Welcome to the Navigator for the Medical Management of Kidney Stones adapted from AUA Guidelines
Steps:
- Describe Prior Stone Analysis
- Describe Metabolic Testing Results
- Follow the most update AUA guidelines recommendations to generate a treatment plan
Step 1:
-
Prior Stone Analaysis:
Step 2: Metabolic Testing
Serum Values
Calcium:
PTH:
Uric Acid:
Bicarbonate:
Urine Values
Creatinine:
14-26 mg/kg for men and 11-20 mg/kg for women
Total Urinary Volume:
pH:
Citrate:
Low is< 550mg/day
Calcium:
Elevated is > 250 mg/day for males and > 200 mg/day for females)
Sodium:
Elevated is > 150mEq/day
Oxalate:
>Elevated is > 40mg/day
Uric Acid:
Elevated is > 800mg/day
Sulfate:
Elevated is > 80meq/day
Magnesium:
Lab Dependent
pH:
Total Urinary Volume:
Total Cystine:
mg/day
Cystine Supersaturation:
Only applicable if not on Sulfhydryl drugs.
Cystine Capacity*:
*Only with Litholink >150 mg/L is considered normal
Step 3: Diagnosis and Treatment Recommendations
Stone: Unknown stone composition
Stone: Calcium (Excluding Carbonate Apatite)
Stone: Uric Acid
Recommendations
Pharmacology: Urinary pH should be 6-6.8. Supplement with Potassium Citrate if serum potassium level is normal and patient does not have CKD. Otherwise consider sodium bicarbonate and titrate to effect.
Other: Allopurinol should not be used as first line therapy! Diet and urinary pH should be addressed first.
Stone: Cystine
Recommendations
Dietary: Increase hydration, limit sodium and protein intake.
Stone: Likely Cystine (based on elevated urinary cystine)
Recommendations
Dietary: Increase hydration, limit sodium and protein intake.
Stone: Evaluate for Cystine (based on indeterminant urinary cystine)
Recommendations
Dietary: Increase hydration, limit sodium and protein intake.
Stone: Infection (Struvite/Carbonate Apatite)
Recommendations
Pharmacology: If complete stone removal is not deemed possible, offer acetohydroxamic acid (AHA) to patients with residual or recurrent struvite stones.
Surgical: Eliminate all stone burden if possible.
Other: Monitor patients with struvite stones for reinfection with urease producing organisms and treat or prevent accordingly. Urinary pH should be < 8 if the urease bacteriuria is resolved.
Metabolic Abnormality: Primary Hyperparathyroidism
Recommendations
Other: Refer to endocrine surgery.
Metabolic Abnormality: Consider Renal Tubular Acidosis
Recommendations
Other: No specific recommendation.
Metabolic Abnormality: Concern for Renal Tubular Acidosis
Recommendations
Pharmacology: Supplement with Potassium Citrate if serum potassium level is normal and patient does not have CKD. Otherwise consider sodium bicarbonate and titrate to effect.
Metabolic Abnormality: Hyperuricemia
Recommendations
Dietary: Decrease non-dairy animal protein.
Metabolic Abnormality: Hypercalciuria with Elevated Urinary Sodium
Recommendations
Dietary: Sodium restriction (<2300mg/day) and repeat 24 hour urine in approximately 6 weeks.
Metabolic Abnormality: Hyperoxaluria
Recommendations
Dietary: Limit intake of oxalate-rich foods and maintain normal calcium consumption (1000-1200mg/day); if hyperoxaluria persists despite dietary changes screen for primary hyperoxaluria.
Metabolic Abnormality: Elevated Urinary Sodium
Recommendations
Dietary: Sodium restriction (<2300mg/day) and repeat 24 hour urine in approximately 6 weeks.
Metabolic Abnormality: Hypercalciuria without Elevated Urinary Sodium
Recommendations
Dietary:
- Decrease non-dairy animal protein
- consume 1000 to 1200 mg dietary Ca per day
- Avoid Ca supplements unless prescribed for high urinary oxalate
- Consider fish-oil supplement
Pharmacology: Start thiazide (e.g. indapamide 1.25 - 2.5 mg daily or chlorthalidone 25 mg daily).
Metabolic Abnormality: Hyperuricosuria
Recommendations
Dietary: Decrease non-dairy animal protein and repeat 24-hour urine collection study.
Pharmacology: Start allopurinol (at either 100mg or 300mg daily and periodically check CBC), if despite dietary changes, hyperuricosuria persists.
Metabolic Abnormality: Hyperuricosuria with Low Urinary Sulfate
Recommendations
Dietary: Consider evaluating for unusual high purine food sources such as nuts and seed products and modify diet accordingly.
Pharmacology: Start allopurinol, if despite dietary changes, hyperuricosuria persists.
Metabolic Abnormality: Low Urinary Magnesium
Recommendations
Pharmacology: Supplement with Magnesium Oxide or Magnesium Citrate (Can cause diarrhea)
Metabolic Abnormality: Low Urinary Magnesium
Recommendations
Other: Magnesium may be depleted by incorporation into struvite stones. Therefore, do not supplement magnesium
Metabolic Abnormality: Hypocitraturia
Recommendations
Dietary: Supplement with lemon and lime.
Pharmacology: Supplement with Potassium Citrate if serum potassium level is normal and patient does not have CKD. Otherwise consider sodium bicarbonate or over the counter supplements and titrate to effect*. *It is important to note that the presence of bacteriuria will decrease the ability of pharmacotherapy to increase urinary citrate due to bacterial degradation of citrate and increasing the pH in this situation may increase bacterial growth.
Metabolic Abnormality: Hypocitraturia
Recommendations
Other: Hypocitraturia can be due to degradation of citrate by bacteriuria. Therefore, there is no role for citrate supplementation in the presence of bacteriuria.
Metabolic Abnormality: Low Urinary pH
Recommendations
Dietary: Increase intake of vegetables and fruit and decrease intake of non-dairy dietary animal protein if urinary sulfate is elevated.
Pharmacology: Supplement with Potassium Citrate if serum potassium level is normal and patient does not have CKD. Otherwise consider sodium bicarbonate or over the counter supplements and titrate to effect*. *It is important to note that the presence of bacteriuria will decrease the ability of pharmacotherapy to increase urinary citrate due to bacterial degradation of citrate and increasing the pH in this situation may increase bacterial growth.
Metabolic Abnormality: Low Urinary pH Affects Uric Acid Level
Recommendations
Pharmacology: Supplement with Potassium Citrate if serum potassium level is normal and patient does not have CKD. Otherwise consider sodium bicarbonate or over the counter supplements and titrate to effect*. *It is important to note that the presence of bacteriuria will decrease the ability of pharmacotherapy to increase urinary citrate due to bacterial degradation of citrate and increasing the pH in this situation may increase bacterial growth.
Other: Low urinary pH may cause uric acid to crystallize, decreasing its ability to be detected.
Metabolic Abnormality: Low Urinary pH
Recommendations
Dietary: Increase intake of vegetables and fruit and decrease intake of non-dairy dietary animal protein if urinary sulfate is elevated.
Pharmacology: Supplement with Potassium Citrate if serum potassium level is normal and patient does not have CKD. Otherwise consider sodium bicarbonate and titrate to effect. The goal is to achieve urine pH of 7-7.5 (monitor Calcium Phosphate supersaturation to minimize risk of secondary Calcium Phosphate stone formation from over alkalization).
Metabolic Abnormality: Elevated Urinary pH
Recommendations
Pharmacology: Consider titrating alkali therapy down to avoid formation of Calcium Phosphate stones.
Metabolic Abnormality: Extremely High Urinary pH
Recommendations
Other: Test for urea splitting infection (severe hypocitraturia usually associated from bacterial metabolism of urinary citrate).
Metabolic Abnormality: Low Urinary Cr
Recommendations
Other: Inadequate collection: recommend reviewing the instructions with the patient and repeating 24-hour urine collection.
Metabolic Abnormality: High Urinary Cr
Recommendations
Other: Over-collection: recommend reviewing the instructions with the patient and repeating 24-hour urine collection.
Metabolic Abnormality: Low Urinary Volume
Recommendations
Dietary: Increase hydration to a minimum of 3 Liters of fluid/day to make at least 2.5 Liters or urine
Metabolic Abnormality: Low Urinary Volume
Recommendations
Dietary: Increase hydration to make at least 3 Liters or urine/day
Metabolic Abnormality: Abnormal Cystine Capacity or Saturation
Recommendations
Pharmacology: Despite urinary alkalinization, cystine metabolism remains abnormal; therefore, initiate cystine-binding thiol drugs (e.g. alpha-mercaptopropionylglycine[tiopronin])
Metabolic Abnormality: None
Recommendations
Dietary: All stone formers should have adequate fluid intake that will achieve a urine volume of at least 2.5 liters daily.
Other: Consider repeating 24-Hour Urine Collection
Metabolic Abnormality: None
Recommendations
Other: Consider repeating 24-Hour Urine Collection
This app was adapted by Dr. Jonathan Katz, Dr. Robert Marcovich, and Dr. Roger Sur based on the AUA guidelines, “Medical Management of Kidney Stones (2019).” This app has not been approved or endorsed by the American Urological Association. Users should refer to the complete guideline at https://www.auanet.org/guidelines/guidelines/kidney-stones-medical-management-guideline.
This app is meant to assist clinical providers in navigating through the guideline. All clinical decisions are the sole responsibility of the provider and should be made based on their expertise and discretion.
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