From the Guidelines
For a 64-year-old man with an incidentally discovered 0.5 cm non-obstructing stone in the lower pole of the right kidney, active follow-up is generally not required. This approach is supported by the European Association of Urology (EAU) guidelines, which suggest that active surveillance is acceptable for stones up to 15 mm in diameter 1. Given the small size of the stone, the risk of complications or symptoms is low, and the benefits of conservative management outweigh the risks of intervention.
The patient can be advised to manage the condition conservatively with increased fluid intake of at least 2-2.5 liters of water daily to prevent stone growth and facilitate potential spontaneous passage. Additionally, the patient should be informed to strain their urine if they experience symptoms suggestive of stone passage. Follow-up imaging is typically unnecessary unless the patient develops symptoms such as flank pain, hematuria, or urinary tract infection.
Dietary modifications may also be beneficial, including limiting sodium intake to less than 2,300 mg daily, reducing animal protein consumption, and maintaining normal calcium intake (1,000-1,200 mg daily) through dietary sources rather than supplements. If the patient develops symptoms or if future imaging for other reasons shows stone growth beyond 1 cm, referral to urology would be appropriate. This conservative approach is recommended because small, asymptomatic lower pole stones have a low probability of causing problems, and the risks of intervention typically outweigh the benefits for stones of this size and location, as suggested by the guidelines evaluated in the study published in The Journal of Urology 1.
Key points to consider in the management of this patient include:
- Stone size and location: The stone is small (0.5 cm) and located in the lower pole of the right kidney.
- Symptom status: The patient is asymptomatic.
- Risk of complications: The risk of complications or symptoms is low for small, asymptomatic lower pole stones.
- Benefits and risks of intervention: The risks of intervention typically outweigh the benefits for stones of this size and location.
From the Research
Follow-up Imaging and Management
The patient has a non-obstructing lithiasis measuring 0.5 cm in diameter in the right kidney lower pole. Considering the size of the stone, the following options are available:
- Observation: Since the stone is smaller than 1 cm in diameter, observation is a viable option 2.
- Shock wave lithotripsy: This treatment modality has similar stone-free rates to ureteroscopy and may be preferable due to more favorable secondary outcomes 2.
- Ureteroscopy: This is another treatment option for lower pole stones smaller than 1 cm in diameter 2.
Imaging Techniques
For follow-up imaging, the following techniques can be used:
- Non-contrast enhanced CT scan: This has high sensitivity and specificity, but concerns about radiation exposure and costs remain 3, 4.
- Ultrasonography: This can be used as an alternative to CT scan, especially in pregnant patients and children 3.
- Magnetic resonance imaging: This can also be used as an alternative to CT scan in certain cases 3.
Frequency and Type of Imaging
There is no evidence to support strong recommendations regarding the frequency and type of imaging for follow-up of patients with urolithiasis (treated or under observation) 3. The choice of imaging technique and frequency of follow-up will depend on the individual patient's characteristics and the available resources.