Vitamin A Flashcards
What are the important roles of vitamin A
- constituent of visual pigments
- normal differentiation of epithelial cells into specialized tissue (pancretic, mucus-secreting cells)
- prevents squamous metaplasia
Vitamin A can be used to treat
measles
acute promylocytic leukemia
Where can you find vitamin A
liver
leaft vegetables
what is used to treat APL
all-trans retinoic acid
What are characteristics of vitamin A deficiency
- night blindness (nyctalopia)
- dry scaly skin (xerosis cutis)
- corneal squamous metaplasia (bitot spots, keratin debris)
- corneal degeneration (keratomalacia)
- immunosuppression
Causes of vitamin A deficiency
- diet
- pancreatic insufficiency
- cholestatic liver/biliary obstruction
- intestinal malabsorption (bariatric, IBS)
What are characteristics of acute vitamin A excess
nausea
vomiting
vertigo
blurred vision
What are characteristics of chronic vitamin A deficiency
- alopecia
- dry skin/scaliness
- hepatic toxicity/enalrgement
- arthalgias
- idiopathic intracranial HTN
What teratogenic effects come from vitamin A
- cleft palate
- cardiac abnormalities
what is required before prescribing isotretinoin for severe acne
- negative pregnancy test
- two forms of contraception
Where is vitamin A stored
hepatic stellate cells
Where will you see squamous metaplasia most in vitamin A deficiency
lungs
increase risk for respiratory infections
Symptoms of Vitamin A toxicity
- Diarrhea
- sweating
- brittle nails
To see at night what needs to happen with the eye rod cells
- Decrease glutamate at bipolar cells
- GABA will not be stimulated at the optic nerve
- optic nerve can see
