From the Guidelines
For an asymptomatic 1.3 cm kidney stone found on ultrasound, the best course of action is typically surgical intervention, most commonly shock wave lithotripsy (SWL) or ureteroscopy with laser lithotripsy, as this size of stone is unlikely to pass spontaneously and carries risk for future complications if left untreated 1.
Key Considerations
- The patient should increase fluid intake to at least 2-3 liters of water daily to prevent stone growth and maintain hydration.
- Pain management with medications like ibuprofen (600-800 mg every 6-8 hours) or acetaminophen (650-1000 mg every 6 hours) should be available if symptoms develop.
- A medical expulsive therapy with tamsulosin 0.4 mg daily might be prescribed if the stone moves into the ureter.
- Before proceeding with any intervention, a non-contrast CT scan is recommended to confirm the stone's exact size, location, and density, which helps determine the optimal treatment approach 1.
Dietary Modifications
- Reducing sodium intake to less than 2,300 mg daily
- Limiting animal protein
- Avoiding foods high in oxalate if the stone is composed of calcium oxalate
Rationale for Intervention
The rationale for intervention is that stones of this size rarely pass spontaneously and can lead to obstruction, infection, or kidney damage if left untreated 1.
Additional Recommendations
- Clinicians should inform patients that SWL is the procedure with the least morbidity and lowest complication rate, but URS has a greater stone-free rate in a single procedure 1.
- URS is recommended for patients with suspected cystine or uric acid ureteral stones 1.
- Routine stenting should not be performed in patients undergoing SWL 1.
From the Research
Asymptomatic Kidney Stone Treatment
For an asymptomatic patient with a 1.3 cm kidney stone found on ultrasound, the following points should be considered:
- The size and location of the stone are crucial in determining the treatment approach 2.
- Ultrasound is a useful initial imaging modality for detecting kidney stones, but its accuracy may be limited, especially for smaller stones 3.
- Computed Tomography (CT) scan is considered the gold standard for evaluating kidney stones, but it may also have limitations, such as motion artifact, which can affect stone size measurement 2.
Imaging and Stone Size Measurement
- The accuracy of stone size measurement can be improved by using techniques such as adjusting gain and depth, alternate modes like flash angle imaging, harmonic mode, and S mode, and using shadow for size measurement 3.
- A new automated computerized stone-sizing program can also improve the accuracy of stone size calculation and reduce user variability 3.
- Low-dose CT scan protocols can be effective in detecting stone fragments, but the minimum radiation dose required may vary depending on stone composition 4.
Treatment Approach
- For asymptomatic kidney stones, the treatment approach may depend on the size, location, and composition of the stone, as well as the patient's overall health and medical history.
- Percutaneous nephrolithotomy (PCNL) is a common treatment approach for larger stones, but it may be associated with complications, such as bleeding and infection 2, 5.
- The optimal duration of antibiotic therapy after PCNL is unknown, and further research is needed to determine the best approach 5.
Key Considerations
- The patient's symptoms, medical history, and overall health should be taken into account when determining the best course of action for an asymptomatic kidney stone.
- Imaging modalities, such as ultrasound and CT scan, should be used to evaluate the size, location, and composition of the stone, and to guide treatment decisions 2, 3, 6, 4.