02-03-2011, 03:26 AM
A 63-year-old man is brought to the emergency department 3 hours after the acute onset of severe right-sided flank pain. He has a 9-year history of gout. His blood pressure is 110/84 mm Hg, pulse is 78/min, and respirations are 16/min. Examination shows normal bowel sounds and no abdominal tenderness or masses. Urinalysis shows 40 erythrocytes/hpf. Intravenous pyelography confirms a right ureteral calculus. Which of the following is the most likely underlying mechanism of this patient's urolithiasis?
A) An increase in urinary pH
B) Damage to the epithelial lining of the ureters
C) Lack of inhibitors of crystal formation
D) Presence of urease-splitting bacteria
E) Urinary supersaturation with uric acid
A) An increase in urinary pH
B) Damage to the epithelial lining of the ureters
C) Lack of inhibitors of crystal formation
D) Presence of urease-splitting bacteria
E) Urinary supersaturation with uric acid