Những gì là sự thật các triệu chứng là cũng đúng cho những dấu hiệu của PV, mà bây giờ thường xuyên được công nhận khi một thói quen hoàn thành số lượng máu thu được trong một bệnh nhân không có triệu chứng. Thật không may, như thể hiện trong | 286 Chapter 16 Polycythemia Vera - Clinical Aspects symptom complex that should suggest the presence of PV or its companion myeloproliferative disorder ET. In an era of improved access to medical care it is important to remember that PV patients are being recognized much earlier in the course of the disease often when they are still asymptomatic. Signs What is true for symptoms is also true for the signs of PV which is now frequently recognized when a routine complete blood count is obtained in an asymptomatic patient. Unfortunately as shown in Table more often than not simultaneous elevation of the red cell white cell and platelet counts is not found. Of course as observed by Osler and endorsed by the PVSG some patients can present with erythrocytosis and splenomegaly alone Osler 1903 . Because of a propensity to hemorrhage particularly in the gastrointestinal tract PV patients can present with a microcytosis. Microcytic er-ythrocytosis is an important diagnostic clue but can be seen with other forms of erythrocytosis and in thalassemia trait in the latter situation in the absence of iron deficiency however the red cell distribution width RDW will be normal Bessman 1977 . PV is a hyper-coagulable state and thus the disorder needs to be considered with any unexplained episode of thrombosis and particularly intra-abdominal venous thrombosis since PV is the commonest cause of hepatic vein thrombosis in the Western hemisphere Parker 1959 . In young women hepatic vein thrombosis is a frequent presenting manifestation Valla et al. 1985 . Plethora particularly of the face conjunctiva mucous membranes and hands can be striking and hypertension is another sign of the expanded red cell mass. Easy bruising epistaxis or gingival bleeding occur as a consequence of circulatory stasis or of acquired type IIa von Willebrand s disease if the platelet count is in excess of 1 000 000 pl. Splenomegaly is the most common physical finding other than plethora and is usually
