polycythemia Flashcards
what is polycythemia?
over production In RBC’s
what are the two types of polycythemia?
relative and absolute
what is the cause of relative polycythemia?
dehydration
-fluid loss is relative to an increase in RBC, hemoglobin and hematocrit
how do you resolve relative polycythemia?
fluid intake
what are the kinds of absolute polycythemia?
primary and secondary
what causes primary polycythemia?
the abnormal regulation of the multipotent hematopoietic steam cells
what is polycythemia vera independent from?
EPO
what is indirect cause of secondary polycythemia?
increase of EPO as normal response to chronic hypoxia
(inappropriate response to EPO-secreting hormones)
what are the direct causes the secondary polycythemia?
- tissue hypoxia
(COPD, high elevations, smoking, heart disease) - autonomous EPO production
-2 tumors (hepatoma, ovarian carcinoma)
what is polycythemia vera classified as?
chronic neoplastic nonmalignant conditon
what does polycythemia have an increase in what cells?
RBC, frequently associated with WBC and platelets
what can polycythemia develop into?
leukemia
what are the symptoms of polycythemia vera?
- splenomegaly-abdominal pain and discomfort
- intense painful itching that intensifies with exposure of heat or o2 (cause by increase in mast cells)
what are the symptoms of polycythemia vera as the disease progresses?
increase in bp
redness in color
thrombosis (blood clots in vessels due to increase in platelets)
what does EPO transduce the signal through?
the JAK-STAT pathway
why was JAK-2 then called the janus enzyme?
JAK2 is in pseudokinase.
Janus kinases after the Roman God of gates and passages. These non receptor kinases have two similar ‘active’ and ‘inactive’ domains and this is reminiscent of the God Janus who had the ability to look simultaneously in two directions
what does JAK1do?
signal pro-inflammatory cytokines (IL1,IL6,TNF)
what does JAK2 do?
important for hematopoietic growth factor-signal for EPO
what does JAK3 do?
mediates the immune response
what point mutation happens in JAK2 (base pair change) causing PV?
valine-fenialine
what are the treatments for PV?
phelb-withdraw 300-500mL
low dose aspirin
interferon A-inhibtis growth
Hydroxyurea-block DNA synthesis
