Flashcards in L63 Deck (26)
Name 5 causes of Ca kidney stones
1. ↑U Ca (↑P Ca)
2. 1ary hyperPT
3. ↓U citrate
4. ↑U uric acid, cysteine
5. RTA - can't acidify urine, basic urine supports Ca deposition
TEST Q: why does hypo-citrat-uria cause kidney stones?
Citrate inhibits formation stones!
What is the most common type kidney stone (composition)?
Ca oxalate - look for diamond squares or 2 fans
See on XR (think: Ca in bone)
Does high or low urine volume facilitate the formation of stones?
Low - more [urine]
Explain the pathophys of Ca oxalate stones - ↓ in what 3 things ↑chance of these?
Ca ox stone = +
Urine has proteins, GAGs and citrate: all negative
+ bind - to keep everything soluble
Decrease in any of the (-) means + stone binds the neg charged endothelium
Clinical presentation of kidney stones
Acute pain, worsening
CVA tender // flank pain radiates to groin
Waxes + wanes
Feel need to pee but nothing comes out
ALL symptoms go away suddenly if you pass stone (into ureter)
Why do you get micro hematuria w/ kidney stones?
Destruction of urothelium
Imaging options for kidney stones
CT - see level of the blockage, 1st choice for eval b/c will never miss it
US - quick rule in/out
What stones are pts with chronic diarrhea at risk for?
Ca ox - loose tight jxns in GI
Hyper absorb oxalate
What are the higher risk stones (more likely to recur)?
Dietary treatment for kidney stones
↑Fluids = more dilute urine
NO CHANGE CA INTAKE
Why don't you limit Ca intake for kidney stone pts?
Low Ca would stimulate PTH to increase reabsoprtion of Ca and oxalate from GI
You want NEITHER of those things
1. Thiazide + Na restrict = ↑Ca reaborption and may lead to bone mineralization
2. Amiloride = K sparing = ↑Ca reabsorbed at CD
3. K citrate or PO4 (prevent hypocitrate)
Why do you get uric acid stones?
Over produce it -> over excrete it
+ Dehydration = ↓urine vol
Are uric acid stones visible on XR?
No - radiolucent
Do uric acid stones form in a basic or acidic urine?
3 scenarios of ↓urine volume that can lead to uric acid stones
Disorders that produce too much uric acid -> stone
What are struvite stones make of? Cause?
Mg NH4 PO4 stones
Bacteria: proteus, pseudomonas, kleb
Are struvite stones made in an acidic or basic urine?
Basic U pH
What is cystinuria?
Genes mutated - can't reabsorb + AAs
What do the crystals in cystinuria look like?
Ground glass, 6 sided
What drug can cause stones? Type of stone + treatment
Protease inhibitors (indinvir, tenofavir)
Accumulate in the renal pelvis - crystals made of the drug
Treat w/ hydration
Treat chronic uric acid stones
Allipurinol = uric acid inhibitor (gout)