Anaemia- B12 and Folate Deficiency

Question 1

What are causes B12 deficiency?

Answer 1

Intrinsic factor from gastric parietal cells binds B12 absorbed in distal ileum

Causes
- Pernicious anaemia- autoimmune loss of parietal cells
– investigate via anti-parietal cell antibodies (sensitive) and Anti IF antibodies (specific)
- Drugs- Metformin, PPI
- Malabsorption- Crohn’s disease, gastrectomy
- Malnutrition- animal products help prevent

Question 2

What causes folate deficiency?

Answer 2

Folate is absorbed in the proximal small intestine

Causes
- Dietary deficiency or excess alcohol
- Malabsorption- Coeliac, IBD
- Drugs- alcohol, antiepileptics, methotrexate, trimethoprim

Question 3

What are clinical features?

Answer 3

Tiredness
SoB
Dizziness
Cognitive impairment

Question 4

What are signs?

Answer 4

Angular chellitis- inflammation around mouth
Glossitis- red, sore, smooth beefy tongue
Neurological signs- peripheral neuropathy

Question 5

What are investigations?

Answer 5

FBC: MCV >100
Blood film- hypersegmented neutrophils
Serum B12 <200
- if low check anti-intrinsic factor antibodies
Folate <3mcg
- If low screen for coeliac disease

Question 6

What is the management of B12 deficiency?

Answer 6

Neurological involvement
- specialist input required
- Alternate day IM hydroxocobalamin

No neurological involvement
- if loading required then IM hydroxocobalamin three times a week for 2 weeks
- then maintenance
– if diet related then PO cyanocobalamin 50-150mcg daily
– non diet IM hydroxocobalamin 1mg every 2-3 months

Question 7

What is the management of folate deficiency?

Answer 7

Oral folic acid 5mg OD- normally for 4 months
Continue longer if cause persists e.g. alcohol excess

Always correct B12 first to prevent subacute combined degeneration of the cord