recently realized she has visual problems. There is hx of burning sensation in fingers and toes.
On exam: splenomegaly, itchy after hot bath. Labs: RBC=87, Hgb=31.9, Plt=796. What is the dx?
a. CML
b. CLL
c. Polycythemia vera
d. Myelofibrosis
e. NHL
ANSWER: C
POLYCYTHEMIA VERA
• stem cell disorder characterized by elevated RBC mass (erythrocytosis) ± increased white cell
and platelet
production
Clinical Features
• symptoms are secondary to high red cell mass and
hyperviscosity
• bleeding
complications: epistaxis, gingival bleeding, ecchymoses, and GI bleeding
-
due to platelet abnormalities
• thrombotic complications: DVT, PE, thrombophlebitis,
increased incidence of stroke, MI
-
due to increased blood viscosity, increased
platelet number and/or activity
• erythromelalgia (burning
pain in hands and feet and erythema of the skin)
-
associated with platelets >400,000/mm3
-
pathognomonic microvascular thrombotic
complication in PV and ET
• pruritus,
especially after warm bath or shower (40%)
-
due to cutaneous mast cell degranulation and
histamine release
• epigastric distress, PUD
-
due to increased histamine from tissue
basophils, alterations in gastric mucosal blood flow
-
due to increased blood viscosity
• gout (hyperuricemia)
-
due to
increased cell turnover
• characteristic physical findings
-
plethora (ruddy
complexion) of face (70%), palms
-
splenomegaly
(70%), hepatomegaly (40%)
Investigations
• Erythrocytosis
• must rule out
secondary polycythemia: increased EPO suggests autonomous production
or hypoxia, and is used to rule out PV
• diagnosis (WHO 2008) requires either both major
criteria plus one minor criteria OR the first
major criterion plus 2 minor criteria
Major Criteria
1. hemoglobin >18.5 g/dL in men, 16.5 g/dL in women or
other evidence of increased red
cell volume
2. presence of JAK2 V617F or other functionally similar
mutation such as JAK2 exon 12
mutation
Minor Criteria
1. bone marrow biopsy showing hypercellularity for age
with trilineage growth
(panmyelosis) with prominent erythroid, granulocytic, and
megakaryocytic proliferation
2. serum erythropoietin
level below the reference range for normal
3. endogenous erythroid colony formation in vitro
Treatment
• phlebotomy to keep
hematocrit <45%
• hydroxyurea (prior
thrombosis or symptoms, severe coronary artery disease, refractory to
phlebotomy)
• low-dose Aspirin® (for
antithrombotic prophylaxis, will also treat erythromelalgia)
• allopurinol: as needed
• antihistamines: as
needed
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