Autoimmune hemolytic anemia (AHA) is a group of conditions where a person’s immune system destroys their red blood cells (RBCs). These rare conditions occur when antibodies—proteins that normally protect us from viruses or other infections—attach to a person’s own RBCs by mistake.
Normally, RBCs have a lifespan of around 120 days. However, when antibodies bind to them by mistake, they become targets for the immune system. They are then destroyed before the end of their natural lifespan. When this happens, your body will probably step up its production of new red blood cells. However, it is difficult to keep up with the rate of destruction over time. Eventually the overall number of RBCs falls. This causes a shortage known as anemia.
AHA can occur suddenly. It may also develop slowly over time.
The different types of AHA are classified by their cause.
About half of AHA cases are idiopathic. This means they have no known cause.
Other times, AHA is associated with an illness. Some illnesses that can cause AHA include:
You can also acquire AHA after taking certain medications. Antibiotics such as penicillin and the sulfonamides have been known to cause this condition.
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:
- tiredness and weakness
- paler skin
- a fast heart rate
- shortness of breath
- 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. He or she will likely run one or more tests, and will also check to see if your spleen is enlarged.
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 has increased production in an attempt to overcome your anemia.
Urine hemoglobin tests can show that RBCs are being broken down.
The direct Coombs test looks for increased levels of antibodies attached to your RBCs. It is 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 part of your lymphatic system. This organ protects your body by clearing our old and broken down red blood cells from your system. The spleen is located behind the stomach, on the left side of your abdomen. If your spleen is enlarged, it may mean that your body is overloaded with worn out or damaged RBCs.
Your doctor will check to see if your spleen is enlarged. He or she can do this by physically feeling for spleen enlargement. If needed, your doctor may also use an ultrasound to measure the size of your spleen.
If you have mild symptoms, or if your condition seems to be improving, you may not need any treatment.
If you are severely anemic, you may need a blood transfusion. However, this will only help your condition temporarily. Other treatments will still be necessary.
Where an underlying illness is causing your condition, your treatment may consist of managing that illness. If drugs are the cause, you will most likely be instructed to stop taking them.
Steroids are often the first treatment for symptomatic anemia or anemia that is 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 RBCs are destroyed.
Immunosuppressant medications may be used 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.
Some people find that AHA clears up completely. It may not even need treatment. For others, AHA is a long-term problem. It may come and go for years.