Hematological Disorder
POLYCYTHEMIA VERA
Polycythemia Vera, or primary polycythemia, is a proliferative disorder. The bone marrow is hypercellular, and the RBC, WBC, and platelet counts in the peripheral blood are elevated. The hematocrit can exceed 60%. This phase can last for an extended period (10 years or longer). Over time, the bone marrow may become fibrotic, with inability to produce as many cells
Clinical Manifestations
Patients typically have splenomegaly (enlarged spleen). The symptoms result from the increased blood volume (headache, dizziness, tinnitus, fatigue, paresthesias, and blurred vision) or from increased blood viscosity (angina, claudication dyspnea, and thrombophlebitis), particularly if the patient has atherosclerotic blood vessels.
generalized pruritus, which may be caused by histamine release due to the increased number of basophiles.
Erythromelalgia, a burning sensation in the fingers and toes, may be reported and is only partially relieved by cooling
Assessment and Diagnostic Findings
Diagnosis is made by finding an elevated RBC mass (a nuclear medicine procedure), a normal oxygen saturation level, and an enlarged spleen. Other factors useful in establishing the diagnosis include elevated WBC and platelet counts.
The erythropoietin level is not as low as would be expected with an elevated hematocrit; it is normal or only slightly low.
Complications
Patients with polycythemia vera are at increased risk for thromboses resulting in a CVA (brain attack, stroke) or heart attack (MI); thrombotic complications are the most frequent cause of
death. Bleeding is also a complication, possibly due to the fact that the platelets (often very large) are somewhat dysfunctional.
The bleeding can be significant and can occur in the form of nosebleeds, ulcers, and frank gastrointestinal bleeding.
Medical Management
The objective of management is to reduce the high blood cell Mass :
Phlebotomy is an important part of therapy and can be performed repeatedly to keep the hematocrit within normal range.
This is achieved by removing enough blood (initially 500 mL once or twice weekly) to deplete the patient’s iron stores, thereby rendering the patient iron deficient and consequently unable to continue to manufacture RBCs excessively
Patients need to be instructed to avoid iron supplements, including those within multivitamin supplements. If the patient has an elevated uric acid concentration, allopurinol (Zyloprim) is used to prevent gout attacks.
Antihistamines are not particularly effective in controlling itching. If the patient develops ischemic symptoms, dipyridamole (eg, Persantine) is sometimes used. Radioactive.
Radiotherapy or chemotherapeutic agents can be used to suppress marrow function, but they may increase the risk for leukemia.
The use of aspirin to prevent thrombotic complications is controversial. Low dose aspirin is frequently used in patients with cardiovascular disease, but even this dose is often avoided in patients with prior bleeding, especially bleeding from the gastrointestinal tract.
Nursing Management
The nurse’s role is primarily that of educator. Risk factors for thrombotic complications should be assessed, and patients should be instructed regarding the signs and symptoms of thrombosis. Patients with a history of bleeding are usually advised to avoid aspirin and aspirin-containing medications, because these medications alter platelet function. Minimizing alcohol intake should also be emphasized to further diminish any risk for bleeding. For pruritus, the nurse may recommend bathing in tepid or cool water, along with applications of cocoa butter–based lotions and bath products.
SECONDARY POLYCYTHEMIA
Secondary polycythemia is caused by excessive production of erythropoietin. This may occur in response to a reduced amount of oxygen, which acts as a hypoxic stimulus, as in cigarette smoking, chronic obstructive pulmonary disease, or cyanotic heart disease. Secondary polycythemia can also occur from neoplasms eg, renal cell carcinoma) that stimulate erythropoietin production