A 32-year-old woman comes to the emergency department due to right flank pain for the last 12 hours. The patient describes severe, intermittent pain lasting 20-30 minutes at a time. She has also had nausea and several episodes of vomiting but no fever, chills, dysuria, or diarrhea. The patient had similar symptoms 2 years ago and was found to have a renal calculus. The stone passed spontaneously and no analysis was performed. She has no other medical conditions and takes no medications.
Temperature is 36.8 C (98.2 F) , blood pressure is 132/74 mm Hg, pulse is 90/min, and respirations are 16/min. BMI is 32 kg/m². Physical examination shows dry mucous membranes. There is mild right flank tenderness without guarding or rebound tenderness.
Blood cell counts are within normal limits, serum creatinine is 1.4 mg/dL, and blood urea nitrogen is 33 mg/dL. Urinalysis shows moderate blood with numerous erythrocytes and a pH of 6.5. Urine pregnancy test is negative. Noncontrast abdominal CT scan reveals a high-density, 15-mm calculus in the proximal right ureter without hydronephrosis.
Intravenous analgesics, antiemetics, and fluids are administered. Which of the following is the most appropriate next step in management of this patient?

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Quizplus · Accepted Answer

11ec193a_96ac_b0fb_853d_815a360756d7_MD0002_00 Initial medical management for nephrolithiasis includes pain control and hydration; further therapy depends on stone size and patient presentation. Noncontrast CT scan is the preferred imaging modality to assess stone size, location, and presence of obstruction, although ultrasound is recommended for pregnant patients to reduce radiation exposure. Kidney stones <10 mm are likely to pass spontaneously. Patients who do not have clinical complications can be managed conservatively with pain control, hydration, and medical expulsive therapy (eg, alpha blockers, calcium channel blockers); urine should be strained to ensure appropriate stone passage (Choice C).Patients with stones ≥10 mm (as in this patient), those with complicated nephrolithiasis (eg, acute kidney injury [AKI], sepsis, complete ureteral obstruction, uncontrolled pain), and those whose stones do not pass within 4-6 weeks should be evaluated by a urologist for stone removal. Shock wave lithotripsy or ureteroscopy is commonly employed, but stones >15 mm typically require endoscopic stone fragmentation. Kidney stones <10 mm are likely to pass spontaneously. Patients who do not have clinical complications can be managed conservatively with pain control, hydration, and medical expulsive therapy (eg, alpha blockers, calcium channel blockers); urine should be strained to ensure appropriate stone passage (Choice C). Kidney stones <10 mm are likely to pass spontaneously. Patients who do not have clinical complications can be managed conservatively with pain control, hydration, and medical expulsive therapy (eg, alpha blockers, calcium channel blockers); urine should be strained to ensure appropriate stone passage (Choice C). Patients with stones ≥10 mm (as in this patient), those with complicated nephrolithiasis (eg, acute kidney injury [AKI], sepsis, complete ureteral obstruction, uncontrolled pain), and those whose stones do not pass within 4-6 weeks should be evaluated by a urologist for stone removal. Shock wave lithotripsy or ureteroscopy is commonly employed, but stones >15 mm typically require endoscopic stone fragmentation. Patients with stones ≥10 mm (as in this patient), those with complicated nephrolithiasis (eg, acute kidney injury [AKI], sepsis, complete ureteral obstruction, uncontrolled pain), and those whose stones do not pass within 4-6 weeks should be evaluated by a urologist for stone removal. Shock wave lithotripsy or ureteroscopy is commonly employed, but stones >15 mm typically require endoscopic stone fragmentation. (Choice A) Alpha blockers (eg, tamsulosin) are commonly recommended to facilitate stone passage for stones <10 mm, but their use is controversial and some studies have indicated minimal benefit for stones ≥10 mm. (Choice B) Percutaneous nephrostomy tube placement relieves urinary obstruction in cases of nephrolithiasis with hydronephrosis and rapidly progressive renal failure. However, the procedure does not facilitate stone removal and is typically offered following urologic evaluation to patients who are poor candidates for emergency stone removal (eg, due to multiple medical comorbidities). It is not indicated in this patient with no contraindications to a urologic intervention and no hydronephrosis (her AKI is likely prerenal given her vomiting and her blood urea nitrogen/creatinine ratio >20). (Choice D) Sodium bicarbonate infusion is used to alkalinize the urine in patients with uric acid stones. However, uric acid stones generally occur in persistently acidic urine (pH <5.5) and are radiolucent (unlike high-density, calcium-based stones); this patient's urine pH of 6.5 and high-density stone make this diagnosis unlikely. Educational objective: Patients with stones ≥10 mm, those with complicated nephrolithiasis (eg, acute kidney injury, sepsis, complete ureteral obstruction, uncontrolled pain), and those whose stones do not pass within 4-6 weeks should be evaluated by a urologist for stone removal. __________

A 32-Year-Old Woman Comes to the Emergency Department Due to Right