Pernicious anaemia

Question 1

What is pernicious anaemia?

Answer 1

A cause of B12 deficiency as there is inadequate absorption of B12 from the gut

Question 2

What is the pathophysiology in pernicious anaemia?

Answer 2

Stomach cells produce intrinsic factor - essential for absorption of B12 in the ileum
PA –> autoimmune antibodies to intrinsic factor or parietal cells –> lack of intrinsic factor –> prevents B12 absorption

Question 3

Vitamin B12 deficiency can cause

Answer 3

Peripheral neuropathy - pins and needles
Loss of proprioception and vibration sense

Mood/ cognitive changes
Visual changes

Question 4

Diagnosis of pernicious anaemia involves:

Answer 4

Testing for:
IF antibodies - first line
Gastric parietal cell antibodies - less useful

Question 5

Management of pernicious anaemia

Answer 5

Dietary deficiency - managed with cyanocobalamin - unless deficiency is severe

Pernicious anaemia - oral supplementation is insufficient
1mg Hydroxycobalamin IM 3x weekly for 2 weeks then every 3 months
If there are neuro symptoms - more intense regimen e.g. 1mg every day until they resolve

Question 6

Why is it important to treat B12 def first if there is also folate deficiency?

Answer 6

Giving folic acid to someone with B12 def can lead to subacute combined degeneration of the cord