Approach to polycythemia dr bikal

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1. Dr Bikal Lamichhane 1 st yr resident,IM NAMS Approach to polycythemia

2. INTRODUCTION Polycythemia ( erythrocytosis ) is an abnormal elevation of hemoglobin ( Hb ) and/or hematocrit ( Hct ) in peripheral blood . Increased hemoglobin:  >16.5 g/ dL (10.3 mmol /L) in men or >16.0 g/ dL (10.0 mmol /L) in women. Increased hematocrit :  >49 percent in men or >48 percent in women

3. Relative polycythemia   Hemoconcentration , or an elevation of Hb and/or Hct due to a decrease in plasma volume alone ( ie , without an increase of the RBC mass) is referred to as relative polycythemia . The most common reasons for plasma volume depletion are diuretic use, vomiting, or diarrhea

4. Absolute polycythemia    Absolute polycythemia refers to an increase of RBC mass, which has multiple causes and can be categorized as either primary or secondary polycythemia . Primary polycythemia  – Primary polycythemia refers to an increase of RBC mass caused by a mutation (either acquired or inherited) in RBC progenitor cells. Secondary polycythemia  – Secondary polycythemia refers to an increase of RBC mass caused by elevated serum erythropoietin (EPO ).  

5. INITIAL EVALUATION Polycythemia may be encountered in the course of evaluating other clinical findings or as an incidental abnormality on a complete blood count (CBC) and differential. Distinguish between relative polycythemia ( ie , plasma volume depletion) versus absolute polycythemia ( ie , increased red blood cell [RBC] mass ). Urgency of evaluation  — Patients with medical emergencies related to polycythemia ( eg , cerebrovascular accident, chest pain) should receive emergency management 

6. History  —  Symptoms that may be caused by the elevated Hb / Hct and/or suggest the presence of PV/MPN include Hyperviscosity symptoms:  Chest or abdominal pain, myalgia and weakness, fatigue, headache, blurred vision, transient loss of vision, paresthesias , slow mentation , and/or a sense of depersonalization Thrombosis or bleeding:  Thromboses at unusual sites ( eg , mesenteric, hepatic, portal, or retinal veins; arterial thromboses) or excessive bleeding/bruising Symptoms associated with PV:  Unexplained fever, sweats, weight loss; pruritus (especially after bathing); erythromelalgia (intense, burning pain and/or redness of the extremities); gout; early satiety due to splenomegaly

7. C lues to the underlying disorder:- Volume depletion : Use of diuretics, vomiting, diarrhea, anorexia, lightheadedness, and/or orthostatic symptoms. Cardio-pulmonary disease : Chronic lung disease, dyspnea at rest or with exertion, chronic cough; sleep apnea/ hypersomnolence ; history of cyanotic heart disease, extensive mucocutaneous telangiectasia ( eg , from hereditary hemorrhagic telangiectasia . Abdomino -pelvic tumor : Unexpected weight loss, hematuria , abdominal/pelvic pain or fullness (which may point to an intra-abdominal EPO-secreting tumor), history of renal transplantation 

8. Social history should evaluate :- Cigarette or cigar smoking, including the number smoked and whether the patient inhales Exposure to carbon monoxide (CO) from smoking, work ( eg , engine exhausts or combustion products, work in underground parking lots or tunnels, employment as an auto mechanic, truck or taxicab driver ) Use of products to improve athletic performance, including androgens ( eg , testosterone) or anabolic steroids, self-injection of recombinant erythropoiesis -stimulating agents ( eg ,  epoetin alfa ), or transfusion of stored autologous blood

9. Family history   should examine whether relatives have polycythemic conditions ( eg , high oxygen affinity hemoglobinopathies ) or documented elevation of Hb or Hct , or other hematologic or systemic syndromes.

10. Physical examination  —  General examination Cyanosis in the lips, earlobes and fingers, and clubbing in the nailbeds associated with hypoxia. Plethoric facies , dilated lingual or retinal veins, or areas of painful erythema may be seen in patients with PV. Cardiopulmonary  –  Breathing pattern, other respiratory findings, cardiac murmurs or bruits ( eg , from pulmonary arteriovenous shunts or right-to-left cardiac shunts ).   Organomegaly  – Hepatomegaly and/or splenomegaly (from PV or another MPN) or other masses that may be associated with or an EPO-secreting tumor

11. Laboratory testing   —   CBC/blood smear  — CBC and differential count may demonstrate abnormalities in RBCs alone, or may also reveal findings in white blood cells (WBC) and/or platelets. Increased hemoglobin:  >16.5 g/ dL in men or >16.0 g/ dL in women. Increased hematocrit :  >49 percent in men or >48 percent in women. Elevation of RBC count alone ( ie , not accompanied by increased Hb or Hct ) is not a criterion for polycythemia

12. Pulse oximetry  : estimate of tissue oxygenation. Pulse oximetry should be performed at rest and after modest exertion. Hypoxia may suggest the presence of cardiopulmonary disease or other processes as the cause of polycythemia , which should be further evaluated as described. Serum erythropoietin (EPO)  — obtaining serum EPO for all patients, except when the initial evaluation indicates that the elevation of Hb / Hct is due to volume contraction alone ( ie , relative polycythemia ). Important for distinguishing between primary (low or absent EPO) and secondary causes of polycythemia (elevated EPO)  

13. Other screening labs  — Other laboratory studies that are useful in the initial evaluation of patients with polycythemia include:- Serum chemistries  – Serum electrolytes and kidney and liver function tests can indicate volume contraction or organ dysfunction that may be associated with renal disease or an underlying tumor . urinalysis  – Hematuria may point to a kidney tumor or other renal abnormalities.

14. JAK2 testing/bone marrow exam  :- Patients with clinical findings from the history and physical examination that suggest PV or other MPN ( eg , pruritus , erythromelalgia , arterial or venous thrombosis, unexplained bleeding/excessive bruising)  . patients with low or normal serum EPO and no evidence of volume contraction ( ie , relative polycythemia )

15. A n increased red cell mass using the principle of isotope dilution by administering 51Cr-labeled autologous red blood cells to the patient and sampling blood radioactivity over a 2-h period. If the red cell mass is normal (<36 mL /kg in men, <32 mL /kg in women), the patient has spurious or relative polycythemia . If the red cell mass is increased (>36 mL /kg in men, >32 mL /kg in women), serum EPO levels should be measured

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