Causes

Until today, the causes of leukemia are largely unknown. However, factors are known which increase the risk of developing leukemia in children: Leukemia is not a hereditary disease in the classical sense. However, there are some hereditary diseases that play an important role in the development of the disease.

For example, it is known that children with Down syndrome (trisomy 21) have an approximately 20 times higher risk of developing leukemia. Other, rarer hereditary diseases such as neurofibromatosis type 1 or the Shwachman-Bodian-Diamond syndrome also increase the risk. In addition, genetic changes associated with acute lymphoblastic leukemia (ALL) can be found in some children.

However, these children do not necessarily develop ALL until much later. Therefore, external factors also seem to play an important role. Recent studies show that children who grow up near a nuclear power plant have a measurably higher risk of developing leukemia. Similar effects of radioactive radiation are already known from nuclear disasters, such as Hiroshima or Chernobyl. X-ray examinations of the expectant mother are just as harmful to the still unborn child.

Symptoms

Symptoms of acute leukemia usually develop within a few weeks. In chronic leukemias, however, symptoms develop much more slowly. Leukemia cells can affect not only the bone marrow but also all other organs.

The possible symptoms are therefore very broad. At the beginning of both types of leukaemia, children are often more likely to notice unspecific symptoms such as fatigue, loss of appetite or listlessness. Small children often do not want to play or walk.

The other symptoms are caused by the fact that the healthy formation of red and white blood cells and of blood platelets in the bone marrow is suppressed by the degeneration of the leukemia cells.

Often a striking paleness of their child jumps into the parents’ eyes. This can be explained by the reduced number of red blood cells (erythrocytes) (see: anaemia).
As functional white blood cells (leukocytes) decrease at the same time, the immune defence system increasingly weakens.
Children then often suffer from persistent and feverish infections.
Numerous bruises, bleeding gums or frequent nosebleeds can be an indication of a reduced number of blood platelets (thrombocytes) (see: thrombocytopenia).
If the leukemia cells migrate into bones, lymph nodes or other organs (spleen, liver), the children suffer from pain of varying severity. Many parents report their child’s abdominal pain, but also bone pain in the arms or legs.

Lymph node swelling often occurs, e.g. in the neck or groin area. Less frequent are attacks of the nervous system or the eye, which can manifest themselves as severe headaches or visual disturbances.

A special form of leukemia, T-ALL, causes an infiltration of the thymus. The thymus is a small organ in the thorax that plays an important role in the maturation of the child’s immune system. It regresses on its own in the course of young adulthood.

If the leukemia cells of a T-ALL attack the organ, the children suffer from respiratory distress. In chronic leukemias, which are less common in children than in adults, symptoms are caused by too many cells (normal blood cells and leukemia cells) in the blood. This can lead to painful vascular occlusion.

Nevertheless, the following applies: symptoms of leukemia are different in each child. Even the presence of one or more symptoms is absolutely not proof of the presence of the disease! Often comparatively harmless, more frequent diseases are hidden behind the symptoms.

Nevertheless, you should consult a doctor as soon as possible. Only then can the cause of the symptoms be found. You can find more information here: How to recognize leukemia The first step in diagnosing leukemia in children is a detailed investigation of the previous symptoms and the course of the disease (anamnesis).

If leukemia is suspected, a detailed blood test is performed. Among other things, the blood count, i.e. an overview of the individual blood cells (leukocytes, erythrocytes, thrombocytes) plays an important role here. If there are now more and more indications of leukemia in the child, the patient is referred directly to a pediatric clinic with an appropriate department (Pediatric Oncology and Hematology).

Since the bone marrow is always the point of origin of a leukemia disease, the next diagnostic step is a bone marrow puncture. In a short procedure, tiny tissue samples can be taken from the iliac crest or sternum. In newborns or infants, samples may be taken from the tibia.

Since bone marrow puncture can be stressful and painful for many children, it is performed either under general or local anesthesia. Afterwards, the bone marrow obtained in this way is subjected to a fine tissue examination and prepared for further complex examinations. In most cases, the initial assessment by microscope is performed very quickly, so that the diagnosis of leukemia can usually be made shortly after the bone marrow puncture.

In addition to the bone marrow, other organs can also be affected by the leukemia cells. Ultrasound examinations, MRI scans or a nerve fluid extraction (lumbar puncture) can provide a comprehensive overview of the progress of the disease. Leukemia can change the blood values in children in many directions.

However, the focus is often on white blood cells, also known as leukocytes. The word “leukemia”, for example, comes from ancient Greek and means “white blood”. However, the leukocyte count need not always be elevated.

If leukemia is present, the leukocytes can be decreased, normal or increased. Much more significant is the presence of immature precursor cells (which normally only occur in the bone marrow) in the blood. This means that the so-called blasts are detected in the blood.

In many children, the value of the red blood pigment (haemoglobin) drops below the normal value – this leads to anaemia. Furthermore, a drop in the blood platelets can be observed relatively often. This is called thrombocytopenia.

However, blood values play an important role not only in diagnosis but also in leukemia therapy. This is because during aggressive chemotherapy, there is not only an intended destruction of the leukemia cells, but also an unavoidable, severe impairment of the remaining blood-forming cells. Therefore, the blood values of all children undergoing therapy must be checked at very close intervals!