hematology

overview

The medical field of hematology - the study of blood - deals with all pathological changes in the blood, with the underlying causes as well as with the symptoms that result from them.

differentiation

The Hemato-oncology deals with the different types of blood cancer (leukemia) and related diseases such as blood disorders in the Bone marrow, as well as with malignant Lymph node changes.

The Hemostaseology treats pathological changes in the Blood clotting, being between those with Bleeding tendency (hemorrhagic diathesis) - i.e. one who has too little coagulation, and those with an excessive tendency to coagulate (Thrombophilia) - i.e. too much coagulation - is differentiated. A reduced coagulability of the blood leads to blood loss as a result of slowly stopped internal and external bleeding, which, depending on the degree of severity, can be caused by minor injuries (minor trauma) or even without external influences.

A Coagulability of the blood leads to the formation and maintenance of clots in the bloodstream (Thrombi), which can then block vessels locally or after being carried over by the bloodstream (Thromboembolism) and thus prevent the supply of the downstream tissue.

The third field of work - without a special name - is research on, diagnosis and treatment of anemia (anemia) to call. However, this is often not - as the name misleadingly suggests - a lack of blood in general, but rather an inadequate transport capacity of the blood for oxygen. Anemia is the inability of the blood to function properly despite the heart's pumping capacity lung, the body sufficiently with oxygen to supply.

Ultimately, the assessment of defense-related (immunologicalChanges in the blood, such as changes in the concentration of immune cells (Leukocytes) and Acute phase proteins, in this sub-area of ​​medical teaching and research.

In medical practice, however, a strict subdivision of these subgroups of hematology is often only useful to a limited extent, as many (frequent) diseases, such as acute and chronic blood cancers (Leukemia) can also cause anemia, changes in blood coagulability and the amount of immune cells (leukocytes) and acute phase proteins.

Symptoms

In cancerous (oncological) diseases of the blood, in addition to subtype-specific symptoms such as immunodeficiency, anemia or changes in coagulability, there are also so-called general symptoms such as fever, night sweats, weakness, weight loss and fatigue, which could also be an expression of various alternative diseases. Other symptoms such as lymph node swelling and lymph node pain after drinking alcohol in so-called Hodgkin lymphoma or bone pain and kidney damage (with its consequences) in so-called multiple myeloma are quite clear clinical pictures that put the experienced doctor on the right track very quickly.

In the case of coagulation disorders with reduced blood coagulability (hemorrhagic diathesis), a distinction is made between two sub-types. If the disease is based on a reduction in the function or number of blood platelets (thrombocytes), this manifests itself primarily in so-called thrombocytic bleeding such as pinhead bleeding of the skin (petechiae), nosebleeds (epistaxis) and a prolonged menstrual period (menorrhagia). If the problem is a lack or malfunction of the coagulation factors, so-called plasmatic bleeding such as bruises (hematoma), muscle and joint bleeding (hemarthrosis) can be expected. Depending on the severity, bleeding in the gastrointestinal tract with blood in or on the stool is possible.

In the case of coagulation disorders (thrombophilia) with increased coagulability, the symptoms arise when a clot (thrombus) clogs a vessel and the underlying tissue is then not, or only insufficiently, supplied with oxygen (and other things such as sugar). Tissue damage can also be damaged by the lack of removal of metabolic products. If the under-supplied tissue is muscle, pain and cramps are to be expected. A dragged-out clot (embolus) does more damage in the heart (myocardial infarction), brain (apoplexy) and lungs (pulmonary embolism). A clot in a larger vein, for example in the leg (leg vein thrombosis) causes swelling and pain.

Depending on the cause of anemia (anemia), numerous other symptoms are conceivable, but this itself leads to fatigue and poor concentration and muscle weakness, especially when exerted to shortness of breath (dyspnea), as well as a faster pulse (tachycardia) and can make the heartbeat noticeable ( Palpitations). In addition, anemic patients are often pale and have a tendency to cool and sometimes bluish limbs (cyanosis). Lips and tongue are also often colored in this way.

Changes in the blood, which are to be understood as a reaction of the body in the sense of an inflammatory process, can express themselves in tiredness, fatigue and fever.

causes

Haemato-oncological diseases are always based on a dysregulation in the formation and reproduction of blood cells. This dysregulation finds its molecular genetic counterpart in a genetic change (mutation), which stimulates the affected cell to pathological reproduction.This genetic change, in turn, can be caused by cancer-causing substances, radiation or an innate tendency (predisposition). The development of cancer is always a multi-stage process influenced by numerous factors. In addition to an increased tendency for cancer cells to degenerate, what is particularly necessary is an ineffective immune system that does not fulfill its task of identifying degenerating cells and removing them from circulation.

If a defense cell degenerates outside of the bone marrow (in a lymph node), one speaks of a lymph node cancer (lymphoma), which knows many subspecies. If the problem lies in the bone marrow itself, depending on the type, one speaks of blood cancer (leukemia), or of so-called myelodysplastic or myeloproliferative syndromes, which also contain many subspecies. Congenital genetic changes (mutations) are also possible, but very rare.

A distinction is made between congenital and acquired coagulation disorders. Congenital coagulation disorders are based on inherited genetic defects, the most common representatives among the plasmatic diseases (coagulopathies) are hemophilia A and B as well as the Von Willebrand-Jürgens syndrome, among the thrombocytic diseases (thyrombopathies) the very rare Bernard-Soulier syndrome and also very rare Glanzmann-Naegeli disease. Hereditary hemorrhagic telangiectasia (Osler's disease) is somewhat more common.

Acquired disorders of the plasmatic coagulation are mostly caused by a deficiency in vitamin K (often medically induced, but also due to malnutrition or absorption disorders). It is less common that the body reacts to the immune system against its own coagulation factors or is due to a lack of factors due to excessive consumption. Insufficient production (synthesis) of coagulants in a diseased liver can also explain a coagulation factor deficiency. The so-called Purpura-Schoenlein-Enoch is probably triggered by infections or medication.

Important acquired disorders of platelet coagulation are above all immune thrombocytopenia, an autoimmune disease that is directed against the body's own blood platelets, and heparin-induced thrombocytopenia, in which an immune reaction occurs during heparin therapy. A distinction is made here between two types, with type 2 being the much more dangerous. Another disease that leads to an enlarged spleen (splenomegaly) can lead to a decrease in the number of blood platelets (thrombocytes) due to complications (hyperspenism). The intake of acetylsalicylic acid (ASA, aspirin) and related substances of the group of non-steroidal anti-inflammatory drugs (NSAIDs) irreversibly limit the functionality of the blood platelets. Only new platelets that have been formed over the course of days are fully functional again.

Anemia is a disease with many possible causes. A rough distinction is made between those due to a lack of volume (after actual blood loss), a blood disorder (hemolysis) - in which red blood cells (erythrocytes), which contain the carrier protein for oxygen (hemoglobin) - are destroyed, a distribution disorder in which the red blood cells are in an enlarged spleen, and an educational disorder. A blood disorder, in turn, can either be caused by defective red blood cells or by infectious diseases, medication, autoimmune diseases, etc. An educational disorder is usually due to a deficiency (iron, folic acid or vitamin B12), but also chronic kidney failure or a cancerous disease (either directly related to the blood-forming system such as aplastic anemia, myelodysplastic syndrome or a tumor) can be the cause.

A change in the blood count in the sense of an inflammatory reaction can be triggered by an infection, an autoimmune disease, but also by a tumorous disease or injury or surgery.

Diagnosis and therapy

In addition to the conscientious implementation of a medical survey (anamnese) and examination are usually laboratory tests of the patient's blood necessary for hematological diseases. In some cases, but especially when a haemato-oncological disease is suspected, one is Bone marrow examination of necessity. For this purpose, a tissue sample is taken from the blood-forming tissue, usually from the iliac crest, under local anesthesia with a needle Bone marrow taken and examined under a microscope using various staining techniques.

Depending on the cause of the haematological disease, the type and scope of therapeutic measures vary widely. While a simple Iron deficiency anemia can usually be cured by adding iron supplements, sometimes complicated combination therapies are necessary for cancerous (oncological) diseases. So come with blood cancers (Leukemias) Above all, multidrug chemotherapy and stem cell transplantation should be considered, while lymphomas can also be treated with radiological radiation and surgery.

In general, a consistent distinction must always be made between symptomatic therapies that do nothing to address the underlying disease, and causal therapies that resolve the underlying problem. For a large number of hereditary diseases in particular, this is still not possible today, despite enormous research advances.

forecast

The prognosis also depends to a large extent on the underlying hematological disease. While some, like the Iron deficiency anemia, harmless and easy to treat, others, such as severe forms of haemato-oncological diseases, can mean significant reductions in quality and duration of life for the patient.