Teaching Case

8-hour history of right-sided lower abdominal pain.

The prisoner was brought to the hospital by police with 8-hour history of right-sided lower abdominal pain. He denied any urinary, gastrointestinal or systemic symptoms. 3 other members of his family had past history of appendicectomy including his parents. Clinical examination was equivocal with minimal tenderness in right iliac fossa with no peritonism. Microscopic urine analysis, full blood count and liver function tests were within normal limits. In view of equivocal clinical findings, chest and abdominal radiographs were requested.
Plain abdominal films (AP and lateral) showed a 3-cm lamellated round calcification in the right lower abdomen.
Within a few hours, clinical signs of became obvious with guarding and rebound tenderness in right iliac fossa. Surgical exploration revealed gangrenous retrocaecal appendicitis with a giant hard appendicolith (3cm) at its base.

An appendicolith favours the diagnosis of appendicitis [1]. Perforation and abscess formation is more common with appendicoliths [1, 2]. Three quarters of these cases have gangrenous appendicitis.
Clinical findings and physical examination alone can diagnose most cases with acute appendicitis. However, in patients with atypical findings, radiological imaging may be necessary. Appendicolith can be identified in about 13% cases on abdominal films and 23% cases on CT abdomen [3]. Sometimes, a gas filled appendix on plain or oblique abdominal films produces a meniscus appearance. This sign is specific for appendicitis as it outlines the obstructing stone [4]. There is high correlation between the presence of calcified appendicolith and appendicitis. An appendicolith detected on abdominal film has a positive predictive value of 90%. An appendicolith detected on CT has a sensitivity of 65% and a specificity of 86%. Its positive and negative predictive values are 74% and 24% respectively [5]. The detection of an isolated appendicolith on CT in the absence of clinical symptoms of appendicitis cannot be justified for the diagnosis of acute appendicitis.
Giant appendicolith as seen in our case is rare. Most appendicoliths are less than 1 cm in size. In our case, the abdominal radiograph helped us in avoiding the delay of the appropriate management.