Pseudopolycythaemia
Overview
An acquired condition where the blood has the normal number of red blood cells but has a reduced plasma volume. It usually occurs in males with weight and blood pressure problems who smoke
Symptoms
* Tenseness * Nervousness * Conjunctival congestion * Reduced blood plasma volume * Headache * Fatigue * Weakness
Causes
In polycythemia vera, uncontrolled and rapid cellular reproduction and maturation cause proliferation or hyperplasia of all bone marrow cells (panmyelosis). The cause of such uncontrolled cellular activity is unknown but it’s probably due to a multipotential stem cell defect. Polycythemia vera usually occurs between ages 40 and 60, most commonly among males of Jewish ancestry; it seldom affects children or blacks and doesn’t appear to be familial.
Diagnosis
In addition to blood gas analysis, blood volume studies, CBC, platelet count, chemistry panel, urinalysis, and sedimentation rate, most patients should have an IVP and pulmonary function tests and a chest x-ray. A hematology consult would be wise before undertaking any of the more expensive studies.
Treatment
Phlebotomy can reduce RBC mass promptly. The frequency of phlebotomy and the amount of blood removed each time depend on the patient’s condition. Typically, 350 to 500 ml of blood can be removed every other day until the HCT is reduced to the low-normal range. After repeated phlebotomies, the patient develops iron deficiency, which stabilizes RBC production and reduces the need for phlebotomy. Pheresis permits the return of plasma to the patient, diluting the blood and reducing hypovolemic symptoms. Phlebotomy doesn’t reduce the white blood cell or platelet count and won’t control the hyperuricemia associated with marrow cell proliferation. For severe symptoms, myelosuppressive therapy may be used. Chemotherapeutic agents may be used to suppress the bone marrow, but these agents may cause leukemia and should be reserved for older patients and those with problems uncontrolled by phlebotomy. The current preferred myelosuppressive agent is hydroxyurea, which isn’t associated with leukemia. Patients who have had previous thrombotic problems should be considered for myelosuppressive therapy. The use of antiplatelet therapy is controversial because it may cause gastric bleeding. Allopurinol may be given for hyperuricemia.