Polycythaemia

Question 1

What is polycythaemia. (3)

Answer 1

It is a premalignant disorder.

It is defined as an increase in Hb, PCV and RCC.

Question 2

What are the characteristics of polycythaemia. (8)

Answer 2

Raised RCC. 
Raised PVC (haematocrit). 
Raised Hb. 
Raised haematocrit. 
Raised WBCs. 
Raised platelts. 
Low serum erythropoietin. 
Raised B12.

Question 3

Who is most affected by polycythaemia.

Answer 3

Men are more often affected than women.

Question 4

What is the mean age of onset of polycythaemia rubra vera.

Answer 4

Patients over 40.

Question 5

What are the causes of polycythaemia. (2)

Answer 5

It can be primary or secondary.

Question 6

What is a primary cause of polycythaemia.

Answer 6

Polycythaemia rubra vera.

Question 7

What are some secondary causes of polycythaemia. (2)

Answer 7

Hypoxia (eg high altitude, pulmonary disease).

Inappropriate erythropoietic secretion (eg cerebellar haemagioblastoma, renal tumours).

Question 8

What are the symptoms of polycythaemia vera. (9)

Answer 8

May be an incidental blood test finding.
Insidious onset: 
Headaches. 
Dizziness. 
Tiredness. 
Depression. 
Vertigo. 
Tinnitus. 
Visual disturbances. 
Pruritus after bathing. 
Erythromelalgia (a burning sensation in fingers and toes).

Question 9

What are the clinical signs of polycythaemia. (4)

Answer 9

Facial plethora.
Bleeding.
Splenomegaly.
Bruising.

Question 10

What is the best indicator of polycythaemia.

Answer 10

PCV.

This is because Hb may be disproportionately low in iron deficiency.

Question 11

What can polycythaemia be divided into. (2)

Answer 11

True erythrocytosis (true increase in red cell volume). 
Relative erythrocytosis (red cell volume is normal, but there is a decrease in the plasma volume).

Question 12

What are the two main causes of true erythrocytosis.

Answer 12

Primary polycythaemia.

Secondary polycythaemia.

Question 13

What is secondary polycythaemia due to. (2)

Answer 13

Due to an appropriate (hypoxic) increase in erythropoietin (high altitude, chronic lung disease, cardiovascular disease, sleep apnoea, morbid obesity, heavy smoking, increased affinity of Hb).
Due to an inappropriate increase in erythropoietin (renal disease - renal carcinoma, Wilms’ tumour; HCC, adrenal tumours, cerebellar haemangioblastoma, massive uterine leiomyoma, overadministration of erythropoietin, Chuvash polycythaemia, mutation in von Hippel-Lindau gene).

Question 14

What are the causes of primary polycythaemia. (3)

Answer 14

Polycythaemia vera.
Mutations in erythropoietin receptor.
High oxygen affinity haemoglobins.

Question 15

What is polycythaemia vera. (4)

Answer 15

A clonal stem cell disorder in which there is an alteration in the pluripotent progenitor cell leading to excessive proliferation of erythroid, myeloid and megakaryocytic progenitor cells.
It is a malignant proliferation of a clone derived from one pluripotent marrow stem cell - the erythroid progenitor offspring are unusual in not needing erythropoietin to avoid apoptosis.
There is excessive proliferation of RBCs, WBCs, and platelets, leading to hyperviscosity and thrombosis.
Commoner in those over 60.

Question 16

What is the most common gene mutation in polycythaemia vera.

Answer 16

Over 95% of patients have mutations of the gene Janus Kinase 2 (JAK2).

Question 17

What are the clinical features associated with polycythaemia vera. (6)

Answer 17

Hypertension.
Angina.
Intermittent claudication.
Tendency to bleed.
Gout (due to increased urate from RBC turnover).
Peptic ulcer disease occurs in a minority of patients.
Plethoric.

Question 18

What are the main complications of polycythaemia vera. (2)

Answer 18

Thrombosis.

Haemorrhage.

Question 19

What are the physical signs of polycythaemia vera. (5)

Answer 19

Plethoric. 
Deep dusky cyanosis. 
Injection of the conjunctivae is commonly seen. 
Splenomegaly in 70%. 
Hepatomegaly in 50%.

Question 20

What is the diagnosis criteria for polycythaemia vera. (5)

Answer 20

Major criteria: Hb >185g/L in men, 165g/L women; presence of JAK2 or other mutation.
Minor criteria: bone marrow biopsy showing hypercellularity with prominent erythroid, granulocytic and megakaryocytic proliferation; serum erythropoietin level below reference range; endogenous erythroid colony formation in vitro.

Question 21

What criteria is necessary to make a positive diagnosis of polycythaemia vera. (2)

Answer 21

Two major and one minor criteria.

One major criteria and two minor criteria.

Question 22

What percentage of cases of polycythaemia vera cases go on to develop into myelofibrosis and AML. (2)

Answer 22

30% develop into myelofibrosis.

5% develop into AML.

Question 23

What is Gaisbock’s syndrome. (2)

Answer 23

The red cell volume is normal, but as a result of a decreased plasma volume there is relative polycythaemia.
May present with cardiovascular problems (MI or cerebral ischaemia).

Question 24

Who gets Gaisbock’s syndrome. (4)

Answer 24

Middle aged men.
Smokers.
Obese.
Hypertensive.

Question 25

What is seen on a bone marrow biopsy of a patient with polycythaemia rubra vera. (2)

Answer 25

Hypercellularity with erythroid hyperplasia.

Question 26

How often should you monitor the FBC of a patient with polycythaemia rubra vera.

Answer 26

Every 3 months.