Fecal impaction

Clinical History

A case of fecal impaction is described. The CT examination showed grossly distended rectum and sigmoid colon loaded with fecal matter causing displacement and compression of the urinary bladder and ureters.

Imaging Findings

A 19-year-old Kuwaiti female patient was admitted with severe right iliac fossa pain. She lost 15 kg in 4 months. Abdominal examination showed her abdomen firm, tender, distended. She was not febrile, and the vital signs were normal. Laboratory findings were unremarkable. Urgent US study revealed dilated pelvicalyceal systems bilaterally, more on the right side. The US study was of limited value due to gross abdominal distension from the gaseous bowels. CT showed the large bowel, mainly the rectum and sigmoid colon grossly distended and full with fecal matter with innumerable air lucencies (Fig.1). The rest of the large bowel loops, the small bowels and the stomach were compressed by the mass effect of the dilated rectum and sigmoid colon. The urinary bladder was also compressed and displaced to the right side (Fig. 2). Both kidneys showed moderately dilated collecting systems and dilated ureters (Fig. 3). Cleaning enema was performed and the bowels were evacuated. The patient’s symptoms were relieved and the abdomen became soft and relaxed. She was discharged soon after the enema.

Discussion

Fecal impaction represents an extreme form of constipation when there is a large mass of dry, hard stool that can accumulate in the rectum due to chronic constipation. It can occur in all age groups and have many etiologies, including dietary (low fiber, minimal water, medications), systemic diseases (diabetes mellitus, multiple sclerosis, Parkinson’s disease, hypothyroidism), mechanical (malignant lesion, benign stricture, rectal prolapse, rectocele), functional (immobility, spinal cord injury, slow transit, dementia), painful perianal lesions (perianal abscess and fistula), congenital (Hirschsprung’s disease) ^[2,3]. Complications of unrecognized fecal impaction include electrolyte disturbances, renal insufficiency, dehydration, stercoral ulceration, lower gastrointestinal bleeding, and even colonic perforation ^[4,5]. In our case obstructive uropathy was the leading complication. Physical examination may demonstrate abdominal distention and a palpable abdominal mass. A digital rectal examination can secure the diagnosis. Our patient presented only with severe right iliac fossa pain. Laboratory investigations are often unremarkable but may demonstrate an increased white cell count and electrolyte disturbances. The plain abdominal x-rays demonstrate impacted stool or obstruction in the form of gas distension with loaded large bowels and air trapping, or in case of large bowel perforation, free intraperitoneal air. A water-soluble contrast enema can function as diagnostic as well as therapeutic procedure ^[6]. Surgery should be reserved for failed medical management or complicated cases with colonic perforation. Surgical options typically include resection of the involved colonic segment, with or without colostomy. CT scan can ascertain the extent of fecal loading but is not always necessary for the diagnosis.

Differential Diagnosis List

Final Diagnosis

Fecal impaction.

URL:	https://eurorad.org/case/6602
DOI:	10.1594/EURORAD/CASE.6602
ISSN:	1563-4086