From the Guidelines
Referral to urology is not necessary for this 64-year-old man with an incidentally discovered 0.5 cm non-obstructing kidney stone in the lower pole of the right kidney. Small kidney stones less than 1 cm that are not causing symptoms or obstruction can typically be managed conservatively with observation and increased fluid intake. The patient should be advised to drink at least 2-3 liters of water daily to promote stone passage and prevent new stone formation.
Key Considerations
- Dietary modifications may also help, including limiting sodium intake to less than 2,300 mg daily, reducing animal protein consumption, and maintaining normal calcium intake (about 1,000-1,200 mg daily) from food sources.
- The patient should be monitored with follow-up imaging in 6-12 months to assess for stone growth or development of new stones.
- If the patient develops symptoms such as severe flank pain, blood in urine, fever, or signs of urinary tract infection, prompt medical attention should be sought, and referral to urology would then be appropriate. As noted in the 2007 guideline for the management of ureteral calculi 1, for ureteral stones <10 mm, observation with periodic evaluation is an option for initial treatment, which can be applied to small, asymptomatic kidney stones as well. The conservative approach is justified because small, asymptomatic lower pole stones have a low likelihood of causing complications and often remain stable or pass spontaneously without intervention.
From the Research
Patient Characteristics
- The patient is a 64-year-old man with a non-obstructing lithiasis in the lower pole of the right kidney, measuring 0.5 cm in diameter.
Treatment Options
- According to the study 2, most asymptomatic non-obstructing renal calculi remain asymptomatic, and less than 30% cause renal colic.
- The study 3 suggests that small non-obstructing calyceal stones can cause pain, and treatment with ureteroscopy can relieve this pain.
- The study 4 compares retrograde intrarenal surgery (RIRS) and extracorporeal shock wave lithotripsy (ESWL) for lower pole kidney stones up to 15 mm, and found that RIRS has the same results as ESWL in terms of stone-free rate, but is superior in terms of absence of clinically significant residual fragments.
Referral to Urology
- Based on the study 2, the patient's stone size and location (lower pole) suggest a low risk of symptoms or spontaneous passage, and active surveillance may be a suitable management option.
- However, the study 3 suggests that even small non-obstructing stones can cause pain, and the patient's age and overall health should be taken into account when deciding on referral to urology.
- The American Urological Association (AUA) guidelines recommend that patients with asymptomatic kidney stones be referred to urology if they have a stone larger than 1 cm, or if they have a history of stone-related symptoms or complications 2, 4.
Decision
- Given the patient's stone size (0.5 cm) and location (lower pole), and the low risk of symptoms or spontaneous passage, referral to urology may not be immediately necessary.
- However, the patient's age and overall health should be taken into account, and regular follow-up imaging may be recommended to monitor the stone and prevent potential complications 2, 4.