The physician suspects that a client with kidney stones has developed magnesium ammonium phosphate (struvite) stones based on which of the following urinalysis results? Select all that apply

Question

A) Elevated uric acid levels
B) Alkaline urine pH
C) High urine phosphate level
D) High bacterial count
E) Presence of cystine particles

Answer 1

Ans: B, C, D
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Magnesium ammonium phosphate stones, also called struvite stones, form only in alkaline urine and in the presence of bacteria that possess an enzyme called urease, which splits the urea in the urine into ammonia and carbon dioxide. The ammonia that is formed takes up a hydrogen ion to become an ammonium ion, increasing the pH of the urine so that it becomes more alkaline. Because phosphate levels are increased in alkaline urine and because magnesium always is present in the urine, struvite stones form. Uric acid stones develop in conditions of gout and high concentrations of uric acid in the urine. Cystine stones account for less than 1% of kidney stones overall but represent a significant proportion of childhood calculi. They are seen in cystinuria, which results from a genetic defect in renal transport of cystine.