Urinary Lithiasis Flashcards

1
Q

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

A

Calcium; calcium oxalate

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2
Q

Stone formation depends on 4 factors

A

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

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3
Q

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

A

Precipitation-crystallization

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4
Q

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

A

Epitaxy

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5
Q

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

A

Pelvis, calyx, ureter

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6
Q

Renal colic typically radiates where

A

Anteriorly to the scrotum or labia

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7
Q

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

A

Furosemide, medullary sponge kidney

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8
Q

Most accurate study to diagnose urolithiasis

A

Unenhanced spiral CT of the abbdomen and pelvis

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9
Q

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

A

T

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10
Q

MC metabolic abbnormality in children with CaOx and CaPhos calculi

A

Normocalcemic hypercalciuria

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11
Q

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

A

Oxalate

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12
Q

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

A

20

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13
Q

Extrarenal deposition of CaOx

A

Oxalosis

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14
Q

Renal insufficiency + elevated plasma oxalate

A

Oxalosis

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15
Q

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

A

Hypocitraturia

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16
Q

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

A

Cystinuria

17
Q

4 dibasic amino acids unabsorbed in cystinuew

A

Cysteine, ornithine, arginine, lysine

18
Q

Calculi resulting from UTI caused by urea-splitting organisms

A

Struvite calculi

19
Q

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

A

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

20
Q

Presence of urea-splitting organisms in the urine causes

A

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

21
Q

Staghorn calculi

A

Struvite calculi

22
Q

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

A

α-adrenergic blockers (tamsulosin, terazosin, doxazosin

23
Q

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

A

Uric acid, furosemide-associated calculus, cysteine calculi

24
Q

Effective management strategies for children with hypercalciuria to prevent stone formation

A

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

25
Q

Effective management strategies for children with uric acid stones

A

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

26
Q

Effective management strategies for children with cysteine stones

A

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