High RBC, high platelets, and high WBC
High RBC or high hemoglobin
Often confused with polycythemia.
Caused by burns, diarrhea, or dehydration.
Blood plasma levels are decreased, so RBC occupy a higher percentage and appear elevated, even though they are not.
High EPO Without Hypoxia
Any decrease in oxygen delivery to the kidney.
- Renal artery stenosis
- High affinity hemoglobin
- Carboxy-HGB (carbon monoxide)
High EPO With Hypoxia
Any decrease in oxygenation of arterial blood will cause an increase in EPO. Common causes include...
- High altitude
- Sleep apnea
- Chronic lung disease
- Cyanotic heart diseases
Autonomous Bone Marrow Production
Will result in a production of blood cells with a corresponding low EPO.
Bone marrow is highly active. This can be from familial forms (congenital) or can be from polycythemia vera (acquired).
Mutated in polycythemia vera.
JH2 no longer inhibits JH1, and the receptor is activated in the absence of EPO binding. This causes it to continuously produce blood cells.
A neoplasm in which the bone marrow makes too many blood cells. Caused by a JAK-2 mutation which causes the receptor to be activated, even in the absence of EPO (which is normally needed for proliferation).
Most of the health concerns occur as a result of the thicker blood.
Consequences of Erythrocytosis
- Blood viscosity increase
- Decreased blood flow which results in decreased oxygen delivery which can manifest as headache, confusion, or chest pain
- Vascular dilation which can cause redness or hemorrhage
- Significantly increased risk of thrombosis
Clinical Presentation of Polycythemia Vera
Non-specific symptoms such as headache, weakness, dizziness, sweating, gouty arthritis.
Pruritis (particularly aquagenic - feel VERY itchy after getting out of the shower)
Erythromelagia (burning in hands)
Physical Examination of PV
Facial plethora (redness)
PV Lab Features
Elevated Hct - 95%
Thrombocytosis - 60%
Leukocytosis - 40%
Hypercellular bone marrow - 90%
Low/absent iron stores in marrow - 94%
Low EPO - 95%
JAK-2 mutation - 95%
+ Phlebotomy to keep Hct < 0.45
+ Low-dose ASA
+ Hydroxyurea (if platelets >1000 or 60+ years old)
Prognosis of PV
6-18 months if untreated
13.5 years if treated