Acute Streptococcus constellatus Pyogenic Liver Abscess Due to an Atypical Presentation of Sigmoid Diverticulitis Complicated by Pericolonic Abscess

Diverticulitis is a result of diverticulum inflammation that involves protrusion of the colonic wall. It is considered to be complicated when associated with an abscess, fistula, perforation of large bowel, or obstruction. The incidence of diverticulitis increases with age, and it most commonly presents as constant abdominal pain in the left lower quadrant. We report a case of a 54-year-old male with a history of hypertension who was admitted to our hospital with systemic symptoms and right shoulder pain noted to have Streptococcus constellatus bacteremia and an incidental finding of a single large hepatic abscess on chest imaging. Additional imaging studies revealed the presence of acute sigmoid diverticulitis complicated by pericolonic abscess. He had no known risk factors and had not experienced any abdominal pain before admission. A liver abscess due to S. constellatus is a rare complication from sigmoid diverticulitis, and there are only a few cases reported as per the PubMed medical literature review. Only four other unique cases with few or no risk factors were discovered to have a pyogenic liver abscess initially, and later source was found to be due to perforated diverticulitis. Due to this rare clinical presentation, diagnosis is often delayed leading to complications requiring surgical intervention. This can result in higher mortality. Our patient had ultrasound-guided drainage of the abscess and completed a six-week course of intravenous antibiotics (ceftriaxone and metronidazole) with successful recovery.