Lecture 5: Clinical approach to patient with anaemia

Question 1

Define anaemia, its features and some factors that influence its levels over life:

Answer 1

Heamoglobin lower than normal for age and sex of patient (NOT RBC COUNT)

Features: Pallor, Tiredness, SOB, enhanced CV and resp symptoms

NB: Hb high at birth then falls 3m-1y

• HB increases with age, falling in later years
• Hb in M > F

Question 2

What is a heamacrit?

Answer 2

% RBC of total volume of blood

Packed cell volume / PCV is synonymous

Question 3

How is anaemia classified?

Answer 3

1. Basic mechanism / physiological approach.
   i. e Impaired production vs blood loss / haemolysis
2. Morphological approach
   i. e based on the appearance of the red cells

Question 4

What can the basic mechanism approach be broken down into?

Answer 4

Ineffective production vs impaired red cell survival

Question 5

What are the causes of impaired red cell production?

Answer 5

• Deficiency of substances essential for red cell production i.e iron, vitmain B12, folate
• Genetic defects in RBC production
  i. e thalassemia
• Failure of bone marrow
  i. e infiltration i.e leukemia, irradiation or drug damage

Question 6

What impairs RBC survival?

Answer 6

Blood loss i.e usually acute; treuma or surgery

Haemolysis
- Shortened survival of the red cell

Question 7

What indicates haemolysis?

Answer 7

Increased EPO
Increased billirubin (non-conjugated, possibile yellow sclera)
Increased reticulocytes

Pale conjuctiva

Question 8

Whats the morphological approach to anaemia?

Answer 8

Morphological approach: Uses mean cell volume, average cell Hb concentration and blood film comment

Question 9

What are the notable morphological anaemias?

Answer 9

• Microcytic hypochromic anaemia (MCV <76)
• Normochromic normocytic anaemia (MCV 76 - 96)
• Macrocytic anaemia (MCV > 96)

Question 10

What are some red cell values from a lab test?

Answer 10

Heamoglobin : g/L
Red cell count
Heamatocrit or packed cell volume (%)

Red cell absolute values:

• MCV
• Mean cell HB (MCH)
• Mean cell Hb concentration (MCHC)

Question 11

What are some other helpful investigations of anaemia?

Answer 11

• WBC and platelet count (leukemia)
• Reticulocyte count
• Examination of blood film
• Bone marrow examination

Question 12

What can cause microcytic hypochromic anaemia?

Answer 12

Iron deficiency

Chronic illness - Iron block

Genetic - Thalassaemia

i. e decreased heame production
appear: Smaller, less pink, tear shaped, hypochromic

Question 13

How is iron deficiency diagnosed?

Answer 13

Measure: Serum iron (low), iron binding capacity (transferrin, high b/c trying to get iron from gut), and iron saturation (low)

Measure: Serum ferritin (soluble iron storage, decreased)

Rarely examine iron stores in bone marrow

Question 14

What sort of protein is serum ferritin?

Answer 14

Acute phase protein and can increase in sickness

Question 15

Is iron deficiency anaemia enough?

Answer 15

No, iron deficiency is NOT A DIAGNOSIS, must identify the cause of deficiency

Anaemia occurs late in iron deficiency

Question 16

What are the causes of iron deficiency?

Answer 16

Diet - Vegetarian
Malabsorption - Proximal small bowel
Increased demands - Pregnancy
Chronic blood loss - GI or GU tract

Question 17

Who are most likely predisposed to iron deficiency/

Answer 17

Children - Low dietary intake

Pre-menopausal females - Imbalance between diet intake and menstural loss

Males and post menopausal women - occult blood loss

Question 18

Whats the treatment for iron deficiency?

Answer 18

Iron replacement therapy

• Oral tablets i.e ferrograd
• IV infusion i.e ferric carboxymaltose

Hb conc. increases ~20

Question 19

What is the profile of chronic inflammation anaemia?

Answer 19

“Iron block”

• Normochromic to mildly hypochromic
• Mild anaemia

Iron studies:

• Normal to raised ferritin
• Low normal Fe
• Low normal TIBC
• Normal saturation

Question 20

What probably causes the iron block?

Answer 20

Hepcidin synthesis in the liver because of inflammation

Question 21

What is thalassemia?

Answer 21

One or both alpha or beta chains reduced / absent

Recessive, heterozygous

Heterozygote : Mild anaemia
Homozygote: Severe anaemia (requires transfusions)

Diagnosied through gene panel

Question 22

What causes a macrocytic anaemia?

Answer 22

B12 or folate deficiency, (Megablastic anaemia (descriptive term)

Liver disease

Also:

• Alcohol
• Primary bone marrow disorder
• Hypothyroidism

Question 23

In macrocytic anaemia is the chromatin affected?

Answer 23

No, no hyper ot hypochromic

Question 24

Why does the anaemia result in B12/folate deficiency?

Answer 24

Because impaired DNA synthesis results in abnormal maturation

Question 25

How else can B12/Folate deficiency affect all bloods?

Answer 25

• Impaired DNA synthesis

- May affect all cell lineages if severe

Question 26

How is B12/folate deficiency diagnosed?

Answer 26

Measure serum B12 and folate leves

Need to determine cause

RBC most sensitive

Question 27

What can cause low B12 levels?

Answer 27

Diet - Vegans

Malabsorption

• Gastrectomy
• Immune i.e pernicious anaemia
• Terminal ilium disease

NB: Body has stores for 3-4 years

Question 28

What can cause low folate levels?

Answer 28

Diet i.e lack of vegetables

Malabsorption i.e Coeliac disease

Increased demands i.e pregnancy, haemolytic anaemia

Question 29

What is haemolytic anaemia:

Answer 29

Shortened survival of red cells

Intrinsic defect in the red cell i.e inherited defect in red cell membrane

Environmental or extrinsic i.e autoimmune destruction of red cell

Question 30

What are the clinical features of heamolytic anaemia?

Answer 30

Increased red cell destruction: Anaemia, Mild jaundice, increased spleen size

Increased RBC production: Raised reticulocyte count

Question 31

Key points:

Answer 31

Define anaemia

Classification/investigation of anaemia
Pathologic: Production vs loss
Morphology: Microcytic vs macrocytic

Microcytic: Iron deficient

Macrocytic: B12 or folate deficiency