Macrocytic Anaemia

Question 1

Macrocytic Anaemia Aetiology + Microcytosis Aetiology

Answer 1

• Macrocytosis due to problems with synthesis, i.e. B12 or folic acid deficiency
• Microcytosis is usually deficiency of haemoglobin production

Question 2

Macrocytic Anaemia Smear Result

Answer 2

• Macrocytes on a blood film, with raised MCV
• Macrocytosis is common finding
• Macrocytic anaemia can be megaloblastic or non-megaloblastic

Question 3

Macrocytic Anaemia Epidemiology

Answer 3

-Most common cause of macrocytosis is medication followed by alcoholism

Question 4

Macrocytic Anaemia Aetiology

Answer 4

Megaloblastic anaemia is folate/B12 deficiency
-Liver has abundant stores of B12, if absorption is impaired it can take 4-5 years before deficiency develops
B12 deficiency due to
-Autoimmune addisonian pernicious anaemia, potential after-effects of surgery
Folate deficiency due to
-Dietary deficiency, malabsorption
Causes of non-megaloblastic macrocytosis
-Alcohol is a common cause
-Severe hypothyroidism

Question 5

Macrocytic Anaemia Presentation

Answer 5

As for anaemia

-SOB, fatigue, palpitations, pallor etc.

Question 6

Macrocytic Anaemia Ix

Answer 6

• FBC with blood film
• Folate
• B12
• LFTs (alcoholism)
• Urinalysis, U/Es (associated with diabetes (autoimmune in T1, metformin in T2 and homocystinuria)

Question 7

Macrocytic Anaemia Associated Diseases

Answer 7

-Pernicious anaemia often associated with other autoimmune diseases e.g. diabetes and hypothyroidism

Question 8

Macrocytic Anaemia Management

Answer 8

• Correct deficiency, treat underlying cause
• Hydroxocobalamin parenteral injection as usually an absorption problem
• If both a folate and B12 deficiency, treat B12 first (!), latter may aggravate B12 deficiency

Question 9

Macrocytic Anaemia When to Refer

Answer 9

Refer to haematology
Urgently if:
-Neurological signs (can cause neuropathy in late stages), pregnancy, suspected malignancy 
-Routinely if cause uncertain
Refer to gastroenterologist if:
-Suspected malabsorption (other than pernicious)
-Pernicious anaemia and GI symptoms
-Cancer 
-Coeliac