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A. Causesnavigator

  1. Post-Operative
    1. Adhesions
    2. Pseudo-obstruction (functional)
  2. Cancer Involving Mesentery
    1. Colon Adenocarcinoma
    2. Carcinoma of pancreatic head
    3. Small bowel tumors, especially lymphoma
    4. Ovarian and other gynecologic cancers spread locally
    5. Melanoma invades small intestinal submucosa causing constriction
  3. Inflammation
    1. Infection - gastroenteritis, abscess, tuberculosis
    2. Ischemic - mesenteric ischemia
    3. Crohn's Disease
    4. Celiac sprue
    5. Eosinophilic gastroenteritis
    6. Sarcoidosis
    7. Vasculitis
  4. Gallstone Induced Ileus
  5. Peptic Ulcer Disease (with stricture)
  6. Intussusception
  7. Volvulus
  8. Herniation
  9. Functional Obstruction
    1. Elevated sympathetic (autonomic) signalling
    2. Reduced parasympathetic signalling
    3. Combinations of the above
    4. Common in intensive care setting, post-operatively, sepsis (stress)
    5. Pancreatic disorders
  10. Congenital
    1. Web
    2. Annular pancreas
    3. Preduodenal portal vein
    4. Choledochal cyst
    5. Paraduodenal hernia
  11. Other [2]
    1. Inflammatory adhesions
    2. Hematoma of GI tract
    3. Superior mesenteric artery syndrome
    4. Bouveret's syndrome
    5. Hyperlasia of Burnner's glands
    6. Idiopathic retroperitoneal fibrosis

B. Symptoms and Signsnavigator

  1. Crampy abdominal pain
  2. High pitched bowel sounds
  3. Vomiting (Nausea)
  4. Fecal Vomiting (>3 days of ileal obstruction)
  5. Abdominal distension and Obstipation
  6. Diarrhea (non-bloody)

C. Diagnosisnavigator

  1. History of adhesions, recent surgery (within ~6 months), other abdominal illnesses
  2. Focal pain on physical exam
  3. Opiate treatment may alter physical exam findings but no significant change in management in patients with abdominal pain [6]
  4. Serum electrolyte abnormalities
    1. Acidosis, Low HCO3-
    2. Hyponatremia, hypokalemia
  5. Abdominal Radiograph
    1. Dilated fixed loop (compare supine and upright films)
    2. Air-fluid levels
    3. Absence of colonic gas implies complete obstruction
    4. Edematous Bowel wall
  6. Endoscopy in selected cases when needed

D. Pathophysiologynavigator

  1. Obstruction causes Distension
  2. Lymphatic Compromise leading to Third Spacing
  3. Venous Compromise with Increased Edema and Stasis
  4. Bacterial Overgrowth in Static Intestine
  5. Inflammation causes Edema leading to Arteriolar Compromise and Ischemia
  6. Ischemia leads to Infarction, Necrosis and Gangrene
  7. Perforation and Peritonitis can occur

E. Complicationsnavigator

  1. Ischemia (Strangulation)
  2. Gangrene (necrosis) with infection
  3. Perforation with peritonitis

F. Strangulationnavigator

  1. Progression from Crampy pain to Continuous pain
  2. Fever, Leukocytosis (with Left Shift)
  3. Loss of Bowel Sounds
  4. Peritonitis (involuntary guarding)
  5. Mass present

G. Treatmentnavigator

  1. Resuscitation
    1. Fluids
    2. Blood pressure support as needed
    3. Broad Spectrum Antibiotics usually given
  2. Nasogastric Tube Decompression
  3. Surgery (indications):
    1. Complete Obstruction (no air in rectum, continued BM)
    2. Patient not improving
    3. Peritonitis (signs)
  4. Laparoscopic adhesiolysis [5] - no better than diagnostic laparoscopy for chronic pain [5]
  5. Expandable metal stents for obstruction due to gastrointestinal cancer [4]

H. Ileus (Functional Obstruction)navigator

  1. Constipation, Air Fluid levels
  2. No structural problems identified
  3. Causes
    1. Peripheral (autonomic) neuropathy: diabetics, chemo agents
    2. Drugs: opiates, Ca channel blockers (such as verapamil), anti-cholinergics, barbiturates
    3. Idiopathic
    4. Irritable Bowel Syndrome
    5. Scleroderma
    6. Infiltrative Disorders (eg. amyloid, lymphoma)
    7. Hypothyroidism
  4. Treatment
    1. Promotility agents for autonomic neuropathy
    2. Senekot for opiate induced ileus
    3. Laxatives - careful with distal obstructions; may cause perforation
    4. Enemas
    5. Colace® (stool softener)
    6. Cholinergic agonists: bethanechol (see below)
  5. Promotility Agents
    1. Bethanechol (urocholine®) 25mg qid
    2. Metoclopramide (Reglan®) 10mg qid
    3. Cisapride (Propulsid®) 10mg qid - effective but limited use due to QTc prolongation
    4. Dazopride - substituted dazamide, investigational

OBSTRUCTION OF THE LARGE INTESTINE

A. Causesnavigator
  1. Diverticulosis / Diverticulitis
  2. Sigmoid Volvulus
  3. Colon Cancer, particularly Left sided
  4. Hernia, incarcerated, usually sigmoid
  5. Metastatic CA
  6. Congenital bands
  7. Inferior mesenteric artery occlusion (Atherosclerosis, Vasculitis)
  8. Hirschprung's Disease
  9. Functional obstruction
    1. Autonomic Dysfunction
    2. Often associated with sympathetic overdrive
    3. Abnormal or lack of peristalsis

B. Symptoms and Signsnavigator

  1. Little vomiting, especially when ileocecal valve is competent
  2. Severe distension
  3. Constipation and obstipation

C. Diagnosisnavigator

  1. Radiography: gas filled colon to point of obstruction
  2. Rectal lesions are palpable in most patients on Physical Examination
  3. Barium Enema (air contrast)

D. Complicationsnavigator

  1. Obstruction (pathophysiology similar to small intestine)
  2. Ischemia
  3. Carcinomatosis
  4. Perforation and Peritonitis leading to Sepsis

E. Treatmentnavigator

  1. Underlying condition
  2. Colonoscopic decompression
  3. Neostigmine [3]
    1. Acetylocholinesterase inhibitor with short onset and duration of action
    2. Parasympathomimetic agent
    3. Intravenous infusion of 2mg neostigmine was >90% effective in relieving acute colonic pseudoobstruction (ileus)
    4. Side effects include bradycardia, abdominal bloating, nausea, bronchospasm
    5. Overall was well tolerated and very effective
  4. Surgical decompression
  5. Endoscopic placement of expandable metal stent for cancerous obstruction [4]
  6. Colectomy (complete or partial)

References navigator

  1. Holder WD Jr. 1988. Gastroenterol Clin North Amer. 17(2):317 abstract
  2. Ross AM IV, Anupindi SA, Balis UJ. 2003. NEJM. 348(15):1464 (Case Record) abstract
  3. Ponec RJ, Saunders MD, Kimmey MB. 1999. NEJM. 341(3):137 abstract
  4. Baron TD. 2001. NEJM. 344(22):1680
  5. Swank DJ, Swank-Bordewijk SCG, Hop WCJ, et al. 2003. Lancet. 361(9365):1247 abstract
  6. Ranji SR, Goldman LE, Simel DL, Shojania KG. 2006. JAMA. 296(14):1762