Hematology Case Histories Case 11 Polycythemia
Basics
• A 62-year-old male complained of weakness, headache, lightheadedness, and fatigue. Upon physical examination, the following
information was available:
• Erythrocytes 8.5 million/cu mm
• Leukocytes 12,500/cu mm
• Thrombocytes 400,000/cu mm
• Hct 58%
• O2 saturation (arterial) 94%
• Serum erythropoietin Undetectable
• Erythrocytes and leukocytes were immature in the peripheral blood
smear.
• Spleen was enlarged. determined therapy of choice was phlebotomy,
• 300-500 mL every other day, until the hematocrit was <45% with the
• possibility of myelosuppressive therapy, if needed.
1. What are Erythrocytes?
Red blood cells
2. What is the normal range for red blood
cell count?
RBC (varies with altitude): Note: cells/mcl =
cells per microliter
male: 4.7 to 6.1 million cells/mcl
female: 4.2 to 5.4 million cells/mcl
3. What are leukocytes?
White blood cells
4. What is the normal white blood cell count
for leukocytes?
4,500-10,000 white blood cells/mcl (cells per
microliter)
5. What are thrombocytes?
Platlets
6. What is a normal thrombocyte count?
150,000 to 400,000/mm3
7. What is a hematocrit?
The percentage of whole blood that is
composed of RBC
8. What is a normal hematocrit?
Males: 42-50 %
Females: 36-44 %
9. what is erythropoietin?
A growth factor hormone that tells stem
cells in bone marrow to grow into RBCs.
It increases the amount of RBCs in the
blood.
10. What is a normal value for arterial
oxygen saturation?
94-100%
11. How do the patients test results compare with
normal blood test results?
The patient has more of everything
12. What are possible causes for an increased
hematocrit?
dehydration, diarrhea, burns, erythrocytosis
(excessive rbc production), or polycythemia
13. What is hypoxemia, and why can it be eliminated as a
cause?
Hypoxemia is a low oxygen content, and this person has
normal oxygen levels.
14. What are Pluripotential hemopoietic stem cells?
Precursors to blood cells
15. What does pluripotent mean?
A type of cell that can differentiate into many different types
16. What is the disorder of this individual?
The disorder of this individual is
polycythemia. Polycythemia vera is an
Abnormal increase in blood cells
(primarilyred blood cells) resulting from
excess production by the bone marrow.
17. Why are the arterial O2 saturation and
erythropoietin levels important in making this
decision?
The arterial O2 saturation and erythropoietin levels
are important in confirming that the increased
hematocrit is not due to hypoxemia or an
abnormally elevated
erythropoietin level. The O2 saturation level
would indicate if there is a physiologic
stimulus for the increased erythrocyte
production.
18. Define phlebotomy
Phlebotomy is the letting of blood for transfusion pheresis,
diagnostic testing, or experimental procedures.
19. How does phlebotomy help correct this problem?
Phlebotomy (removal of the whole blood) removes both
blood cells and plasma. The plasma volume is replaced
within days, whereas the erythrocytes take several
weeks to be replaced.
20. Define myelosuppressive therapy.
Myelosuppressive therapy is therapy for the suppression
of the bone marrow's production of blood cells and
platelets.
21. Why may myelosuppressive therapy be needed?
Myelosuppressive therapy may be needed to suppress the
erythrocyte production in the myeloid tissue if the
hematocrit continues to rise after the phlebotomies.