CE/CME Kidney Stones Current Diagnosis and Management

Catherine C. Wells, DNP, ACNP, Kiran B. Chandrashekar, MD, Garikiparthy N. Jyothirmayi, PhD, PA-C, Vikesh Tahiliani, MD, John C. Sabatino, MD, Luis A. Juncos, MD, FASN, FAHA The lifetime risk for nephrolithiasis is estimated between 15% and 25%, and changes in diet and lifestyle may have contributed to increased incidence in women and adolescents. The high Urinary stones can be classifi ed as calcium-based, rate at which urinary stones recur—and the potential in patients struvite, uric acid, or cystine stones, and mixed with chronic stone disease for impaired kidney function—should stone types exist. Stone composition will determine strategies to prevent recurrence. prompt primary care providers to seek a fuller understanding of urinary stone disease.

CE/CME INFORMATION

TARGET AUDIENCE: This activity has been de- Assistant Professor in the Department of Radiology at METHOD OF PARTICIPATION: The fee for signed to meet the educational needs of physician assis- UMDNJ–New Jersey Medical School. Luis A. Juncos, participating and receiving CME credit for this activ- tants and nurse practitioners in primary care with pa- MD, FASN, FAHA, is the John D. Bower Chair of Ne- ity is $10.00. During the period February 2012 tients who have signs and symptoms of nephrolithiasis. phrology and Hypertension and Professor of Medi- through February 28, 2013, participants must 1) read • Original Release Date: February 2012 cine, Physiology, and Biophysics in the Department of the learning objectives and faculty disclosures; 2) study • Expiration Date: February 28, 2013 Medicine Division of Nephrology at the University of the educational activity; 3) go to www.clinician • Estimated Time to Complete This Activity: 1 hour Mississippi Medical Center. reviews.com/CECourses.aspx, follow links to the • Medium: Printed journal and online CE/CME posttest for this activity, and provide payment informa- ACCREDITATION STATEMENT: tion via our secure server; 4) complete the 10-question PROGRAM OVERVIEW: The primary objective of PHYSICIAN ASSISTANTS posttest by recording the best answer to each question; this educational initiative is to provide clinicians in pri- This program has been reviewed and is approved for a and 5) record their response to each of the additional mary care with the most up-to-date information re- maximum of 1.0 hour of American Academy of Physi- evaluation questions. garding the risk factors for kidney stones and the detec- cian Assistants (AAPA) Category I CME credit by the If you have any questions, e-mail CR.evaluations@ tion and management of stone disease. Physician Assistant Review Panel. Approval is valid for qhc.com. Upon successful completion of an online one year from the issue date of February 2012. Par- posttest, with a score of 70% or better, and the comple- EDUCATIONAL OBJECTIVES: After completing ticipants may submit the self-assessment at any time tion of the online activity evaluation form, a statement this activity, the participant should be better able to: during that period. of credit will be made available immediately. • List conditions in the differential diagnosis for uri- This program was planned in accordance with AA- nary tract stones, as well as systemic disorders that are PA’s CME Standards for Enduring Material Programs DISCLOSURE OF UNLABELED USE: This ed- associated with stone disease. and for Commercial Support of Enduring Material ucational activity may contain discussion of published • Explain the known advantages and disadvantages of the Programs. and/or investigational uses of agents that are not indi- imaging options used in the diagnosis of stone disease. Successful completion of the self-assessment is re- cated by the FDA. AAPA, The NPA, and Quadrant • Discuss appropriate use of pharmacology, nephroli- quired to earn Category I CME credit. Successful com- HealthCom Inc. do not recommend the use of any thotripsy, and endoscopic surgery in the acute and pletion is defi ned as a cumulative score of at least 70% agent outside of the labeled indications. chronic management of uncomplicated and obstruc- correct. The opinions expressed in this educational activity tive stone disease. are those of the faculty and do not necessarily represent • Describe strategies to prevent stone recurrence, both ACCREDITATION STATEMENT: the views of AAPA, The NPA, or Quadrant Health- general and specifi c to stone type. NURSE PRACTITIONERS Com Inc. Please refer to the offi cial prescribing infor- This program has been approved by the Nurse Practi- mation for each product for discussion of approved in- FACULTY: Catherine C. Wells, DNP, ACNP, is a tioner Association New York State (The NPA) for 1.0 dications, contraindications, and warnings. certifi ed nephrology nurse practitioner at University of contact hour. Mississippi Health Care and a clinical instructor in the DISCLAIMER: Participants have an implied respon- Division of Nephrology at the University of Mississip- DISCLOSURE OF CONFLICTS OF INTER- sibility to use the newly acquired information to en- pi Medical Center (UMC) in Jackson. Kiran B. Chan- EST: The faculty reported the following fi nancial rela- hance patient outcomes and their own professional drashekar, MD, is a postdoctoral research fellow in the tionships or relationships to products or devices they or development. The information presented in this activ- Division of Nephrology at UMC. Garikiparthy N. their spouse/life partner have with commercial inter- ity is not meant to serve as a guideline for patient man- Jyothirmayi, PhD, PA-C, is a physician assistant in the ests related to the content of this CME activity: Cath- agement. Any procedures, medications, or other cours- Department of Academic Medicine at the University of erine C. Wells, DNP, ACNP, Kiran B. Chandrashek- es of diagnosis or treatment discussed or suggested in Medicine and Dentistry of New Jersey (UMDNJ)– ar, MD, Garikiparthy N. Jyothirmayi, PhD, PA-C, this activity should not be used by clinicians without New Jersey Medical School in Newark. Vikesh Tahil- Vikesh Tahiliani, MD, John C. Sabatino, MD, and evaluation of their patient’s conditions and the possible iani, MD, is the Divisional Medical Director for Mid- Luis A. Juncos, MD, FASN, FAHA, reported no signifi - contraindications or dangers in use, review of any ap- west Physicians at Centerpoint Medical Center in cant fi nancial relationship with any commercial entity plicable manufacturer’s product information, and com- Independence, Missouri. John C. Sabatino, MD, is an related to this activity. parison with recommendations of other authorities.

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idney or urinary dence from several studies sug- FIGURE 1 tract stones (whose gests that patients with a history 7 presence is referred of stone disease have a higher Ethnic diversity in the prevalence of kidney stones to as nephrolithiasis) probability of experiencing a Asian women 4.9% areK hard, crystalline mineral signifi cant reduction in renal concretions that form within the function (ie, decrease in glomer- kidney or the urinary tract. ular fi ltration rate) and hence Black They are a common problem, end-stage renal disease, when women with an estimated annual inci- compared with non–stone form- 6.2% dence of 1% and a lifetime risk ers.9-11 This accentuates the im- Hispanic White men of 15% to 25%; this constitutes a portance of early diagnosis, 24.6% women signifi cant health care burden, treatment, and initiation of steps 8.6% particularly for people of work- to prevent further recurrence of ing age.1 this condition. White women Nephrolithiasis is currently 9.4% more prevalent in men than in PATHOGENESIS women (13% vs 7%, respective- Stones in the urinary tract de- Hispanic men ly), and it is three to four times velop under specifi c urinary Black men 18.6% more likely to present in white conditions, including supersatu- 12.2% than nonwhite patients.2 How- ration of the with stone- ever, recent epidemiologic data forming ions (ie, calcium, oxa- suggest an alarming increase in late, uric acid, and phosphate) Asian men the number of women and ado- and defi ciency of urinary stone 15.5% lescents primarily diagnosed inhibitors (citrate, magnesium, with stone disease.3-6 The pat- zinc, macromolecules, and pyro- tern of increasing incidence in phosphate). Stone formation oc- Relative prevalence of kidney stones by race and gender in US residents.

women can be attributed in part curs in a mucoprotein matrix Adapted from Romero et al. Rev Urol. 2010.7 to changes in diet and lifestyle.4,5 that attaches to the renal epithe- Figure 17 represents the preva- lium. Urine becomes supersatu- phosphate stones, whereas acidic must be part of the initial work- lence of stone disease, specifi c to rated as a result of increasing urine favors uric acid and cys- up when a patient is being evalu- gender and race.2,4 levels of solutes (such as the tine stone formation.13 ated for stone disease; patients Due to kidney stones’ rela- stone-forming ions) and/or de- Kidney stones can be divided with any of these risk factors tively common occurrence, the creasing free water volume. into four broad types: calcium- should be investigated further. diagnosis, management, and When the concentration of based, struvite, uric acid, and cys- The risk factors for stone dis- prevention of stone disease have stone-forming ions exceeds solu- tine stones (see Figure 2, page ease can be broadly categorized become increasingly relevant for bility in the urine (equilibrium 33). Among these, calcium- as either individual risk factors the primary care practitioner. In solubility product), these ions based stones are by far the most or dietary risk factors. the course of stone disease man- can combine to form crystals.12,13 common, with nearly 80% of agement, the clinician should be Stones are typed based on the stones composed of calcium Individual Risk Factors aware of a vital fact: Stones have a ion composition of their crystals compounds (usually calcium A positive family history increas- tendency to recur.1 Indeed, evi- (see Table 1,2,12 page 33). Once oxalate, and rarely calcium es the risk for stone formation by dence suggests that following an crystals are formed, they can phosphate).4 The etiologies of two- to three-fold. Other indi- initial diagnosis of nephrolithia- also aggregate with other crys- these four types are vastly dif- vidual risk factors include con- sis, the probability of kidney tals, developing into a calculus.12 ferent, and prevention of stone genital anatomic defects, such as stone recurrence increases to Urinary pH infl uences ion crys- formation must be tailored to medullary sponge kidney, horseshoe nearly 50% after fi ve years.8 tallization: Alkaline urine favors the stone type. Once stones kidney, and ureteropelvic junction Even more concerning, evi- formation of calcium and/or form, however, the appropriate obstruction (UPJ).14-16 These can Catherine C. Wells is a certifi ed nephrology nurse practitioner at University of Missis- treatment strategies have many cause obstruction that leads to sippi Health Care and a clinical instructor in the Division of Nephrology at University of similarities. urinary stasis, and subsequently Mississippi Medical Center (UMC) in Jackson. Kiran B. Chandrashekar is a postdoc- to stone precipitation. toral research fellow in the Division of Nephrology at UMC. Garikiparthy N. RISK FACTORS Certain systemic disorders Jyothirmayi is a physician assistant in the Department of Academic Medicine at the University of Medicine and Dentistry of New Jersey (UMDNJ)–New Jersey Medical Specifi c risk factors for stone (eg, hyperparathyroidism) and School in Newark. Vikesh Tahiliani is the Divisional Medical Director for Midwest formation vary widely and are situations have also been associ- Physicians at Centerpoint Medical Center in Independence, Missouri. John C. Sabatino unique to the type of stone. A ated with stone disease and is an Assistant Professor in the Department of Radiology at UMDNJ–New Jersey Medi- cal School. Luis A. Juncos is the John D. Bower Chair of Nephrology and Hypertension thorough history, including a should be considered risk fac- and Professor of Medicine, Physiology, and Biophysics in the Department of Medicine family or personal history of tors. (See Table 2,12,17 page 34). Division of Nephrology at the University of Mississippi Medical Center. stone disease and dietary history, In patients who undergo gas-

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3311 CE-CMECE-CME KidneyKidney StonesStones FINAL.inddFINAL.indd 3232 11/24/12/24/12 2:192:19 PMPM TABLE 1 FIGURE 2 Prevalence and Composition of Commonly occurring kidney stones Common Renal Stones2,12 Stone type Prevalence Risk factors / contributing factors Calcium oxalate 36% – 70% Hypercalciuria Hypercalcemia Calcium-based stones Struvite stones Hypocitraturia Gouty diathesis Low urine volume 2e Calcium 6% – 20% Distal renal tubular acidosis phosphate Hyperparathyroidism Uric acid stones Cystine stones Low urine volume Courtesy of Louis C. Herring Company Kidney Stone Analysis Laboratory, www.herringlab.com. Urinary tract Mixed calcium 11% – 31% (See above) stone formation is high, Romero evated urinary calcium and uric oxalate and et al7 predict, nephrolithiasis in- acid and decreased urinary ci- phosphate cidence could rise from 40% to trate.17 Struvite 6% – 20% Urinary tract infections 56% by 2050 as a result of the ef- Low dietary calcium inges- (- (twice as Urea-splitting organisms fects of global warming.) tion and high oxalate consump- related); includes common in (eg, Proteus, Klebsiella, Lastly, an individual’s ability tion, resulting in increased oxa- “staghorn women as men) Pseudomonas, (or inability) to metabolize cal- late absorption, can also calculi” Staphylococcus) cium salts plays a vital role in the exacerbate the risk for stones.7,27 Uric acid 17% Gouty diathesis pathogenesis of stone disease. By contrast, a diet high in calci- Arthritis Intestinal calcium absorption is um (≥ 1,200 mg/d) reduces the Nephropathy a major determinant of hyper- risk for calcium oxalate stone re- calciuria, as nearly 90% of in- currence,17 although the effec- Hyperuricosemia gested calcium is absorbed in the tiveness of supplemental calcium Low urine volume intestines. People can broadly be has been questioned.26-28 Urinary pH < 6 Obesity divided into high or low calcium Patients who are advised to Myeloproliferative disorders absorbers. Hypercalciuria (mean make specifi c dietary adjust- Alcohol abuse urinary calcium excretion ≥ 300 ments should later undergo re- Congenital metabolic mg/d in men and ≥ 250 mg/d in peat urine chemistries to deter- errors women on a 1,000-mg/d calcium mine the effectiveness of these diet) is detected in 20% to 40% changes.17 Cystine 0.5% – 3% Cystinuria of those with calcium stones.21-23 (predominantly Congenital intestinal tract Hypocitraturia (mean urinary CLINICAL PRESENTATION in children, defect citrate excretion ≤ 320 mg/d) and Nephrolithiasis typically pres- teens) Congenital renal transport hyperoxaluria (mean urinary ents with colicky fl ank pain, of- error oxalate excretion > 45 mg/d) can ten accompanied by nausea and Other 1% – 4% Use of specific medications also increase the risk for stone vomiting.29 The pain radiates to (including indinavir, formation.12,24 the ipsilateral groin, and the pa- ephedrine, triamterene) tient typically has diffi culty Sources: Schade and Faerber. Prim Care. 20102; Johri et al. Nephron Clin Pract. 2010.12 Dietary Risk Factors fi nding a comfortable position. These are primarily related to Nephrolithiasis may also present trointestinal bypass surgery, risk, especially in women.4,20 fl uid intake and dietary calci- with chronic, episodic fl ank pain the development of hyperoxal- Environment plays a very im- um.7,17,25,26 Drinking less than 1 or may even be asymptomatic.30 uria, hypercalciuria, and de- portant role in stone formation. L of fl uids daily is associated Physical examination may re- creased urinary volume are as- Persons who live in a hot, arid with an increased risk for form- veal signs of severe pain, such as sociated with an increased risk climate, for example, and those ing stones; this risk is magnifi ed tachycardia and hypertension. for stone formation,18,19 and who work outdoors in hot weath- when the urine volume is also Presence of fever indicates asso- these patients should be watched er are at increased risk for stone decreased.7,17,27 Increased dietary ciated for this development. Obesity formation due to excessive fl uid intake of animal protein can el- and possibly pyelonephritis. and weight gain are directly loss from sweating.2,4,7 (In re- evate the risk for formation of Some larger stones can cause proportional to nephrolithiasis gions where the risk for kidney uric acid stones as a result of el- urinary tract obstruction; if ob-

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TABLE 2 TABLE 3 Systemic Disorders and Circumstances Associated Evaluation for Stone Disease2 With Stone Disease12,17 Serum studies Spot urine studies Disorder/condition Associated mechanism(s) Creatinine Spot urine cystine screen Primary hyperparathyroidism Hypercalcemia (qualitative) (present in 5% of stone Hypercalciuria Blood urea nitrogen Spot protein creatinine ratio (only formers) reliable if creatinine is stable) Urinary tract infections Precipitation of calcium Calcium Fasting urine screen for pH phosphate and magnesium Phosphorus Urinary electrolytes ammonium phosphate in alkaline urine Parathyroid hormone levels Bicarbonate Struvite stones Fasting blood glucose or Distal renal tubular acidosis Decreased urine ammonium A1C excretion Vitamin D 25 Low urinary pH Protein content Chronic inflammatory Increased oxalate absorption Order a 24-hour urine collection; measure the metabolic bowel disease determinants of stones and calculate supersaturation indices. Gout (doubles the risk for Hyperuricemia These will indicate the composition of the stone, after which both uric acid and calcium recommendations can be made, based on these findings. oxalate stones) The 24-hour urine collection should be repeated at a later date. Insulin resistance Decreased urine ammonium Source: Schade and Faerber. Prim Care. 2010.2 excretion Low urinary pH protein, or leukocyte esterase, studies to be considered are men- History of ileostomy Loss of bicarbonate and fluid indicating stones or fragments tioned in Table 3.2 This evalua- Low urine volume of stones present in the urinary tion is critical to prevent forma- tract. While nearly 10% of pa- tion of future stones and the Low urinary pH tients with stone disease exhibit associated complications. In the Prolonged immobilization Hypercalciuria due to bone loss gross , nearly 90% of patient with a history of stone re- Potential for urinary stasis patients have microscopic hema- currence or stone formation of 2 Congenital, surgical, Urinary stasis turia. identifi ed cause, evaluation is anatomical defects should be needed for three metabolic reviewed to assess urine concen- abnormalities—hypercalciuria, 12 17 Sources: Johri et al. Nephron Clin Pract. 2010 ; Curhan. Nephrology Rounds. 2004. tration. Serum chemistries hyperuricosuria, and hypoci- should be ordered to evaluate traturia—as these conditions struction occurs along with a elonephritis, and UPJ.2,32,33 All kidney function. Elevated creat- predispose patients to recurrent preexisting urinary tract infec- patients with suspected nephro- inine may indicate acute rather stone formation.1,25,34 tion, it can potentially lead to lithiasis should be carefully eval- than chronic kidney disease. The patient should also be en- pyelonephritis, pyonephrosis, uated using laboratory and ra- Electrolytes and carbon dioxide couraged to collect stones passed and eventually urosepsis—a po- diologic investigations. should be measured to evaluate for further clinical evaluation. tentially life-threatening condi- the kidneys’ ability to concen- Infrared spectroscopy or quanti- tion that requires immediate LABORATORY EVALUATION trate urine and maintain an tative wet analysis is used to surgical drainage.31 The goals in this two-step pro- acid–base balance. The CBC identify the specifi c composition Before a diagnosis of renal cess are to confi rm the diagnosis may reveal mild leukocytosis in of the stone.32,35 stones can be confi rmed, care of nephrolithiasis, then to iden- nephrolithiasis; presence of sig- should be exercised to rule out tify the composition of the nifi cant leukocytosis indicates Radiologic Evaluation the differentials, including ab- stones formed and the associated infection.2 Radiologic evaluation of stones is dominal aortic aneurysm, ap- risk factors. currently performed through pendicitis, bowel obstruction, Secondary Evaluation plain x-rays, ultrasonography, cholecystitis, drug-seeking be- Initial Evaluation This step begins with a thorough and noncontrast spiral CT.12,32,33 havior (eg, painkiller addiction), Tests include dipstick urine as- review of the patient’s medical When a patient presents with gastritis, mesenteric ischemia, sessment, serum chemistries, record and a detailed patient in- acute signs of nephrolithiasis, a musculoskeletal pain, ovarian and a complete blood count terview to ascertain all risk fac- plain fi lm x-ray of the kidneys, abscess, ruptured ovarian cyst, (CBC). Urine dipstick assess- tors for stone formation (as sum- ureters, and bladder (KUB) is ac- pelvic infl ammatory disease, py- ment may be positive for blood, marized in Table 1). Specifi c ceptable as the fi rst imaging

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3311 CE-CMECE-CME KidneyKidney StonesStones FINAL.inddFINAL.indd 3434 11/24/12/24/12 2:192:19 PMPM FIGURE 3 FIGURE 4 Bilateral staghorn calculi shown on plain x-ray Findings on noncontrast spiral CT

A B

A. Bilateral staghorn calculi B. Left ureteral stone C. Left hydronephrosis

C

Figure courtesy of John C. Sabatino, MD. Figures courtesy of John C. Sabatino, MD.

study, as it is inexpensive and of ease of use and reduced typically pass spontaneously taken to monitor fl uids, as pa- available in most areas.33 Plain risks.33 within a few weeks,1,29 but larger tients with kidney stones may fi lm KUB x-rays will identify cal- Stones may also be seen on re- stones usually require interven- have a limited ability to urinate cium oxalate, calcium phosphate, nal ultrasound—particularly uric tion—in some cases, surgery. (due to urinary obstruction and/ struvite, and cystine stones. acid stones, which are radiolu- Patients should be hospital- or acute or chronic renal failure). However, the sensitivity of plain cent (see Figure 5). Ultrasound ized if they require IV fl uids or Whenever possible, all urine fi lm x-rays has been documented is appropriate for evaluation of pain management. Isotonic IV should be strained to collect any between 24% and 59%, and patients whose exposure to radi- fl uids should be given to increase stones for analysis. stones that overlie a bone may be ation should be limited, such as the urine volume and facilitate One new strategy to assist missed.32,36 (See Figure 3.) children or pregnant women. In passage of stones. Care must be with stone passage is medical ex- Hence, because of these limi- addition to plain fi lm x-rays, re- tations and the increasing avail- nal ultrasound may also be use- FIGURE 5 12 ability of noncontrast spiral CT, ful for surveillance of stones. Kidney stones shown on ultrasound noncontrast spiral CT is now the most commonly used and TREATMENT useful test in the diagnosis of Nephrolithiasis treatment varies kidney stones (sensitivity, 95% between acute and chronic care. to 100%).32,36 Spiral CT accu- Acute care for nephrolithiasis in- rately defi nes the size as well as volves management of acute pain the location of stones, and may and urinary obstruction, as well additionally rule out other dif- as patient stabilization. Chronic ferential diagnoses (see Figures care includes prevention of re- 4a, 4b, and 4c). Historically, IV currence and management of pyelograms and urograms were risks. considered useful in locating urinary tract stones and diag- Acute Management nosing related complications,12 Patients who present with acute but these modalities carry addi- nephrolithiasis most often re- tional risks related to IV con- quire fl uid administration, ag- trast dye and radiation expo- gressive pain management, and sure. As a result, they have been treatment for nausea or vomit- 31,32 almost completely replaced by ing. Most ureteral stones Figure courtesy of John C. Sabatino, MD. noncontrast spiral CT because measuring 5.0 mm or less will

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struction can be relieved direct- FIGURE 6 ly by nephrostomy tubes (and/or For temporary relief of obstruction stents) or by interventions in which the stone is removed and normal urinary fl ow is restored. Typically, endoscopy is used for direct removal of stones that cause obstruction.44 Nephrosto- my tubes and ureteral stents (see Figures 6a and 6b) are placed to relieve obstruction temporarily and provide an alternate route for drainage of urine. The goal is to prevent renal damage until the obstruction can be relieved. Stents can remain in place for several months, but nephrosto- my tubes are associated with a higher risk for infection (be- cause they are externalized), and duration of use should be limited to only a few weeks.12,29,38 Stents are also associated with infections, but coated stents are available to reduce infection. As with any catheter material in- A. Nephrostomy tube shown on IV pyelogram B. Double-J ureteral stent shown on plain x-ray serted into the urinary tract,

Figures courtesy of John C. Sabatino, MD. ureteral stents are a prime loca- tion for development of a persis- tent bacterial biofi lm, thus lead- pulsive therapy (MET), using ously (typically ≥ 8 mm); if they until they can be removed by en- ing to infection. Recent advances calcium channel blockers (eg, cause acute renal obstruction; or doscopic surgery.29,43 in stent manufacturing have in- nifedipine) or α-blockers (eg, if they are located at a site with a Obstruction, which may be cluded coating stents with vari- tamsulosin).1,37 While there is potential for complications or partial or complete, is more like- ous biomaterials to decrease the confl icting evidence regarding can lead to persistent symptoms ly when stone size exceeds 10 development of this bacterial the effi cacy of calcium channel without evidence that they are mm.44 Signs of obstruction in- biofi lm. In a preliminary study blockers for MET, one meta- passing.1,3 Renal obstruction clude sudden-onset, excruciat- in 10 patients using a diamond- analysis revealed a 29% im- should be treated aggressively to ing fl ank pain that radiates to like, carbon-coated ureteral provement in stone passage with preserve renal function. the groin, along with nausea and stent, Laube et al45 demonstrat- α-blockers.1,38 The type of intervention cho- vomiting (renal colic). Larger ed a reduction in formation of Pain management can often be sen depends on the size and loca- obstructive stones, such as stag- this biofi lm, hence lowering the accomplished with NSAIDs (eg, tion of the stone, as well as the horn calculi (as shown in Figures probability of stent-induced in- ketorolac, diclofenac).29 Since this presence or absence of obstruc- 3 and 4a), can present with fection. class of medications can compro- tion. Stones that measure less symptoms of a urinary tract in- mise renal function, however, than 20 mm are commonly fection, mild fl ank pain, or he- Chronic Stone Management they must be used with caution. treated with extracorporeal maturia.33 As previously mentioned, one of Many patients require narcotic shockwave lithotripsy (unless Presence of signs of obstruc- the seminal characteristics of medications to control pain ade- they overlie the sacroiliac joint), tion or infection mandates stone disease is its ability to recur. quately.39-41 Antiemetic agents whereas patients with larger or emergent treatment. Infections After incidental detection of kid-

(such as the H1-receptor blocker more complex stones may re- of the urinary tract (as serious as ney stones through routine diag- dimenhydrinate42) should be ad- quire percutaneous nephroli- pyelonephritis or urosepsis) nostic procedures, the risk for ministered to control nausea and thotomy. Nonobstructive or un- should be treated with antibiot- recurrence in patients who do not vomiting. complicated ureteral stones may ics: initially with broad cover- receive chronic medical manage- Surgical and interventional be managed medically, whereas age, according to the appropri- ment is 30% to 40% within fi ve management. Surgical interven- obstructive or complicated ure- ate guidelines for urinary tract years.17,28 In treated patients, by tion may be required if stones teral stones require placement of infections, then tailored to the comparison, this risk falls by ap- are too large to pass spontane- a stent or a nephrostomy tube results of urine cultures. Ob- proximately 50%.17,26

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3311 CE-CMECE-CME KidneyKidney StonesStones FINAL.inddFINAL.indd 3636 11/24/12/24/12 2:192:19 PMPM Patients with a history of 2011 Sep 21. [Epub ahead of print] cal treatment of nephrolithiasis. J Endourol. stone recurrence must be eval- Our CE/CME posttest can 19. Patel BN, Passman CM, Fernandez A, et al. 2001;15(2):181-186. Prevalence of hyperoxaluria after bariatric sur- 36. Jackman SV, Potter SR, Regan F, Jarrett TW. uated for metabolic defects that be taken or viewed at gery. J Urol. 2009;181(1):161-166. Plain abdominal x-ray versus computerized precipitate stones, since their www.clinicianreviews 20. Taylor EN, Stampfer M, Curhan GC. Obesity, tomography screening: sensitivity for stone local- risk for chronic kidney disease weight gain, and the risk of kidney stones. ization after nonenhanced spiral computerized .com/CECourses.aspx JAMA. 2005;293(4):455-462. tomography. J Urol. 2000;164(2):308-310. 34 is increased. All patients with 21. Hodgkinson A, Pyrah LN. The urinary excre- 37. Hollingsworth JM, Rogers MA, Kaufman SR, a history of stone disease tion of calcium and inorganic phosphate in 344 et al. Medical therapy to facilitate urinary stone patients with calcium stone of renal origin. Br J passage: a meta-analysis. Lancet. 2006;368 should be instructed to in- REFERENCES Surg. 1958;46(195):10-18. (9542):1171-1179. crease their fl uid intake to 1. Moe OW, Pearle MS, Sakhaee K. Pharmaco- 22. Curhan GC, Willett WC, Speizer FE, Stampfer 38. Preminger GM, Tiselius HG, Assimos DG, et therapy of urolithiasis: evidence from clinical tri- maintain a daily urinary output MJ. Twenty-four-hour urine chemistries and the al. 2007 guideline for the management of ure- als. Kidney Int. 2011;79(4):385-392. risk of kidney stones among women and men. teral calculi. J Urol. 2007;178(6):2418-2434. of at least 2.5 L, unless contra- 2. Schade GR, Faerber GJ. Urinary tract stones. Kidney Int. 2001;59(6):2290-2298. 39. 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