Non-calculus causes of renal colic on CT KUB

Transcription

1 Non-calculus causes of renal colic on CT KUB Poster No.: C-1341 Congress: ECR 2010 Type: Scientific Exhibit Topic: Genitourinary Authors: A. Afaq, E. L. Leen; London/UK Keywords: renal colic, CT KUB, appendicitis DOI: /ecr2010/C-1341 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 17

2 Purpose To investigate the causes of pain in patients presenting with renal colic, other than renal calculi as demonstrated on CT KUB. Methods and Materials The imaging as well as the clinical indications and reports of all cases referred for CT KUBs at two major teaching hospital sites in West London, UK were reviewed over a 20 week period. Studies were reported by either Consultants or Registrars with completed postgraduate examinations in Radiology (FRCR). The studies were then retrospectively reviewed by a Radiologist, and findings compared to the original report. Studies for patients without acute loin pain e.g. follow-up of calculi or pre-pcnl were excluded. Selected patients did go onto receive IV contrast to evaluate suspected pathology. Results 362 CT KUBs were performed in total, across both sites. Of these, 201 cases were new presentations of renal colic. 127 of these patients were male and 74 were female. The mean age was 42.4 (20-85). 106/201 (53%) were positive for renal tract calculi, corresponding to the symptoms. However, there were 24 cases (12%) where other pathologies were demonstrated, correlating with the site of pain. Page 2 of 17

3 These were appendicitis (4 cases), diverticulitis (4 cases), pyelonephritis (7 cases), adnexal lesions (4 cases), angiomyolipoma with haemorrhagic change (1 case), haemorrhage into renal cysts (2 cases) and PUJ obstruction (2 cases). 71/201 cases (35%), no cause of the symptoms were identified. Figures 1-12 show a range of pathologies encountered on CT KUBs, some of which were the cases seen during the study period. Images for this section: Page 3 of 17

4 Fig. 1: Hyperdense cysts in the right kidney due to haemaorrhage within the cysts (White arrows). Page 4 of 17

5 Fig. 2: Haemorrhage into an angiomyolipoma (AML) in the right kidney (white arrow). The hyperdense component represent haemorrhage whereas the background lesion is of fat density. The risk increases with increasing size of the AML. Page 5 of 17

6 Fig. 3: A complex pelvic mass with septations (white arrow). Page 6 of 17

7 Fig. 4: A right adnexal cystic lesion (white arrow). Page 7 of 17

8 Fig. 5: A urachal cyst (white arrow). Representing a sinus remaining from the allantois during embryogenesis, a urachal cyst occurs in the remnants between the umbilicus and bladder. This is a type of cyst occurring in a persistent portion of the urachus, presenting as an extraperitoneal mass in the umbilical region. Although usually clinically silent, urachal cysts can become infected. Page 8 of 17

9 Fig. 6: Sigmoid diverticulitis. Note the fat stranding around the bowel wall indicating active inflammation (white arrow). Page 9 of 17

10 Fig. 7: Acute appendicitis. Note the larger than expected diameter of the appendix, surrounding fat stranding and appendicolith at its base (white arrow). Page 10 of 17

11 Fig. 8: Acute appendicitis. Inflamed appendix with surrounding fat stranding (white arrow). Page 11 of 17

12 Fig. 9: Acute appendicitis on coronal reformat. Same patient as figure 8. Page 12 of 17

13 Fig. 10: Post contrast image of acute appendicitis. The same patient as in figure 8 an 9. The enhancing thick walled appendix is visualised more clearly. Page 13 of 17

14 Fig. 11: Emphysematous cystitis. An uncommon, but severe manifestation of infection of the urinary bladder produced by gas forming organisms. Note gas in the bladder wall on this axial image(white arrow). Page 14 of 17

15 Fig. 12: Emphysematous cystitis. An uncommon, but severe manifestation of infection of the urinary bladder produced by gas forming organisms. Note gas in the bladder wall on this coronal image(white arrow). Page 15 of 17

16 Conclusion CT is well recognised as having a very high sensitivity (95-98%) and specificity (98-99%), (1,2). With studies being performed within a door to door time of 5 minutes for most patients, and the lack of need for IV contrast, the technique has become the gold standard for investigating renal colic. Previous studies have suggested one third to one half of CT KUB examinations are positive for renal tract calculi, and our results also agree with those findings. The proportion of alternative causes identified in this study is also similar to that demonstrated by several other investigators of between 9-29% (3,4,5). The reason why many pathologies can mimic renal colic is due to the receptors of many visceral organs as well as the body wall transmit sensation through pain fibres shared with the kidneys. Clinical examination can therefore be non specific due to poor pain localisation (2,6). Previous studies have also mirrored our findings of the range of non-calculus pathologies encountered, with pyelonephritis, appendicits, diverticulitis and adnexal/ pelvic inflammatory causes being amongst the highest. One important consideration is that of suspected pyelonephritis on CT KUB. The appearances are indistinguishable from a recently passed calculus due to unilateral inflammatory change around the kidney. In these cases, contrast should be given to look for typical post contrast appearances of pyelnephritis such as wedge shaped areas of low attenuation or a striated pattern of enhancement. In all but the very young, renal or urothelial tumours would also enter the differential based on the non enhanced appearances and therefore also require contrast for clarification. Non-calculus causes of suspected acute flank pain may be encountered in up to to a third of studies, and the range of differentials should be actively sought to explain the patient's symptoms. In particular, the commonest alternative diagnoses in our study group were pyelonephritis, appendicits, diverticulits and adnexal masses. By considering the differential when reviewing the non enhanced study, one can also be ready for those occasions, such as the distinguishing between pyelonephrits and a recently passed stone, when a post contrast assessment is advisable. Page 16 of 17

17 References 1. Anderson K, Smith R. CT for the evaluation of flank pain. J Endourol 2001;15: Dalla Palma L, Pozzi-Mucelli R, Stacul F. Present day imaging of patients with renal colic. Eur Radiol 2001;11: Dalrymple N, Verga M, Anderson K et al. The value of unenhanced helical computerized tomography in the management of acute flank pain. J Urol 1998;159: Nachmann M, Harkaway R, Summerton S et al. Helical CT scanning: the primary imaging modality for acute flank pain. Am J Emerg Med 2000;18: Ather MH, Faizullah K, Achakzai I et al. Alternate and incidental diagnoses on noncontrast-enhanced spiral computed tomography for acute flank pain. Urology journal 2009;6: Rucker CM, Menias CO, Bhalla S. Mimics of renal colic: Alternative diagnoses at unenhanced helical CT. Radiographics 2004;24:S Personal Information Page 17 of 17