Urinary Lithiasis

Question 1

Approx 75% of all stones contain ___ as major constituent and 60% are composed of ___

Answer 1

Calcium; calcium oxalate

Question 2

Stone formation depends on 4 factors

Answer 2

1) Matrix 2) Precipitation-crystallization 3) Epitaxy 4) Absence of inhibitors of stone formation

Question 3

Refers to supersaturation of the urine with specific ions composing the crystal

Answer 3

Precipitation-crystallization

Question 4

Refers to the aggregation of crystals of different composition but similar lattice structure

Answer 4

Epitaxy

Question 5

If the calculus is present in these areas, then severe abdominal or flank pain (renal colic) occurs

Answer 5

Pelvis, calyx, ureter

Question 6

Renal colic typically radiates where

Answer 6

Anteriorly to the scrotum or labia

Question 7

Nephrocalcinosis is seen most commonly in premature neonates receiving ___ and in children with ___

Answer 7

Furosemide, medullary sponge kidney

Question 8

Most accurate study to diagnose urolithiasis

Answer 8

Unenhanced spiral CT of the abbdomen and pelvis

Question 9

T/F Metabolic evaluation should be undertaken in ALL children with urolithiasis

Answer 9

T

Question 10

MC metabolic abbnormality in children with CaOx and CaPhos calculi

Answer 10

Normocalcemic hypercalciuria

Question 11

Increases solubility product of calcium oxalate crystallization 7-10x more than calcium

Answer 11

Oxalate

Question 12

Death from renal failure occurs in untreated patients with hyperoxaluria by age ___

Answer 12

20

Question 13

Extrarenal deposition of CaOx

Answer 13

Oxalosis

Question 14

Renal insufficiency + elevated plasma oxalate

Answer 14

Oxalosis

Question 15

Risk factor for formation of CaOx and CaPhos stones due to low excretion of an important inhibitor of calcium stone formation

Answer 15

Hypocitraturia

Question 16

Rare autosomal recessive disorder of the EC of the renal tubules that prevents absorption of 4 dibasic amino acids resulting in excessive urinary excretion of these products

Answer 16

Cystinuria

Question 17

4 dibasic amino acids unabsorbed in cystinuew

Answer 17

Cysteine, ornithine, arginine, lysine

Question 18

Calculi resulting from UTI caused by urea-splitting organisms

Answer 18

Struvite calculi

Question 19

Urea-splitting organisms, infection of which causes formation of struvite calculi

Answer 19

Most often Proteus, occasionally Kleb, E.coli, Pseudomonas

Question 20

Presence of urea-splitting organisms in the urine causes

Answer 20

Urinary alkalinization and excessive production of ammonia –> precipitation of magnesium ammonium phosphate (struvite) and calcium phosphate

Question 21

Staghorn calculi

Answer 21

Struvite calculi

Question 22

Shown to facilitate stone passage in adults by decreasing ureteral pressure below stone and decreasing frequency of peristaltic contraction of the obstructed ureter

Answer 22

α-adrenergic blockers (tamsulosin, terazosin, doxazosin

Question 23

Alkaline therapy may be effective in dissolution of what type of stones

Answer 23

Uric acid, furosemide-associated calculus, cysteine calculi

Question 24

Effective management strategies for children with hypercalciuria to prevent stone formation

Answer 24

1) Reduction in calcium and sodium intake 2) Thiazide diuretics (reduces renal Ca excretion) 3) K citrate (calcium stone inhibitor)

Question 25

Effective management strategies for children with uric acid stones

Answer 25

1) Allopurinol 2) Urinary alkalinization >6.5 with NaHCO3 or Na citrate

Question 26

Effective management strategies for children with cysteine stones

Answer 26

1) Urinary alkalinization 2) D-penicillamine (increases solubility of cysteine)