Clinical History
Elderly woman presenting at emergency department complaining of lower abdominal and perineal pain. Eight days before, she had evacuation proctography requested because of difficult evacuation attributed to descending perineum syndrome. Physically she was found suffering, hypotensive without peritonism.
Laboratory assays showed leukocytosis and severely increased (344 mg/L) C-reactive protein.
Imaging Findings
She denied further evacuation after proctography, despite cleansing enemas. Digital rectal exploration revealed soft stools. Urgent radiographs (Fig. 1) and unenhanced CT (Fig. 2) showed overdistended rectum persistently occupied by barium paste, with gas bubbles in the right ischiorectal fossa suggesting an impending anorectal perforation.
Two days later, surgical exploration found barium residues among extensive ischioanal necrosis and purulent exudate, attributed to the chemical effect of barium. Manual rectal emptying and colonostomy were performed. After surgical toilette including swab dressings, repeated CT (Fig. 3) showed collapsed rectal stump, appearance of perirectal fluid and of extensive inflammatory changes and some extravasated barium in the right ischiorectal fossa.
Serial surgical toilettes allowed slow clinical improvement with a residual local cavity due to the local sclerosing action of the barium. Three months later, follow-up CT (Fig. 4) confirmed resolved perirectal and ischiorectal necrotic-inflammatory changes, with appearance of a retractile soft-tissue density consistent with fibrosis.
Discussion
Otherwise considered a safe contrast agent, barium sulphate (BaS) has been known for decades to cause an intense fibrotic reaction when placed on a serosal surface, where it is not absorbed and may remain in place indefinitely. Therefore, BaS should not be administered if leakage into the peritoneal cavity is possible, such as in patients with suspected gastrointestinal tract perforations. Perforation of the colon or rectum is a rare (0.02-0.04% of studies) but life-threatening complication of double-contrast barium enema (BE), which most usually occurs secondary to anorectal injury by the enema catheter tip or retention balloon, or alternatively results from excessive hydrostatic pressure or weakened rectal wall by stricture, tumour, chronic inflammation, previous irradiation and recent endoscopic procedures. Intraperitoneal perforation causes barium peritonitis with associated shock, which usually needs intensive care, emergency laparotomy and diverting colostomy, and is associated with 35-50% mortality. Preventive measures include postponing the examination after rectal instrumentation, applying special care in the positioning of the catheter tip, and avoiding excessive elevation of the barium bag and overinflating the balloon [1-4].
Although less catastrophic, extraperitoneal barium perforation (EBaP) below the anal sphincter complex is associated with significant morbidity including local infection, sepsis, and anorectal stricture. Sometimes poorly symptomatic, EBaP usually manifests with pain, fever, perineal swelling, bleeding and/or discharge. The hallmark of EBaP includes the detection of air, barium and/or faeces in the perirectal and ischiorectal fat, which may become visible on post evacuation radiographs or on CT images [3-5].
As this case demonstrates, EBaP may occasionally occur after evacuation proctography (EP), which uses BaS paste to allow a combined morphologic and dynamic assessment of the anorectal region and pelvic floor in patients with evacuation disorders. Most usually, EP is requested to assess functional anorectal disorders associated with symptoms that are loosely categorized as “difficult defecation” such as constipation, prolapses, incomplete evacuation or incontinence, mucous discharge or bleeding, pelvic pain or discomfort. Also termed “defecography”, EP is a rather cost effective and rapid technique, which usually shows the complete emptying of BaS paste from the normal rectum within a few seconds, although patients with rectocele and puborectalis muscle dyskinesia have prolonged evacuation time and incomplete emptying. In conclusion, awareness of this exceptional complications may allow prompt recognition and treatment, which are crucial to limit the associated morbidity and mortality [6, 7].
Differential Diagnosis List
Ischiorectal fossa gangrene from extraperitoneal barium extravasation
Iatrogenic colonic perforation
Haemoperitoneum
Splenic rupture
Acute pancreatitis
Final Diagnosis
Ischiorectal fossa gangrene from extraperitoneal barium extravasation
