Description

Appendicitis in a remaining duplicate appendix is a rare phenomenon and we report such a case. The unusual presentation of this anomaly can cause diagnostic dilemmas. Awareness of this condition is important because failure to recognise the condition may lead to errors in diagnosis and subsequent management.

A young woman was admitted with a 3 day history of sudden onset, severe, central abdominal pain radiating towards the right iliac fossa, anorexia, rigors and vomiting. Her only significant past history was open appendectomy 4 years previously for a gangrenous appendix. The patient was pyrexial on admission but haemodynamically stable. Abdominal examination revealed a mass in right iliac fossa with localised peritonism. The inflammatory markers were elevated. The urine analysis was negative and a pregnancy test was negative. An ultrasound scan suggested an intussuscepting mass involving the ileocaecal region (fig 1).

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Figure 1

Ultrasound scan images of the patient showing intussusception involving the ileocaecal region. (A) Sagittal section abdominal scan. (B) Axial transverse section.

The patient underwent a lower midline laparotomy where a diffuse mass in the ileocaecal region enclosing a tubular structure was found and resected. The patient made an uneventful recovery and was discharged home. The histopathology confirmed the inflammatory mass to be the result of acute transmural appendicitis in an appendix containing faecolith and pus. There was no evidence of any scarred tissue in the appendiceal tip to suggest stump appendicitis.

The first report of a duplex appendix was in 1892. The true incidence of duplex appendices is not accurately known. In a study looking at 50 000 human appendices, four duplex appendices were found giving an incidence of 1 in 12 500.1 So far, fewer than 100 cases have been reported in the literature. Appendiceal duplication should be kept in mind in all cases presenting with lower abdominal pain, who have previously had an appendicectomy. Although a rare phenomenon, the unusual presentation of this anomaly can cause diagnostic dilemmas, and possible errors in subsequent management.

Based on reported cases, Wallbridge2 has classified them into three types.

• Type A consists of various degree of partial duplication on a normally localised appendix with a single caecum.

• Type B consists of a single caecum with two completely separate appendices located symmetrically on either side of the ileocaecal valve (B1, ‘bird-like type’) or a normally located appendix along with a rudimentary appendix located along the line of one of the taenia (‘B2 or taenia-coli type’).

• Type C consists of duplicated caecum each with an appendix.

A missed second appendix may result in serious clinical and medico-legal consequences.3 It may remain totally asymptomatic or mimic other intra-abdominal conditions such as carcinoma,4 caecal diverticulum, diverticulosis of the appendix5 or stump appendicitis. In our patient, it presented as a mass in the right iliac fossa mimicking intussusception.

Careful inspection of the caecum, therefore, should be carried out to avoid missing any other appendiceal anomalies.