not yet established, but often involves a combination of drugs. Careful, frequent monitoring of both mother and fetus by the obstetrician is an important part of overall care.
Everyone is concerned about the viral risk of blood transfusion. Fortunately, blood screening has become extremely effective, and the current risks of contracting HIV or hepatitis C are respectively only about 1/1,000,000 and 1/750,000 per unit transfused. All blood donations are checked; units positive for any virus are discarded. Blood testing is extremely important but remains imperfect. Thus donors' medical and social histories are reviewed to improve the screening process.$$PAGE$$
Because blood transfusions (including red blood cells, platelets, and plasma) are not absolutely safe, and because multiple units may be required in some cases, transfusion is reserved for times when the risk of not transfusing would be significant, and there isn't enough time for the patient to produce enough of his or her own blood cells or components.
Sometimes, before elective surgery, the doctor advises the patient to set aside his or her own blood for possible transfusion. Such blood is referred to as “autologous.” Blood can be donated by friends or relatives and used if the blood type is compatible, but this is not necessarily safer than blood from people one doesn't know; even one's closest friends and relations may be reluctant to reveal personal lifestyle information that affects how safe they are as donors.
Bone Marrow Testing
Blood cells are made in the bone marrow, but most blood cell problems in lupus occur after the cells leave the marrow and enter the blood stream. Thus, most hematological questions in lupus can be answered from the results of blood tests alone. Occasionally, however, a bone marrow test provides important information to help in planning treatment.
On the Internet
MedlinePlus: Drug Information
Muscular Dystrophy Association: Facts About Plasmapheresis
The Thrombosis Interest Group of Canada (French and English)
To learn more about:
- Thrombic Thrombcytopenic Purpura - TTP
- White Blood Count - WBC
- Complete Blood Count - CBC
visit MedlinePlus and type or paste the term into the search window.