L63

Question 1

Name 5 causes of Ca kidney stones

Answer 1

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

Question 2

TEST Q: why does hypo-citrat-uria cause kidney stones?

Answer 2

Citrate inhibits formation stones!

Question 3

What is the most common type kidney stone (composition)?

Answer 3

Ca oxalate - look for diamond squares or 2 fans

See on XR (think: Ca in bone)

Question 4

Does high or low urine volume facilitate the formation of stones?

Answer 4

Low - more [urine]

Question 5

Explain the pathophys of Ca oxalate stones - ↓ in what 3 things ↑chance of these?

Answer 5

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

Question 6

Clinical presentation of kidney stones

Answer 6

Acute pain, worsening
CVA tender // flank pain radiates to groin
Waxes + wanes
Feel need to pee but nothing comes out
Microscopic hematuria
N+V+fever
ALL symptoms go away suddenly if you pass stone (into ureter)

Question 7

Why do you get micro hematuria w/ kidney stones?

Answer 7

Destruction of urothelium

Question 8

Imaging options for kidney stones

Answer 8

CT - see level of the blockage, 1st choice for eval b/c will never miss it
US - quick rule in/out

Question 9

What stones are pts with chronic diarrhea at risk for?

Answer 9

Ca ox - loose tight jxns in GI

Hyper absorb oxalate

Question 10

What are the higher risk stones (more likely to recur)?

Answer 10

Uric acid
Cystine
Struvite

Question 11

Dietary treatment for kidney stones

Answer 11

↑Fluids = more dilute urine
↓Protein
Limit Na
NO CHANGE CA INTAKE

Question 12

Why don’t you limit Ca intake for kidney stone pts?

Answer 12

Low Ca would stimulate PTH to increase reabsoprtion of Ca and oxalate from GI
You want NEITHER of those things

Question 13

Treat hyperCa

Answer 13

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)

Question 14

Why do you get uric acid stones?

Answer 14

Over produce it -> over excrete it

+ Dehydration = ↓urine vol

Question 15

Are uric acid stones visible on XR?

Answer 15

No - radiolucent

Question 16

Do uric acid stones form in a basic or acidic urine?

Answer 16

Acidic, pH

Question 17

3 scenarios of ↓urine volume that can lead to uric acid stones

Answer 17

Exercise
Dehydration
Chronic diarrhea

Question 18

Disorders that produce too much uric acid -> stone

Answer 18

Gout

Myeloprolif

Question 19

What are struvite stones make of? Cause?

Answer 19

Mg NH4 PO4 stones

Bacteria: proteus, pseudomonas, kleb

Question 20

Are struvite stones made in an acidic or basic urine?

Answer 20

Basic U pH

Question 21

What is cystinuria?

Answer 21

Genes mutated - can’t reabsorb + AAs

• Lysine
• Ornithine
• Arginine

Question 22

What do the crystals in cystinuria look like?

Answer 22

Ground glass, 6 sided

Question 23

Treat cystinuria

Answer 23

Hydration

Alkalinization

Question 24

What drug can cause stones? Type of stone + treatment

Answer 24

Protease inhibitors (indinvir, tenofavir)
Accumulate in the renal pelvis - crystals made of the drug
Treat w/ hydration

Question 25

Treat chronic uric acid stones

Answer 25

Allipurinol = uric acid inhibitor (gout)

K citrate

Question 26

Treat chronic struvite stones

Answer 26

Surgery

Antibiotics vs inciting organism