Evaluation and Medical Management of Urinary Lithiasis

Question 1

Give the appearance of the FF

Calcium oxalate monohydrate

Calcium oxalate dihydrate

Calcium phosphate-apatite
Brushite
Magnesium ammonium phosphate (struvite)
Cystine Uric acid

Answer 1

Question 2

Lesch-Nyhan syndrome is a rare inherited disorder that leads to hyperuricemia and hyperuricosuria with resulting ___ formation.

Answer 2

uric acid stone

Question 3

Medullary sponge kidney may lead to calcium stone formation through :

Answer 3

URINARY STASIS and POOLING

Question 4

Based on expert opinion of the guidelines panel, metabolic testing should consist of one or two 24-hour urine collections obtained on a random diet and analyzed at minimum for total volume,(8)

Answer 4

total volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium and creatinine .

Question 5

Normal 24-hour creatinine per kilogram for a male is between __, for females ___. The high value, near 50 in the example, is indicative of excess creatinine in the specimen, most commonly caused by overcollection of urine beyond a 24-hour time period. studies more than 50 is invalid

Answer 5

20 and 25

for females 15-20

Question 6

Patients with enteric hyperoxaluria are more likely to form __ stones owing to increased urinary excretion of __ and decreased inhibitory activity from ___ secondary to __ and __. In addition, __ from persistent diarrhea from inflammatory bowel disease may cause an extremely concentrated environment that is suitable for stone formation.

Answer 6

Calcium Oxalate stones

urinary excretion of oxalate

Decreased inhibitory activity fro hypo hypocitraruria

Chronic metabolic acidosis

hypomagnesiuria

Fluid loss from diarrhea

Question 7

Colonic resection may be of benefit in those patients refractory to medical management because the primary site of intestinal absorption of ___ is the large bowel.

Answer 7

OXALATE

Question 8

Although low urine volumes and hyperuricosuria contribute to the possibility of uric acid stone formation, the most critical determinant of the crystallization of uric acid remains___.

Answer 8

URINARY PH

In addition, uric acid stones may be formed in patients with primary gout with associated severe hyperuricosuria and other secondary causes of purine overproduction, such as myeloproliferative states, glycogen storage disease, and malignancy. Patients with uric acid stones will characteristically have urinary pH lower than the dissociation constant for uric acid (5.5). In fact, many will have a urine pH consistently close to 5. Whereas serum and urine uric acid levels may be elevated in patients with uric acid calculi, the urine pH remains the most cost-effective means of screening for this condition and monitoring therapy.