Immune hemolytic anemia
Anemia - immune hemolytic; Autoimmune hemolytic anemia (AIHA)
Anemia is a condition in which the body does not have enough healthy red blood cells. Red blood cells provide oxygen to the body's tissues.
Red blood cells last for about 120 days before the body gets rid of them. In hemolytic anemia, red blood cells in the blood are destroyed earlier than normal.
Immune hemolytic anemia occurs when antibodies form against the body's own red blood cells and destroy them. This happens because the immune system mistakenly recognizes these blood cells as foreign.
Antigens are large molecules (usually proteins) on the surface of cells, viruses, fungi, bacteria, and some non-living substances such as toxins, chemicals, drugs, and foreign particles. The immune system recognizes antigens and produces antibodies that destroy substances containing antigens.
Causes
Possible causes include:
- Certain chemicals, drugs, and toxins
- Infections
- Transfusion of blood from a donor with a blood type that does not match
- Certain cancers
When antibodies form against red blood cells for no reason, the condition is called idiopathic autoimmune hemolytic anemia.
The antibodies may also be caused by:
- Complication of another disease
- Past blood transfusions
- Pregnancy (if the baby's blood type is different from the mother's)
Risk factors are related to the causes.
Do you feel tired and listless? Do you find your mind drifting during the day? Do you get dizzy or short of breath whenever you climb the stairs? There are a few possible reasons for the way you feel, but you could have anemia. You could even have anemia without noticing any symptoms at all. Anemia is a problem with hemoglobin, a substance in red blood cells that carries oxygen throughout your body. Without enough hemoglobin, your heart and other organs can't get the oxygen they need to work. When your organs slow down, you slow down and you start feeling tired and listless. Many different health conditions can cause anemia, from heavy blood loss during a woman's period, to pregnancy, to an underactive thyroid gland. Healthy red blood cells are made in your bone marrow, the soft tissue in the middle of your bones. Any disease that damages blood marrow, such as lymphoma or leukemia, can also affect your red blood cell production. Anemia can also be caused by an immune system problem that damages red blood cells, or surgery to the stomach or intestines. How do you know if you have anemia? You may feel tired, dizzy, and have trouble concentrating. You may get sick more often. People with anemia often complain of chest pain, headaches, or shortness of breath. Your skin might look pale, like you haven't seen the sun for months. Because these can also be symptoms of other conditions, your doctor will confirm that you have anemia by taking a blood test to check your red blood cell count and hemoglobin level. Blood tests can also look for problems that may be causing your anemia, such as a vitamin or iron deficiency. If you are anemic, it's very important to treat it. When your body isn't getting enough oxygen, it can starve vital organs like your heart. This can lead to a heart attack. How you treat anemia really depends on the cause. If the problem is with your bone marrow, you may take a medicine called erythropoietin, which will help your bone marrow make more red blood cells. If the problem is a vitamin or mineral deficiency, your doctor may prescribe iron, vitamin B12, or folic acid supplements. Or, you may need a blood transfusion to replace damaged red blood cells with healthy ones. How well you do really depends on what's causing your anemia. Call your doctor if you have any symptoms like fatigue or shortness of breath. Once your doctor can find and treat the cause of your anemia, you should have more energy and start feeling like your old self again.
Symptoms
You may not have symptoms if the anemia is mild. If the problem develops slowly, symptoms that may occur first include:
- Feeling weak or tired more often than usual, or with exercise
- Headaches
- Problems concentrating or thinking
If the anemia gets worse, symptoms may include:
- Lightheadedness when you stand up
- Pale skin color (pallor)
- Shortness of breath
- Sore tongue
Exams and Tests
You may need the following tests:
- Absolute reticulocyte count
- Direct or indirect Coombs test
- Hemoglobin in the urine
- LDH (level of this enzyme rises as a result of tissue damage)
- Red blood cell count (RBC), hemoglobin, and hematocrit
- Serum bilirubin level
- Serum haptoglobin
- Donath-Landsteiner test
- Cold agglutinins
- Platelet count
- Protein electrophoresis - serum
- Pyruvate kinase
Treatment
The first treatment tried is most often a steroid medicine, such as prednisone. If steroid medicine do not improve the condition, treatment with intravenous immunoglobulin (IVIG) or removal of the spleen (splenectomy) may be considered.
You may receive treatment to suppress your immune system if you do not respond to steroids. Drugs such as azathioprine (Imuran), cyclophosphamide (Cytoxan), and rituximab (Rituxan) have been used.
Blood transfusions are given with caution, because the blood may not be compatible and it may cause more red blood cell destruction.
Outlook (Prognosis)
The disease may start quickly and be very serious, or it may stay mild and not need special treatment.
In most people, steroids or splenectomy can totally or partially control anemia.
Possible Complications
Severe anemia rarely leads to death. Severe infection may occur as a complication of treatment with steroids, other medicines that suppress the immune system, or splenectomy. These treatments impair the body's ability to fight infection.
When to Contact a Medical Professional
Contact your health care provider if you have unexplained fatigue or chest pain, or signs of infection.
Prevention
Screening for antibodies in donated blood and in the recipient may prevent hemolytic anemia related to blood transfusions.
References
Michel M. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 151.
Michel M, Jäger U. Autoimmune hemolytic anemia. In: Hoffman R, Benz EJ, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 7th ed. Philadelphia, PA: Elsevier; 2018:chap 46.
Wong E, Rose MG, Berliner N. Disorders of red blood cells. In: Wing EJ, Schiffman FJ, eds. Cecil Essentials of Medicine. 10th ed. Philadelphia, PA: Elsevier; 2022:chap 48.
Version Info
Last reviewed on: 1/25/2022
Reviewed by: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
