Guideline sources The following summarized guidelines for the evaluation and management of nephrolithiasis are prepared by our editorial team based on guidelines from the Canadian Urological Association (CUA 2022), the European Association of Urology (EAU 2021), the American Urological Association (AUA/ES 2016), and the American Urological Association (AUA 2014). 1 2 3 4 5 Calculator STONE score for uncomplicated https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 1/13 6/30/23, 1:16 AM Nephrolithiasis Pathway Guidelines 1. Diagnostic investigations Clinical evaluation: As per EAU 2021 guidelines, elicit a medical history including stone history (former stone events, family history), dietary habits and medication history in patients with stones of unknown composition. A As per AUA 2014 guidelines, obtain a detailed clinical evaluation in patients with newly diagnosed kidney or ureteral stones, including: a medical history, in order to screen for conditions associated with nephrolithiasis, such as obesity, hyperthyroidism, gout, renal tubular acidosis type 1, diabetes mellitus type 2, bone disease, primary hyperparathyroidism and malabsorptive gastrointestinal states a dietary evaluation, in order to screen for dietary habits associated with nephrolithiasis, such as low calcium intake, low fluid intake, high sodium intake, limited intake of fruits and vegetables, and high intake of animal-derived purines. B Blood tests: As per CUA 2022 guidelines: Obtain basic metabolic screening including serum electrolytes (sodium, potassium, calcium, bicarbonate) and creatinine. B Obtain an in-depth metabolic evaluation in patients with risk factors for recurrent stone disease or any of the following: children (< 18 years of age) bilateral or multiple stones recurrent stones ( 2 kidney stone episodes) non-calcium stones (such as uric acid, cystine) pure calcium phosphate stones any complicated stone episode resulted in a severe (if even temporary) AKI, sepsis, hospitalization, or complicated hospital admission any stone requiring percutaneous nephrolithotomy stones in the setting of a solitary (anatomical or functional) kidney renal insufficiency history of systemic disease increasing the risk of kidney stones (such as gout, osteoporosis, inflammatory bowel disorders, hyperparathyroidism, renal tubular acidosis, sarcoidosis, diabetes mellitus/metabolic syndrome) occupation where public safety is at risk (such as pilots, air traffic controller, police officer, military personnel, firemen) family history of kidney stones. B As per EAU 2021 guidelines: https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 2/13 6/30/23, 1:16 AM Nephrolithiasis Pathway Obtain serum chemistries, including creatinine, uric acid, (ionized) calcium, sodium, potassium, as well as blood cell count and CRP in patients with nephrolithiasis. A Obtain a coagulation test (PTT and INR) if intervention is likely or planned. A As per AUA 2014 guidelines: Obtain serum chemistries, including electrolytes (sodium, potassium, chloride, bicarbonate, calcium), creatinine and uric acid, in patients with newly diagnosed kidney or ureteral stones. B Obtain a serum intact PTH level as part of the screening evaluation in patients in whom primary hyperparathyroidism is suspected. B Urine tests: As per CUA 2022 guidelines: Obtain basic metabolic screening including a urinalysis, with or without a urine culture. B Prefer two 24-hour urine collections when possible balanced by the practicality and importance of obtaining at least one collection. B As per EAU 2021 guidelines: Obtain dipstick test of spot urine sample for red cells, white cells, nitrites, approximate urine pH, urine microscopy and/or culture in patients with nephrolithiasis. B Obtain urinalysis with the following measurements in patients with stones of unknown composition: urine pH (measurement after each voiding, minimum QID) dipstick test: white cells, red cells, nitrites, protein, urine pH, specific weight urine culture microscopy of urinary sediment (morning urine) cyanide nitroprusside test (cystine exclusion). A As per AUA 2014 guidelines, obtain urinalysis, including both dipstick and microscopic evaluation, in order to assess urine pH and indicators of infection and to identify crystals pathognomonic of stone type in patients with newly diagnosed kidney or ureteral stones. B Show 3 more Diagnostic imaging: As per EAU 2021 guidelines, obtain immediate imaging in patients with fever or solitary kidney, and if diagnosis is doubtful. A Show 2 more As per AUA 2014 guidelines, obtain or review available imaging studies to quantify stone burden. B Bone mineral density testing: consider obtaining bone mineral density testing in calcium stone forming patients with evidence of hypercalciuria and/or distal renal tubular acidosis. C 2. Diagnostic procedures https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 3/13 6/30/23, 1:16 AM Nephrolithiasis Pathway Stone analysis: As per CUA 2022 guidelines: Perform stone analysis when available. B Perform stone analysis when stones are collected by patients or removed at the time of surgical intervention. B As per EAU 2021 guidelines: Obtain stone analysis in first-time formers using a valid procedure (X-ray diffraction or infrared spectroscopy). A Repeat stone analysis in patients presenting with: recurrent stones despite drug therapy early recurrence after complete stone clearance late recurrence after a long stone-free period because stone composition may change. A As per AUA 2016 guidelines, send stone material for analysis. B As per AUA 2014 guidelines, obtain stone analysis, if available, at least once. B 3. Medical management Observation: As per EAU 2021 guidelines: Offer initial periodic evaluation in patients with newly diagnosed small ureteral stones, if active removal is not indicated. A Offer active surveillance in patients at high risk of thrombotic complications in the presence of an asymptomatic calyceal stone. B As per AUA 2016 guidelines, consider offering active surveillance in patients with asymptomatic, non-obstructing caliceal stones. C As per AUA 2016 guidelines, offer observation in patients with uncomplicated ureteral stones < 10 mm. B Medical expulsive therapy: As per EAU 2021 guidelines: Offer medical expulsive therapy with alpha-blockers as a treatment option in patients with (distal) ureteral stones > 5 mm. A Offer medical expulsive therapy in patients experiencing stent-related symptoms and after Ho:YAG laser lithotripsy to facilitate the passage of fragments. A As per AUA 2016 guidelines, offer medical expulsive therapy with alpha-blockers in patients with distal ureteral stones < 10 mm. B Show 2 more Updated evidence: STONE https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 4/13 6/30/23, 1:16 AM Nephrolithiasis Pathway In adult patients with a symptomatic urinary stone in the ureter < 9 mm in diameter, as demonstrated on CT, tamsulosin was not superior to placebo with respect to the rate of urinary stone passage at the end of 28-day treatment period. Meltzer AC et al. JAMA Intern Med. 2018 Aug 1. Oral chemolysis: As per CUA 2022 guidelines: Offer urinary alkalization to a pH of 6.5 as first-line therapy in patients with uric acid stones. Consider offering allopurinol as adjunctive therapy in patients with hyperuricemia or hyperuricosuria. B Offer urinary alkalization targeting a urine pH of 7-7.5 as initial therapy in cystine stone forming patients. Consider offering thiol-binding agents as second-line therapy. B As per EAU 2021 guidelines, instruct patients how to monitor urine pH by dipstick and to modify the dosage of alkalinizing medication according to urine pH, as changes in urine pH are a direct consequence of such medication. A Show 2 more Management of struvite stones: As per EAU 2021 guidelines, perform surgical removal of the struvite stone material as completely as possible. A Show 3 more As per AUA 2014 guidelines, consider offering acetohydroxamic acid in patients with residual or recurrent struvite stones, if surgical options have been exhausted. C Pain management: offer an NSAID as the first drug of choice in patients with renal colic, including dipyrone (metamizol), alternatively acetaminophen or, depending on cardiovascular risk factors, diclofenac, indomethacin or ibuprofen. A Show 2 more 4. Nonpharmacologic interventions Dietary modifications: As per CUA 2022 guidelines, obtain specific dietary assessment with an involvement of a registered dietitian, when possible. B Show 7 more As per EAU 2021 guidelines, advise maintaining a generous fluid intake, allowing for a 24-hour urine volume > 2.5 L, for the prevention of recurrence. A Show 2 more As per AUA 2014 guidelines, advise patients with nephrolithiasis the following dietary modifications according to the stone type: https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 5/13 6/30/23, 1:16 AM Nephrolithiasis Pathway Situation Guidance Maintain sufficient fluid intake to achieve a urine volume of at least 2.5 L/day B All types Limit sodium intake Calcium stones and relatively high urinary calcium Consume 1-1.2 g/day of dietary calcium B Limit intake of non-dairy animal protein E Calcium stones and relatively high urinary uric acid Limit intake of oxalate-rich foods Calcium oxalate stones and relatively high urinary oxalate Maintain normal calcium consumption E Limit intake of non-dairy animal protein E Uric acid stones and relatively high urinary uric acid Limit sodium and protein intake. E Cystine stones Dietary supplements: advise patients taking calcium supplements, if required, at mealtimes. B Show 3 more 5. Therapeutic procedures Indications for stone treatment: As per EAU 2021 guidelines, offer active treatment for renal stones in patients with stone growth, de novo obstruction, associated infection, and acute and/or chronic pain. B As per AUA 2016 guidelines, offer definitive stone treatment in most patients with ureteral stones if observation with or without medical expulsive therapy is not successful after 4-6 weeks and/or the patient/clinician decide to intervene sooner based on a shared decision-making approach. B Show 2 more Choice of procedure (general principles): evaluate stone composition before deciding on the method of removal, based on patient history, former stone analysis or HU on unenhanced CT. A Show 2 more Choice of procedure, renal stones: As per EAU 2021 guidelines, offer percutaneous nephrolithotomy as first-line therapy in patients with larger stones > 2 cm. A Show 4 more As per ES/AUA 2016 guidelines, offer percutaneous nephrolithotomy as first-line therapy in symptomatic patients with a total renal stone burden > 20 mm. B Show 11 more Choice of procedure, ureteral stones: https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 6/13 6/30/23, 1:16 AM Nephrolithiasis Pathway As per EAU 2021 guidelines, inform patients that ureteroscopy has a better chance of achieving stone-free status with a single procedure, but also has higher complication rates when compared to shock wave lithotripsy. A Show 2 more As per ES/AUA 2016 guidelines, inform patients with ureteral stones that shock-wave lithotripsy is the procedure with the least morbidity and lowest complication rate, but ureteroscopy has a greater stone-free rate in a single procedure. B Show 6 more Choice of procedure (steinstrasse): Prefer percutaneous nephrostomy for the management of patients with steinstrasse associated with UTI/fever. B Offer shock wave lithotripsy or ureteroscopy (in absence of signs of UTI) for the management of steinstrasse if large stone fragments are present. B Technical considerations (shock wave lithotripsy): ensure correct use of the coupling agent because this is crucial for effective shock wave transportation. A Show 3 more Technical considerations, ureterorenoscopy: As per EAU 2021 guidelines, use Ho:YAG laser lithotripsy for (flexible) ureteroscopy. A Show 2 more As per ES/AUA 2016 guidelines, do not place a ureteral stent routinely before ureteroscopy in patients with ureteral stones. D Show 3 more Technical considerations, percutaneous nephrolithotomy: As per EAU 2021 guidelines, perform a tubeless (without nephrostomy tube) or totally tubeless (without nephrostomy tube and ureteral stent) percutaneous nephrolithotomy procedure in uncomplicated cases. A As per ES/AUA 2016 guidelines, consider placing a nephrostomy tube in patients undergoing uncomplicated percutaneous nephrolithotomy presumed stone-free. C Show 2 more Urgent decompression: As per EAU 2021 guidelines, perform urgent decompression of the collecting system by percutaneous drainage or ureteral stenting in patients with sepsis with obstructing stones. A Show 2 more As per AUA 2016 guidelines: Perform urgent drainage of the collecting system with a stent or nephrostomy tube and delay stone treatment in patients with obstructing ureteral stones and suspected infection. B Abort stone removal procedures, establish appropriate drainage, continue antibiotic therapy, and obtain a urine culture if purulent urine is encountered during endoscopic intervention. B https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 7/13 6/30/23, 1:16 AM Nephrolithiasis Pathway 6. Perioperative care Preoperative evaluation, laboratory tests: As per EAU 2021 guidelines: Obtain a urine culture or perform urinary microscopy before any treatment is planned. A Exclude or treat UTIs before stone removal. A As per ES/AUA 2016 guidelines: Obtain CBC and platelet count in patients undergoing procedures with a significant risk of hemorrhage or in patients with symptoms suggesting anemia, thrombocytopenia or infection. Obtain serum electrolytes and creatinine if there is suspicion of reduced renal function. E Obtain urinalysis before intervention. Obtain urine culture in patients with clinical or laboratory signs of infection, urine culture. B Preoperative evaluation, imaging: As per EAU 2021 guidelines, obtain preprocedural imaging, including contrast medium where possible or retrograde study, before percutaneous nephrolithotomy to assess stone comprehensiveness and anatomy of the collecting system to ensure safe access to the renal stone. A As per ES/AUA 2016 guidelines, obtain non-contrast CT before percutaneous nephrolithotomy. B Show 4 more Preoperative precautions: take appropriate measures regardless of the treatment provided since in myelomeningocele patients latex allergy is common. A Preoperative antibiotic prophylaxis: As per EAU 2021 guidelines, administer perioperative antibiotic prophylaxis in all patients undergoing endourological treatment. A As per AUA 2016 guidelines, administer prophylactic antimicrobials before stone intervention based primarily on prior urine culture results, the local antibiogram, and in consultation with the current best practice policy statement on urologic surgery antibiotic prophylaxis. B Postoperative evaluation: obtain imaging after shock wave lithotripsy, ureteroscopy or percutaneous antegrade ureteroscopy to determine presence of residual fragments. A 7. Surgical interventions Surgical stone removal: As per EAU 2021 guidelines, offer laparoscopic or open surgical stone removal in rare cases when shock wave lithotripsy, retrograde or antegrade ureteroscopy and percutaneous nephrolithotomy fail or are unlikely to be successful. A As per AUA 2016 guidelines: https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 8/13 6/30/23, 1:16 AM Nephrolithiasis Pathway Do not offer open/laparoscopic/robotic surgery as first-line therapy in most patients with stones, except rare cases of anatomic abnormalities, large or complex stones, or requiring concomitant reconstruction. D Consider offering percutaneous nephrolithotomy, laparoscopic, open or robot-assisted stone removal in patients with ureteral stones failed or unlikely having successful results with shock- wave lithotripsy and/or ureteroscopy. C Nephrectomy: consider performing nephrectomy if the involved kidney has negligible function in patients with renal stones requiring treatment. C 8. Specific circumstances Pregnant patients: As per EAU 2021 guidelines, obtain ultrasound as the preferred imaging in pregnant patients. A Show 3 more As per AUA 2016 guidelines, coordinate pharmacological and surgical intervention in pregnant patients with the obstetrician. B Show 2 more Pediatric patients: As per CUA 2022 guidelines, obtain an in-depth medical evaluation in all pediatric patients with stone disease and consider providing a multidisciplinary approach with urology and nephrology. B As per EAU 2021 guidelines, obtain a metabolic evaluation based on stone analysis in all pediatric patients. A Show 8 more As per AUA 2016 guidelines, consider offering active surveillance with periodic ultrasound in asymptomatic patients with non-obstructing renal stones. E Show 7 more Patients at high thrombotic risk: offer active surveillance in patients at high risk of thrombotic complications in the presence of an asymptomatic calyceal stone. B Show 2 more Patients with transplanted kidneys: offer shock wave lithotripsy, flexible ureteroscopy or percutaneous nephrolithotomy for the management of nephrolithiasis in patients with transplanted kidneys. B 9. Preventative measures Prevention of stone recurrence: As per CUA 2022 guidelines, offer thiazide diuretics and alkali citrates to decrease urinary calcium, increase urinary citrate and reduce stone recurrence in calcium stone forming patients. https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 9/13 6/30/23, 1:16 AM Nephrolithiasis Pathway B Show 5 more As per EAU 2021 guidelines, offer the following agents and dietary modifications for the prevention of stones, according to the composition abnormalities: Situation Guidance Thiazide Hypercalciuria Alkaline citrates A Oxalate restriction B ; reduced dietary fat in enteric hyperoxaluria B ; calcium supplements in enteric hyperoxaluria B ; alkaline citrates in enteric hyperoxaluria B ; pyridoxine in primary hyperoxaluria A Hyperoxaluria Reduced dietary animal protein Hyperuricosuria Alkaline citrates Allopurinol Febuxostat as second-line therapy A Alkaline citrates Hypocitraturia Sodium bicarbonate A Increased fluid intake allowing for a 24-hour urine volume > 3 L Cystinuria Potassium citrate 3-10 mmol BID or TID, to achieve pH > 7.5 in patients with cystine excretion < 3 mmol/day Tiopronin 250-2,000 mg/day in addition to other measures in patients with cystine excretion > 3 mmol/day or when other measures are insufficient A Alkaline citrates. A Distal renal tubular acidosis As per AUA 2014 guidelines, offer thiazide diuretics in patients with high or relatively high urine calcium and recurrent calcium stones. B Show 7 more 10. Follow-up and surveillance Serial laboratory assessment: obtain 24-hour urine specimen for stone risk factors within 6 months to assess response to dietary and/or medical therapy. E Show 3 more https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 10/13 6/30/23, 1:16 AM Nephrolithiasis Pathway Serial imaging assessment: As per EAU 2021 guidelines, obtain periodic follow-up in patients with untreated renal stones initially after 6 months then yearly, evaluating symptoms and stone status, either by ultrasound, kidney-ureter bladder XR, or CT. A As per AUA 2014 guidelines, obtain follow-up imaging studies (plain abdominal imaging, renal ultrasound or low-dose CT) periodically to assess for stone growth or new stone formation, based on stone activity. E Clinical findings Symptoms Past medical history Abdominal pain Crohn's disease Blood in urine IBD Burning on urination Obesity Chills UTI Cloudy urine Family history Colicky abdominal pain Fever Family or personal history of kidney stones Hematuria LLQ pain Integument exam LUQ pain Nausea Dehydration RLQ pain RUQ pain Imaging findings Scrotal pain Hydronephrosis Urinary urgency Hydroureter Vomiting Renal stones Past surgical history Recent surgery Social history High-protein diet High-sodium diet Physical inactivity Lab findings Cystinuria Hyperkalemia Metabolic acidosis serum PTH https://web.pathway.md/diseases/rec5SNVxI0UraUE6Y 11/13 6/30/23, 1:16 AM Nephrolithiasis Pathway serum creatinine Histological findings RBCs Studies 2018 STONE In adult patients with a symptomatic urinary stone in the ureter < 9 mm in diameter, as demonstrated on CT, tamsulosin was not superior to placebo with respect to the rate of urinary stone passage at the end of 28-day treatment period. 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