Renal (Uto/kidney Stones)

Front 1

Can ultrasound detect obstruction?

Back 1

no, it can only pick up dilatation of the calices (hydronephrosis)...but if obstruction doesn't dilate the calices, then US can't pick it up

Front 2

what are the most common causes of anuria:
- intratubular?
- ureter?
- urethra?

Back 2

intratubular = protein casts, crystals (related to medications)

ureter = stones, tumors, fibrosis

urethra = prostate, strictures, blood clots, stones

Front 3

most common cause of UTO in children vs adults

Back 3

children = congenital
adults = BPH, stones

Front 4

what are the effects of urinary tract obstruction on renal fxn after 1 hour? after 24 hours?

Back 4

after 1 hr = vasodilation, increase RBF, decreased GFR (due to increase pressure of blood, nothing filters), decreased Na absorption, inc tubule pressure

after 24 hours = vasoconstriction, dec RBF and GFR, inc Na absorption (kidney thinks its in shock), stable tubule pressure

Front 5

what's the difference in renal response b/w mild vs complete ureteral obstruction

Back 5

unilateral obstruction = initially, vasodilation through prostaglandin, inc bloodflow kidney, maintain GFR; later, inc AG II to constrict efferent arteriole, inc thromboxane A2 to constrict afferent arteriole

complete obstruction = similar to unilateral obstruction events as detailed above early on; at 24 hrs, inflammatory cells will come in and cause vasoconstriction to preserve other critical parts of the body, lose GFR bc you decrease RBF; WHAT'S DIFFERENT IS THAT also will have ANP released that enhances efferent constriction and lessens afferent arteriole constriction

BUT BASICALLY, THE REDUCTIONS IN RBF AND GFR 24 HRS ARE THE SAME FOR BOTH UNILATERAL AND BILATERAL URETERAL OBSTRUCTION

Front 6

what is the outstanding clinical feature of complete UTOs?

Back 6

anuria!!

Front 7

what is the hallmark of UTO on radiography?

Back 7

hydronephrosis (use Ultrasound first bc you'd have to use dye for CT that can actually cause obstruction)

Front 8

what is post-obstructive diuresis

Back 8

polyuria after release of bilateral obstruction (when urea is excreted after relief of UTO, it'll pull water with it as an osmotic agent)

so you'll see hyperkalemia, acidemia, kidney failure, and polyuria (find out why...)

Front 9

tx for unilateral kidney stones

Back 9

hydrate, remove it

Front 10

tx for ureteral obstruction with kidney failure (like from tumor)

Back 10

percutaneous stents

Front 11

tx for urethral obstruction

Back 11

catherization

Front 12

pt just returned from the summer vacation on the beach, with severe flank pain that radiates into the groin. she reports nausea, vomiting and frequent urination.

what's the probable dx?

Back 12

possible kidney stone

Front 13

what are the most common kinds of stones?

Back 13

- calcium-based stones (can be mixed with oxalate or phosphate)
- struvite stones (magnesium ammonium phosphate)
- uric acid stones
- cystine stones

Front 14

what is the hallmark of UTO on radiography?

Back 14

hydronephrosis (use Ultrasound first bc you'd have to use dye for CT that can actually cause obstruction)

Front 15

what are the changes in obstruction in terms of early vs. chronic phase

Back 15

early (days): tubule dilated, interstitial edema, macrophage infiltrate, adhesion molecules appear/early inflammation

chronic (weeks): HYDRONEPHROSIS, tubule atrophy, chronic interstitial inflammation, intersitital fibrosis

Front 16

which may show polyuria?

a. complete UTO
b. partial UTO

Back 16

B.

Front 17

what are some signs and sx's of urinary obstruction

Back 17

H/P: fluctuation of urine flow (anuria = complete UTO)
- pain, if ureteral obstruction
- lower urinary sx's: dribbling, frequency, incontinence, nocturia

Front 18

what might you expect to find on the labs of a pt with possible UTO?

Back 18

-kidney failure (elevated BUN:creatinine ratio)
-hematuria
- hyperkalemia
-acidemia
-excretion of dilute urine

Front 19

what is the general pathogenesis of kidney stone formation?

Back 19

when conc of solute (ie. calcium, oxalate, etc) in urine becomes really high, it will eventually precipitate and become a stones

SUPERSATURATION --> NIDUS --> STONE

Front 20

name 2 protective mechanisms against stone formation despite supersaturated urine with multiple ionic species

Back 20

- quick transit time through the tubules
- crystallization inhibitors (like citrates and magnesium ... remember that citrates coat crystals and prevent growth/aggregation, though it does not prevent nucleation)

Front 21

which of these will form in alkaline pH (pick as many as possible):

a. calcium oxalate
b. calcium phosphate
c. Mg-NH4-phosphate
d. uric acid
e. cystine

Back 21

B, C. remember that phosphate stones will form.

Front 22

which type of stones form independently of pH?


a. calcium oxalate
b. calcium phosphate
c. Mg-NH4-phosphate
d. uric acid
e. cystine

Back 22

A

Front 23

which type of stones form in acidic pH urine environment (pick as many as possible)?


a. calcium oxalate
b. calcium phosphate
c. Mg-NH4-phosphate
d. uric acid
e. cystine

Back 23

D, E

Front 24

which type of stone is formed as a result of chronic infection by urea-splitting organisms?


a. calcium oxalate
b. calcium phosphate
c. Mg-NH4-phosphate
d. uric acid
e. cystine

Back 24

C.

Front 25

T or F. high urinary citrate and magnesium allow formation of kidney stones.

Back 25

F. they are both inhibitors of kidney stone formation. so the more you have, the less likely you'll have stones

Front 26

tx of calcium oxalate stones due to hyperoxaluria?

Back 26

supplement dietary calcium, low oxalate diet (less beans, greens, teas, chocolate, vit C), pyridoxine (bc pyridoxine deficiency can lead to hyperoxaluria)

Front 27

tx of calcium phosphate stones due to idiopathic hypercalciuria

Back 27

hypercalciuria = potassium citrate (inhibitor of stone formation within urine), thiazide diuretic (lower urinary calcium excretion)

Front 28

what are three reasons for calcium phosphate stones due to idiopathic hypercalciuria

Back 28

-idiopathic hyperabsorption from GI tract (normal vit D levels, low PTH)
-fasting can cause release of Ca from bone, leaving PTH levels normal
- abnormal renal absorption of calcium or phosphate

Front 29

name 3 causes of calcium phosphate stones due to secondary hypercalciuria

Back 29

- conditions that elevate serum Ca (sarcoidosis, TB)
- endocrine (hyperPTH, hyperthyroidism, cushing's syndrome)
- medications (diuretics, vit D, tums)

Front 30

would you give calcium as a supplement to a patient with calcium oxalate stones due to hyperoxaluria? why or why not?

Back 30

yes, it will decrease the GI absorption of oxalate

Front 31

which of the following does NOT lead to struvite stones (magnesium ammonium phosphate)?

a. haemophilus
b. yersinia
c. E. coli
d. proteus

Back 31

C.

Front 32

which type of kidney stones are radiolucent (show up on x-ray as dark)?

Back 32

uric acid stones

Front 33

you suspect your pt has uric acid stones so you want to do a IVP. what is the disadvantage of doing so?

Back 33

requires IV contrast, which is nephrotoxic

Front 34

young pt comes in with a family hx of "mad stones"... you order a urine microscopy exam that shows up with hexagonal crystals. what do you suspect?

Back 34

cystinuria (cystine kidney stones taht are due to high urinary cysteine)

- large genetic componenet

Front 35

tx for cystinuria

Back 35

potassium citrate
low Na diet

Front 36

which of the following disorders underlying kidney stones would you give thiazide diuretic for?

a. idiopathic hypercalciuria
b. hypocitraturia
c. hyperuricosuria
d. cystinuria

Back 36

a.

Front 37

T or F:

- you want to give Ca to a patient with stones
- you want to avoid high sodium diet in a patient with stones
- you want to give everyone with stones potassium citrate
- you want to protect kidney stone pts who ahve stones with vit C

Back 37

T, T, T, F