Renal - Stones

Question 1

when do stones most commonly occur?

Answer 1

middle age (40-59)

Question 2

where geographically are higher incidence areas?

Answer 2

south and east

in summer –> volume depletion

Question 3

recurrence?

Answer 3

50-60% in 10 years

Question 4

nidus (small something which starts it) which begins saturation process below supersaturation point

Answer 4

heterogeneous nucleation

Question 5

alkaline urine favors?

Answer 5

calcium phosphate

Question 6

acidic urine favors?

Answer 6

uric acid

Question 7

key inhibitors

Answer 7

citrate
proteins
glycosaminoglycans

Question 8

most prevalent stone?

Answer 8

calcium oxalate

Question 9

radiolucent on KUB?

Answer 9

uric acid

Question 10

idiopathic CaOX stone formation

Answer 10

Initiate: Randall’s plaques
white deposits on papillae
interstitial deposits of CaP on BM of thin limb of hence
CaOx deposits on top
Number of plaques –> Ca levels in urine and LOW urine VOLUME

Question 11

Calcium phosphate stones

Answer 11

deposits in the medullary collecting ducts

Question 12

cause of calcium oxalate stones

Answer 12

hypercalciuria
hyperPTHism
hypocitraturia
hyperoxaluria (IBD–>high lipids cause saponification)
hyperuricosuria
low calcium intake
Everyone ingests oxalate, but this usually binds Ca and it’s excreted, if there’s no calcium present oxalate is absorbed

Question 13

cause of calcium phosphate stones

Answer 13

distal RTA (via acidosis --> bone release)
primary hyperparathyroidism

Question 14

GN anaerobe bacteria that eats oxalate in gut

Answer 14

oxalobacter formigenes
stone formers have less of this bacteria
abx/dietary oxalate may affect OF

Question 15

oxalate 8

Answer 15

spinach, rhubarb, beets, black/green tea, coccoa, nuts/seeds, soy beans, potatoes, french fries

Question 16

seen with urine pH < 6, also high uric acid levels, gout

Answer 16

Uric acid stones
Xanthine stones (w/allopurinol)

Question 17

recessive stone defect, radiolucent stones in kids/young adults, more in males

Answer 17

cystine stones

Question 18

hexagonal crystals

Answer 18

cystine

Question 19

stone associated with infections

Answer 19

struvite

due to urea-splitting orgs

Question 20

pH w/struvite stones?

Answer 20

high >7
need surgery (these are big)

Question 21

stones cause AKI?

Answer 21

not usually –> unilateral obstruction

may see a bump in crib

Question 22

KUB xray for?

Answer 22

radioopaque stones

Question 23

passage prognosis

Answer 23

1cm - will not pass (need surg)

Question 24

urine Ca levels in hyperPTH?

Answer 24

high

PTH causes kidney to reabsorb BUT threshold is reached and then it is excreted

Question 25

if patient can’t drink? UTI? single fxn kidney obstruction?

Answer 25

hospitalize

Question 26

urine goal?

Answer 26

2L/day

50% reduction in stone formation

Question 27

Tx for calcium stones

-hypercalciuria

Answer 27

restrict sodium (if you eat salt you pee salt: if you excrete sodium you excrete calcium --> more Ca in urine)
thiazide diuretics

Question 28

Tx for calcium stones

-Hypocitrauria

Answer 28

potassium citrate

Question 29

Tx for calcium stones

-hyperoxaluria

Answer 29

oxalate restriction

probiotics?

Question 30

Tx for calcium stones

-nidus of uric acid

Answer 30

Allopurinol

Question 31

What to not restrict for calcium stones?

Answer 31

Dietary calcium!

It binds oxalate in the gut and prevents absorption

Question 32

pH goal?

Answer 32

> 6 unlikely to form stones

Question 33

changes to urine if increase Ca in diet?

Answer 33

no change in Ca levels

decreased oxalate levels

Question 34

if you excrete citrate into the tubule?

Answer 34

prevent stones

Question 35

secretion of citrate based on urine pH?

Answer 35

higher pH –> more excreted

lower pH –> less excreted

Question 36

citrate keeps…

Answer 36

new crystals from forming

old ones from getting back together

Question 37

to get pH >6 for UA stones?

Answer 37

K+ citrate
low purine diet
allopurinol

Question 38

to get pH >7 for cystine stones?

Answer 38

cysteine-binding drugs

penicillamine/THIOLA/captapril