Nephrolithiasis

Question 1

ureteral colic may mimic any intra-abdominal process.what would make you this diagnosis

Answer 1

if the paatient has abdominal pain with hematuria. hematuria is a big clue in the presence of stones

Question 2

what are some important terms when discussing nephrolithiasis?

Answer 2

• interplay of concentration (calcium oxalate, uric acid, and other solutes)
• degree of supersaturation

Question 3

patients with recurrent kidney stones have low numbers of what

Answer 3

citrate which is an inhibitor of stones

Question 4

which medication has a mechanism to reduce uric acid can produce xanthine stones?

Answer 4

allopurinol

Question 5

an antiseizure medication but can cause proximal RTA and possibly kidney stones

Answer 5

topirimate

Question 6

what are the most common form or types of kidney stones

Answer 6

calcium oxalate or calcium phosphate
cystine
uric acid
struvite

Question 7

which types of stones are always associated with urinary tract infections?

Answer 7

struvite

stones due to UTIs especially with urea splitting organisms that produce urease and produce a special kind of stone

Question 8

if the stones are Ca phosphates then you should think

Answer 8

of primary hyperparathyroidism or distal RTA (renal tubular acidosis)

Question 9

What measurements in urine chemistry do you need to be aware of?

Answer 9

• Na
• Volume
• Ca
• Uric Acid
• Oxalate
• Citrate
• Cystine
• pH
• Creatinine

Question 10

which levels that are high will increase the risk factors for calcium oxalate?

Answer 10

-calcium, oxalate, uric acid

Question 11

which levels if low will increase the risk factors for calcium oxalate

Answer 11

citrate, volume, dietary calcium, potassium, phytate

Question 12

what will increase the risk factor for calcium oxalate when the dietary levels are increased?

Answer 12

purines, animal protein, sodium, sucrose, calcium-supplemental, vitamin C fluid(interferes with oxalate catabolism)

Question 13

what are the major risk factors for calcium stones?

Answer 13

• hypercalciuria
• hypocitraturia
• hyperuricosuria
• hyperoxaluria
• low urine volume
• infection with urea splitting organisms-proteus
• medullary sponge kidney

Question 14

what is medullary sponge kidney

Answer 14

genetic disease that has calcifications in the renal medulla that causes stone formation

Question 15

patient comes in with substance abuse, works in garage, gets seizures, renal failure, met acidosis, he has tons of these in his urine what is the pathogenesis of his disorder

Answer 15

he has ethylene glycol which interferes with oxalate metabolism and he gets Ca oxalate stones

Question 16

what are the two causes of hypercalciuria

Answer 16

• increased filter load

- decreased absorption which parallels Na in PCT

Question 17

hypercalciuria may be

Answer 17

idiopathic (increased vit d and decreased bone mineral density, especially in women) or secondary to Primary hyperparthyroidsm, RTA, Sarcoidosis, immobilization, pagets disease, hyperthyroidism, vitamin D intoxication, granulomatous disease, Multiple myeloma

Question 18

what are the dietary treatments of hypercalciuria?

Answer 18

• high fluid intake reduces the supersat index
• restrict dietary sodium
• but do not restrict dietary Ca becuase it will result in more oxalate stones and too high will result in Ca stones
• restrict protein from other animals because they increase urinary acidity

Question 19

what is the mechanism of thiazide diuretics

Answer 19

reduce urinary calcium by (mild) reducing the volume increasing both Na and Ca reabsorption

Question 20

potassium citrate do what

Answer 20

they decrease and inhibit the formation of Ca stone formers

potassium is preferred to Na and citrate is preferred to HCO3

Question 21

lemon juice is preffered to what and why

Answer 21

orange (oxalate)

Question 22

what two things reduce citrate

Answer 22

acidosis and hypokalemia

Question 23

what two GI problems can cause stones?

Answer 23

Intestinal oxaluria (malabsorption of bile or fatty acids seen in IBD or short bowel
you get increased urinary excretion of oxalate

Question 24

treatment of hyperoxaluria?

Answer 24

• avoid high oxalate foods
• such as tea coffee, nuts, chocolate, green leafy vegetables, collard greens, wheat barn,
• have a low fat diet

Question 25

what is essential in the formation of struvite stones?

Answer 25

bacteria that release urea or urease which is

Question 26

what are the characteristics to the formation of struvite stones?

Answer 26

• magnesium ammonium phosphate and Ca carbonate
• can fill the entire renal pelvis
• occurs only when NH3 produced and pH is high
• must have infection with urease producing organism
• requires complete removal

Question 27

what is cystine stones based on?

Answer 27

• it is a genetic transmission of cystinuria
• hexagonal crystals
• malabsorption of dibasic amino acids COLA
• radioopaque

Question 28

which amino acids in cystine are not absorbed properly?

Answer 28

Cysteine, ornothine, Lysine and arginine

Question 29

what is the treatment for cystinuria?

Answer 29

• high fluid intake
• low Na diet
• alkalinization
• Chelating agents-D-penicillamine, tiopronin, captopril

Question 30

nephrolithiasis vs nephrocalcinosis

Answer 30

nephrolithiasis is outside the body in the tublues and nephrocalcinosis is the actual parenchyma

Question 31

what are the risk factors for uric acid stones

Answer 31

• low volume, high concentration with low pH
• Low purine diet, alkalinization with
• has plate- like stones