Incomplete Pelvi-Ureteric Junction Obstruction Mimicking Appendicitis

M Chandramohan, K Gopal, D Seriki, E Nandakumar Department of Radiology, Blackburn Royal Infirmary, Blackburn


Simple non-invasive investigation such as ultrasound should be sought when the clinical findings of acute appendicitis are equivocal, particularly in young female patients in order to exclude other causes that can mimic acute appendicitis.


Acute appendicitis is the commonest cause of acute abdomen in the United Kingdom. The presentation is variable and the diagnosis is essentially clinical. In this report, we present the case of a patient whose abdominal pain was because of a grossly distended pelvi-calyceal system due to incomplete pelvi-ureteric junction obstruction (PUJ) which was mistaken as acute appendicitis(1).


A 16-year-old girl presented to accident and emergency with right-sided abdominal pain. The girl was admitted with a provisional diagnosis of acute appendicitis. On examination, she was apyrexic and tender in the right lumbar and iliac region. The pulse rate was normal. Her blood results did not show leucocytosis. Her pain failed to settle and therefore underwent laproscopy and appendicectomy, the second day following admission. At surgery she was noted to have an inflamed right fallopian tube and some seropurulent free fluid in the pelvis. A diagnosis of salphingo-oophoritis was made and appendix removed. She was commenced on metronidazole and tetracycline. There was no complete resolution of her symptoms and was discharged 2 days later. The culture of the peritoneal fluid did not grow any organism and the appendix was normal on histology.

The girl presented 6 months later with frank hematuria following fall over a fence. The patient was investigated for renal injury. Ultrasound scan of the abdomen showed enlarged right kidney with grossly dilated pelvi-calyceal system giving the configuration of longstanding PUJ obstruction. There was evidence of acute clot within the distended calyces. The renal parenchymal thickness was normal. On CT, the enlarged right kidney showed extension in to the pelvis and to the anterior abdominal wall displacing small and large bowel loops (Fig 1). It showed excretion and there were no renal parenchymal contusion or laceration seen. No free fluid was demonstrated. The patient then came out with longstanding history of right abdominal discomfort despite appendicectomy. The patient was treated conservatively for hematuria and is awaiting pyeloplasty for her incomplete PUJ obstruction.


Appendicitis is the commonest cause of acute abdomen in the UK. The presentation is variable and the diagnosis is essentially clinical. It most often affects teenagers and young adults. Classically it presents with colicky periumbilical pain, which radiates to right iliac fossa. Loss of appetite and nausea are common. The clinical signs include fever, flushing, tachycardia and white blood cells of more than 12,000 mm3 in 25%. On palpation, maximum tenderness occurs over McBurney's point. The differential diagnosis would include mesenteric adenitis, meckels diverticulitis, terminal ileitis, ureteric colic, acute salphingitis, ruptured ectopic pregnancy, perforated viscus and acute pancreatitis(2).
Appendicectomy is the treatment for unequivocal presentation. If the presentation is equivocal or when the diagnosis is in doubt, simple non-invasive investigation such as ultrasound of the abdomen should be considered, which may not confirm appendicitis, but can exclude other causes, which can mimic acute appendicitis thereby avoiding unnecessary surgery in young female patients (3-5).

Pelvi-ureteric junction (PUJ) obstruction is a major cause of obstructive uropathy at all ages. The causes of PUJ obstruction range from congenital lesions like intrinsic stenosis, valves, adhesions, lower pole artery etc., to acquired causes due to scarring, reflux, and tumour. PUJ obstruction is more common in males, with the left kidney being affected about twice as often as the right. Incomplete or intermittent PUJ obstruction commonly presents with loin pain, worse after alcohol. Ideally investigations should be performed during an episode of flank pain, if not between obstructive episodes they typically have no hydronephrosis. Treatment options include open pyeloplasty or endopyelotomy (6).

In this case, the actual cause for pain and discomfort in the right iliac fossa is thought to be due to incomplete PUJ obstruction. Ultrasound was not requested at the time of initial admission though the clinical findings were equivocal and the patient was taken for surgery only on day 2 following admission. The plain abdomen radiograph, when viewed retrospectively did show enlarged right kidney extending in to the pelvis which never came for Radiologists opinion.

In conclusion, whenever the presentation of acute appendicitis is not classic, then simple investigation such as ultrasound of the abdomen should be considered. It may not confirm but can exclude causes that can mimic acute appendicitis, thereby avoid unnecessary surgery and to plan appropriate treatment.




(1)Sauerland S. Misdiagnosis of acute appendicitis. JAMA.2002 Jan 2;287(1):43-4

(2) Bailey & Love's short practice of surgery. 21st edition. 1199-1205.

(3) Jain KA, Ablin DS, Jeffrey RB, Brant WE. Sonographic differential diagnosis of right lower quadrant pain other than appendicitis. Clinical imaging 1996. Jn-Mar;20(1): 12-6

(4) Ripolles T, Martinez-Perez MJ, Morote V, Solaz J. Diseases that simulate acute appendicitis on ultrasound. Br J Radiol 1998 Jan;71(841):94-8. Review

(5) Jain KA, Quam JP, Ablin DS, Gerscorich EO, Shelton DK. Imaging findings in patients with right lower quadrant pain :alternative diagnosis to appendicitis.J Comput Assist Tomogr.1997 Sep-Oct;21(5):693-8. Review

(6) Lowe FC, Marshall FF.Ureteropelvic junction obstruction in adults. Urology 1984 Apr;23(4):331-5

First Published May 2004

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