Managing Urolithiasis

Abstract

SEE EDITORIAL, P. 433. Urolithiasis is a common disease, estimated to affect 11% of men and 7% of women in their lifetime.1Scales C.D. Smith A.C. Hanley J.M. et al.Project Urologic Diseases of America ProjectPrevalence of kidney stones in the United States.Eur Urol. 2012; 62: 160-165Abstract Full Text Full Text PDF PubMed Scopus (1559) Google Scholar Ureteral stones can cause acute unilateral flank pain radiating to the groin, often accompanied by nausea, vomiting, and urinary symptoms.2Teichman J.M.H. Clinical practice. Acute renal colic from ureteral calculus.N Engl J Med. 2004; 350: 684-693Crossref PubMed Scopus (293) Google Scholar More than 1 million patients with suspected urolithiasis present to an emergency department (ED) each year in the United States.3Fwu C.-W. Eggers P.W. Kimmel P.L. et al.Emergency department visits, use of imaging, and drugs for urolithiasis have increased in the United States.Kidney Int. 2013; 83: 479-486Abstract Full Text Full Text PDF PubMed Scopus (159) Google Scholar This review will describe ED evaluation, therapies, and the identification of patients who require urgent urologic intervention, with recommendations based on clinical trials; on guidelines from the American College of Emergency Physicians (ACEP), American College of Radiology, and American Urologic Association; and on anecdotal experience. When ureteral stone is suspected, our foremost goal is to identify those patients who require urgent, and in some cases, emergency treatment, either for important alternative diagnoses (eg, appendicitis, cholecystitis, ovarian torsion)4Moore C.L. Daniels B. Singh D. et al.Prevalence and clinical importance of alternative causes of symptoms using a renal colic computed tomography protocol in patients with flank or back pain and absence of pyuria.Acad Emerg Med. 2013; 20: 470-478Crossref PubMed Scopus (44) Google Scholar or “stone-related emergencies” (Figure 1).2Teichman J.M.H. Clinical practice. Acute renal colic from ureteral calculus.N Engl J Med. 2004; 350: 684-693Crossref PubMed Scopus (293) Google Scholar, 5Preminger G.M. Tiselius H.-G. Assimos D.G. et al.2007 Guideline for the management of ureteral calculi.J Urol. 2007; 178: 2418-2434Abstract Full Text Full Text PDF PubMed Scopus (646) Google Scholar Approximately 10% of ED patients with suspected urolithiasis are admitted,6Westphalen A.C.H.R. Maselli J. Wang R.C. et al.Radiological imaging of patients with suspected urinary tract stones: national trends, diagnoses, and predictors.Acad Emerg Med. 2011; 18: 699-707Crossref PubMed Scopus (131) Google Scholar, 7Smith-Bindman R. Aubin C. Bailitz J. et al.Ultrasonography versus computed tomography for suspected nephrolithiasis.N Engl J Med. 2014; 371: 1100-1110Crossref PubMed Scopus (392) Google Scholar, 8Moore C.L. Bomann S. Daniels B. et al.Derivation and validation of a clinical prediction rule for uncomplicated ureteral stone—the STONE score: retrospective and prospective observational cohort studies.BMJ. 2014; 348: g2191Crossref PubMed Scopus (100) Google Scholar with prospective research identifying a 3.7% and 5.3% prevalence of important alternative diagnoses.8Moore C.L. Bomann S. Daniels B. et al.Derivation and validation of a clinical prediction rule for uncomplicated ureteral stone—the STONE score: retrospective and prospective observational cohort studies.BMJ. 2014; 348: g2191Crossref PubMed Scopus (100) Google Scholar, 9Wang R.C. Rodriguez R.M Moghadassi M. et al.External validation of the STONE score, a clinical prediction rule for ureteral stone: an observational multi-institutional study.Ann Emerg Med. 2016; 67: 423-432Google Scholar Our secondary goal of confirming the presence of urolithiasis is of lesser importance because patients with an uncomplicated stone are almost always managed expectantly. Ureterolithiasis causes severe unilateral colicky flank pain, and patients usually present soon (within hours) of onset. The pain may radiate from the flank anteromedially toward the groin into the genitals and may be accompanied by nausea, vomiting, and hematuria.2Teichman J.M.H. Clinical practice. Acute renal colic from ureteral calculus.N Engl J Med. 2004; 350: 684-693Crossref PubMed Scopus (293) Google Scholar, 8Moore C.L. Bomann S. Daniels B. et al.Derivation and validation of a clinical prediction rule for uncomplicated ureteral stone—the STONE score: retrospective and prospective observational cohort studies.BMJ. 2014; 348: g2191Crossref PubMed Scopus (100) Google Scholar Lower urinary tract symptoms such as dysuria and urgency suggest distal ureteral stones. The classic appearance is that of a patient in distress, unable to find a position of comfort. Vital signs are often normal. Atypical clinical features such as hypotension or abnormalities on abdominal, testicular, or pelvic examination suggest alternative diagnoses. Complicated urolithiasis should be suspected if there is persistent pain, vomiting, fever, pyuria, elevated creatinine level, anuria, or a history of a solitary or transplanted kidney. A history of urolithiasis decreases the risk of important alternative diagnosis.10Goldstone A. Bushnell A. Does diagnosis change as a result of repeat renal colic computed tomography scan in patients with a history of kidney stones?.Am J Emerg Med. 2010; 28: 291-295Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar Although hematuria is common in urolithiasis, it does not by itself exclude or reliably identify the diagnosis, with reported sensitivities ranging from 71% to 95% and specificities ranging from 18% to 49% for urolithiasis.11Kobayashi T. Nishizawa K. Watanabe J. et al.Clinical characteristics of ureteral calculi detected by nonenhanced computerized tomography after unclear results of plain radiography and ultrasonography.J Urol. 2003; 170: 799-802Abstract Full Text Full Text PDF PubMed Scopus (28) Google Scholar, 12Bove P. Kaplan D. Dalrymple N. et al.Reexamining the value of hematuria testing in patients with acute flank pain.J Urol. 1999; 162: 685-687Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar, 13Luchs J.S. Katz D.S. Lane M.J. et al.Utility of hematuria testing in patients with suspected renal colic: correlation with unenhanced helical CT results.Urology. 2002; 59: 839-842Abstract Full Text Full Text PDF PubMed Scopus (48) Google Scholar A positive pregnancy test result should lead to consideration of ectopic pregnancy as a cause of pain and also limits the choice of imaging to ultrasonography. With urolithiasis, the absence of pyuria cannot exclude a complicating urinary tract infection, with a reported sensitivity and specificity of 86% and 79%, respectively.14Abrahamian F.M. Krishnadasan A. Mower W.R. et al.Association of pyuria and clinical characteristics with the presence of urinary tract infection among patients with acute nephrolithiasis.Ann Emerg Med. 2013; 62: 526-533Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar Accordingly, stone patients at higher risk (female patients and those with pyuria or urinary tract infection symptoms) should receive a urine culture.14Abrahamian F.M. Krishnadasan A. Mower W.R. et al.Association of pyuria and clinical characteristics with the presence of urinary tract infection among patients with acute nephrolithiasis.Ann Emerg Med. 2013; 62: 526-533Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar The need for and type of imaging vary with underlying risk of important alternative diagnosis, ureteral stone, or a stone-related emergency (Figure 2). Emergency physicians should use clinical judgment to make this assessment. The STONE score is a clinical decision rule that sorts patients with suspected ureterolithiasis into low-, moderate-, and high-risk groups, with those with a high score in the original study having an 89% probability of a stone and a 1.6% probability of alternative diagnosis.8Moore C.L. Bomann S. Daniels B. et al.Derivation and validation of a clinical prediction rule for uncomplicated ureteral stone—the STONE score: retrospective and prospective observational cohort studies.BMJ. 2014; 348: g2191Crossref PubMed Scopus (100) Google Scholar In an external validation, the sensitivity and specificity of a high score were 53% and 87%, with a 1.2% probability of important alternative diagnosis (upper 95% confidence interval of 3.6%).9Wang R.C. Rodriguez R.M Moghadassi M. et al.External validation of the STONE score, a clinical prediction rule for ureteral stone: an observational multi-institutional study.Ann Emerg Med. 2016; 67: 423-432Google Scholar Thus, the STONE score alone cannot rule in or rule out stones or exclude clinically important diagnoses. Its role for imaging decisions remains undefined but has the potential to be used as part of an algorithm for suspected urolithiasis. Patients at moderate or high risk of a stone emergency or a clinically important alternative diagnosis should receive an unenhanced computed tomography (CT) scan. The accuracy of CT scan for ureteral stones is excellent, and CT scan can identify hydronephrosis, characterize stone size and location, and detect important alternative diagnoses.15Smith R.C. Verga M. McCarthy S. et al.Diagnosis of acute flank pain: value of unenhanced helical CT.AJR Am J Roentgenol. 1996; 166: 97-101Crossref PubMed Scopus (515) Google Scholar, 16Dalrymple N.C. Verga M. Anderson K.R. et al.The value of unenhanced helical computerized tomography in the management of acute flank pain.J Urol. 1998; 159: 735-740Abstract Full Text Full Text PDF PubMed Scopus (299) Google Scholar, 17Smith R.C. Verga M. Dalrymple N. et al.Acute ureteral obstruction: value of secondary signs of helical unenhanced CT.AJR Am J Roentgenol. 2012; 167: 1109-1113Crossref Scopus (229) Google Scholar, 18Hoppe H. Studer R. Kessler T.M. et al.Alternate or additional findings to stone disease on unenhanced computerized tomography for acute flank pain can impact management.J Urol. 2006; 175: 1725-1730Abstract Full Text Full Text PDF PubMed Scopus (75) Google Scholar The American College of Radiology gives their highest appropriateness rating for CT in patients with first-time acute flank pain,19Fritzsche P. Amis Jr., E.S. Bigongiari L.R. et al.Acute onset flank pain, suspicion of stone disease. American College of Radiology. ACR Appropriateness Criteria.Radiology. 2000; 215: 683PubMed Google Scholar and 70% of patients who received a diagnosis of urolithiasis received a CT scan in 2007.3Fwu C.-W. Eggers P.W. Kimmel P.L. et al.Emergency department visits, use of imaging, and drugs for urolithiasis have increased in the United States.Kidney Int. 2013; 83: 479-486Abstract Full Text Full Text PDF PubMed Scopus (159) Google Scholar Despite this, routine CT does not appear to improve outcomes. A national survey found no change in the diagnosis of kidney stone, alternative diagnoses, or hospitalization despite a 10-fold increase in CT use between 1995 and 2007.20Westphalen A.C. Hsia R.Y. Maselli J.H. et al.Radiological imaging of patients with suspected urinary tract stones: national trends, diagnoses, and predictors.Acad Emerg Med. 2011; 18: 699-707Crossref PubMed Scopus (37) Google Scholar The ability of CT to characterize stone size and location at the initial ED visit is not routinely necessary, and this imaging increases costs, incidental findings, length of stay, and the risk of subsequent cancer.21Smith-Bindman R. Lipson J. Marcus R. et al.Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer.Arch Intern Med. 2009; 169: 2078Crossref PubMed Scopus (1824) Google Scholar, 22Smith-Bindman R. Miglioretti D.L. Johnson E. et al.Use of diagnostic imaging studies and associated radiation exposure for patients enrolled in large integrated health care systems, 1996-2010.JAMA. 2012; 307: 2400-2409Crossref PubMed Scopus (637) Google Scholar, 23Smith-Bindman R. Miglioretti D.L. Larson E.B. Rising use of diagnostic medical imaging in a large integrated health system.Health Aff (Millwood). 2008; 27: 1491-1502Crossref PubMed Scopus (418) Google Scholar Thus, CT should be reserved for patients who would most benefit by increasing diagnostic certainty for clinically important diagnoses or experience less harm from radiation exposure. ACEP recommends avoiding CT scan in patients younger than 50 years and with a history of kidney stones presenting with recurrent symptoms. There is promise for reduced-dose CT scan protocols.24Moore C.L. Daniels B. Ghita M. et al.Accuracy of reduced-dose computed tomography for ureteral stones in emergency department patients.Ann Emerg Med. 2015; 65: 189-198.e182Abstract Full Text Full Text PDF PubMed Scopus (32) Google Scholar, 25Smith-Bindman R. Moghadassi M. Computed tomography radiation dose in patients with suspected urolithiasis.JAMA Intern Med. 2015; 175: 1413-1416Crossref PubMed Scopus (23) Google Scholar Patients at low risk of a stone emergency or a clinically important alternative diagnosis should receive ultrasonography, performed by either an emergency physician or the radiology department. Ultrasonography is less sensitive (24% to 57%) than CT for the identification of ureteral stone, especially small stones, and missed occasional occurrences of hydronephrosis in older studies, perhaps in dehydrated patients.26Fowler K.A.B. Locken J.A. Duchesne J.H. et al.US for detecting renal calculi with nonenhanced CT as a reference standard.Radiology. 2002; 222: 109-113Crossref PubMed Scopus (210) Google Scholar, 27Catalano O. Nunziata A. Altei F. et al.Suspected ureteral colic: primary helical CT versus selective helical CT after unenhanced radiography and sonography.AJR Am J Roentgenol. 2002; 178: 379-387Crossref PubMed Scopus (121) Google Scholar, 28Coursey C.A. Casalino D.D. Remer E.M. ACR Appropriateness Criteria® acute onset flank pain—suspicion of stone disease.Ultrasound. 2012; 28: 227-233Crossref Scopus (127) Google Scholar In a more recent prospective study, it was shown to accurately identify hydronephrosis (Figure 3).28Coursey C.A. Casalino D.D. Remer E.M. ACR Appropriateness Criteria® acute onset flank pain—suspicion of stone disease.Ultrasound. 2012; 28: 227-233Crossref Scopus (127) Google Scholar, 29Ripollés T. Agramunt M. Errando J. et al.Suspected ureteral colic: plain film and sonography vs unenhanced helical CT. A prospective study in 66 patients.Eur Radiol. 2004; 14: 129-136Crossref PubMed Scopus (120) Google Scholar Ultrasonography is first line for a number of important alternative diagnoses, such as cholecystitis and ovarian torsion, and is an acceptable initial test in appendicitis and aortic aneurysm. ACEP has identified urinary tract point-of-care ultrasonography as a core application since 2001.30American College of Emergency Physicians. Emergency ultrasound guidelines.Ann Emerg Med. 2009; 53: 550-570Abstract Full Text Full Text PDF PubMed Scopus (481) Google Scholar Its main limitation is operator skill; fellowship-trained emergency physicians have excellent sensitivity and good specificity for hydronephrosis, whereas those without fellowship training have modest accuracy.31Herbst M.K. Rosenberg G. Daniels B. et al.Effect of provider experience on clinician-performed ultrasonography for hydronephrosis in patients with suspected renal colic.Ann Emerg Med. 2014; 64: 269-276Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar In a multicenter randomized trial of point-of-care ultrasonography versus radiology ultrasonography versus CT scan, there was no significant difference in missed serious diagnosis or adverse events.7Smith-Bindman R. Aubin C. Bailitz J. et al.Ultrasonography versus computed tomography for suspected nephrolithiasis.N Engl J Med. 2014; 371: 1100-1110Crossref PubMed Scopus (392) Google Scholar A CT scan may be obtained if the clinician is still uncertain about the presence of a clinically important diagnosis after ultrasonography; in the randomized trial, 25% of patients in the radiology ultrasonography arm and 40% of those in the point-of-care ultrasonography arm ultimately received a CT scan.7Smith-Bindman R. Aubin C. Bailitz J. et al.Ultrasonography versus computed tomography for suspected nephrolithiasis.N Engl J Med. 2014; 371: 1100-1110Crossref PubMed Scopus (392) Google Scholar Ultrasonography is preferred in patients at highest risk for complications from ionizing radiation (pregnant or pediatric patients) or who are less likely to benefit from CT (history of kidney stones).19Fritzsche P. Amis Jr., E.S. Bigongiari L.R. et al.Acute onset flank pain, suspicion of stone disease. American College of Radiology. ACR Appropriateness Criteria.Radiology. 2000; 215: 683PubMed Google Scholar In my opinion, well-appearing, afebrile patients with mild or transient symptoms could receive ultrasonography or instead be discharged without imaging, with a plan to return for persistent or worsening symptoms. In a national survey of ED imaging in 2005 to 2007, approximately half of patients with suspected urolithiasis did not receive either ultrasonography or CT.20Westphalen A.C. Hsia R.Y. Maselli J.H. et al.Radiological imaging of patients with suspected urinary tract stones: national trends, diagnoses, and predictors.Acad Emerg Med. 2011; 18: 699-707Crossref PubMed Scopus (37) Google Scholar These may have been patients who had an alternative diagnosis that did not require imaging (such as pyelonephritis or low back pain) or had transient or straightforward renal colic. Pain relief. Provide analgesia, antiemetics, and intravenous hydration as needed at the evaluation. Nonsteroidal anti-inflammatories (eg, ketorolac 15 to 30 mg intravenously) can provide effective analgesia,32Holdgate A. Pollock T. Systematic review of the relative efficacy of non-steroidal anti-inflammatory drugs and opioids in the treatment of acute renal colic.BMJ. 2004; 328: 1401Crossref PubMed Scopus (176) Google Scholar with opioids administered either concurrently for rapid relief or if the nonsteroidal anti-inflammatory effect is insufficient. Use oral nonsteroidal anti-inflammatories with or without opioids for patients who are less symptomatic or for analgesia after discharge. Intravenous hydration will benefit patients who are dehydrated or have been unable to drink as a result of vomiting; however, this use of such fluids to “flush out” a stone has not been shown to improve clinical outcomes.33Worster A.S. Bhanich Supapol W. Fluids and diuretics for acute ureteric colic.Cochrane Database Syst Rev. 2012; : CD004926PubMed Google Scholar Patients at risk for a stone-related emergency should be admitted and receive urology consultation (Figure 1). When an obstructing stone is accompanied by sepsis, the urinary collecting system should be decompressed as quickly as possible.5Preminger G.M. Tiselius H.-G. Assimos D.G. et al.2007 Guideline for the management of ureteral calculi.J Urol. 2007; 178: 2418-2434Abstract Full Text Full Text PDF PubMed Scopus (646) Google Scholar Given the limitations of pyuria for the diagnosis,14Abrahamian F.M. Krishnadasan A. Mower W.R. et al.Association of pyuria and clinical characteristics with the presence of urinary tract infection among patients with acute nephrolithiasis.Ann Emerg Med. 2013; 62: 526-533Abstract Full Text Full Text PDF PubMed Scopus (15) Google Scholar patients with a suspected urinary tract infection in the absence of hydronephrosis, fever, or ill appearance could be discharged with oral antibiotic treatment, a urine culture, and close follow-up.5Preminger G.M. Tiselius H.-G. Assimos D.G. et al.2007 Guideline for the management of ureteral calculi.J Urol. 2007; 178: 2418-2434Abstract Full Text Full Text PDF PubMed Scopus (646) Google Scholar Among patients receiving a diagnosis of urolithiasis, 20% are admitted.7Smith-Bindman R. Aubin C. Bailitz J. et al.Ultrasonography versus computed tomography for suspected nephrolithiasis.N Engl J Med. 2014; 371: 1100-1110Crossref PubMed Scopus (392) Google Scholar, 20Westphalen A.C. Hsia R.Y. Maselli J.H. et al.Radiological imaging of patients with suspected urinary tract stones: national trends, diagnoses, and predictors.Acad Emerg Med. 2011; 18: 699-707Crossref PubMed Scopus (37) Google Scholar, 34Foster G, Stocks C, Borofsky MS. Statistical brief #139. Agency of Healthcare Research and Quality Report. 2012:1-10.Google Scholar Patients with urolithiasis and no indications for urgent intervention can be discharged home with a plan of observation for spontaneous stone passage. Large and proximally located stones are less likely to pass spontaneously; stones less than 5 mm and 5 to 10 mm have been noted to pass in 68% and 47% of cases, respectively.35Coll D.M. Varanelli M.J. Smith R.C. Relationship of spontaneous passage of ureteral calculi to stone size and location as revealed by unenhanced helical CT.AJR Am J Roentgenol. 2002; 178: 101-103Crossref PubMed Scopus (349) Google Scholar, 36Papa L. Stiell I.G. Wells G.A. et al.Predicting intervention in renal colic patients after emergency department evaluation.CJEM. 2005; 7: 78-86PubMed Google Scholar Urologists typically offer ureteroscopy or shock wave lithotripsy to patients with retained stones and persistent symptoms.5Preminger G.M. Tiselius H.-G. Assimos D.G. et al.2007 Guideline for the management of ureteral calculi.J Urol. 2007; 178: 2418-2434Abstract Full Text Full Text PDF PubMed Scopus (646) Google Scholar The American Urologic Association recommends urology consultation for stones greater than 10 mm and medical expulsive therapy (most commonly tamsulosin) for smaller stones.5Preminger G.M. Tiselius H.-G. Assimos D.G. et al.2007 Guideline for the management of ureteral calculi.J Urol. 2007; 178: 2418-2434Abstract Full Text Full Text PDF PubMed Scopus (646) Google Scholar Tamsulosin was reported as effective in enhancing stone passage in a recent Cochrane review of 28 randomized controlled trials (risk ratio 1.5; 95% confidence interval 1.3 to 1.6).37Campschroer T. Zhu Y. Duijvesz D. Alpha-blockers as medical expulsive therapy for ureteral stones.Cochrane Database Syst Rev. 2014; : CD008509PubMed Google Scholar Two subsequent multicenter randomized trials have yielded conflicting results; one found no benefit, and one restricted to distal stones noted benefit in patients with larger stones (>5 mm).38Pickard R. Starr K. MacLennan G. et al.Medical expulsive therapy in adults with ureteric colic: a multicentre, randomised, placebo-controlled trial.Lancet. 2015; 386: 341-349Google Scholar, 39Furyk J.S. Chu K. Banks C. et al.Distal ureteric stones and tamsulosin: a double-blind, placebo-controlled, randomized, multicenter trial.Ann Emerg Med. 2016; 67: 86-95Google Scholar Given that larger stones are less likely to spontaneously pass, it seems logical that these patients may actually benefit more from tamsulosin.35Coll D.M. Varanelli M.J. Smith R.C. Relationship of spontaneous passage of ureteral calculi to stone size and location as revealed by unenhanced helical CT.AJR Am J Roentgenol. 2002; 178: 101-103Crossref PubMed Scopus (349) Google Scholar, 39Furyk J.S. Chu K. Banks C. et al.Distal ureteric stones and tamsulosin: a double-blind, placebo-controlled, randomized, multicenter trial.Ann Emerg Med. 2016; 67: 86-95Google Scholar The principal adverse effect of these α-blockers is orthostatic hypotension (number needed to harm 19), although in most studies this did not require cessation of therapy.37Campschroer T. Zhu Y. Duijvesz D. Alpha-blockers as medical expulsive therapy for ureteral stones.Cochrane Database Syst Rev. 2014; : CD008509PubMed Google Scholar Dosing just before bedtime can mitigate the risk. Despite conflicting results between the Cochrane review and the trial with negative results, I believe currently the preponderance of the evidence suggests a benefit, and I would provide tamsulosin to patients who received a diagnosis of a ureteral stone. Finally, patients who receive a diagnosis of a ureteral stone should be instructed to follow up with a urologist and given appropriate instructions to return for worsening symptoms. The Importance of an Accurate Diagnosis for Renal ColicAnnals of Emergency MedicineVol. 68Issue 5PreviewWe thank Dr. Wang1 for his review of urolithiasis management in US emergency departments (EDs), and we appreciate the opportunity to provide commentary. There are several issues that we would like to address in regard to his recommendations for diagnosis and treatment of urinary stone disease. In general, our concerns are centered on the perception that a specific and accurate diagnosis of urinary stone disease is unnecessary unless suspected in the context of a stone emergency. Full-Text PDF