What Is Autoimmune Hemolytic Anemia?
Autoimmune hemolytic anemia (AHA) is a group of disorders where your immune system mistakenly destroys your own red blood cells (RBCs). These rare conditions occur when antibodies — proteins that normally protect us from viruses or other infections — attach to your own RBCs by mistake.
RBCs normally have a lifespan of around 120 days. However, when antibodies bind to RBCs by mistake, they become targets for the immune system. The immune system then destroys the RBCs before the end of their natural lifespan (also known as premature death). When this happens, your body will likely step up its production of new red blood cells. However, over time it becomes difficult for your body to keep up with the rate of destruction. Eventually the overall number of RBCs drops and this causes a shortage known as anemia.
AHA can occur suddenly or it may develop slowly over time.
The different types of AHA are classified by their cause. About half of AHA cases are idiopathic. This means that they have no known cause.
AHA sometimes occurs with an illness. Some illnesses that can cause AHA include:
- systemic lupus erythematosus (SLE, or lupus)
- infectious mononucleosis (Mono)
You can also acquire AHA after taking certain medications. Antibiotics such as penicillin and sulfonamides have been known to cause this condition.
The National Organization for Rare Disorders reports that women are more likely to develop AHA. Other factors that increase risk include:
- a family history of hemolytic anemia
- having leukemia or other cancers
- a recent viral infection
- having certain autoimmune diseases
- taking medications known to cause AHA
AHA is more common in people middle-aged and older.
Not everyone with AHA has symptoms. If you do experience symptoms, they may include:
- excessive fatigue and weakness
- pale skin
- a fast heart rate
- shortness of breath
- jaundice (yellow skin)
- dark-colored urine
- discomfort or fullness in your abdomen
- muscle pain
- diarrhea, nausea, or vomiting
To diagnose AHA, your doctor will ask questions and examine you thoroughly. They’ll likely run some tests, and will also check to see if you have an enlarged spleen.
Blood and Urine Tests
Blood tests can provide evidence that your RBCs have been destroyed. Doctors can count the number of immature or young RBCs in your blood. High numbers may show that your body increased production in an attempt to overcome your anemia.
Urine hemoglobin tests can show that RBCs are in the process of breaking down.
The direct Coombs test looks for increased levels of antibodies attached to your RBCs. It’s a test specifically designed to diagnose AHA.
A test for cold agglutinins looks for high levels of antibodies associated with infections known to cause AHA, such as Mycoplasma pneumoniae. This is a type of bacteria that can infect the lungs. It causes a pneumonia that mostly affects people under the age of 40.
The Spleen and AHA
The spleen is an essential part of your lymphatic system. This organ protects your body by clearing your old and broken-down red blood cells from your system. The spleen is behind the stomach, on the left side of your abdomen. If you have an enlarged spleen, it may mean that your body has too many worn-out or damaged RBCs.
Your doctor will check to see if you have an enlarged spleen. They can do this by physically feeling for spleen enlargement. Your doctor may also use an ultrasound to measure the size of your spleen.
If your symptoms are mild or if your condition seems to be improving, you may not need any treatment.
If you’re severely anemic, you may need a blood transfusion. However, this will only help your condition temporarily and other treatments will still be necessary.
If an underlying illness is the cause of your condition, your treatment may consist of managing that illness. If drugs are the cause, you will most likely need to stop taking them.
Steroids are often the first treatment for symptomatic anemia or anemia that’s getting worse.
If steroids fail to work, you may need to have your spleen removed surgically. The spleen is one of the main places in your body where the destruction of RBCs occurs.
Immunosuppressant medications may be necessary if spleen removal doesn’t work or is inappropriate. These drugs suppress your immune system and prevent those antibodies (proteins) from attacking your blood cells. However, immunosuppressant drugs can leave you vulnerable to infections. Some people get sick more often as a complication of this treatment. Your doctor will weigh the risks and benefits, then decide whether you should be treated with such drugs.
Some people find that AHA clears up completely and you may not even need treatment. For others, AHA is a long-term problem and it may come and go for years. Your doctor will help you to determine a treatment that will give you the best outlook.