Polycythaemia

Question 1

Define Polycythaemia?

Answer 1

An increase in haemoglobin concentration above the upper limit of normal for a person’s age and sex

Question 2

How is Polycythaemia classified?

Answer 2

Relative Polycythaemia = Normal red cell mass but low plasma volume
Absolute (True) Polycythaemia = increased red cell mass

Question 3

What is the aetiology of Polycythaemia Rubra Vera?

Answer 3

Characterised by clonal proliferation of myeloid cells
They have varied morphologic maturity and haematopoietic efficiency
Mutations in JAK2 tyrosine kinase are involved

Question 4

What are the two types of Secondary Polycythaemia?

Answer 4

Appropriate increase in erythropoietin

Inappropriate inrease in erythropoietin

Question 5

What is the aetiology of Secondary Polycythaemia where there is an Appropriate increase in erythropoietin?

Answer 5

Due to chronic hypoxia (e.g. chronic lung disease, living at high altitude)
This leads to upregulation of erythropoiesis

Question 6

What are the causes of Secondary Polycythaemia where there is an Inappropriate increase in erythropoietin?

Answer 6

Renal (carcinoma, cysts, hydronephrosis)
Hepatocellular carcinoma 
Fibroids 
Cerebellar Haemangioblastoma 
Secondary polycythaemia may be due to erythropoietin abuse by athletes

Question 7

What is the aetiology of Relative Polycythaemia?

Answer 7

Dehydration (e.g. diuretics, burns, enteropathy)

Gaisbock’s Syndrome

Question 8

What is Gaisbock’s Syndrome?

Answer 8

Occurs in young male smokers with hypertension, which results in a decrease in plasma volume and an apparent increase in red cell count

Question 9

What is the epidemiology of Polycythaemia?

Answer 9

Annual UK incidence: 1.5/100,000

Peak age: 45-60 years

Question 10

What are the presenting symptoms of Polycythaemia?

Answer 10

Headaches
Dyspnoea 
Tinnitus 
Blurred Vision 
Pruritis after hot bath 
Night Sweats 
Thrombosis (DVT, Stroke)
Pain from peptic ulcer disease 
Angina 
Gout 
Choreiform movements

Question 11

What are the signs of Polycythaemia on physical examination?

Answer 11

Plethoric complexion (red, ruddy)
Scratch marks from itching
Conjuctival suffusion (redness of the conjuctiva)
Retinal venous engorgement
Hypertension
Splenomegaly (in 75% of cases)
Signs of underlying aetiology in secondary polycythaemia

Question 12

What investigations do we do for general Polycythaemia?

Answer 12

Investigations required for diagnosis

Isotope Dilution Techniques

Question 13

What investigation do we do for diagnosis of Polycythaemia and what do we see?

Answer 13

FBC:

• High Hb
• High Haematocrit
• Low MCV

Question 14

What are Isotope Dilution Techniques and why do we do it for Polycythaemia?

Answer 14

Allows confirmation of plasma volume and red cell mass

Distinguishes between relative and absolute polycythaemia

Question 15

What investigations do we do for Polycythaemia Rubra Vera?

Answer 15

High WCC 
High Platelets 
Low Serum EPO
JAK2 mutation
Bone marrow trephine and biopsy shows erythroid hyperplasia and raised megakaryocytes

Question 16

What investigations do we do for Secondary Polycythaemia?

Answer 16

High Serum EPO
Exclude chronic lung disease/hypoxia
Check for EPO-secreting tumours