Polycythemia (Erythrocytosis)

What sample is needed to study the cause of Polycythemia?

• EDTA blood sample is required.

How will you define Polycythemia?

1. Polycythemia is an increase in the total blood RBCs, more than the normal upper limit.
2. There is increased hemoglobin and hematocrit.
3. This is an uncontrolled proliferation of red blood cells.
   1. There is increased hemoglobin concentration above the normal upper limit.

What are the Criteria for labeling polycythemia?

1. RBCs = count increased, more than the normal upper limit.
2. PCV = Increased.
3. Hemoglobin = Increased >18 g/dL (180 g/L).
   1. Male  = 18 g/dL (170 g/L)
   2. Female  = 16 g/dL (160 g/L).
4. Hematocrit = Increased.
   1. Male = >55%
   2. Female = >50%

How would you classify Polycythemia?

1. Types of  Polycythemia. There are three types :
   1. Primary polycythemia (also known as polycythemia rubra vera).
   2. Secondary polycythemia.
   3. Relative polycythemia.
2. There is pseudopolycythemia, where red cell volume is normal, but the plasma volume is reduced.

What is the importance of Polycythemia?

1. There is hyperviscosity.
2. In primary polycythemia, there is an uncontrolled clonal proliferation of stem cells.
3. A chromosomal abnormality of the deletion of 9p or 20q was found in the minority of the cases.

Polycythemia Rubra Vera (primary)

7. The patient may have neurologic symptoms like vertigo, tinnitus, headache, and eye problems, particularly after a hot bath, and may become a severe problem.
8. Hypertension is seen in 1/3 of the patients.
9. There may be generalized pruritus.
10. The spleen may be palpable in 75% of the cases (60% to 90%). It is more common in patients with leucocytosis.
11. Hepatomegaly is less common but seen in 40% to 50% of the cases.
12. Gout may be seen due to a raised level of uric acid.
13. Peptic ulceration is seen in 5% to 10% of the patients.
14. In these patients, there is a tendency to develop peptic ulcer and gout.
15. There is a tendency to develop venous thrombosis.

How will you diagnose Polycythemia (Rubra) Vera?

1. Hemoglobin is raised.
2. Hct may be >60%.
3. Normal MCV and MCH.
4. Total red cell mass:
   1. Male >35 mL/Kg
   2. Female = >32 ml/Kg.
5. Arterial oxygenation is >92%.
6. There is an increased number of WBCs and platelets. You may see a shift to the left.
   1. A raised platelet count is seen in half of the patients.
7. Increased leucocytosis is seen in more than half of the patients, and even may see increased basophils.
   1. Increased neutrophil alkaline phosphatase score (NAP).
8. Bone marrow is hypercellular with prominent megakaryocytes.
9. The serum erythropoietin level is usually low.
10. Blood viscosity is increased.
11. Serum LDH level is normal,
12. Serum uric acid is increased in up to 40% of the cases due to the turnover of RBCs.
13. There is splenomegaly.
14. The JAK2 mutation is seen in granulocytes in almost 100% of the cases.
15. There is increased serum vitamin B₁₂ and B12-binding capacity.
16. Typical parameters for the diagnosis are:
    1. Increased RBC mass (Increased RBC and hematocrit).
    2. Leucocytosis and Thrombocytosis.
    3. Splenomegaly.

How will you treat polycythemia Rubra Ver?

1. Venesection to keep hematocrit low.
2. Cytotoxic myelosuppression by chemotherapy. Phosphorus-32 therapy is used in older patients.
3. Interferon (α-interferon) suppresses the bone marrow.
4. Aspirin prevents thrombotic complications.

What will the prognosis be for polycythemia Rubra Vera?

• Mostly, the prognosis is good, and the median survival is 10 to 16 years.
• The major complications are thrombosis and hemorrhage.
• It may progress to myelofibrosis with myeloid metaplasia in about 20% to 25%.
• 5% to 6% of the cases end up in acute leukemia.

Secondary polycythemia

1. Secondary polycythemia is true polycythemia caused by either natural or artificial increases in erythropoietin production, leading to increased RBC production.
2. RBCs count maybe 6 to 8 million (occasionally 9 million cmm).
3. Secondary polycythemia resolves when the underlying cause is treated.

What are the causes of Causes of secondary polycythemia?

• Or physiological polycythemia may be caused by:

1. High Altitude (altitude sickness).
2. Hypoxic disease.e.g., cyanotic heart and hypoxic lung disease (COPD). And chronic obstructive sleep apnea.
   1. Smoker’s polycythemia is due to the formation of the carboxyhemoglobin.
3. Idiopathic or Iatrogenic can be induced directly by phlebotomy, which can concentrate the erythrocytes.
4. Genetic abnormalities in hemoglobin oxygen release.
5. Renal diseases like cystic disease and hydronephrosis.
6. Less common causes are:
   1. Renal-cell carcinoma (1% to 5%).
   2. Liver tumors (Hepatoma = 3% to 12%).
   3. Pheochromocytoma.
   4. Adrenal adenoma with Cushing’s syndrome.
7. Anabolic steroids use (athletes abuse steroids).
8. Testosterone replacement for hypogonadism.
9. People who take erythropoietin may develop secondary polycythemia.

How will you diagnose Secondary polycythemia?

1. Increased RBC count.
2. Increased hemoglobin.
3. Increased hematocrit.
4. Normal MCV and MCH.
5. White cells and platelets are normal.

Relative polycythemia (Pseudopolycythemia)

How will you define Relative polycythemia?

1. A total normal RBC mass falsely appears to have increased due to a decrease in the plasma volume.
2. Dehydration is the most common cause.

What are the causes of Relative Polycythemia?

1. It is caused by:
   1. Stress,
   2. Smoking.
   3. Dehydration in case of water deprivation and vomiting.
   4. Plasma loss in burn and enteropathy.

What are the characteristics of Relative Polycythemia?

1. This is characterized by the following:
   1. Raised hemoglobin.
   2. Normal TLC.
   3. Normal platelets.
   4. Normal red cell mass.
   5. Decreased plasma volume.

What are the laboratory findings of Relative Polycythemia?

1. Laboratory findings are:
   1. Increased RBC count, Hb, Hct,
   2. Normal WBCs and platelets.
2. Relative polycythemia is seen in decreased plasma volume and may be seen in dehydration or hemoconcentration.

How will you treat the Polycythemia?

1. The treatment of the choice is phlebotomy.
2. Donate one point of blood until the Hct is <45%.
3. The patient should be given a low-iron diet.
4. Chemotherapy like myelosuppressive drugs may be given.

How will you summarize various Polycythemias?

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