Macrocytosis Flashcards
macrocytosis
term used to describe red blood cells that are larger than normal
causes of macrocytosis
- alcoholism
- folate deficiency
- B12 deficiency
- hypothyroidism
- medication side effects
macrocytosis
importance of intrinsic factor
necessary binding protein
- B12 released from food + IF from stomach parietal cells
- IF binds w B12 : B12-IF complex
- B12-IF complex travels to ileum
- B12 absorbed
- B12 vital for RBC production
- w/o IF only a tiny amount of B12 can be absorbed
type 1 IF antibody fucntion
blocks B12 from binding to receptor site on IF
type 2 IF antibody function
prevents B12-IF complex from connecting to ileum
parietal cell antibodies
attack parietal cells
pernicious anaemia
( what is it? causes? )
- autoimmune condition that prevents body from absorbing B12
- immune system targets its own tissues and develops antobides against IF/parietal cells
- target specific autoimmune condition causing IF to fail
- causes poor RBC development
- inherited form detected in children - autosomal recessive
pernicious anaemia - who is at risk?
- northern european or african descent
- older people due to lack of IF
- diseases that increase risk : hypothyroidism, Graves + Addisons disease
pernicous anaemia - average age when symptoms shown
60
pernicious anaemia
signs & symptoms - early stage
- light headedness
- lethargy/fatigue
- loss of apetite
- nauses
- blotchy skin pigmentation
signs & symptoms - later stage when B12 has caused nerve damage
- confusion
- hallucinations
- delusions
- short term memory loss
- depression
- loss of balance
treatment - pernicious anaemia
- foods high in B12
- vitamin B12 supplements
- hydroxocobalamin
treatment - pernicious anaemia - hydroxocobalamin
penicious anaemia w/o neurological involvement :
* 1mg 3 times a week for 2 weeks, then 1mg every 2-3months
pernicious anaemia w neurological involvement :
* 1mg/ day on alternate days until no further improvement, then 1 mg every 2 months
