According to definition, the neutropenia is a decrease in total number of neutrophils to level less than 1,5*109/l. The term "agranulocytosis" is often used for designation of suddenly arisen deep neutropenia. At this disease, as well as at a pancytopenia, there are a lot of reasons, and only some of them are internal in relation to marrow. The neutropenia can develop owing to as reduced products of cells in marrow (as a result of a hypoplasia of a granulotsitarny sprout or an inefficient granulopoiesis), and the accelerated loss of cells from blood. Such loss can be in turn caused by immune or not immune processes. In certain cases the chronic neutropenia is probably caused by dysfunction of T lymphocytes. The neutropenia and tranzitorny thrombocytopenia are often connected with viral infections less often — with bacterial and rickettsial.
The reduced granulopoiesis is characteristic of a chronic hypoplasia of marrow, but can meet and as the isolated cytopenia at a tumoral infiltration of marrow and after use of cytotoxic drugs. Thus, marrowy insufficiency leads to reduced products of granulocytes, and at the same time there is also exhaustion of granulotsitarny pools of an organism — deposited and circulating (in a spleen and a blood channel). In such cases life expectancy of neutrophils is not broken though occasionally in blood unripe cells can appear. Products of granulocytes can be lowered at some constitutional and acquired diseases which manage to be diagnosed only in later period of life. Carry a cyclic neutropenia, a so-called high-quality family neutropenia, a chronic hypoplastic neutropenia and a chronic idiopathic neutropenia to number of such syndromes.
The Neytropenichesky syndrome which is especially often found in Blacks of West Indies is caused by rather broken delay of granulocytes in the deposited pool, but not decrease in their development. Such "pseudo-neutropenia" does not lead to decrease in lump of granulocytes in an organism, and at patients in response to an infection the adequate neutrophylic leukocytosis develops. Clinical manifestations of many of these syndromes are poorly expressed.
It is considered that those medicines which cause an erythrocyte aplasia can be also the cause of a neutropenia. It is unclear, why one and too medicine in one person causes a pancytopenia, and in another — the isolated cytopenia. In addition to cytotoxic to the drugs, antimetabolites and drugs causing the hidden injuries of marrow the separate group of substances which quite often are the reason of a neutropenia is identified. Can be an example fenotiazin which quite often causes a neutropenia in patients of insane hospitals. This drug breaks synthesis of DNA only at some patients, and weight of a neutropenia corresponds to the general dose of medicine. Also some tireostatik, anticonvulsants and antibiotics, including penicillin and other beta lactams belong to drugs of this group.
Penicillin causes a neutropenia only in high doses, and it is caused by maturing disturbance, but not a hypoplasia, and is reversible. In this case the neutropenia is caused by genetically determined metabolic defect and often develops gradually. More acute beginning of an agranulocytosis is caused most likely by immunologic mechanisms.
Treatment of a neutropenia
Treatment depends on weight of a clinical picture. The susceptibility to an infection increases when falling number of granulocytes lower than 1·109/l and sharply increases at decrease in this indicator lower than the level 0,5·109/l; the exception is made by the listed above high-quality neytropenichesky syndromes. The acute agranulocytosis is among the medical medical emergencies demanding intensive treatment. At less heavy neutropenia the caused insufficiency of marrow, it is necessary to identify the reason, for example influence of medicine or immunological disturbances, and already then to appoint treatment. Research of marrow allows to distinguish a granulocytopoiesis hypoplasia from maturing disturbance. The last most often is caused by a chronic immunospecific injury; the autoimmune neutropenia is recognized as separate nosological unit. The short course of corticosteroids is shown to patients of this group. Attempts to use a plasma exchange were made, and in some cases it was reported about very good effect of this method. Sometimes the splenectomy gives a certain effect. For treatment of chronic hypoplastic neutropenias it was offered to use lithium salts, however such attempts yielded the disappointing results; besides, the risk of toxic action on kidneys forces to control attentively drug level in plasma.