Updated: 10/16/2017

Polycythemia Vera

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Snapshot
  • A 59-year-old woman presents to her primary care physician with overwhelming fatigue, headaches, and some blurry vision. She is worried that old age is finally catching up. While she is happy about losing 10 lbs over the past month, she is also confused since she has not changed her diet or exercise routine. On further questioning, she reveals that she is extremely itchy after a hot bath or shower. She is otherwise healthy. A blood smear shows RBC precursors.
Introduction
  • Myeloproliferative neoplasm characterized by increased production of RBCs
    • leads to highly viscous blood
  • Epidemiology
    • presentation in those aged 60-70
  • Pathogenesis
    • mutations in JAK2 (Janus kinase) 
      • V617F mutation
      • constitutively active Janus kinase unregulated myeloproliferation
    • erythrocytosis ↑ blood viscosity
    • leukocytosis
    • thrombocytosis
  • Associated conditions
    • risk of progression to myelofibrosis or leukemia
    • Budd-Chiari syndrome 
      • caused by occlusion of IVC or hepatic veins leading to congestive liver disease
  • Prognosis
    • 1.6x higher mortality than general population
Presentation
  • Symptoms
    • headaches
    • visual disturbance
    • bleeding
      • caused by engorged vessels
    • constitutional symptoms
      • fatigue
      • night sweats
      • weight loss
      • fever
      • malaise
    • pruritus
      • caused by histamine release from increased basophils
      • often triggered by hot shower or bath
  • Physical exam
    • erythromelalgia (rare but classic)  
      • caused by thrombosis
      • characterized by painful burning sensation with increased temperatures in digits and episodic blood clots in extremities
    • hepatosplenomegaly
    • bruising
    • ischemic digits
    • large retinal veins on funduscopy
Evaluation
  • Labs
    • complete blood count with smear will show
      • ↑ hemoglobin > 16 g/dL (females) or > 16.5 g/dL (males)
      • ↑ hct > 48% (F) or > 49% (M)
    • JAK2 mutation in peripheral blood
    • ↓ serum EPO 
      • ↑ RBC despite low EPO
      • if EPO is high, consider ectopic EPO production (e.g., in renal cell carcinoma)
    • ↓ MCV
    • SaO2 normal
  • Bone marrow biopsy 
    • shows hypercellularity and prominent proliferation of all cell lines
      • commonly see precursor cells
    • used to confirm diagnosis
    • used as a baseline for assessing disease progression
Differential Diagnosis
  • Secondary polycythemia
  • Tumor-driven polycythemia
  • Other myeloproliferative neoplasm
Treatment
  • Reduce risk of thrombosis
    • low-dose aspirin
    • phlebotomy
      • indicated for a hematocrit < 45%
  • Myelosuppression
    • hydroxyurea
  • Gout prophylaxis
    • allopurinol
Complications
  • Thrombosis
    • leading cause of morbidity and mortality
  • Peptic ulcers
    • increased histamine release from basophils
  • Gout
    • increased uric acid from high number of cell turnover
  • Progression to
    • myelofibrosis 
    • CML 
    • AML 
 

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Questions (3)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M1.ON.4798) A 66-year-old male with a history of diabetes and knee osteoarthritis presents to his primary care provider in July complaining of headaches and blurry vision. He reports a 6-month history of occasional dull diffuse headaches and blurry vision. He notes that the episodes have increased in severity since the weather got warmer and that he occasionally feels extremely itchy when he spends time outdoors. The patient lives in southern Arizona. Moreover, he has felt chronically fatigued and has lost 10 pounds without dieting or changing his appetite. He currently takes metformin and his most recent hemoglobin A1c was 6.5%. Physical examination reveals multiple bruises on the bilateral upper and lower extremities and hepatosplenomegaly. Fundoscopic examination demonstrates enlarged retinal veins. Multiple laboratory tests are pending. At steady state, which of the following sets of findings is most likely in this patient? Review Topic

QID: 109194
1

Increased plasma volume, increased RBC mass, decreased EPO, normal SaO2

43%

(36/83)

2

Normal plasma volume, increased RBC mass, increased EPO, normal SaO2

19%

(16/83)

3

Decreased plasma volume, normal RBC mass, normal EPO, normal SaO2

12%

(10/83)

4

Normal plasma volume, increased RBC mass, increased EPO, decreased SaO2

18%

(15/83)

5

Increased plasma volume, decreased RBC mass, decreased EPO, normal SaO2

4%

(3/83)

M1

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PREFERRED RESPONSE 1

(M1.ON.75) A 56-year-old man presents to his primary care physician endorsing fatigue, episodic pruritus, and headaches. These symptoms have been occurring for the last 1-2 months but have gotten progressively worse over time. His wife has noticed a new "ruddy" color to his skin that has developed during this period. He is otherwise healthy, with no medical problems. On examination, the patient appears fatigued and plethoric. A complete blood cell count reveals a hematocrit of 59% with no other abnormalities. A peripheral blood smear is shown in Figure A. Mutation in which of the following genes is responsible for the patient's condition? Review Topic

QID: 106754
FIGURES:
1

BCR-ABL

9%

(9/99)

2

RET

6%

(6/99)

3

p53

8%

(8/99)

4

JAK2

74%

(73/99)

5

FLT3

1%

(1/99)

M1

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PREFERRED RESPONSE 4
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