EVERYTHING THE USMLE CAN ASK YOU ABOUT VITAMIN A
– is a cofactor in PTH (Caclium and PO4 are always in opposite direction – is a PTH problem)
– helps in csf production
– epithelial cell maturation (vitamin a does this)
– night vision is the most unique function of vitamin A
– slight antioxidant
– poor night visiion (test wont say explicity “night vision”)
– lowered csf production
– failure of epithelial cells to mature
** knowing the most unique function is imperative to know because these are the things the usmle will test on.
**translocation 15;17 promyeloblastic leukemia, give vitamin A and cells mature to AML, allowing to live longer since promyeloblastic patients die fast, where AML lasts a bit longer.
** any disease wearing away at an organ, giving vitamin A can regenerate epithelium, no matter what cell is being worn away
** calcium and PTH direction in same direction, PO4 opposite
Vitamin A excess:
– excessive csf = pseudotumor cerebri (papilledema, headache) – this combo should always be suspect of increased ICP, always want to rule out a brain mass by doing a ct or mri. if there is not a mass, check csf with LP
hyperparathyroidism = hypercalcemia (what are hypercalcemia sx: stones, moans, groans, bones)
main sign – papilledema
main symptom – headache
1st evaluating tool – ct scan will show enlargement of ventricles
managment – stop vitamin a administration + serial lumbar punctures
Main complication of P. Cerebri is blindness.
** NOTE: this is the only time when an increase in ICP is not worrisome of a herniating condition. Only 30cc because any more will cause an osmotic shift