Impact of CT-guided drainage in the treatment of diverticular abscesses: size matters.

OBJECTIVE: Our objective was to determine whether abscess size can be used as a discriminating factor to guide management of patients with diverticular abscesses.
MATERIALS AND METHODS: We performed a word search of our CT database between July 2001 and July 2002 for the CT diagnosis of diverticulitis. CTs were retrospectively reviewed as consensus opinion of two reviewers. CTs were evaluated for presence of an abscess, its location, maximum diameter, and feasibility of percutaneous abscess drainage. Abscesses were categorized into smaller than 3 cm and larger than or equal to 3 cm, and the management of these groups was compared.
RESULTS: Thirty-one abscesses were noted in 30 (17%) of 181 patients with a CT diagnosis of diverticulitis. Twenty-two (73%) of 30 patients had 23 abscesses, all of which were smaller than 3 cm and were treated and resolved with antibiotics alone (p < 0.001). Eight (36%) of 22 required surgical treatment. Eight (26%) of 31 abscesses had a maximum diameter larger than or equal to 3 cm. Four (50%) of eight patients with abscesses 3.4-4.1 cm were treated with antibiotics alone. Four (50%) of eight abscesses, all larger than 4.1 cm, were treated with CT-guided drainage and one abscess required repeat drainage. After resolution of symptoms, surgery was performed in five (62.5%) of eight of the larger abscesses.
CONCLUSION: Patients with abscesses smaller than 3 cm in size can be treated with antibiotics alone and, in some cases, as outpatients, and may not uniformly require surgery. This is also likely true for patients with abscesses 3-4 cm in size, although our results in this group were limited by a small sample size. Patients with abscesses larger than or equal to 4 cm can be managed with CT-guided abscess drainage followed by referral for surgical treatment.