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Three Part Question

[in patients presenting with loin pain] [is KUB sensitive] [at detecting urinary calculi?]

Clinical Scenario

A 27 year old male arrives at the Emergency Department due to pain in his flank. A urinalysis and KUB are performed. the SHO wonders whether the KUB is an accurate method of detecting calculi.

Search Strategy

Ovid/medline 1966- week4 2005
Embase 1980-week 27 2005
Pubmed
[Kidney Diseases/ or exp Kidney/ or exp Back Pain/] OR
[loin pain.mp. [mp=title, original title, abstract, name of substance word, subject heading word] OR [exp Kidney Diseases/ or exp Colic/] OR [renal colic.mp. [mp=title, original title, abstract, name of substance word, subject heading word] OR [exp Kidney Diseases/ or exp Flank Pain/ or exp Bacterial Infections/ or exp Pyelonephritis/] OR [ flank pain.mp. [mp=title, original title, abstract, name of substance word, subject heading word] AND [exp Hematuria/ or exp Urinary Calculi/ or exp Urography/ or exp Ureteral Calculi/ or exp Kidney Diseases/] OR [KUB.mp. [mp=title, original title, abstract, name of substance word, subject heading word]OR
[XRAY.mp.] AND [CALCULI.mp. or exp URETERAL CALCULI/ or CALCULI/ or exp URINARY CALCULI/ or exp KIDNEY CALCULI/] OR [Calculi/ or exp Urinary Calculi/ or exp Kidney Calculi/ or exp Ureteral Calculi/]
limit 19 to (full text and human)
(KUB and CALCULI).mp. [mp=title, original title, abstract, name of substance word, subject heading word]

Search Outcome

506 papers found ovid
506 papers found embase
5 papers found pubmed
6 relevent papers however 1 discarded due to foreign language material therefore 5 remain relevent

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
T. Ripolles, M. Agramunt, J. Errando, M.J. Martinez, B. Coronel, M. Morales 2004 SPAIN	Emergency Room patients with acute flank pain during a 4 month period from Aug to Nov 2001	Diagnostic study:to study the value of KUB in detecting calculi. 66 patients underwent KUB.	number of lithiasis detected by KUB	KUB detected 36 of the 56 ureteral stones- sensitivity 64%. However 6 false positive cases occured	Only patients admitted between 8am and 3pm were used in the study.
O. Eray, M.S Cubuk, C. Otkay, S. Yilmaz, Y. Crete, F.F Ersoy 2002 Turkey	Patients presenting to the ED during the daytime over a 1 year period.	Prospective diagnostic study- to see the value of KUB in 138 patients with renal colic presenting to the ED. Sensitivity and specificity was calculated using the Chi-Squared test.	Sensitivity and specificity of KUB, number of calculi identified by KUB	calculi were detected in 39 out of 65 patients- sensitivity 69% specificity 82%	34 patients were lost to follow up. Also confirmation about the passage of stones was obtained over the telephone- patients may have missed small stones being passed. The sensitivity of the KUB was lower in this study compared to others- this may have been due to lack of bowel preparation, poor quality images or technical ability of the radiologists.
H.S Teh, M.B.K Lin, T.K Khoo 2001 Singapore	Patients ranging from 18 to 80 years old attending the ED with flank pain in Feb 1998	Diagnostic study:of 110 patients attending the ED for emergency IVU, the KUB films were traced and reviewed for 98 patients.	sensitivity and specificity of KUB	KUB sensitivity 79.4% specificity 90%. 32 patients had a stone show up on KUB. 52 patients had no evidence of stone on KUB	KUB may reveal false positive results due to phleboliths or vascular calcification. Also small stones may not be seen on KUB therefore a IVU or CT scan is needed as a reference.
L. Dalla Palma, F. Stacul, M. Bazzocchi, L. Pagnan, G. Festini, D. Marega 1993 Italy	Patients with suspected ureteric colic presenting to the ED over a 8 month period from Jan 1991 to Aug 1991	Clinical Trial: 105 patients with renal colic had a KUB+US and an IVU within 3.5 days. These were performed by 15 different radiologists who were on duty throughout the 24 hours. The patients were then followed up by telephone within a month.	number of patients with calculi detected by KUB.	KUB identified stones in 34 of the 44 patients. There were 20 false positive KUBs. Sensitivity of KUB 77% specificity 87%	Some patients were lost to follow up. The results were reviewed by 15 different radiologists of varying expertese and training in image interpretation therefore affecting the accuracy of the study. KUB was performed alongside US therfore its accuracy as an individual mode of imaging is questionable and needs evaluating.
D. Katz, J.P McGahan, E.O Gerscovich, S.A Troxel, R.K Low 2003	Patients in the ED with acute flank pain	Clinical Trial: 30 patients underwent KUB and CT scan for the evaluation of renal colic.	size of calculi detected	mean transverse diameter and length similar in KUB and CT (P=0.29 AND 0.57 respectively) patient outcome similar in KUB as CT scan	Stone length was estimated by multiplying the number of cuts demonstrating the stone - 1x5 mm. The limitation of this is that if CT collimation is too large relative to the stone, the entire stone may not be scanned, therefore underestimating the stone length.

Comment(s)

In some studies,KUB was found to have low sensitivity and specificity on its own . It is however more useful if used with US to guide the US towards areas suggestive of a stone, shortening evaluation time and improving results. It is also useful in monitoring the progression of a calculus. calculi not identified on US or KUB need no further examination. KUB is also cheaper and gives off less radiation than other modes e.g. IVU and CT which should be reserved for patients with symptoms of severe colic.

Clinical Bottom Line

KUB is sufficiently sensitive as an initial test for patients presenting with flank pain in the ED. Use alongside US improves its sensitivity for calculi and should be performed before an IVU or CT scan is offered.

References

1. T. Ripolles, M. Agramunt, J. Errando, M.J. Martinez, B. Coronel, M. Morales Suspected ureteral colic: plain film and sonography vs unenhanced CT European Radiology 2004;14:129-136
2. O. Eray, M.S Cubuk, C. Otkay, S. Yilmaz, Y. Crete, F.F Ersoy The efficacy of urinalysis, plain films and spiral ct in ED patients with suspected renal colic Am J Emerg Med Mar 2003;21(2):152-4
3. H.S Teh, M.B.K Lin, T.K Khoo Flank pain: is intravenous urogram necessary? Singapore medical journal 2001;42(9): 425-427
4. L. Dalla Palma, F. Stacul, M. Bazzocchi, L. Pagnan, G. Festini, D. Marega Ultrasonography and plain film versus intravenous urography in ureteric colic Clinical Radiology 1993;47:333-336
5. D. Katz, J.P McGahan, E.O Gerscovich, S.A Troxel, R.K Low Correlation of ureteral stone measurements by CT and plain film radiography: utility of the KUB Journal of endourology Dec 2003;17(10):847-50