This illness is characterized by significant increase in maintenance of thrombocytes, morphology and which functions are often changed that is the reason of such clinical manifestations as fibrinferments and bleedings. Most often the essential thrombocytosis strikes persons of middle and advanced age. Displays of an illness are very variable, sometimes find an essential thrombocytosis accidentally in the persons which do not have clinical symptoms. However usually the first symptoms of a disease are the spontaneous bleedings of various weight which are often arising in a digestive tract and quite often repeating within several years. Spontaneous hypodermic hemorrhages are characteristic. The thromboses affecting usually small vessels are followed by formation of peripheral ulcers and (or) gangrenes, sites of perfigeration and an eritromelalgiya. At a small number of patients the splenomegaly — sometimes very expressed and combined with a hepatomegalia is observed. Quite often there are spleen heart attacks. Hess's test usually, is negative.
Laboratory researches demonstrate increase in number of thrombocytes to 1000 — 3000·109/l, and thrombocytes are characterized by morphological and functional disturbances with which it is possible to explain a paradoxical combination of bleeding and thromboses. Level of hemoglobin and morphology of erythrocytes, as a rule, are in norm limits if only shortly before research there was no bleeding. The number of leukocytes is normal. Activity of an alkaline phosphatase of leukocytes is often increased, however the Philadelphian chromosome is absent. The bleeding time is quite often extended, but time of coagulation is in norm limits. In marrow significant increase in number and the sizes of megacaryocytes, and also a hyperplasia of erythroidal and myeloid sprouts is found.
The illness tends to a chronic current with slow increase in number of thrombocytes; at the patients who are not receiving treatment the myelofibrosis can develop. The death can be caused by bleeding, a thrombembolia or another, not connected with a basic disease reason. The purpose of treatment consists in decrease to normal amounts of number of thrombocytes for what use 32P or melfalan. It is necessary to enter a high dose 32P (370 — 444 MBK). For decrease in risk of bleedings it is necessary to treat also asymptomatic patients. At trombotichesky disturbances acetylsalicylic acid gives quite good effect.