What is aplastic anemia?
The blood cells that keep our body running are produced in the bone marrow. There are three types of blood cells: red blood cells (erythrocytes), white blood cells (leukocytes) and blood platelets (thrombocytes). Various diseases can affect this blood formation – such as leukemia, sickle cell anemia or myelodysplastic syndrome. In aplastic anemia, those affected suffer from a deficiency of at least two of the three blood components. Depending on the extent of the granulocyte deficiency (part of the white blood cells), experts differentiate between three forms based on the blood values:
- moderate aplastic anemia
- severe aplastic anemia
- Very severe aplastic anemia
In some cases, the bone marrow produces fewer cells than normal (hypoplastic production), in others no cells at all (aplastic production). Apparently, in such cases the body’s own immune system attacks the bone marrow and prevents new cells from being formed there. The reasons for this derailment of the immune system are still a mystery to experts. In addition, radiation or chemotherapy can also trigger aplastic anemia, as can certain medications or toxins in individual cases.
Frequency and age
Aplastic anemia is very rare. It can be congenital or triggered by other diseases or toxins. In more than two thirds of cases, however, doctors are unable to find the exact cause of aplastic anemia. The disease usually becomes apparent at a young age or in young adults. In principle, however, the disease can occur at any age, especially if it is caused by other factors.
Aplastic anemia: causes and risk factors
In most cases, no direct trigger for aplastic anemia can be identified. Experts then speak of an idiopathic disease. They suspect that an incorrect reaction of the immune system is the cause of aplastic anemia. What triggers this has not yet been clarified. In around one in five to ten cases, drugs or toxins are held responsible. Drugs such as chloramphenicol or phenylbutazone and toxic substances such as benzene are suspected of impairing the formation of blood components. We also assume that viral infections can trigger aplastic anemia in some cases.
Recognized causes of aplastic anemia are
- Irradiation
- certain chemicals such as benzene, pesticides, lindane
- Viruses such as Epstein-Barr virus, cytomegalovirus, hepatitis virus or parvovirus B19
- certain medications, such as thyroid medication, anti-rheumatics or antibiotics
- Pregnancy
Symptoms: Fatigue in aplastic anemia
Many symptoms of aplastic anemia are rather general and are not immediately noticeable. If left untreated, they get worse over time. Often the symptoms can only be assigned to the disease in conjunction with a blood count. The individual symptoms depend on which specific blood components are missing.
Lack of red blood cells (anemia):
- Fatigue
- Paleness
- Weakness, especially during physical exertion
- Shortness of breath, for example when climbing stairs
- Headache
Lack of blood platelets (thrombocytopenia):
- Frequent nosebleeds and bleeding gums
- Tendency to bruises and bruising
- Small, punctiform hemorrhages in the skin (petechiae)
Lack of white blood cells (leukopenia):
- Frequent and particularly severe infections
- Tendency to fever
- Frequent fungal diseases(mycoses)
Since at least two types of blood cells are missing in aplastic anemia, various symptoms usually occur together. Even if a toxin is the cause of the disease, the symptoms often only appear weeks or even months after contact.
Aplastic anemia: Diagnosis with us
If you tell us about your typical symptoms, we will first order a complete blood count. This allows us to see immediately which blood cells are present and in what numbers, or are missing. We also have the number of reticulocytes (immature red blood cells that are formed in the bone marrow and mature in the blood) determined. If these factors indicate that too few blood cells are being produced, we perform a bone marrow biopsy. To do this, we usually remove some bone marrow from the pelvis using a hollow needle and examine it under the microscope. This allows us to rule out leukemia and other diseases.
If these factors indicate aplastic anemia, the blood is tested for possible triggers and secondary symptoms such as various viruses, bacteria and fungi. In some cases, genetic testing of the chromosomes is also useful. Since aplastic anemia is a very serious and life-threatening disease, we at the USZ should take over the therapy.
Aplastic anemia: prevention, early detection, prognosis
In most cases, you cannot prevent aplastic anemia. Good body protection or, if possible, restraint is only recommended when handling toxic substances. Particular care should be taken with benzene, which is used in the production of paints, plastics, motor gasoline, insecticides and medicines.
The first signs of aplastic anemia can be frequent infections that are more severe than in healthy people. A constantly recurring infection with fungi can also be an indication – but it also occurs with other diseases. Frequent bleeding gums or nosebleeds are often an indication of aplastic anemia.
Course and prognosis (aplastic anemia)
The earlier the disease is detected and treated, the better the chances of survival. Whereas just a few decades ago, aplastic anemia inevitably led to death, the prospects are much better today. The chances are particularly good if there is an HLA-identical sibling donor for bone marrow in the family – i.e. a brother or sister whose white blood cells are very similar to those of the person with the disease. Treatment can then lead to a cure in 80 to 90 percent of young patients.
But other patients can also lead a normal life again in the long term if the therapy works for them. The therapy involves a combination of immunosuppressive drugs and a drug to stimulate blood formation.
However, around a third of those affected suffer a relapse after successful treatment. There is also a risk of secondary diseases. For this reason, patients should have regular follow-up examinations with us. If toxins or medications are the cause of aplastic anemia, contact with these must of course be prevented or an alternative medication chosen. Then the chances are good that the blood values will normalize again after a while.
Aplastic anemia: treatment by stem cell transplantation
There are two main options available to us for the treatment of aplastic anemia: stem cell transplantation and immunosuppressive therapy.