********** Polycythemia vera (PV)...

**********

Polycythemia vera (PV) is a chronic myeloproliferative disorder characterized by means of an increased red blood enclosed space mass (RCM), or erythrocytosis, which leads to hyperviscosity and an increased risk of thrombosis. Patients may ready with complaints of pruritus after bathing, burning pains in the distal extremities (erythromelalgia), gastrointestinal disturbances, or nonspecific complaints as it was as weakness, headaches, or dizziness. Other patients are diagnosed after an incidental finding of an elevated hemoglobin and/or hematocrit flush on a complete blood count

The median age of patients diagnosed with PV is 60 years, although it can be found in persons in all age form into groupss (1) PV occurs with a slight predominance in men A comprehensive review (1) reported the incidence of PV to be 23 by 100,000 persons per year. Therefore, a typical family physician can rely upon to make a diagnosis of PV one time or twice during his or her career, and will ofttimes have at least one patient in his or her patient panel who carries the diagnosis. The seriousness of PV is underscored by way of the fact that the median survival in untreated symptomatic patients after diagnosis is six to 18 month (2) With treatment, the median survival is more than 10 years. (2)

Diagnosis

PV should be suspected when hemoglobin and/or hematocrit on a levels are elevated (i.e., hemoglobin even greater than 18 g through dL [180 g per L] in white men and 16 g through dL [160 g per L] in blacks and women; hematocrit of the same height greater than 52 percent (052) in white men and 47 percent (047) in blacks and women) (3) PV also should be suspected in patients with portal venous thrombosis and splenomegaly with or without thrombocytosis and leukocytosis. Other signs and symptoms are listed in Table 1 (14)

In making the diagnosis of PV the physician must first omit a secondary erythrocytosis. (5,6) one time a secondary cause is rul gone out (Table 2 (7)), the diagnosis of PV is made using a combination of major and minor criteria defined by the agency of the Polycythemia Vera Study clump (PVSG). Although new diagnostic modalities have been cause to growed these criteria remain the standard order to diagnose PV. (8)

Major diagnostic criteria include increased RCM normal oxygen saturation, and the port of splenomegaly. The test for RCM is a nuclear medicine contemplation involving autologous infusion of radio-labeled r vital fluid cells followed by serial phlebotomy to determine distribution. Physicians may deliver over patients to a specialty laboratory for this study

Changes to these diagnostic criteria have been propos For example, determinations of RCM classically given in milliliters by kilogram (mL per kg), can be misleading if the patient is obese, because visible form [i]or[/i] frame fat is relatively avascular. The International Council for Standardization in Haematology (ICSH) has amended the RCM assessment, recommending distribution. Physicians may give in charge patients to a specialty laboratory for this study

Changes to these diagnostic criteria have been propos For example, determinations of RCM classically given in milliliters for kilogram (mL per kg), can be misleading if the patient is obese, because corpse fat is relatively avascular. The International Council for Standardization in Haematology (ICSH) has amended the RCM assessment, recommending the use of formulas incorporating material substance surface area, weight, gender, and plasma convolution (8-10) [Level of evidence: C consensus opinion] A patient with PV could have grave oxygen saturation levels, because it is possible to have the pair PV and an unrelated hypoxic disorder. (1) Palpable splenomegaly is an important physical finding and major criterion. However, palpation is solely 58 percent sensitive for diagnosis (11) (i.e., if near it will not be ascertained by examiners in 42 percent of cases). Specificity is to a great degree better. This lack of sensitivity has l to about discussion about the use of imaging techniques to answer the question, although similar a finding by imaging might be relegated to the status of a minor criterion. (10) In addition, the minor criteria of leukocyte alkaline phosphatase (LAP) and serum vitamin [Bsub12] and [Bsub12] binding capacity may be dropp in the coming events because of inter-laboratory error regarding LAP and the unavailability of vitamin B12 binding capacity. (10) Furthermore, neither of these criteria is sensitive nor specific. (1) Nonetheless, the PVSG criteria remain the diagnostic standard.

Serum erythropoietin (EPO) bone marrow histopathology and karyotype, and the neighborhood of endogenous erythroid colonies (EEC) have been propos as diagnostic standards for PV. Because PV is an autonomous (i.e., EPO-independent) erythroid proliferation, serum EPO on a levels in PV are low or normal. (15) Low-serum EPO horizontals for PV have a sensitivity of 70 percent and a specificity of 90 percent (1)

In PV bone marrow displays characteristic histologic findings, (10) and clonal cytogenetic abnormalities can be ascertained (5) Use of this standard requires the availability of a histologist who is specially trained in marrow histology. Finally, EEC shooting is based on the ability of erythroid lonely dwellings from peripheral blood and bone marrow samples in PV to make progress in vitro without the addition of EPO (1213) This unique finding, along with serum EPO evens forms the basis for a recent diagnostic approach, (5) but has the disadvantages of cost and limited availability. (10)