validation of emergency physician ultrasound in diagnosing hydronephrosis in ureteric colic

Emergency Medicine Australasia (2007) 19 188ndash195 doi 101111j1742-6723200700925x

copy 2007 The AuthorsJournal compilation copy 2007 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine

Blackwell Publishing AsiaMelbourne AustraliaEMMEmergency Medicine Australasia1742-6731copy 2006 The Authors Journal compilation copy 2006 Australasian College for Emergency Medicine and Australasian Society forEmergency Medicine2007193188195Xxxx XxxxHydronephrosis studyS Watkins

et al

Correspondence Dr Stuart Watkins Department of Emergency Medicine Liverpool Hospital Locked Bag 7103 Liverpool BC NSW 1871 Australia Email stuartwatkinsswsahsnswgovau

Stuart Watkins MBChB Registrar Justin Bowra MB BS FACEM Staff Specialist Director of Emergency Medicine Training Praneal SharmaMB BS FRANZCR Director Anna Holdgate MB BS FACEM MMed Director of Emergency Medicine Research Unit Alan Giles MB BSFACEM Senior Staff Specialist Lewis Campbell MBChB Registrar

ORIGINAL RESEARCH

Validation of emergency physician ultrasound in diagnosing hydronephrosis in ureteric colicStuart Watkins1 Justin Bowra12 Praneal Sharma3 Anna Holdgate12 Alan Giles12 and Lewis Campbell1

Departments of 1Emergency Medicine and 3Radiology Liverpool Hospital and 2Conjoint University of New South Wales Sydney New South Wales Australia

Abstract

Objective Patients presenting to the ED with obstructive nephropathies benefit from early detectionof hydronephrosis Out of hours radiological imaging is expensive and disruptive toarrange Emergency physician ultrasound (EPU) could allow rapid diagnosis and dispo-sition If accurate it might avert the need for formal radiological imaging exclude anobstruction and improve patient flow through the ED

Methods This was a prospective study of a convenience sample of all adult non-pregnant patientswith presumed ureteric colic attending the ED with prior ethics committee approval Anemergency physician or registrar performed a focused ultrasound scan and were blindedto the patientrsquos other management A computerized tomography scan was also performedfor all patients while in the ED or within 24 h of the EPU The accuracy of EPU detectionof hydronephrosis was determined using computerized tomography scans reported by asenior radiologist as the lsquogold-standardrsquo

Results Sixty-three patients with suspected ureteric colic were enrolled of whom 57 completed bothEPU and computerized tomography imaging Forty-nine had confirmed nephrolithiasis bycomputerized tomography with 39 having evidence of hydronephrosis Overall prevalenceof hydronephrosis was 68 (95 confidence interval [CI] 56ndash79) compared with com-puterized tomography EPU had a sensitivity of 80 (95 CI 65ndash89) specificity of 83(95 CI 61ndash94) positive predictive value of 91 (95 CI 75ndash98) and negativepredictive value of 65 (95 CI 43ndash83) The overall accuracy was 81 (95 CI 69ndash89)

Conclusion Although the accuracy of detection of hydronephrosis after focused training in EPU isencouraging further experience and training might improve the accuracy of EPU andallow its use as a screening tool

Key words computerized tomography emergency physician hydronephrosis renal colic ultrasound

Hydronephrosis study


189

Introduction

Patients presenting to the ED with an obstructive neph-ropathy benefit from early detection and treatment par-ticularly in the context of associated renal tract infectionor renal failure Complete ureteric obstruction mightlead to loss of renal function with an increased occur-rence of irreversible damage after 1ndash2 weeks1 Conven-tional modalities available for detecting renal tractobstruction include formal ultrasound (US) and comput-erized tomography (CT) However both CT and formalUS require patient transfer and monitoring in areasremote to the ED and generally have limited availabil-ity out of hours

The detection of hydronephrosis by bedside US in theED could allow a more rapid diagnosis and dispositionof patients and be used in situations where iodizingradiation or intravenous contrast material are contrain-dicated andor formal US is not available Rapid EDscreening for hydronephrosis might exclude obstruc-tion and focus assessment on other potential diagnosesand might allow the selection of patients for furtherstudies to be refined

An estimated 2ndash5 of the population will form asymptomatic renal calculus at some point in their lives1

Clinical history and microscopic haematuria suggestthe diagnosis with a sensitivity of 69ndash892ndash4 CT hasproved a more accurate test than US with greater sen-sitivity for hydronephrosis and calculus detection5ndash10

With intravenous contrast it can give the same infor-mation on renal function as IVU12568911 but also carriesthe same risks of radiation exposure allergy and neph-rotoxicity7 The advantages of CT have made US asecond choice investigation because of its relatively lowsensitivity of 19 (specificity of 97) for detectingcalculi compared with sensitivity of 94ndash97 (specificityof 96ndash97) for CT68 However patients with uretericstones have a relatively high prevalence of partial andor temporary renal tract obstruction but seldom causecomplete obstruction1 Because of this high prevalencethis population provides a convenient group in whomto explore options for diagnosing obstruction and thesepatients will require definitive renal tract imaging aspart of their usual management

The use of emergency physician US (EPU) for trau-matic intraperitoneal and pericardial fluid and abdom-inal aortic aneurysm detection has been increasing inAustralasian ED with accreditation processes thatfollow the Australasian College of Emergency Medi-cine (ACEM) guidelines12ndash14 Internationally EPU hasexpanded into areas of ED practice such as intravenous

access lower limb deep venous thrombosis and fluidlocalization for either diagnosis or drainage12ndash14 Therole of EPU in assessing renal tract obstruction remainssomewhat controversial with various studies showinga wide range of accuracy215ndash17

We postulated that EPU might be safe and accurateand could be used to screen patients for hydronephrosisdue to ureteric calculi

Aim

The aim of the present study was to determine theaccuracy of EPU in detection of hydronephrosis com-pared with radiologist-reported non-contrast CT

Methods

Study design and setting

This was a prospective study of a convenience sampleof patients with presumed ureteric colic undertaken inthe ED of a tertiary teaching hospital with an annualcensus of 46 000 The study had Area Ethics committeeapproval

Study population and protocol

All non-pregnant patients over 18 years old whoattended the ED with a clinical diagnosis of uretericcolic as determined by the treating ED medical officerwere eligible for enrolment Written informed consentwas obtained from all patients Foreign language inter-preters were utilized when required

Emergency registrars and emergency physicians (EP)who had attended an ACEM-accredited US workshopand undertaken a further 1 h of training in basic renalUS by a senior radiologist were able to enrol patientsin the study Recruited patients underwent EPU by theenrolling doctor during their ED stay The doctor per-forming the EPU was not involved in the treatment ofthe patient and was blinded to the CT scan result Anon-contrast CT scan of the renal tract also was per-formed on each patient either while they were in theED or organized externally at a single designated privateradiology suite within 24 h of EPU One senior radiolo-gist blinded to the EPU result reported the CT scans

Measurements

Using a Toshiba US machine Model SSA-550A(Tochigi-Ken Japan) and a 35ndash5 MHz curved array

S Watkins et al

190 copy 2007 The AuthorsJournal compilation copy 2007 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine

probe on abdominal preset investigators obtained andrecorded images and measurements of both kidneys(diameters of each renal pelvis and of each kidneyrsquoslongitudinal and transverse sections) Images weresaved digitally and printed Investigators completed areporting form that included demographic data thelocation of symptoms the presence or absence ofhydronephrosis for each kidney and the severity ofhydronephrosis (mild moderate or severe) if presentAn US diagnosis of hydronephrosis was made based onthe features listed in Table 1 Bladder size was esti-mated and documented (as empty half or full)

CT images were performed on a four-slice ToshibaAquilion (TSX-101A) scanner or a 16-slice ToshibaAquilion scanner Information recorded by the radiolo-gist included the presence or absence of hydronephrosisand its severity the presence of calculus and incidentalfindings

Data analysis

The accuracy of the EPU was determined by calculatingthe sensitivity specificity positive (PPV) and negativepredictive values (NPV) with 95 confidence intervals(CI) using the CT scan report as the reference standardAssuming a rate of hydronephrosis of 75 in patientswith renal colic19 we estimated approximately 50patients would be required to detect a sensitivity of90 with 95 CI of plusmn10

Microsoft Excel 2004 for Mac version 112 andVassarstats Statistical Computation website (httpfacultyvassaredulowryVassarStatshtml) were usedfor analysis

Results

Sixty-three patients were enrolled in the study Sixpatients did not complete the study because CT scanswere not performed or were not available for analysisOf the remaining 57 there were 48 men (84) and 9women (16) In the present study 34 (54) patientspresented with left-sided symptoms and 29 (46)

presented with right-sided symptoms The mean agewas 437 years (range 18ndash67) Two patients presentedmore than once during the study period and each pre-sentation was recorded separately

Of the 57 patients 48 had CT-confirmed diagnosis ofnephrolithiasis and 39 had CT-confirmed hydro-nephrosis Nine patients had negative CT scans fornephrolithiasis and hydronephrosis The prevalence ofhydronephrosis in the study population was 3957 or68 (CI 56ndash79)

Thirty-one of 39 patients with CT-proved hydroneph-rosis had positive EPU scans The main results aresummarized in Table 2 EPU demonstrated sensitivityof 80 (CI 65ndash89) and specificity of 83 (CI 61ndash94) a PPV of 91 (CI 75ndash98) and an NPV of 65(CI 43ndash83) Overall accuracy of EPU for the detectionof hydronephrosis was 81 (CI 69ndash89)

The study authors performed 60 of the scans12 other EP or trainees (registrars) performed theremainder

Discussion

The present study found that with minimal training EPand trainees were able to achieve a sensitivity of 80and a specificity of 83 for the diagnosis of hydroneph-rosis using bedside US in the setting of suspected acuterenal colic

Emergency physician US has potential advantages inthe diagnosis of hydronephrosis It can be performed atthe bedside using a portable machine is immediatelyavailable and repeatable 24 h a day 7 days a weekPatients do not leave the department to go to potentiallyless monitored areas which obviates the need for por-table monitoring andor nurse escort EP have been

Table 1 Grades of hydronephrosis

Grade I Grade II ndash mild Grade III ndash moderate Grade IV ndash severe

Slight blunting of calyceal fornices

Obvious blunting of calyceal fornices andenlargement of calices but intruding shadows of papillae are easily seen

Rounding of calices withobliteration of papillae

Extreme calyceal ballooning

Adapted from the study by Grainger and Allison18

Table 2 Comparison of emergency physician US (EPU) andCT in detection of hydronephrosis

CT ndash positive CT ndash negative

EPU ndash positive 31 3EPU ndash negative 8 15



191

using bedside US in the ED over recent years and inAustralia have training and accreditation proceduresfor its use in other conditions12ndash14

In the present study we investigated the ability of EPwith 1 h of focused training in renal US in addition toan ACEM-accredited US workshop to detect the pres-ence of hydronephrosis Previous studies have com-pared EPU with IVP215ndash17 or compared radiologist-performed US with CT59 This is the first study thatdirectly compares EPU detection of hydronephrosiswith the current lsquogold-standardrsquo of radiologist-reportedCT scan

Previous studies have demonstrated US sensitivity of85ndash94 and specificity of 100 in detection of hydro-nephrosis when performed by radiologists or sonogra-phers19102021 CT has proved a more accurate test withgreater sensitivity for hydronephrosis and calculusdetection5ndash10

The accuracy reported in our study is comparable tothat previously reported in most other EPU trials Rosenet al with 5 h training compared EPU diagnosis ofhydronephrosis with IVP and CT in 126 patients find-ing a sensitivity of 72 specificity of 73 PPV of85 NPV of 54 and accuracy of 7216 By contrastHenderson et al found a sensitivity of 97 for lsquopathol-ogy consistent with nephro-ureterolithiasis when com-pared to IVPrsquo in 108 patients but did not specificallyreport the detection of hydronephrosis as an outcome2

Lanoix et al reported an accuracy of 94 and sensitiv-ity of 96 after 4 h tuition based on 45 subjects and 39EPtrainees15 However the reference standard used inthat study is unclear

In an Australian study with 3 days of US trainingRowland et al reported 68 accuracy for EPU usingthree grades of hydronephrosis nil subtle or obvious17

They reported a sensitivity of 93 but only a specific-ity of 47 (PPV 59 NPV 89) and used IVP formalUS within 24 h or radiologist review of the EPU as theirlsquogold-standardrsquo Four investigators obtained images

from 31 subjects They reported more false-positivesthan false-negatives whereas our study reports theopposite In the above studies the difference betweenthe US and CT grading were in subjects with low-gradehydronephrosis A comparison of these studies isshown in Table 3

It is worth noting that the sonographic grading ofhydronephrosis into mild moderate or severe correlatespoorly with the clinical severity of disease2223 Hencefor the purposes of data analysis in our study hydro-nephrosis was reported simply as either present orabsent

To be effective as a screening test EPU wouldrequire a high sensitivity (ie few false-negatives) Ourfinding of a sensitivity of 79 and NPV of 65 sug-gests that EPU is currently not an acceptable screeningtest to rule out hydronephrosis However althougheight cases of CT-confirmed hydronephrosis were notdetected by EPU seven of these false-negative scanswere reported as mild hydronephrosis on CT Theeighth patient with false-negative EPU had moderatehydronephrosis demonstrated on CT but this scan wasperformed more than 24 h after the EPU hence it isuncertain whether this truly reflects the presence ofhydronephrosis at the time of the EPU but has beenincorporated into our results for completeness

Radiological diagnosis of hydronephrosis on CT issubjective with several studies reporting inter-observervariability between radiologists and between radiolo-gists trainees and urologists23ndash27 The amount of hydro-nephrosis shown by US varies dynamically with partialobstruction and with hydration status of the patient1125

as hydronephrosis can be induced in healthy volunteerswith forced fluid intake In serial US following hydra-tion mildndashmoderate hydronephrosis was induced in80 of subjects28 Repeating the US in dehydratedpatients following hydration might alter previouslyfalse-negative results11 Studies have demonstrated sim-ilar dynamic changes with CT Perinephric stranding

Table 3 Comparison of the previous studies of emergency physician US and detection of hydronephrosis

Sensitivity()

NPV () Comment

The present study (2005) (n = 57) 80 65 CT only 1 h + courseRosen et al16 (1998) (n = 126) 72 54 IVU + CT 5 h trainingHenderson et al2 (1998) (n = 108) 97 92 IVU unclear diagnostic criteriaLanoix et al15 (2000) (n = 45) 94 94 Multiple reference standards 4 h training 39 investigatorsRowland et al17 (2001) (n = 31) 93 89 Used IVUUSradiologist 3 days training 68 accuracy

NPV negative predictive value

S Watkins et al


ureteral dilatation perinephric fluid and collecting sys-tem dilatation showed statistically significant changeover 8 h of study29 Therefore correlation discrepancy inour study might be explained by any of these factorsIt has also been reported that false-negatives on US areusually followed by uncomplicated spontaneous stoneemission3031

What level of minimum training is required to makeEPU an effective screening tool for hydronephrosisLanoix et al15 and Rosen et al16 trained EP for 4 h and5 h respectively with markedly different results asnoted earlier perhaps because of the very different ref-erence standards used in their studies Rowland et aldemonstrated an overall accuracy of 68 for EPU after3 days training whereas our study demonstrates anaccuracy of 81 after 1 h of focused training in renalscans following completion of an ACEM-accreditedworkshop17

From our results it would seem prudent to state thatalthough additional training and experience mightimprove the accuracy of EPU it will not supplant theuse of CT in the foreseeable future However despitesimilar results to ours for EPU accuracy previousauthors have suggested a place for EPU in the detectionof hydronephrosis21516

Australasian and American Colleges for EmergencyMedicine have published policies on the training andaccreditation of EP in focused assessment with sonog-raphy for trauma and abdominal aortic aneurysm12ndash14

However currently there are no guidelines for minimumtraining and accreditation in renal sonography for EP

Limitations

As patients were enrolled on a convenience basis dueto the presence or absence of an investigator to per-form the scans this might have introduced one ormore unknown biases A trend towards improvedinvestigator performance was noted as scan qualityimproved with experience this might have affectedthe detection rate in the earlier stages of the presentstudy Some EP performed less than three studiesothers more than 10 however the sample size was toosmall to afford meaningful subgroup analysis for indi-vidual EP Some of these limitations would be over-come by larger studies

It is worth noting that several of the EPU sono-graphers were relatively inexperienced in the use ofbedside US and were not yet accredited in otherEPU applications such as focused assessment by

sonography in trauma (FAST)abdominal aortic aneu-rysm (AAA) It is possible that accredited EPU sonog-raphers would be more accurate

Because of the dynamic nature of renal colic andurinary obstruction ideally all participants would havehad their EPU and CT scan performed within minimaltime delay to ensure an accurate assessment of EPU inone patient CT scanning was performed more than 24 hlater Finally our study did not include routine evalua-tion of renal resistive indexes that might improve detec-tion of early obstruction28

Conclusion

Using non-contrast CT as the gold standard we havefound EPU detection of hydronephrosis to have anaccuracy of 81 which is comparable to previousstudies However on the basis of the present studyEPU is probably not accurate enough to rule out hydro-nephrosis Further experience and training mightimprove the accuracy of EPU and allow its use as ascreening tool

Acknowledgements

The authors express their thanks to the staff specialistsand registrars from the Departments of EmergencyMedicine and Radiology for their assistance

Author contributions

SW contributed to study design ethics submission con-sent and patient information sheets reporting sheetsdata collation and analysis literature research andmanuscript preparation (85) JB contributed to origi-nal concept study design ethics submission investiga-tion manuscript preparation and supervision (40) PScontributed to investigator training study design andCT reporting (25) AH contributed to research meth-ods data analysis and manuscript preparation (20)AG contributed to study design investigation andmanuscript preparation (10) LC contributed to studydesign investigation and data collation (10)

Competing interests

Justin Bowra is a member of the Ultrasound Committeeof the Australasian College for Emergency MedicineAnna Holdgate holds the position of Section Editor of



193

Original Research for Emergency Medicine AustralasiaAll other authors declare no competing interests

Accepted 11 October 2006

References

1 Rosen P Barkin R Ling LJ Emergency Medicine Concepts andClinical Practice 4th edn St Louis Mosby 1998

2 Henderson SO Hoffner RJ Aragona JL Groth DE Esekogwu VIChan D Bedside emergency department ultrasonography plusradiography of the kidneys ureters and bladder versus intrave-nous pyelography in the evaluation of suspected ureteral colicAcad Emerg Med 1998 5 666ndash71

3 Eray O Cubuk MS Oktay CEM Yilmaz S Cete Y Ersoy FFThe efficacy of urinalysis plain films and spiral CT in EDpatients with suspected renal colic Am J Emerg Med 2003 21152ndash4

4 Brown DFM Rosen CL Sagarin M McCabe C Wolfe RE Impactof bedside ultrasonography by emergency physicians on theclinical likelihood of nephrolithiasis Ann Emerg Med 1996 27818

5 Fowler KAB Locken JA Duchesne JH Williamson MR Ultra-sound for detecting renal calculi with non-enhanced CT as areference standard Radiology 2002 222 109ndash13

6 Yilmaz S Sindel T Arslau G et al Renal colic comparison ofspiral CT US and IVU in the detection of ureteral calculi EurRadiol 1998 8 212ndash17

7 Spencer BA Wood BJ Dretler SP Helical CT and ureteric colicUrol Clin North Am 2000 27 231ndash41

8 Smith RC Verga M McCarthy S Rosenfield AT Diagnosis ofacute flank pain value of un-enhanced helical CT AJR Am JRoentgenol 1996 166 97ndash101

9 Sheafor DH Hertzberg BS Freed KS et al Non-enhanced helicalCT and US in the emergency evaluation of patients with renalcolic prospective comparison Radiology 2000 217 792ndash7

10 Patlas M Farkas A Fisher D Zaghal I Hadas-Halpern I Ultra-sound vs CT for the detection of ureteric stones in patients withrenal colic BJR 2001 74 901ndash4

11 Noble VE Brown DFM Renal ultrasound Emerg Med ClinNorth Am 2004 22 641ndash59

12 American College of Emergency Physicians (ACEP) Board ofDirectors Use of Ultrasound Imaging by Emergency PhysiciansPolicy Statement June 2001 Available from URL httpwwwaceporg16840html [Accessed August 2006]

13 Australasian College of Emergency Medicine (ACEM) CouncilCredentialling for ED Ultrasonography Policy Document P22July 2000 Available from URL httpwwwacemorgauinfo-centreaspxdocId=59 [Accessed August 2006]

14 Australasian College of Emergency Medicine (ACEM) CouncilUse of Bedside Ultrasound by Emergency Physicians Policy Doc-ument P21 July 1999 Available from URL httpwwwacemorgauinfocentreaspxdocId=59 [Accessed August 2006]

15 Lanoix R Leak LV Gaeta T Gernsheimer JR A preliminaryevaluation of emergency ultrasound in the setting of an emer-gency medicine training program Am J Emerg Med 2000 1841ndash5

16 Rosen CL Brown DFM Sagarin MJ Chang Y McCabe CJ WolfeRE Ultrasonography by emergency physicians in patients withsuspected renal colic J Emerg Med 1998 16 865ndash70

17 Rowland JL Kuhn M Bonnin RLL Davey MJ Langlois SLAccuracy of emergency department bedside ultrasonographyEmerg Med 2001 13 305ndash13

18 Grainger RG Allison DJ (eds) Diagnostic Radiology A Textbookof Medical Imaging 4th edn London Churchill Livingstone2001 p 1594

19 Kiely EA Hartnell GG Gibson RN Measurement of bladderVolume by real-time ultrasound Br J Urol 1987 60 33ndash5

20 Sinclair D Wilson S Toi A Greenspan L The evaluation ofsuspected renal colic ultrasound scan vs excretory urographyAnn Emerg Med 1989 18 556ndash9

21 Dalla Palma L Stacul F Bazzocchi M et al Ultrasonography andplain film versus intravenous urography in ureteric colic ClinRadiol 1993 47 333ndash6

22 Oumlzden E Karamuumlrsel T Gouml uuml Ccedil Yaman Ouml Inal T Gouml uuml ODetection rate of ureter stones with US relationship with gradeof hydronephrosis J Ankara Med Sch 2002 24 183ndash6

23 King L Hydronephrosis when is obstruction not obstructionCommon problems in paediatric urology Urol Clin North Am1995 22 31ndash42

24 Holdgate A Chan T How accurate are emergency clinicians atinterpreting non-contrast CT for suspected renal colic AcadEmerg Med 2003 10 315ndash19

25 Jeffrey RB Federle MP CT and ultrasonography of acute renalabnormalities Radiol Clin North Am 1983 21 515ndash25

26 Morse JW Saracino BS Melanson SW Arcona S Heller MBUltrasound interpretation of hydronephrosis is improved by abrief educational intervention Ann Emerg Med 1998 32(Suppl Pt 2) S27

27 Freed KS Paulson EK Frederick MG et al Interobserver vari-ability in the interpretation of unenhanced helical CT for thediagnosis of ureteral stones J Comput Assist Tomogr 1998 22732ndash7

28 Morse JW Hill R Greissinger WP Patterson JW Melanson SWHeller MB Rapid oral hydration results in hydronephrosis asdetermined by bedside ultrasound Ann Emerg Med 1999 34134ndash40

29 Varanelli MJ Coll DM Levine JA Rosenfield AT Smith RCRelationship between duration of pain and secondary signs ofobstruction of the urinary tract on unenhanced helical CT AJRAm J Roentgenol 2001 177 325ndash30

30 Haddad MC Sharif HS Abomelha MS Colour Doppler sonogra-phy and plain abdominal radiography in the management ofpatients with renal colic Eur Radiol 1994 4 529ndash32

31 Catalano O Nunziata A Altei F Siani A Suspected ureteralcolic primary helical CT versus selective helical CT after unen-hanced radiography and sonography AJR Am J Roentgenol2002 178 379ndash87

(g s

(g s

S Watkins et al


Appendix I Validation of ED physician US diagnosing hydronephrosis in ureteric colicCompleted forms to be placed in the marked box in the Resuscitation Room Date

Time

ED Physician name

Right Place patient details sticker here Location of

symptoms (Please circle or

comment)

Left

ULTRASOUND FINDINGS

Hydronephrosis Present

Estimate severity

NO MILD MODERATE SEVERE UNSURE

RIGHT

LEFT

Additional comments

Empty Half Full

Bladder size

Incidental Findings (eg Free fluidascites AAA effusion etc)

Study Group Use only CT scan

Performed Liverpool Hospital South West

RadiologyElsewhere

Date amp Time of scan



195

Appendix II Validation of ED physician US diagnosing hydronephrosis in ureteric colicReporting sheet for dr praneal sharma radiologist

Date Time

Place patient details sticker here

Diagnosis of Renal ureteric colic correct YES NO

Calculus Seen YES NO

Left Right

Position of Calculus

Size of Calculus

CT KUB FINDINGS


Estimate severity


RIGHT

LEFT

Additional Findings



189

Introduction

Patients presenting to the ED with an obstructive neph-ropathy benefit from early detection and treatment par-ticularly in the context of associated renal tract infectionor renal failure Complete ureteric obstruction mightlead to loss of renal function with an increased occur-rence of irreversible damage after 1ndash2 weeks1 Conven-tional modalities available for detecting renal tractobstruction include formal ultrasound (US) and comput-erized tomography (CT) However both CT and formalUS require patient transfer and monitoring in areasremote to the ED and generally have limited availabil-ity out of hours

The detection of hydronephrosis by bedside US in theED could allow a more rapid diagnosis and dispositionof patients and be used in situations where iodizingradiation or intravenous contrast material are contrain-dicated andor formal US is not available Rapid EDscreening for hydronephrosis might exclude obstruc-tion and focus assessment on other potential diagnosesand might allow the selection of patients for furtherstudies to be refined

An estimated 2ndash5 of the population will form asymptomatic renal calculus at some point in their lives1

Clinical history and microscopic haematuria suggestthe diagnosis with a sensitivity of 69ndash892ndash4 CT hasproved a more accurate test than US with greater sen-sitivity for hydronephrosis and calculus detection5ndash10

With intravenous contrast it can give the same infor-mation on renal function as IVU12568911 but also carriesthe same risks of radiation exposure allergy and neph-rotoxicity7 The advantages of CT have made US asecond choice investigation because of its relatively lowsensitivity of 19 (specificity of 97) for detectingcalculi compared with sensitivity of 94ndash97 (specificityof 96ndash97) for CT68 However patients with uretericstones have a relatively high prevalence of partial andor temporary renal tract obstruction but seldom causecomplete obstruction1 Because of this high prevalencethis population provides a convenient group in whomto explore options for diagnosing obstruction and thesepatients will require definitive renal tract imaging aspart of their usual management

The use of emergency physician US (EPU) for trau-matic intraperitoneal and pericardial fluid and abdom-inal aortic aneurysm detection has been increasing inAustralasian ED with accreditation processes thatfollow the Australasian College of Emergency Medi-cine (ACEM) guidelines12ndash14 Internationally EPU hasexpanded into areas of ED practice such as intravenous

access lower limb deep venous thrombosis and fluidlocalization for either diagnosis or drainage12ndash14 Therole of EPU in assessing renal tract obstruction remainssomewhat controversial with various studies showinga wide range of accuracy215ndash17

We postulated that EPU might be safe and accurateand could be used to screen patients for hydronephrosisdue to ureteric calculi

Aim

The aim of the present study was to determine theaccuracy of EPU in detection of hydronephrosis com-pared with radiologist-reported non-contrast CT

Methods

Study design and setting

This was a prospective study of a convenience sampleof patients with presumed ureteric colic undertaken inthe ED of a tertiary teaching hospital with an annualcensus of 46 000 The study had Area Ethics committeeapproval

Study population and protocol

All non-pregnant patients over 18 years old whoattended the ED with a clinical diagnosis of uretericcolic as determined by the treating ED medical officerwere eligible for enrolment Written informed consentwas obtained from all patients Foreign language inter-preters were utilized when required

Emergency registrars and emergency physicians (EP)who had attended an ACEM-accredited US workshopand undertaken a further 1 h of training in basic renalUS by a senior radiologist were able to enrol patientsin the study Recruited patients underwent EPU by theenrolling doctor during their ED stay The doctor per-forming the EPU was not involved in the treatment ofthe patient and was blinded to the CT scan result Anon-contrast CT scan of the renal tract also was per-formed on each patient either while they were in theED or organized externally at a single designated privateradiology suite within 24 h of EPU One senior radiolo-gist blinded to the EPU result reported the CT scans

Measurements

Using a Toshiba US machine Model SSA-550A(Tochigi-Ken Japan) and a 35ndash5 MHz curved array

S Watkins et al




Data analysis



Results






Discussion















191














Sensitivity()

NPV () Comment



S Watkins et al







Limitations





Conclusion


Acknowledgements




Competing interests




193



References
































(g s

(g s

S Watkins et al



Time

ED Physician name



comment)

Left

ULTRASOUND FINDINGS


Estimate severity


RIGHT

LEFT

Additional comments

Empty Half Full

Bladder size




RadiologyElsewhere




195


Date Time




Left Right


Size of Calculus

CT KUB FINDINGS


Estimate severity


RIGHT

LEFT

Additional Findings

S Watkins et al




Data analysis



Results






Discussion















191














Sensitivity()

NPV () Comment



S Watkins et al







Limitations





Conclusion


Acknowledgements




Competing interests




193



References
































(g s

(g s

S Watkins et al



Time

ED Physician name



comment)

Left

ULTRASOUND FINDINGS


Estimate severity


RIGHT

LEFT

Additional comments

Empty Half Full

Bladder size




RadiologyElsewhere




195


Date Time




Left Right


Size of Calculus

CT KUB FINDINGS


Estimate severity


RIGHT

LEFT

Additional Findings



191














Sensitivity()

NPV () Comment



S Watkins et al







Limitations





Conclusion


Acknowledgements




Competing interests




193



References
































(g s

(g s

S Watkins et al



Time

ED Physician name



comment)

Left

ULTRASOUND FINDINGS


Estimate severity


RIGHT

LEFT

Additional comments

Empty Half Full

Bladder size




RadiologyElsewhere




195


Date Time




Left Right


Size of Calculus

CT KUB FINDINGS


Estimate severity


RIGHT

LEFT

Additional Findings

S Watkins et al







Limitations





Conclusion


Acknowledgements




Competing interests




193



References
































(g s

(g s

S Watkins et al



Time

ED Physician name



comment)

Left

ULTRASOUND FINDINGS


Estimate severity


RIGHT

LEFT

Additional comments

Empty Half Full

Bladder size




RadiologyElsewhere




195


Date Time




Left Right


Size of Calculus

CT KUB FINDINGS


Estimate severity


RIGHT

LEFT

Additional Findings



193



References
































(g s

(g s

S Watkins et al



Time

ED Physician name



comment)

Left

ULTRASOUND FINDINGS


Estimate severity


RIGHT

LEFT

Additional comments

Empty Half Full

Bladder size




RadiologyElsewhere




195


Date Time




Left Right


Size of Calculus

CT KUB FINDINGS


Estimate severity


RIGHT

LEFT

Additional Findings

S Watkins et al



Time

ED Physician name



comment)

Left

ULTRASOUND FINDINGS


Estimate severity


RIGHT

LEFT

Additional comments

Empty Half Full

Bladder size




RadiologyElsewhere




195


Date Time




Left Right


Size of Calculus

CT KUB FINDINGS


Estimate severity


RIGHT

LEFT

Additional Findings



195


Date Time




Left Right


Size of Calculus

CT KUB FINDINGS


Estimate severity


RIGHT

LEFT

Additional Findings

validation of emergency physician ultrasound in diagnosing hydronephrosis in ureteric colic

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