By: Eli Baied.
Earlier this year the American Urological Association (AUA) announced their first medical guidelines for management of nephrolithiasis. The 27 guidelines outlined in the AUA review are aimed towards helping healthcare providers in the evaluation, treatment, and follow up for first time and recurrent kidney stones.
The AUA stressed the importance of a thorough screening evaluation, which includes a detailed medical history. Thorough screenings help healthcare providers detect conditions like hypothyroidism, gout, and obesity that might predispose someone to kidney stones. An individual’s dietary history and average daily fluid intake also gives insight into factors that may be associated with stone formation. The AUA also gives timeline recommendations for when a healthcare professional should order a PTH level and when a clinician should obtain a stone analysis.
The 27 guidelines outlined by the AUA are listed below:
1) A clinician should perform a screening evaluation consisting of a detailed medical and dietary history, serum chemistries and urinalysis on a patient newly diagnosed with kidney or ureteral stones.
2) Clinicians should obtain serum intact parathyroid (PTH) level as part of the screening evaluation if primary hyperparathyroidism is suspected.
3) When a stone is available, clinicians should obtain a stone analysis at least once.
4) Clinicians should obtain and review available imaging to quantify stone burden.
5) Clinicians should perform additional metabolic testing in high-risk or interested first-time stone formers and recurrent stone formers.
6) Metabolic testing should consist of one or two 24-hour urine collections obtained on a random diet and analyzed at a minimum for total volume, pH, calcium, oxalate, uric acid, citrate, sodium, potassium and creatinine.
7) Clinicians should not routinely perform “fast and calcium load” testing to distinguish among types of hypercalciuria.
8) Clinicians should recommend to all stone formers a fluid intake that will achieve a urine of at least 2.5 liters daily.
9) Clinicians should counsel patients with calcium stones and relatively high urinary calcium to limit sodium intake and consume 1000-2000 mg daily per day of dietary calcium.
10) Clinicians should counsel patients with calcium oxalate stones and relatively low urinary oxalate to limit intake of oxalate-rich foods and maintain normal calcium consumption.
11) Clinicians should encourage patients with calcium stones and relatively low urinary citrate to increase their intake of fruits and vegetables and limit non-dairy animal protein.
12) Clinicians should counsel patients with uric acid stones or calcium stones and relatively high urinary uric acid to limit intake of non-dairy animal protein.
13) Clinicians should counsel patients with cystine stones to limit sodium and protein intake.
14) Clinicians should offer thiazide diuretics to patients with high or relatively high urine calcium and recurrent calcium stones.
15) Clinicians should offer potassium citrate therapy to patients with recurrent calcium stones and low or relatively low urinary citrate.
16) Clinicians should offer allopurinol to patients with recurrent calcium oxalate stones who have hyperuricosuria and normal urinary calcium.
17) 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.
18) Clinicians should offer potassium citrate to patients with uric acid and cysteine stones to raise urinary pH to an optimal level.
19) Clinicians should not routinely offer allopurinol as first line therapy to patients with uric acid stones.
20) Clinicians should offer cysteine binding thiol drugs, such as alpha-mercaptopropionylglycine (tiopronin), to patient with cystine stones who are unresponsive to dietary modifications and urinary alkalizations, or have large recurrent stone burdens.
21) Clinicians may offer acetohydroxamic acid (AHA) to patients with residual or recurrent struvite stones only after surgical options have been exhausted.
22) Clinicians should obtain a single 24-hour urine specimen for stone risk factors within six months of the initiation of treatment to assess response to dietary and/or medical therapy.
23) After the initial follow-up, clinicians should obtain a single 24-hour urine specimen annually or with greater frequency, depending on stone activity, to assess patient adherence and metabolic response.
24) Clinicians should obtain periodic blood testing to assess for adverse effects in patients on pharmacological therapy.
25) Clinicians should obtain a repeat stone analysis, when available, especially in patients not responding to treatment.
26) Clinicians should monitor patients with struvite stones for reinfection with urease-producing organisms and utilize strategies to prevent such occurrences.
27) Clinicians should periodically obtain follow-up imaging studies to assess for stone growth or new stone formation based on stone activity (plain abdominal imaging, renal ultrasonography or low dose computed tomography (CT).
Disclaimer: Please note that the information above has been obtained from multiple sources for the sole purpose of student education and should not be used in the direct care of patients and/or clinical decision making.
1) Pearle M.S., Goldfarb D.S., Assimos D.G., Curhan G., Denu-Ciocca C.J., Matlaga B.R., Monga M., Penniston K.L., Preminger G.M., Turk T.M., White J.R. (2014). Medical Management of Kidney Stones: AUA Guideline. American Urological Association. pp. 1-26.