Adynamic Ileus

Aka: Adynamic Ileus, Paralytic Ileus, Adynamic Bowel Obstruction, Functional Bowel Obstruction, Neurogenic Bowel Obstruction

1. Pathophysiology
   1. Paralysis of intestinal motility
2. Causes
   1. Abdominal Trauma
   2. Abdominal surgery (i.e. laparatomy)
   3. Serum electrolyte abnormality
      1. Hypokalemia
      2. Hyponatremia
      3. Hypomagnesemia
      4. Hypermagensemia
   4. Infectious, Inflammatory or irritation (bile, blood)
      1. Intrathoracic
         1. Pneumonia)
         2. Lower lobe Rib Fractures
         3. Myocardial Infarction
      2. Intrapelvic (e.g. Pelvic Inflammatory Disease)
      3. Intraabdominal
         1. Appendicitis
         2. Diverticulitis
         3. Nephrolithiasis
         4. Cholecystitis
         5. Pancreatitis
         6. Perforated Duodenal Ulcer
   5. Intestinal Ischemia
      1. Mesenteric embolism, ischemia or thrombosis
   6. Skeletal injury
      1. Rib Fracture
      2. Vertebral Fracture (e.g. lumbar compression Fracture)
   7. Medications
      1. Opioids
      2. Phenothiazines
      3. Diltiazem or Verapamil
      4. Clozapine
      5. Anticholinergic Medications
3. Symptoms
   1. Abdominal distention
   2. Nausea and Vomiting are variably present
   3. Generalized abdominal discomfort
      1. Colicky pain of Mechanical Ileus is usually absent
   4. Flatus and Diarrhea may still be passed
4. Signs
   1. Quiet bowel sounds
   2. Abdominal distention
5. Differential Diagnosis
   1. Mechanical Ileus
   2. Bowel Pseudoobstruction
   3. See Ileus for diagnostic approach
6. Radiology: Plain Flat and Upright Abdominal XRay
   1. Contrast with Mechanical Ileus
   2. Less prominent air fluid levels
   3. Generalized involvement of entire GI tract
   4. Air filled bowel loops tend not to be distended
7. Radiology: Refractory ileus course
   1. Indicated to evaluate for Mechanical Ileus
   2. Upper GI series and Small Bowel follow through
      1. May be diagnostic and therepeutic
      2. Use gastrograffin instead of barium
         1. Barium may further obstruct bowel lumen
         2. Gastrograffin may stimulate bowel motility
      3. Decompress Stomach with Nasogastric Tube
      4. Instill gastrograffin via Nasogastric Tube
   3. CT Abdomen
8. Management
   1. Initial
      1. Limit or eliminate oral intake
      2. Intravascular Fluid Replacement
      3. Correct electrolyte abnormalities (e.g. Hypokalemia)
      4. Consider Nasogastric Tube placement
   2. Refractory Management (anecdotal evidence only)
      1. Consider Reglan 0.1 mg/kg/dose
      2. Consider lower bowel stimulation (e.g. Fleets Enema)
9. Course
   1. Post-operative ileus resolves within 24-48 hours
10. References
    1. Torrey in Marx (2002) Rosen's Emergency Med, p. 1283-7
    2. Townsend (2001) Sabiston Surgery, p. 883-8
    3. Turnage in Feldman (1998) Sleisenger GI, p. 1799-804