icon Mneme

Polycythemia Vera

7 min read

References:

  1. Brunner & Suddarth’s Textbook of Medical-Surgical Nursing, 15th Edition, ISBN 978-197-51-6103-3, by Janice L. Hinkle, Kerry H. Cheever, and Kristen J. Overbaugh (Ch. 30, [ebook] pp. 2643–2648)

In polycythemia vera the bone marrow is hypercellular, and the erythrocyte, leukocyte, and platelet counts in the peripheral blood are often elevated. Erythrocyte elevation predominates; the hematocrit can exceed 60% in some cases. The median age at the onset is 60 years; median survival is typically 14 to 20 years.

Clinical Manifestations

Clinical manifestations are variable. Some patients may be asymptomatic at the time of diagnosis. If symptoms are present, these are often related to erythrocytosis, with or without leukocytosis and/or thrombocytosis.

  • This increase in blood cell mass increases blood viscosity leading to:
    1. Neurologic symptoms such as headache, dizziness, vision changes, and transient ischemic attacks.
    2. Abdominal symptoms such as early satiety, abdominal discomfort/pain (that can also be associated with splenomegaly).
    3. Cardiovascular symptoms including ruddy complexion, angina, claudication, dyspnea, hypertension, and thrombophlebitis.
    4. Constitutional symptoms such as fatigue and night sweats.
  • Pruritus is common due to histamine released from an increase in basophils.
  • Erythromelalgia, characterized by a burning, painful sensation, and erythema in the fingers or toes, may also occur.
  • Uric acid may be elevated as well, resulting in gout and renal stones formation.

Assessment and Diagnostic Findings

Diagnosis is based upon the evaluation of clinical symptoms and laboratory findings as well as the presence of a mutation of the JAK2 gene.

JAK2 Gene Mutation

Some patients with the JAK2 mutation who do not meet the criteria for a diagnosis of polycythemia vera are identified as having “masked polycythemia vera”. These patients are more likely to transform to myelofibrosis (discussed later) or AML and have a poorer overall rate of survival.

Assessment should include palpation of the spleen, and finding if the patient has a history of thrombotic events or has ever received a blood transfusion or medications associated with causing erythrocytosis (e.g., recombinant erythropoietin), as well as assessment of cardiovascular risk factors (e.g., obesity, smoking, and poorly controlled hypertension, diabetes, or hyperlipidemia) as these relate to thrombotic complications.

Complications

Patients with polycythemia vera are at increased risk for thromboses that may be either venous or arterial. Thrombosis can result in strokes or myocardial infarctions; thrombotic complications are the most common cause of death.

  • Patients older than 60 years of age, those with a prior history of thrombosis, or those with an elevated platelet count (exceeding 1 million/mm³) are at greater risk for developing thrombotic complications.
  • Patients with enlarged spleens are also at increased risk for thrombosis. Cardiovascular risk factors thought to increase thrombotic risk include obesity, smoking, and poorly controlled hypertension, diabetes, or hyperlipidemia.
  • Bleeding may also be a complication of polycythemia vera and its treatment. The bleeding can be significant and can occur in the form of nosebleeds, ulcers, frank GI bleeding, hematuria, or intracranial hemorrhage. If the patient with polycythemia vera has a bleeding complication and is taking aspirin, the aspirin should be held until the bleeding is resolved.

Medical Management

The objectives of management are to reduce the risk of thrombosis without increasing the risk of bleeding, reduce the risk of evolution to myelofibrosis or AML, and ameliorate symptoms associated with the disease. Specific therapy is based on an established risk stratification. Patients less than age 60 and no prior history of thrombosis are considered “low risk”; those age 60 or older, or with a history of thrombosis, or both, are considered to be “high risk”.

  1. Phlebotomy is considered the mainstay of therapy and is used to maintain the hematocrit level at less than 45%. It involves removing enough blood (initially 500 mL once or twice weekly) to reduce blood viscosity and to deplete iron stores, thereby rendering the patient iron deficient and consequently unable to continue to manufacture excessive RBCs.
  2. Low-dose aspirin prevents vascular thrombosis without increasing the risk of bleeding and is recommended for all patients with polycythemia vera, regardless of risk.
  3. Cytoreductive therapy should be considered in patients at low risk who are symptomatic due to progressive splenomegaly, leukocytosis, thrombocytosis, or have poor tolerance to phlebotomy, or whose disease has progressed to myelofibrosis or AML. In patients at high risk, cytoreductive therapy is considered first-line treatment and might be pursued in addition to or in place of phlebotomy.
    1. Hydroxyurea, also known as hydroxycarbamide, can be used to suppress bone marrow function, thereby controlling blood counts. It has also been associated with preventing thrombotic complications.
    2. Interferon-alfa is another first-line cytoreductive agent that can be selected; it is indicated in patients younger than 60 years of age, or in patients who are pregnant or intolerant of hydroxyurea. Interferon-alfa can also reduce splenomegaly, prevent thrombosis, and decrease pruritus. However, it may be difficult for patients to tolerate because of its side effects (e.g., flulike symptoms, depression); it is also very costly.
    3. Ruxolitinib is a JAK2 inhibitor; it is used in patients who are resistant or unable to tolerate hydroxyurea and for whom interferon-alfa is not indicated (e.g., patients older than 60 years of age). This drug has been shown to reduce splenomegaly, decrease symptoms, and improve quality of life. Common side effects of ruxolitinib include dose-dependent anemia and thrombocytopenia.
    4. Additional cytoreductive drugs, including busulfan, pipobroman, and anagrelide, have been shown to be effective in controlling blood counts; however, these agents have been linked to an increased risk for leukemic transformation and have significant side effects. These drugs are reserved for patients who are refractory to other cytoreductive agents or with limited life expectancy

Nursing Management

Fatigue

Fatigue is the most commonly reported symptom in patients with polycythemia vera. It is not always correlated to disease severity. The degree of fatigue may vary, but can become so debilitating that it impairs the patient’s quality of life. There are many causes of fatigue, including a release of proinflammatory cytokines (proteins produced by leukocytes that are vital to regulation of hematopoiesis, apoptosis, and immune responses), impaired hematopoiesis, depression, inactivity, and the effects of certain medications (e.g., antihypertensive medications, antihistamines). Management of fatigue can include:

  1. Pharmacologic agents: erythropoiesis-stimulating agents, antidepressant drugs, stimulants such as caffeine or amphetamines
  2. Nonpharmacologic treatments: exercise, yoga, and optimizing sleep.

Pruritus

Another common symptom in patients is pruritus, described as strong itching, stinging, or burning. The exact etiology is not known but is thought to be related to proinflammatory cytokines.

  • Pruritus can be triggered by contact with water of any temperature (including sweat after exercise). Other causes include consuming alcohol or caffeine, having dry skin, experiencing changes in temperature.
  • Antihistamines, emollient lotion, and selective serotonin reuptake inhibitors (SSRIs) are not particularly effective in controlling pruritus.
  • Interferon-alfa and narrow band ultraviolet B phototherapy (which uses ultraviolet light for a prescribed length of time to decrease symptoms) may be used in severe cases.

As the efficacy of pharmacologic strategies may not be optimal, it is important to individualize therapy and monitor for effectiveness. The nurse may recommend bathing in tepid water, avoiding vigorous toweling off after bathing, and using cocoa butter or oatmeal-based lotions.

Thrombosis

Potentially life-threatening complications from the disease are thrombosis or hemorrhage.

  1. Assess: Risk factors for thrombotic complications, particularly a prior history of thrombosis, smoking, obesity, and poorly controlled hypertension, diabetes, and hyperlipidemia should be assessed, and patients should be encouraged to modify their cardiovascular risk factors.
  2. Adopting or maintaining a healthy lifestyle should be encouraged.
  3. Patients should be educated about the signs and symptoms of thrombosis.
  4. To reduce the likelihood of deep vein thrombosis (DVT), sedentary behavior, crossing the legs, and wearing tight or restrictive clothing (particularly stockings) should be discouraged.

Bleeding

  1. Patients with a history of significant bleeding are usually advised to avoid high-dose aspirin and aspirin-containing medications, because these medications alter platelet function.
  2. Minimizing alcohol intake should also be emphasized to further diminish the risk of bleeding.
  3. Patients should be counseled about the signs of bleeding.
  4. The patient needs to be instructed to avoid iron supplements, including those in over-the-counter multivitamin supplements, because the iron can further stimulate RBC production.

Graph View

Backlinks