Clinicians should perform additional metabolic testing in high-risk or interested first-time stone formers and recurrent stone formers.
Metabolic testing should consist of one or two 24-hour urine collections obtained on a random diet and analyzed at minimum for total volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium and creatinine.
Clinicians should recommend to all stone formers a fluid intake that will achieve a urine volume of at least 2.5 liters daily
Clinicians should counsel patients with calcium stones and relatively high urinary calcium to limit sodium intake and consume 1,000 - 1,200 mg per day of dietary calcium.
Clinicians should offer thiazide diuretics to patients with high or relatively high urine calcium and recurrent calcium stones.
Clinicians should offer potassium citrate therapy to patients with recurrent calcium stones and low or relatively low urinary citrate
Clinicians should offer thiazide diuretics and/or potassium citrate to patients with recurrent calcium stones in whom other metabolic abnormalities are absent or have been appropriately addressed and stone formation persists.
Clinicians should offer potassium citrate to patients with uric acid and cystine stones to raise urinary pH to an optimal level.
Clinicians should offer cystine-binding thiol drugs, such as alpha-mercaptopropionylglycine (tiopronin), to patients with cystine stones who are unresponsive to dietary modifications and urinary alkalinization, or have large recurrent stone burdens.
Clinicians should obtain periodic blood testing to assess for adverse effects in patients on pharmacological therapy.
With fever or solitary kidney, and when diagnosis is doubtful, immediate imaging is indicated. Following initial US assessment, non contrast enhanced computed tomography should be used to confirm stone diagnosis in patients with acute flank pain.
In pregnant women, ultrasound is the imaging method of choice.
Always perform stone analysis in first-time formers using a valid procedure.
In all paediatric patients, efforts should be made to complete a metabolic evaluation based on stone analysis.
The dosage of alkalising medication must be modified by the patient according to urine pH, which is a direct consequence of such medication.
Renal stones should be treated in the case of growth, formation of de novo obstruction, associated infection, and acute or chronic pain.
Identification of biochemical risk factors and appropriate stone prevention is particularly indicated in patients with residual fragments or stones.
For recurrence prevention, the aim should be to obtain a 24-h urine volume > 2.5 L, restricted intake of salt, and avoid excessive intake of animal protein.
Comments of Evaluators:
Level of evidence and grade of recommendation given according to Oxford EBM Centre.