| Abstract|| |
The objective of this study is to evaluate the use of ultrasound in the initial evaluation of renal colic. We studied prospectively 21 patients referred for radiographic evaluation for renal colic from January 1998 through April 1998. All sonographic studies were performed with real-time sector scanner (Kertz, Compeson 410 using 3.5 MHz Probe). Our sonographic criteria for a positive examination consisted of the visualization of urinary tract calculus and/or unilateral hydronephrosis with or without ureterectasis. The presence of urinary calculi was proven in 18 out of 21 patients (85%). The absence of calculi was established in three cases either by negative I.V.U. (2 cases) or by the clinical and sonographic demonstration of epididymitis as the cause in one patient. In the 18 patients with proven urinary calculi, ultrasound correctly identified the diagnosis in 15 cases (83%). Of those 15 visualized calculi, 11 were located at the ureterovesicular junction, two in the renal pelvis, one in the proximal third of the ureter, and one in the distal third. The sensitivity of ultasonography to detect renal calculi was 83% and the specificity, 100%. The one false positive examination with unilateral hydronephrosis proved to be due to a retroperitoneal liposarcoma. There were two cases in which the urinary tract ultrasound examination was negative. We conclude that ultrasound has a high diagnostic value when used as the first line investigation for the initial evaluation of renal colic.
Keywords: Renal colic, Ultrasound, Intravenous urography.
|How to cite this article:|
Abu-Ghazzeh Y, Abdu-Alro’f S. The Role of Ultrasound in Initial Evaluation of Renal Colic. Saudi J Kidney Dis Transpl 2000;11:186-90
|How to cite this URL:|
Abu-Ghazzeh Y, Abdu-Alro’f S. The Role of Ultrasound in Initial Evaluation of Renal Colic. Saudi J Kidney Dis Transpl [serial online] 2000 [cited 2020 Sep 30];11:186-90. Available from: http://www.sjkdt.org/text.asp?2000/11/2/186/36676
| Introduction|| |
Renal colic is a common urologic problem. It is defined as acute flank pain radiating to the groin or testicle, with or without nausea, vomiting, dysuria, and hematuria. 
Intravenous urography (IVU) has long been accepted as the primary radiological tool for the diagnosis of renal colic.  We conducted this study to assess the role of ultasonography in the evaluation of renal colic.
| Materials and Methods|| |
We studied prospectively 21 patients referred for radiographic evaluation for renal colic From January 1998 through April 1998. Referrals came from either emergency room or out-patient clinics of Prince Hashim Ben Al-Hussein Hospital, Zarka, Jordan. Inclusion in the study required a history of recent onset of pain suggesting renal colic, most often described as a sharp, spasmodic pain beginning in the flank, radiating to the lower abdomen, groin or inner thigh.
Urinalysis and an abdominal radiograph (KUB) for each patient were obtained prior to the sonographic evaluation.
Each patient was well hydrated with oral or intravenous fluid in an attempt to ensure a distended urinary bladder. All sonographic studies were performed with real-time sector scanner (Kertz, Compeson 410 using 3.5-MHz probe). Sonographic evaluation consisted of visualization of both kidneys for the presence of calculus, hydronephrosis, and peritoneal urinomas. The examination also included the expected course and caliber of the ureters and evidence of calculi in the ureter and/or the urinary bladder. Particular attention was directed to the distal pelvic ureters and ureterovesicular junction (UVJ) to identify calculi and/or edema at these locations. In those patients in whom the screening KUB study demonstrated calcification suggestive of a calculus, additional care was directed to the area of suspicion.
Our sonographic criteria for a positive examination consisted of the visualization of urinary tract calculus and/or unilateral hydronephrosis with or without ureterectasis.
Hydronephrosis was defined as asymmetrical dilatation of the renal pelvocalyceal system.
Ureteral dilation was defined as a persistent visualization of a tubular structure greater than six millimeters in diameter. Calculi were characterized as echogenic shadowing foci within the kidney, ureter, or bladder. 
| Results|| |
Of the 21 patients studied, the presence of urinary calculi was proven in 18 cases by spontaneous passage (and recovery) of a stone, documentation of calculi by IVU and/or surgery. The absence of calculi was established in three cases: by IVU negative for stone and/or hydronephrosis in one; by the presence of hydronephrosis, which turned out to be a retroperitoneal liposarcoma, in another and by the clinical and sonographic demonstration of epididymitis as the cause of pain and hematuria in the third patient.
In the 18 patients with proven urinary calculi, ultrasound correctly visualized the calculus in 15 cases (83%), [Figure - 1]. Of the 15 calculi, 11 were located at the UVJ, two in the renal pelvis, one in the proximal third and one in the distal third of the ureter. In the three patients where the calculus could not be imaged, its presence was suggested by unilateral hydronephrosis. In the first patient, the calculus was in the proximal third of the ureter on the screening KUB, and was passed spontaneously four days later. In the second patient, the suspected calculus was noted on the screening KUB in the middle third of the ureter; a level of obstruction identified by sonography. One day later a calculus was removed from this site during ureterolithotomy. In the third patient, possible stone was noted on KUB in the region of the UVJ. Ultrasound revealed ureteral dilatation at this level, but the UVJ could not be adequately imaged due to insufficient bladder distention. A stone was passed spontaneously the next day.
Unilateral hydronephrosis was detected in 16 of the 18 patients with proven urinary calculi (89%). In the two cases were hydronephrosis was not present, sonography demonstrated UVJ calculi.
Perirenal urinomas were identified in three of the 18 patients with proven calculi. Our sonographic criterion for positive examination consisted of the visualization of urinary tract calculus or unilateral hydronephrosis, with or without ureteroectasis. Using these two criteria, the sensitivity of the ultrasonography to detect calculi in the renal colic patients was 100% with specificity of 66.6%, while the sensitivity to visualize calculi only was 83% and the specificity was 100%. The one false positive examination demonstrated unilateral hydronephrosis that was subsequently found to be secondary to a retroperitoneal liposarcoma rather than a calculus. There were no false positive examinations in those cases in which echogenic calculi were sonographically demonstrated.
| Discussion|| |
The emergency intravenous urogram (IVU) has long been the recommended examination to evaluate patients with renal colic and to elucidates its cause. 
However, IVU carries some risks such as adverse reaction to the contrast media, exposure to ionizing radiation, precipitation of severe renal colic in a patient with urinary obstruction and exacerbation of renal failure in patients with compromised renal function. The ultrasonographic evaluation of the urinary tract is attractive in that it imposes none of these risks. The absence of exposure to ionizing radiation, the high sensitivity, and the ease with which it can be performed makes it an attractive screening modality in general and, in particular, in the pediatric and pregnant patients.
Our study demonstrates that a complete sonographic evaluation offers a viable alternative to the IVU in the initial evaluation of renal colic. Using the sonographic criteria for positive examination as the visualization of a urinary tract calculus or unilateral hydronephrosis and/or a unilateral hydroureter, we correctly identified all of the patients in whom a stone was subsequently demonstrated. As expected, radiolucent calculi were missed by the KUB examination. Such an incident happened in this study when a calculus diagnosed only by sonography turned out to be a 10-mm urate stone. It is of interest that, in another patient, a stone that was imaged ultrasonographically but not visible on the screening KUB, turned out to be a 2-mm calcium oxalate stone.
Sonography is a sensitive examination for the detection of urinary tract obstruction. ,,,,
As part of our study examination technique, patient hydration was attempted prior to, and during the sonographic examination, as a method of emphasizing early mild caliectasis and uterectasis. It was necessary that asymmetrical (unilateral) pelvocayceal dilatation be present on the affected side of the patient for an examination to considered positive for hydronephrosis. In contradistinction to physiologic calyceal dilatation, which is transient and may be observed with diuresis, hydronephrosis was constant and unchanging during the course of the sonographic examination. In our series, 89% of patients with proven calculi had unilateral hydronephrosis with or without ureterectasis. In two patients with UVJ calculi, neither hydronephrosis nor hydroureter was present. The presence of nonobstructing ureteric calculi associated with colic has previously been observed during IVU examination. 
The association of urinomas with renal colic is interesting. Each of the affected patients also had hydronephrosis, so it may be a useful sign indicative of acute obstruction.
The major limitation to the use of ultrasound in evaluating colic is the difficulty in visualizing the middle third of the ureter, particularly if ureteral dilatation is not present. Fortunately, the most frequent site for stone to lodge is in the distal ureter; in our experience it was predominantly at the UVJ.
We included a KUB as a part of our protocol, and found the initial KUB to be complementary to the ultrasonographic evaluation, just as it is a useful part of the IVU examination for calculi. The KUB helped to focus the sonographic search on areas suggestive of urinary calculi.
We conclude that ultrasound may be used as a reliable tool in the initial evaluation of renal colic. Emergency IVU examinations may be reserved for those cases in which the clinical situation strongly suggests renal colic and the ultrasound examination is negative.
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Department of Urology, Prince Hashim Ben Al Hussein Hospital, P.O. Box 211807, Amman 11121
[Figure - 1]