Hemolytic anemia develops when there are not enough red blood cells because the body destroys them sooner than it should. Red blood cells carry oxygen around the body.
Autoimmune hemolytic anemia (AIHA), or immune hemolytic anemia, happens when the immune system does not work properly. It mistakes red blood cells for unwanted substances and attacks them, causing them to die early. This leaves a person without enough red blood cells.
Normally, red blood cells live in the body for 100 to 120 days. However, in severe cases of AIHA, the cells may remain only for a few days.
In children, it is a rare condition that is usually temporary. In some adults, however, AIHA can be a long-term condition that returns frequently.
AIHA can develop rapidly or over time.
AIHA can develop as a complication of an infection or virus.
Blood cells are made in the bone marrow.
There are three basic types:
- White blood cells help the body to fight off fight infections.
- Platelets help blood to clot and prevent bleeding.
- Red blood cells transport oxygen throughout the body in the form of hemoglobin.
White blood cells produce antibodies. Antibodies attach to red blood cells and travel throughout the body, fighting germs and other foreign substances that should not be there.
In AIHA, the body makes antibodies that attack the red blood cells because they think they are foreign or unwanted substances. They destroy the red blood cells, and this results in anemia.
This may happen because of:
- exposure to certain toxins or chemicals, for example in medications
- a complication of an infection
- receiving a blood transfusion when the blood does not match the individual's blood type
- an unborn baby's blood type being different from that of their mother
- some types of cancer
Types and risk factors
There are two classifications for AIHA: warm versus cold and primary versus secondary.
The warm or cold classification depends on the type of antibodies involved.
Also called warm hemolysis, this involves IgG antibodies. These bind red blood cells at 98.6°F (37°C), or normal body temperature. This accounts for 80–90 percent of cases.
Symptoms usually appear gradually, over a period of several weeks to months. Sometimes, however, they can emerge suddenly, within a few days.
- pale or yellowing skin
- heart palpitations
This is also called cold hemolysis. In this type, IgM autoantibodies, or cold agglutinins, bind red blood cells when the blood is exposed to cold temperatures, specifically 32° to 39.2°F (0° to 4°C). This accounts for 10–20 percent of cases.
Cold temperatures or a viral infection can trigger symptoms, which include:
A person with cold AIHA should keep warm because a cold environment can make symptoms worse.
- tiredness and dizziness
- pale or yellowing skin
- cold hands and feet
- pain in the chest and the backs of the legs
- vomiting or diarrhea
- pain and blue coloring in the hands and feet
- Raynaud's disease
- heart problems, such as arrhythmia, a heart murmur, an enlarged heart or heart failure
Primary or secondary AIHA
AIHA can also be primary or secondary.
- Primary AIHA is when there is no sign of any underlying condition.
- Secondary AIHA is when there is a link with another condition.
Autoimmune diseases that have or may have a link with secondary AIHA include:
- rheumatoid arthritis
- systemic erythematous lupus (SLE)
- Sjogren's syndrome
- ulcerative colitis
- thyroid disease
- Hashimoto's thyroiditis
- long-term kidney disease
- other conditions that weaken the immune system
Some common viruses may trigger AIHA. Often, the antibodies and anemia go away once the infection has gone.
Viruses that appear to have a link with AIHA include:
- mycoplasma pneumonia
- Epstein-Barr virus (EBV)
- varicella, which causes chickenpox
These viruses can trigger changes to antibodies that can lead to AIHA.
Types of drugs that, in rare cases, may trigger changes that lead to AIHA include:
A person can also inherit antibodies from their mother at birth, but this is rare.
Common symptoms of AIHA include:
- a low-grade fever
- weakness and tiredness
- difficulty thinking and concentrating
- rapid heartbeat
- shortness of breath
- yellowing skin, or jaundice
- dark urine
- muscle pains
- nausea, vomiting, and diarrhea
- lightheadedness when standing up
- difficulty breathing
- a sore tongue
- heart palpitations or a rapid heartbeat
A doctor will ask about symptoms and carry out a physical examination. They may then order some blood and urine tests to help with the diagnosis.
Complete blood count
The complete blood count (CBC) measures the different parts that make up the blood.
It includes measuring the hemoglobin and hematocrit levels.
- Hemoglobin is a protein that carries oxygen throughout the body.
- Hematocrit shows how much space red blood cells take up.
Low levels of both can be a sign of anemia.
These blood tests look for antibodies that may affect the red blood cells.
This blood test measures the levels of reticulocytes, which are slightly immature red blood cells. It can determine whether the bone marrow is creating red blood cells at a suitable rate.
The range will be higher if the body has low hemoglobin levels due to bleeding or red cell destruction. High red blood cells production can be a sign of anemia.
The liver produces bilirubin, a yellow-colored substance that is present in bile. A blood test can measure the amount of bilirubin in the blood.
When blood cells die, hemoglobin enters the bloodstream. Hemoglobin, in turn, breaks down into bilirubin. This leads to jaundice, when the eyes and skin take on a yellowish color.
High bilirubin levels in the blood can be a sign of anemia, liver damage, or another disease.
Haptoglobin is a protein that the liver produces. Within the body, it connects a specific type of hemoglobin within the blood.
The amount of haptoglobin in the blood shows how fast red blood cells are being destroyed.
Cold agglutinins test
Cold agglutinin disease is a rare type of AIHA in which symptoms become worse when a person is in temperatures between 32º and 50º Fahrenheit.
Agglutinins are antibodies that cause red blood cells to clump together. Cold agglutinins are active at cold temperatures, and warm agglutinins are active at normal body temperatures.
Determining whether there are warm or cold agglutinins can sometimes help explain why the disorder is occurring.
Warm agglutinins can occur with:
Treatment options for AIHA depend on a number of factors. If the anemia is mild, it often passes without treatment. Between 70 and 80 percent of people need no treatment or minimal intervention.
However, some people will need medication, surgery, or a blood transfusion.
Factors affecting the need for treatment include:
- the person's age, overall health, and medical history
- how severe the anemia is
- the cause of the condition
- the individual's tolerance for specific treatments
- how health providers expect the symptoms to progress
If there is an underlying cause—such as cancer, an infection, or the use of some medications—treating the condition or changing the medication may reduce the symptoms of AIHA.
A doctor may prescribe corticosteroids or cortisone-like drugs to weaken the immune response.
This is generally the first type of treatment for people with primary AIHA, and it can help to improve symptoms in many common types of AIHA.
In severe cases, and if these drugs do not work, a doctor may prescribe other drugs that suppress the immune response, known as immunosuppressive therapy.
This drug treatment helps to lower the body's immune response. The drugs help to prevent the immune system from attacking its own bone marrow. Doing so allows the marrow stem cells to grow, and this can increase red blood counts.
However, both cortisone and immunosuppressant drugs can have adverse effects.
If drug treatment is not effective, a doctor may recommend surgery.
The spleen is responsible for removing abnormal red blood cells from the bloodstream, including those with antibodies attached. Removing the spleen can enable the body to preserve those red blood cells. This can help to prevent anemia.
If symptoms are severe and other options are not effective, the person may need a blood transfusion.
AIHA in children
AIHA can occur in children. However, according to the University of Chicago, fewer than 0.2 people in every 100,000 have AIHA before the age of 20 years. The highest rates are in pre-school age children.
When AIHA occurs in children, it is usually the result of a virus or infection.
Often no treatment is necessary, and symptoms will pass without intervention. Children who need treatment will have the same treatment options as adults.
AIHA can disrupt a child's everyday routine due to tiredness and the need for ongoing medical support, including tests.
Parents and caretakers should ensure that the child:
- follows a well-balanced diet
- gets plenty of rest and fluids
- plans activities in a way that will enable the child to manage their condition
A doctor will discuss a specific treatment plan.
It is not possible to prevent some types of AIHA, but doctors can monitor people who have a viral infection or who use certain medications, to ensure that AIHA does not develop.
Severe anemia can worsen many problems, such as heart and lung disease. People should contact a doctor if they experience any symptoms that may indicate AIHA.
For people with AIHA getting a flu jab can help to prevent further complications.
If someone has AIHA, their doctor will work with them to help reduce symptoms and the chance of complications.
Tips to reduce the risk of worsening symptoms or complications include:
- avoiding people with infections or who are sick
- washing hands and brushing teeth regularly to reduce the risk of oral and other infections
- having an annual flu shot
People with cold AIHA should try to keep warm, as a cold environment can trigger the breakdown of red blood cells.
The outlook for AIHA is usually good. The condition usually lasts for a limited time.
If it occurs during the teenage years, it can become a long-term condition. However, medical treatment can help reduce the impact.