Diagnosis of anaemia and polycythaemia

Question 1

Genera clinical signs of anaemia:

Other clinical signs may depend on specific cause:

• Pica (odd animal eating behaviour)
• Melena (internal haemorrhage)
• Icterus (RBC breakdown/liver disease)

Answer 1

1. Pale mucous membranes
2. Lethargy
3. Exercise intolerance (difficult to notice in cats)
4. Tachycardia
5. Tachypnoea
6. Collapse due to hypoxia

Question 2

Diagnostic approach - Haematological examination:

Answer 2

1. Estimation of PCV/Hb concentration
2. Calculation of RBC indices
3. Microscopic examination of RBCs

Further investigations:

• Serum biochemistry
• Urinalysis
• Faecal parasitology
• Blood borne parasites (smear, serology, PCR)
• Thoracic/abdominal radiographs
• Abdominal ultrasonography
• Bone marrow examination
• Immunological tests
• Iron profile

Question 3

Effects of anaemia are due to reduced oxygenation of tissues

Tissue hypoxia activates 4 main compensatory mechanisms:

Answer 3

1. Increased oxygen delivery
   - Affinity of Hb for O2 is reduced
   - Higher proportion of O2 is available to be released to the tissues
2. Increased cardiac output
   - Increases the continuous supply of well-oxygenated blood
3. Increased RBC production
   - Hypoxia causes the release of erythropoietin from the kidneys
   - Blood carries erythropoietin to the bone marrow
   - RBC production is stimulated (release of reticulocytes)
4. Vasoconstriction
   - Shunting of blood away for tissues with low demand (i.e. skin)