Bowel Obstruction Alia Tuqan, M.D.

Goals and Objectives Understand the pathophysiology of bowel obstruction Diagnosis of bowel obstruction Treatment options for bowel obstruction ▫Medical and surgical options

Introduction Blockage at some point in the gastrointestinal tract preventing the passage of food and feces ▫Partial or complete ▫Mechanical and/or functional ▫Benign or malignant ▫Single or multiple Common with certain types of cancers ▫Colorectal ▫Ovarian ▫Metastases from other sites Other causes ▫Surgical adhesions ▫Post-radiation fibrosis ▫Fecal impaction ▫Inflammatory bowel disease

Introduction Morbidity is high and survival is poor in malignant bowel obstruction (MBO) ▫Chakraborty et al., 2011  35 hospitalized patients were included  58% were re-admitted  Median survival was 80 days  17% were alive at 1 year

Pathophysiology Bowel obstruction  gut hypoxia and bacterial overgrowth  gas production and bowel distension  increased production of vaso-active peptides and splanchnic vasodilation  increased production and pooling of secretions  nausea and vomiting and further gas production and bowel distension  increased gut peristalsis  abdominal pain and increased gas, secretions and distension A vicious cycle that feeds on itself

Diagnosis Based on clinical presentation, exam and imaging Patients often present with abdominal pain, nausea, vomiting and inability to tolerate liquids and solids Physical exam reveals high-pitched, hypoactive to no bowel sounds and a tender abdomen Abdominal X-rays show air-fluid levels Abdominal and pelvic CT-scans show a variety of findings: ▫An intraluminal mass at the point of obstruction ▫Peritoneal carcinomatosis diffusely lining the bowel and causing obstruction

Medical Management When possible, conservative measures are tried first Mechanical decompression with a nasogastric tube (NGT) Anti-cholinergic agents (e.g., scopolamine or glycopyrrolate) to reduce secretions Pro-motility agents (e.g., metoclopramide) Steroids (e.g., dexamethasone) to reduce inflammation and tumor burden Manual dis-impaction and bowel regimens to treat fecal impaction Avoidance of constipating medications (e.g., opioids, tricyclic antidepressants and iron supplements)

Medical Management Methylnaltrexone ▫For opioid-induced constipation ▫Works as mu opioid antagonist ▫0.15mcg/kq SQ or 5-12mg SQ x 1 ▫Max dose: 12mg ▫Renally-dosed; if GFR < 30, reduce dose by 50% ▫May repeat after 48hrs ▫Contraindicated in complete bowel obstructions

Medical Management Octreotide ▫Synthetic somatostatin analog ▫Decreases secretions, splanchnic blood flow and peristalsis ▫Provides symptomatic relief ▫Dosing:  Start mcg q8hrs or mcg 2-4 times per day  If this is not effective, a continuous infusion starting at 10-20mcg/hr and at a rate no more than 1200mcg per day ▫PO, PR, SQ and IV ▫Can be efficacious when used in combination with other medications

Interventions: Venting percutaneous endoscopic gastric (PEG) tube ▫Typically reserved for patients with poorer functional status and limited life expectancy when medications are ineffective

Interventions Stenting ▫Typically reserved for patients with better functional status, life expectancy of weeks to months, and a single obstruction ▫Covered versus uncovered stents  Risks: stent failure, biliary obstruction, bowel perforation  Tumor regrowth tends to be more common with uncovered stents  Stent migration tends to be more common with covered stents  Fernandez-Esparrach et al, 2011 concluded that surgery over stenting should be considered in patients with good functional status because of stenting complications

Surgery Typically reserved for patients with better functional status and life expectancy of months Involves bypassing or resecting the lesion

Surgery Diverting stoma (DS) ▫E.g., ileostomy or colostomy ▫Least complex surgery ▫Has lower complication rates in comparison to other surgeries ▫Better for patients with high-tumor burden and multiple areas of obstruction ▫Good for distal obstructions in the small or large bowel

Surgery Internal bypass (IB) ▫More complex of a surgery than DS, less complex than PR ▫Better for proximal obstructions in the small bowel

Surgery Palliative resection (PR) ▫Most complex surgery ▫Carries the highest complication and survival rate ▫Good for patients with low tumor burden, isolated obstruction, and good functional status

Surgery Type of Surgery Success (%)Morbidity (%) Mortality (%) Survival (months) DS IB PR N=43 Englert et al., 2012 Table: Surgical Outcomes in Bowel Obstruction

Sources Anita Chakraborty, Debbie Selby, Kate Gardiner, Jeff Myers, Veronika Moravan, Frances Wright. Malignant Bowel Obstruction: Natural History of a Heterogeneous Patient Population Followed Prospectively Over Two Years. Journal of Pain and Symptom Management. 2011; 41(2): Zachary P. Englert, Michael A. White, Timothy L Fitzgerald, Anusha Vadlamudi, Gus Zervoudakis, and Emmanuel E. Zervos. Surgical Management of Malignant Bowel Obstruction: At What Price Palliative? American Surgeon. 2012; 78: Gloria Fernandez-Esparrach, J.M. Bordas, M.D. Giraldez, A. Gines, M. Pellise, O. Sendino, G. Martinez-Palli, A. Castells, and J. Llach. Severe Complications Limit Long-Term Clinical Success of Self-Expanding Metal Stents in Patients With Obstructive Colorectal Cancer. American Journal of Gastroenterology. 2010; 105: Robert S. Krause. #119 Invasive Treatment Options for Malignant Bowel Obstruction. Fast Facts and Concepts. End of Life/Palliative Education Resource Center, Medical College of Wisconsin.

Sources John Manfredonia. Urgent Medical Conditions: Spinal Cord Compression, Hypercalcemia, Seizures, Bowel Obstruction. AAHPM Intensive Board Review Course DVD Gola Tradounsky. Palliation of gastrointestinal obstruction. Canadian Family Physician. 2012; 58(6): Rodney O. Tucker and Ashley C. Nichols. U4: Managing Non-Pain Symptoms. American Academy of Hospice and Palliative Medicine Charles von Gunten and J Cameron Muir. #45 Medical Management of Bowel Obstruction, 2 nd edition. Fast Facts and Concepts. End of Life/Palliative Education Resource Center, Medical College of Wisconsin. Catherine Weber and Gilbert B. Zulian. Malignant Irreversible Intestinal Obstruction: The Powerful Association of Octreotide to Corticosteroids, Antiemetics and Analgesics. American Journal of Hospice and Palliative Medicine. 2009; 26(2):