Lecture 6: Anaemia

Question 1

What is anaemia?

Answer 1

Lower than normal haemoglobin for the age and sex of the patient

Question 2

Classifications of anaemia?

Answer 2

1. Basic mechanism

• ineffective production
• impaired red cell survival

2. morphology

• small and pale
• large

Question 3

Causes of impaired production?

Answer 3

Deficiency of substances essential for red cell production

• iron, vitamin B12, folate

Genetic defect in red cell production

• thalassaemia

Failure of bone marrow

• Infiltration eg. leukaemia, irratiation or drug damage

Question 4

Reduced red cell survival?

Answer 4

Blood loss

• usually acute trauma or surgery

Haemolysis

• shortened survial of the red cell
• RBC being broken down = billirubin in excess = jaundice

Question 5

Morphological approach to anaemia?

Answer 5

Uses MCV, average Hb concentration and blood film comment

Microcytic hypochromic anaemia (MCV < 76)

Normochromic normocytic anaemia (MCV 76-96)

Macrpcytic anaemia (MCV >96)

(NB: Packed cell volume (PCV) or Haematocrit = % of red cell volume to total blood volume and basically mirrors the Hb)

Question 6

Differential for Microcytic hypochromic anaemia?

Answer 6

1. Iron deficiency - most common cause of anaemia
2. Chronic illness - iron block
3. genetic - thalassaemia (globin chains are insufficient)

Question 7

Diagnosis of Iron deficiency?

Answer 7

• Measure serum iron, iron binding capacity (transferrin normally 30%) and iron saturation
• Measure Serum Ferritin
• Rarely examin iron stores in bone marrow

Question 8

classical patterns of iron deficiency vs anaemia of chronic disorder?

Answer 8

Iron deficiency shows a low serum ferritin but as iron is low the body produces iron transport protein so the trasnferrin % drops.

In anaemia of chronic disorder the serum ferritin is actually normal or elevated whist the serum iron is low along with a low iron transport protein.

Question 9

Causes of Iron Deficiency?

Answer 9

Diet

• eg. vegetarian

Malabsorption (normally only absorb 1-2mg from 15 per day)

• proximal small bowel
• coelaic

Increased demands

• eg. pregnancy and breastfeeding

Chronic blood loss (Most clinically important)

• GI or GU tract