Vitamin B12 + Folate deficiency

Question 1

Define Vitamin B12 deficiency:

Answer 1

Having insufficient Vitamin B12 to meet demands

Question 2

Aetiology/Risk factors for Vitamin B12 deficiency:

Answer 2

B12 is found in meat and animal products.

It is absorbed in the terminal ileum by IF.

80% of megaloblastic anaemia is pernicous anaemia which is an autoimmune condition where there is lack of IF.

Other causes:

• Atrophic gastritis
• gasterectomy

Inadequate intake (vegans)

Malabsorption - Crohn’s and ileum resection

Drugs - metformin and colchicine

Question 3

Epidemiology in vitamin B12 deficiency:

Answer 3

Peak age is 60

Common in vegans

Question 4

Symptoms:

Answer 4

Fatigue 
Lethargy 
Dysponea
faitness
palpitations
headache

Neurological - numbness, parasthesia, visual disturbances (mainly B12)

Question 5

Signs:

Answer 5

Glossitis 
Pallor
Signs of heart failure
irritability
dementia
depression
peripheral neuropathy (mainly B12)

Question 6

Investigations:

Answer 6

serum B12 and folate but not very reliable

Plasma total homocysteine, methylmonoic acid, holotranscolbalamin

FBC - pancytopenia

Blood film - hyper segmented neutrophils, circulating megaloblasts, oval macrocytes

Pernicious anaemia tests:

• Anti-intrinsic factor antibodies
• Anti-parietal cell antibodies
• Schilling test (not really done anymore)

Reticulocyte count

Question 7

Define folate deficiency:

Answer 7

Megaloblastic anaemia with absence of neurological features due to folate deficiency.

Question 8

Aetiology/Risk factors folate deficiency:

Answer 8

Found in leafy greens

For DNA synthesis and homocytseine metabolism

May occur due to decreased dietary intake, decreased i absorption or increased used (growing teenagers and pregnancy)

Question 9

Epidemiology of folate deficiency:

Answer 9

Alcoholism

> 65 years

Pregnant women