an abnormally increased concentration of haemoglobin in the blood, either through reduction of plasma volume or increase in red cell numbers. It may be a primary disease of unknown cause, or a secondary condition linked to respiratory or circulatory disorder or cancer.
2. POLYCYTHEMIA
• Polycythemia is a blood disorder in which the body produces too many blood
cells as a result of a problem with the bone marrow or an increased production
of the hormone erythropoietin(EPO).
Often patients with polycythemia are detected through an incidental finding of
elevated hemoglobin or hematocrit levels.
• Concern that the hemoglobin level may be abnormally high is usually triggered
at 170 g/L (17 g/dL) for men and 150 g/L (15 g/dL)for women. Hematocrit
levels >50% in men or >45% in women may be abnormal.
7. 2.ABSOLUTE POLYCYTHEMIA
• primary polycythemia/polycythemia vera
• Polycythemia vera (PV) is a slow-growing type of blood cancer in which your bone marrow makes too many red
blood cells. Polycythemia vera may also result in production of too many of the other types of blood cells — white
blood cells and platelets.
• PV is a clonal stem cell disorder in which there is an alteration in the pluripotent progenitor cell leading to excessive
proliferation of erythroid, myeloid and megakaryocytic progenitor cells. Over 95% of patients with PV have acquired
mutations of the gene Janus Kinase 2 (JAK2) (kumar and clark’s clinical medicine).
• The JAK2 gene provides instructions for making a protein that promotes the growth and division (proliferation) of cells.
This protein is part of a signaling pathway called the JAK/STAT pathway, which transmits chemical signals from outside
the cell to the cell's nucleus. The JAK2 protein is especially important for controlling the production of blood cells from
hematopoietic stem cells. These stem cells are located within the bone marrow and have the potential to develop into red
blood cells, white blood cells, and platelets.
9. ETIOLOGY
• Mutation causes the disorder
• The problem with blood cell production associated with polycythemia vera is caused by a
change, or mutation, to DNA in a single cell in your bone marrow. In polycythemia vera,
researchers have found this mutation to be a change in a protein switch that tells the cells to
grow. Specifically it's a mutation in the protein JAK2 (the JAK2 V617F mutation). More
than 90 percent of patients with polycythemia vera, and about half of patients with other
myeloproliferative disorders, have this mutation. Doctors and researchers don't understand
the full role of this mutation and its implications for treating the disease.
• The DNA mutation that causes polycythemia vera occurs after conception — meaning that
your mother and father don't have it — so it's acquired, rather than inherited from a parent.
Researchers and doctors don't know what causes the mutation.
10. RISK FACTORS
• Some factors may increase your risk of developing polycythemia vera
• Age. Polycythemia vera is more common in adults and older than 60. It's
rare in people younger than 20.
• Sex. Polycythemia vera affects men more often than it does women.
• Family history. In some cases, polycythemia vera appears to run in families,
indicating that genetic factors other than JAK2 may contribute to the disease.
13. CLINICAL FEATURES
• Headache
• Dizziness
• Itchiness, especially following a warm bath or shower
• Redness of your skin and plethoric facial appearance
• Shortness of breath
• Breathing difficulty when you lie down
• Numbness, tingling, burning or weakness in your hands, feet, arms or legs
14. • Chest pain
• A feeling of fullness or bloating in your left upper abdomen due to an
enlarged spleen
• Fatigue
• Bleeding complications, seen in approximately 1% of patients with PV,
include epistaxis, gum bleeding, ecchymoses, and gastrointestinal (GI)
bleeding. Thrombotic complications (1%) include venous thrombosis or
thromboembolism and an increased prevalence of stroke and other arterial
thromboses.
• Abdominal pain due to peptic ulcer diseasemay be present because PV is
associated with increased histamine levels and gastric acidity or
possible Budd-Chiari syndrome (hepatic portal vein thrombosis).
• Pruritus results from increased histamine levels released from increased
basophils and mast cells and can be exacerbated by a warm bath or shower.
This occurs in up to 40% of patients with PV.
16. INVESTIGATION
• Blood tests
If a person has polycythemia vera, blood tests may reveal :
• An increase in the number of red blood cellsand, in some cases, an increase in
platelets or white blood cells.
• Elevated hematocrit measurement, the percentage of red blood cells that make
up total blood volume.
• Elevated levels of hemoglobin, the iron-rich protein in red blood cells that carries
oxygen.
17. • Lower than normal levels of oxygen in your blood.
• Very low levels of erythropoietin (EPO), a hormone that stimulates bone
marrow to produce new red blood cells, because the excess red blood cells turn off
the production of EPO by the kidneys.
• Bone marrow aspiration or biopsy: Examination of bone marrow shows that it's
producing higher than normal amounts of blood cells, it may be a sign of
polycythemia vera. If you have polycythemia vera, analysis of your bone marrow or
blood also may show the DNA change (JAK2 V617F mutation) that's associated
with the disease.
19. MEDICAL MANAGEMENT
• The objective of management is to reduce the high red blood cell mass. •
Phlebotomy is performed repeatedly to keep the hemoglobin within normal range;
iron supplements are avoided.
• •Chemotherapeutic agents are used to suppress marrow function (may increase risk
for leukemia).
• •Anagrelide (Agrylin) may be used to inhibit platelet aggregation and control the
thrombocytosis related to polycythemia.
• •Interferon alpha-2b (Intron-A) is the most effective treatment for managing the
pruritus associated with polycythemia vera.
20. • •Antihistamines may be administered to control pruritus (not very effective).
• •Allopurinol is used to prevent gouty attacks when the uric acid level is
elevated.
• Low-dose aspirin. Your doctor may recommend you take a low dose of
aspirin to reduce your risk of blood clots. Low-dose aspirin may also help
reduce burning pain in your feet or hands.
21. • Ruxolitinib (Jakafi), a JAK1/JAK2 inhibitor, was approved by the FDA in December 2014
for the treatment of patients with polycythemia vera who have had an inadequate response
to or are intolerant of hydroxyurea. Approval was based on data from the phase III
RESPONSE trial. In this trial, patients treated with ruxolitinib demonstrated superior
hematocrit control and reductions in spleen volume compared with best available therapy. A
greater proportion of patients on the ruxolitinib treatment arm achieved complete
hematologic remission (ie, hematocrit control and lowered platelet count and WBC).
Hematologic adverse reactions are prevalent with ruxolitinib (incidence >20%) and include
thrombocytopenia and anemia.[24]
• Ruxolitinib was initially approved in the United States in 2011 for patients with
intermediate- or high-risk myelofibrosis including primary myelofibrosis, post-polycythemia
vera myelofibrosis, and post–essential thrombocythemia myelofibrosis.
22. NURSING MANAGEMENT
• •Assess risk factors for thrombotic complications and teach patient to recognize signs and
symptoms of thrombosis.
• •Discourage sedentary behavior, crossing the legs, and wearing tight or restrictive clothing
(particularly stockings) to reduce the likelihood of DVT.
• •Advise patient to avoid aspirin and medications containing aspirin (if patient has a history
of bleeding).
• •Advise patient to minimize alcohol intake and avoid iron and vitamins containing iron.
•Suggest a cool or tepid bath for pruritus, along with cocoa butter–based lotions and bath
products to relieve itching.