Macrocytic Anaemia Flashcards
What does macrocytic mean?
Larger than usual RBCs
What are some causes of macrocytic anaemia?
B12 deficiency
Folate deficiency
Alcohol excess, liver disease
Pregnancy
Hypothyroid
Name some sources of B12?
Meat
Fish
Milk
Eggs
What causes B12 deficiency?
Low dietary intake
Impaired absorption in the stomach or small bowel
- pernicious anaemia
- coeliac etc.
Describe how vitamin B12 is absorbed in the body?
Stomach releases acid and gastrin which liberates B12 from protein complexes in food
It then binds to a B12 transporter
Pancreatic enzymes free the B12 from its binder
It becomes bound to intrinsic factor
This travels to the terminal ileum where it is absorbed into bloodstream
What is the function of B12 in the body?
Helps make red blood cells
Facilitates iron function in the body
Has a role in maintenance of nerves
What is pernicious anaemia?
An autoimmune condition in which there is atrophic gastritis, i.e. atrophy of parietal cells
How does pernicious anaemia cause anaemia?
Atrophy of parietal cells = no intrinsic factor
No intrinsic factor means B12 cannot bind to it, so it can’t be absorbed in the small intestine into the blood
Causes B12 deficiency, which causes anaemia
Where is intrinsic factor produced?
Parietal cells
What do the parietal cells produce?
Intrinsic factor
H+ ions
Why does B12 deficiency cause anaemia?
Because B12 has a role in helping production of red blood cells, without it they are not produced properly
Clinical features of pernicious anaemia?
Anaemia
Neurological features
- weakness
- ataxia
- dementia
Nerve damage
Who gets pernicious anaemia?
Middle aged women
Links with other autoimmune conditions: T1DM, Addison’s, vitiligo, Hypothyroid
Treatment of pernicious anaemia?
Intermuscular hydroxycobalamin (B12)
What is folate?
A vitamin, B9
