From the Guidelines
Outpatient treatment for kidney stones should prioritize increased fluid intake to achieve at least 2 L of urine per day to prevent recurrent nephrolithiasis. This approach is supported by low-quality evidence that shows increased fluid intake is associated with a reduction in stone recurrence 1. The American College of Physicians recommends management with increased fluid intake spread throughout the day, and notes that people who already drink recommended amounts of liquids and those in whom increased fluid intake is contraindicated should not be directed to increase their fluid intake further 1.
Some key considerations for outpatient treatment of kidney stones include:
- Increased fluid intake to achieve at least 2 L of urine per day
- Dietary modifications, such as reducing soft drink consumption, particularly those acidified by phosphoric acid, like colas
- Pharmacologic monotherapy with a thiazide diuretic, citrate, or allopurinol may be considered in patients with active disease in which increased fluid intake fails to reduce the formation of stones 1
- Patients should be advised to drink 2-3 liters of water daily to maintain clear or light yellow urine, which helps flush out stones and prevent new formation
It is essential to note that the evidence is limited, and most studies included only patients with calcium stones, with no trials assessing treatment in patients with uric acid or cystine stones 1. Therefore, treatment decisions should be made on a case-by-case basis, taking into account the individual patient's stone composition, medical history, and other factors.
From the Research
Outpatient Treatment for Kidney Stones
- The prevalence of kidney stones in the United States is 8.8%, with men affected more than women 2.
- Risk factors for kidney stone development include renal and ureteral anatomic abnormalities, family history, previous stones, older age, and various drugs 2.
- Symptoms of kidney stones include renal colic, dysuria, urinary frequency, hematuria, fever, flank pain, and groin pain 2.
- Renal ultrasonography is the recommended first-line imaging modality for diagnosing kidney stones, and is preferred in pregnant patients 2.
- Medical expulsive therapy (MET) is considered first-line therapy for patients with uncomplicated distal ureteral stones 10 mm in diameter or less 2, 3.
- Alpha-blockers, such as tamsulosin, are beneficial for increasing stone clearance rates in patients with ureteral stones ≤10 mm treated without lithotripsy 3, 4.
- Increased fluid intake and dietary interventions can reduce the risk of recurrence of kidney stones 2, 5.
Medical Expulsive Therapy (MET)
- MET is recommended for patients with uncomplicated distal ureteral stones 10 mm in diameter or less 2.
- Alpha-blockers, such as tamsulosin, are commonly used for MET 3, 4.
- The efficacy of MET may depend on stone size, with alpha-blockers performing better for stones 10 to 20 mm 3.
- MET can be considered post-lithotripsy for stones 5 to 10 mm, but little benefit may be seen 3.
Treatment Options
- Observation is a reasonable strategy for small, asymptomatic renal stones 6.
- Extracorporeal shock wave lithotripsy (ESWL) is an important treatment for nephrolithiasis in children and adults 6.
- Ureteroscopy is a minimally invasive treatment option for ureteral stones 6.
- Percutaneous nephrolithotomy is a more invasive treatment modality, but remains a good choice for patients with large-stone burdens 6.
- Open or laparoscopic stone surgery should be reserved for unique cases 6.