In this article, we’ll be talking about polycythemia vera, the most common of the myeloproliferative neoplasms (MPNs). Though rare, MPNs are serious conditions that are caused by overproduction (or proliferation) of bone marrow stem cells. Recall that blood cells originate from bone marrow stem cells, so individuals with MPNs have disorders related to the quantity and quality of blood cells. There are three types of MPN:
- Essential thrombocythemia (ET): too many platelets
- Polycythemia vera (PV): overabundance of red blood cells and possibly platelets and white blood cells as well
- Myelofibrosis: fibrosis/scarring of the bone marrow with a decreased ability to produce blood cells
You can listen to the following information in episode 210 of the Straight A Nursing podcast, available from this website or wherever you get your podcasts. This episode is extra special because I get super personal telling you about my own experience with PV in addition to breaking it down using the Straight A Nursing LATTE method.
Polycythemia vera pathophysiology
Polycythemia vera occurs due to a malignant change in the DNA of a single cell in the bone marrow. Studies show that 90% of individuals with PV have a specific mutation of the JAK2 gene, which makes a protein that signals cells to proliferate and grow. This mutation causes neoplastic proliferation of the cells that become RBCs, WBCs and platelets. The result is significantly high levels of RBCs that can occur with or without elevated platelets and WBCs as well.
This overproduction of cells, namely red blood cells, can result in thrombosis. It’s important to note that hemorrhage can also occur. Though the individual with PV may have an abundance of platelets, they are often not mature enough to support the normal clotting mechanisms.
As for complications, there are many. Splenomegaly is one of the most common and is more likely to occur in men than in women. Splenomegaly puts the patient at risk for infection and splenic rupture.
Another notable and serious complication is the “spent” phase, in which the bone marrow is no longer able to produce functioning blood cells. This phase is characterized by an enlarged spleen (splenomegaly), low blood counts, and bone marrow fibrosis. Additionally, the hyperviscous blood that is present puts the patient at risk for impaired blood flow and blood clot formation. This can lead to microvascular and macrovascular infarctions, angina, and pulmonary embolism.
Additionally, hyperuricemia can occur due to the large number of RBCs being produced. This can lead to kidney stones and gout. Further, the excess histamine secretion that occurs in PV can lead to gastrointestinal problems such as peptic ulcers and epigastric distress.
Two types of polycythemia
The cause of the condition determines the type of polycythemia:
- Primary polycythemia (otherwise known as polycythemia vera) occurs due to the genetic mutation, which is typically not hereditary.
- Secondary polycythemia occurs due to chronic hypoxemia. This causes an increase in erythropoietin (EPO), which leads to the overproduction of red blood cells in an attempt to provide the tissues with adequate oxygen.
Polycythemia vera is usually seen in adult males older than 60 years, but can occur at any age. Other risk factors include the JAK2 mutation and exposure to radiation and toxic substances.
Now that you have the basic background of polycythemia vera, let’s go through it using the Straight A Nursing LATTE method:
L: How does the patient LOOK?
In other words, what are the signs and symptoms of PV?
Many times, PV is asymptomatic and many people are not diagnosed until they have a thrombotic event. Many of the symptoms are caused by poor circulation secondary to RBC and platelets impeding blood flow:
- Headache, dizziness, difficulty concentrating and visual disturbances
- Flushed complexion
- Shortness of breath when lying down
- Night sweats
- Itching after a hot shower or bath (can be severe)
- Increased bleeding tendencies such as bleeding gums, nosebleeds, hemoptysis, bruising and heavy menstrual periods
- Numbness or tingling in extremities
- Distended abdomen and feelings of fullness or early satiety due to splenomegaly
A: How do you ASSESS the patient?
Assessments for a patient with PV will generally be around recognizing thrombotic events.
- Assess neuro status and visual acuity as abnormalities can indicate neurological impairment.
- Assess the patient for cardiac dysrhythmias or even chest pain secondary to reduced blood flow to the heart
- Assess level of fatigue and impact on quality of life
- Full set of VS, paying careful attention to blood pressure (may be elevated).
T: What TESTS will be ordered for PV?
When first diagnosing PV, the MD will most likely order a CBC and EPO level. If the level of EPO is normal or lower-than-normal, this is indicative of primary polycythemia. If the EPO level is elevated, this is suggestive for secondary polycythemia.
Other tests include:
- The MD may also order genetic testing to determine if the individual has the JAK2 mutation
- A bone marrow biopsy
- Ultrasound to assess for spleen enlargement and any organ damage associated with the condition
- The individual with PV will have their blood counts routinely tested on an ongoing basis, namely looking at hbg, hct, platelets and WBCs.
- If the patient is taking a medication that impacts the liver or kidneys, then those labs will be followed as well. Expect to see LFTs, BUN and creatinine.
T: What TREATMENTS will be provided?
It is important to note there is no cure for polycythemia vera. Treatments are aimed at reducing the risk for thrombosis and managing symptoms.
For asymptomatic patients at low-risk for disease progression, the standard treatment is low-dose aspirin and phlebotomy to keep the hct below 45%.
For symptomatic patients, the recommendation is for cytoreductive therapy. Some patients may require cytoreductive therapy along with low-dose aspirin and phlebotomy.
Pharmacologic therapies are aimed at managing symptoms, reducing the risk of thrombosis, and decreasing blood cell production.
- Hydroxyurea (Hydrea) is an antineoplastic agent that reduces blood cell production. Long term use puts the patient at higher risk for developing secondary cancers. In addition to placing the patient at risk for infection, other common adverse effects are N/V, diarrhea and headache. Hydroxyurea is taken PO daily as a single dose and the patient will need to avoid exposure to sunlight by wearing protective clothing and sunscreen.
- Ruxolitinib (Jakafi), another antineoplastic medication, may be used in patients who are not able to tolerate hydoxyurea. This medication is an oral chemotherapy administered in tablet form once or twice a day. It comes with all the potential side effects you would expect from an antineoplastic agent, the key one being high risk for infection and risk for development of other cancers (namely skin cancer).
- Busulfan (Busulfex) is another antineoplastic medication that is taken PO. It has been used to treat PV for decades, but isn’t often utilized as first-line therapy due to adverse effects that include pulmonary fibrosis, leukemia and skin pigmentation.
- Low-dose aspirin is used daily to prevent thrombosis.
- Anagrelide is used to lower the platelet count, which decreases the risk of thrombosis as well as the production of immature/non-functioning platelets.
- Interferon alfa is an injectable medication given subcutaneously to reduce blood cells. It comes with a lot of potential side effects including fatigue, alopecia, pruritis, N/V and bone/muscle pain.
- Allopurinol may be utilized to decrease uric acid in the body. Uric acid can develop when blood cells turn over too rapidly, which occurs in PV.
- Antihistamines are utilized to treat pruritis, which can be severe.
Non-pharmacologic treatments include:
- Early ambulation and ROM to improve blood flow and help prevent thrombotic events.
- Lukewarm baths and routine use of skin moisturizer can reduce the severity of pruritis.
- Splenectomy may be needed due to splenomegaly. Recall that the spleen filters the blood. The high number of blood cells in PV means the spleen has to work harder than it normally would. Over time, the spleen grows larger and may need to be removed.
- Blood transfusions may be needed for individuals in the “spent phase” of PV when the bone marrow is no longer able to produce healthy blood cells.
- Phlebotomy which involves removal of blood to reduce the hemoglobin/hematocrit to safe levels. Think of it as a “reverse” blood transfusion.
E: How do you EDUCATE the patient/family?
- Teach the patient how often they should have lab studies conducted. In addition to routine CBC monitoring, some medications will require monitoring of renal and hepatic function.
- Ensure the patient understands how to take their medication. PO antineoplastics should not be handled with bare hands. The patient should wear gloves if touching the medication and then promptly dispose of them in an appropriate container.
- Teach the patient to avoid sitting cross-legged to promote venous blood flow and help prevent blood clots.
- Teach patients undergoing splenectomy to stay current on all vaccines due to their higher risk for infection.
- If your patient is having a phlebotomy, teach them to maintain adequate hydration status after the procedure and to change position slowly due to risk for orthostatic hypotension.
- Teach the patient with fatigue to try to limit napes to 20 minutes in duration so as to not disturb normal sleep patterns at night.
- To help with bathing-induced pruritis, teach the patient to avoid the use of harsh soaps and scrubbing the skin. Advise them to pat dry with a towel rather than scrubbing the skin dry. An oil-based cream and antihistamine can also help reduce pruritus.
I hope this helps you understand polycythemia vera so you can feel confident in clinical and on your nursing school exams!
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