An Unusual Presentation of Acute Appendicitis Mimicking Sigmoid Diverticulitis: A Case Report

Abstract

Acute appendicitis typically causes right lower quadrant pain, but in elderly patients with comorbidities, it can present atypically, complicating diagnosis. This case highlights a rare presentation, mimicking sigmoid diverticulitis. A 70-year-old man with chronic heart failure, arrhythmia, and renal failure presented with two days of left lower quadrant pain. Examination showed tenderness, rebound, and guarding. Laboratory tests revealed a white blood cell count of 12,000/µL and creatinine of 2.5 mg/dL. C-reactive protein was elevated at 25 mg/L. Computed tomography revealed an inflamed appendix with an appendicolith and localized inflammation near the sigmoid colon, but no diverticulitis. An appendectomy confirmed a perforated appendix in contact with the sigmoid colon. In elderly patients, acute appendicitis may present atypically with left-sided pain, risking misdiagnosis. Careful evaluation and imaging are essential for accurate diagnosis and management in those with comorbidities.

Keywords: acute appendicitis; computerize tomography; diverticulitis; geriatric; surgery.

Figure 1. A) The appendix is inflamed and extended. B) An appendicolith is present in the pelvis, with surrounding tissue also exhibiting inflammation. C) and D) The sigmoid colon is inflamed, with no evidence of diverticular disease.

Figure 2. Acute perforated appendicitis with appendicolith.