Complicated diverticulitis (pericolic abscess)

Case contributed by Bruno Di Muzio
Diagnosis certain


Persistent left iliac fossa pain over the last week.

Patient Data

Age: 35 years
Gender: Male

CT Abdomen and Pelvis


Surrounding a short segment of the sigmoid colon there is fat stranding and a small amount of free fluid. The presence of a few colonic diverticula, with a larger one involved by the inflammatory process, makes colonic diverticulitis the most likely diagnosis. 

The patient hasn't improved with the conservative management and represents in ED almost a week later. 

CT A/P one wk later


A pericolic collection containing fluid and gas lies anterior to the sigmoid colon. There is marked adjacent fat stranding within the sigmoid mesocolon. A number of diverticula are noted within the descending colon. No free intra peritoneal air. The liver, spleen, pancreas, adrenal glands and kidneys are unremarkable. No enlarged lymph nodes evident.

Complications related with colonic diverticulitis are:

  • abscess formation
  • fistula formation
    • bladder: colovesical fistula
    • vagina: colovaginal fistula
    • bowel: coloenteric fistula or colocolic fistula
    • skin: colocutaneous fistula
  • small bowel obstructions from adhesions
  • perforation resulting in pneumoperitoneum

In this case, radiology has been asked to insert a percutaneous catheter for the abscess drainage. 

US-guided abscess drainage


The procedure, with its potential risks and complications, was discussed with the patient, including the option of not performing the procedure. Verbal and written consent was obtained. We are thankful to the referring team for organizing the written consent. Time-out: A time-out was observed to confirm the correct patient, procedure, and site. Findings: The collection with gas and fluid content was identified and its relation with the sigmoid colon reviewed under ultrasound. The best safe approach was planned. Procedure: With the patient in supine position, the skin was prepped and draped in usual sterile fashion. Local anesthesia was performed using 1% lidocaine. Under ultrasound guidance, the 12 Fr multipurpose drainage catheter was inserted into the collection. Brownish thick fluid drained spontaneously. 

Case Discussion

This case shows colonic diverticulitis in a young adult that has complicated with the formation of a pericolic abscess anterior to the sigmoid colon. The collection has drained purulent material. It likely represents a complication related to a contained perforation. 

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