A 61-year-old man presented with one week of abdominal distention and pain. He has had nausea and two episodes of vomiting that “smelled like stool,” but denies having a bowel movement or passing flatus in the past five days.
He denies fever, chest pain, trauma, or any past medical history. Here is what you see on examination of the abdomen. What are you concerned about, and what is the evaluation?
Find the diagnosis and case discussion on p. 12.
Diagnosis: Large Bowel Obstruction from Metastatic Adenocarcinoma
Large bowel obstruction, a common problem diagnosed and treated in the emergency department, is caused by a number of etiologies ranging from inflammation, malignancy, post-surgical/trauma, and congenital- and medication-related conditions. The overall mortality rate for large bowel obstruction is approximately 20 percent, but it can be as high as 40 percent if there is an associated colonic perforation.
Patients with large bowel obstruction can present with abdominal distention, crampy abdominal pain, nausea, vomiting, constipation, obstipation, decreased flatus, or decreased stool caliber. They may have tenderness, rigidity (if perforated), an abdominal, rectal, inguinal, or proximal femoral mass, fecal impaction on digital rectal examination, or an imperforated anus (usually in neonates.)
The evaluation for a suspected large bowel obstruction may include laboratory testing, including complete blood count, hemoglobin, serum chemistries, coagulation studies, serum lactate, type and cross-match, and stool guaiac. Stool studies should be obtained if Clostridium difficile is suspected. Imaging is the diagnostic study of choice, however, to confirm the presence of a large bowel obstruction. It can be diagnosed with plain roentgenography, computerized tomography, or contrast enema. (ANZ J Surg 2007;77:160; Colorectal Dis 2008;10:729.)
Colonic distention of 12 cm or more is associated with an increased risk of intestinal ischemia and perforation. (Gastrointest Endosc Clin N Am 2007;17:341.) Cases have occurred, however, at smaller intestinal diameters. (See radiograph.)
The treatment of large bowel obstruction depends on the severity of the condition. (Clin Colon Rectal Surg 2012;25:200.) Patients with partial large bowel obstruction or ileus can be treated conservatively with intravenous hydration, appropriate electrolyte replacement, bowel rest, and proximal decompression with a nasogastric tube. The contents retrieved via nasogastric tube for this patient appeared to be fecal. (Photo.) Fecal impaction causing large bowel obstruction requires disimpaction.
Acute colonic pseudo-obstruction (Ogilvie syndrome, thought to be caused by increased sympathetic tone and inhibition of colonic motility resulting in functional obstruction) may be treated with a single dose of neostigmine if conservative therapy has failed, and there is a risk of perforation and no mechanical colonic obstruction has been identified. (Ann Pharmacother 2012;46:430.)
Complete large bowel obstructions, however, require emergent correction to prevent or inhibit tissue ischemia. An attempt should be made to reduce the strangulated or incarcerated bowel segment if the etiology is related to an inguinal or femoral hernia. Large bowel obstruction with perforation should prompt administration of empiric antibiotics for bowel flora and emergent surgical consultation. Large bowel obstruction related to inflammation associated with diverticulitis (20% of cases) may resolve with antibiotics and close observation. Uncomplicated primary sigmoid volvulus can typically be reduced endoscopically. (Am Surg 2012;78:271.)
Uncomplicated intussusception is often amenable to treatment using a contrast or air enema with a recurrence rate of only about 13 percent in children. (Pediatrics 2014;134:110.) Treatment for large bowel obstruction related to bowel malignancy (60% of cases) can be resection or stenting, which can be performed at times for palliative treatment for functional obstruction or can be performed for strictures related to scarring from previous inflammation or ischemia. (Colorectal Dis 2009;11:642; Ann Surg 2007;246:24.) Percutaneous cecostomy/colostomy has also been described for patients with malignancy-related large bowel obstruction. (J Vasc Interv Radiol 2015;26:182.)
This patient was immediately taken to the operating room for a transverse colon diverting colostomy and resection of a large bowel mass, which was subsequently diagnosed as colonic adenocarcinoma. Staging showed multiple metastases in the liver. He received palliative chemotherapy as an outpatient.
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