American Board of Internal Medicine (ABIM) Certification Practice Exam

Mechanical stone removal is indicated for kidney stones of what size?

1. Greater than 10 mm

2. Greater than 5 mm

3. Less than 5 mm

4. Between 5 and 10 mm

The correct answer is: Greater than 10 mm

Mechanical stone removal is indicated for kidney stones that are greater than 10 mm in size. Stones of this size are less likely to pass spontaneously through the urinary tract without intervention. Typically, stones that are larger can cause significant obstruction, pain, and potential complications such as infection or renal damage. As a result, medical guidelines recommend addressing stones over this size using procedures like ureteroscopy, percutaneous nephrolithotomy, or shock wave lithotripsy to facilitate their removal and relieve any associated symptoms. Stones smaller than 10 mm can sometimes pass on their own, particularly those in the range of 5 to 10 mm, which can still be amenable to medical management or expectant observation in some cases. Conversely, stones less than 5 mm often pass without intervention, and therefore mechanical removal is not typically suggested for those sizes. This understanding is crucial in managing patients with nephrolithiasis effectively.