Initial Treatment of Kidney Stones

Acute Pain Management

The American College of Physicians recommends administering intramuscular diclofenac 75 mg as first-line therapy for acute kidney stone pain, which should provide relief within 30 minutes, and is superior to opioids in efficacy while avoiding dependence risks 1, 2
NSAIDs are the definitive first-line analgesic for acute renal colic, not opioids, as they decrease ureteral smooth muscle tone and spasm, directly addressing the pain mechanism 1, 2
Reserve opioids, such as morphine sulfate with cyclizine, only when NSAIDs are contraindicated due to cardiovascular disease, gastrointestinal comorbidities, hypertension, renal insufficiency, heart failure, or peptic ulcer risk 2

All patients require medical assessment within 30 minutes to exclude life-threatening conditions and determine management setting 2
Immediate hospital admission is mandatory for patients with shock or fever, failure to respond to analgesia within one hour, abrupt recurrence of severe pain after initial relief, patients over 60 years, and women with delayed menses 2

Obtain stone analysis at least once when available, as composition directs specific preventive measures, according to the American Urological Association 3, 4, 5
Perform urinalysis with both dipstick and microscopic evaluation to assess urine pH, infection indicators, and identify pathognomonic crystals 3, 4, 5
Order serum chemistries, including electrolytes, calcium, creatinine, and uric acid, to identify underlying conditions 5
Obtain imaging within 7 days to quantify stone burden, with renal ultrasonography as the first-line modality 2, 5

For uncomplicated ureteral stones ≤10 mm, conservative management with medical expulsive therapy is appropriate if pain is well-controlled, sepsis is absent, and renal function is adequate, as recommended by the European Association of Urology 1, 5
Prescribe alpha-blockers, such as tamsulosin, for medical expulsive therapy, particularly for stones >5 mm in the distal ureter 1, 5
The maximum duration of conservative treatment is 4-6 weeks from initial presentation, with mandatory periodic imaging to monitor stone position and hydronephrosis 1, 2, 5

Instruct patients to drink fluids targeting urine output of at least 2.5 liters daily to promote stone passage, as suggested by the National Institute of Diabetes and Digestive and Kidney Diseases 2, 3, 4
Have patients void into a container or tea strainer to catch stones for analysis 2

For calcium stones, offer thiazide diuretics to patients with high urinary calcium and recurrent stones, and potassium citrate to patients with low urinary citrate, as recommended by the American Urological Association 5, 7
For uric acid stones, potassium citrate is first-line therapy to alkalinize urine to pH ~6.0, and most patients have low urinary pH rather than hyperuricosuria as the predominant risk factor 5, 7
For cystine stones, first-line includes increased fluid intake, sodium/protein restriction, and urinary alkalinization, and add cystine-binding thiol drugs, such as tiopronin, if unresponsive to dietary modifications 5, 7

Do not use opioids as first-line therapy—NSAIDs are superior and avoid dependence risks, as stated by the American College of Physicians 1, 2
Do not prescribe allopurinol as first-line for uric acid stones—urinary alkalinization with potassium citrate is correct, according to the European Association of Urology 5, 7
Do not delay admission for fever with obstruction—this represents sepsis requiring urgent drainage via percutaneous nephrostomy or ureteral stenting, as recommended by the American Urological Association 1