Ileus Adynamic ileus Mechanical ileus

Adynamic ileus Pathophysiology Paralysis of intestinal motility

Adynamic ileus II. Causes Abdominal trauma Abdominal surgery (i.e. laparatomy) Serum electrolyte abnormality 1. Hypokalemia 2. Hyponatremia 3. Hypomagnesemia 4. Hypermagensemia

Adynamic ileus D. Infectious, Inflammatory or irritation (bile, blood) 1. Intrathoracic Pneumonia Lower lobe rib fractures Myocardial Infarction 2. Intrapelvic e.g. Pelvic Inflammatory Disease

Adynamic ileus 3. Intraabdominal Appendicitis Diverticulitis Nephrolithiasis Cholecystitis Pancreatitis Perforated Duodenal Ulcer

Adynamic ileus E. Intestinal Ischemia F. Skeletal injury Mesenteric embolism, ischemia or thrombosis F. Skeletal injury Rib fracture Vertebral fracture (e.g. lumbar compression fracture)

Adynamic ileus G. Medications Narcotics Phenothiazines Diltiazem or Verapamil Clozapine Anticholinergic Medications

Adynamic ileus III. Symptoms Abdominal distention Nausea and Vomiting are variably present Generalized abdominal discomfort Colicky pain of Mechanical Ileus is usually absent Flatus and Diarrhea may still be passed

Adynamic ileus IV. Signs V. Differential Diagnosis Quiet bowel sounds Abdominal distention V. Differential Diagnosis Mechanical Ileus Bowel Pseudoobstruction

Adynamic ileus Decompress stomach with Nasogastric Tube VI. Radiology: Refractory ileus course Indicated to evaluate for Mechanical Ileus Upper GI series and small bowel follow through May be diagnostic and therepeutic Use gastrograffin instead of barium Barium may further obstruct bowel lumen Gastrograffin may stimulate bowel motility Decompress stomach with Nasogastric Tube Instill gastrograffin via Nasogastric Tube

Adynamic ileus D. Contrast with Mechanical Ileus 1. Less prominent air fluid levels 2. Generalized involvement of entire GI tract 3. Air filled bowel loops tend not to be distended

Adynamic ileus VII. Management Initial Limit or eliminate oral intake Intravascular fluid replacement Correct electrolyte abnormalities (e.g. Hypokalemia) Consider Nasogastric Tube placement Refractory Management Consider Prokinatics Consider lower bowel stimulation (e.g. Enema)

Adynamic ileus VIII. Course Post-operative ileus resolves within 24-48 hours

Mechanical ileus Types Simple mechanical obstruction Bowel lumen is obstructed No vascular compromise Closed loop obstruction Both ends of a bowel loop are obstructed Results in strangulated obstruction if untreated Rapid rise in intraluminal pressure Strangulated obstruction 1. Bowel lumen and vascular supply is compromised

Mechanical ileus II. Causes Most Common Causes Postoperative Adhesions (accounts for 50% of cases) Hernia (25% of cases, especially younger patients) Neoplasms (10% of cases, esp. older patients) Colon Cancer (most common) Ovarian Cancer Pancreatic cancer Gastric Cancer

Mechanical ileus Intrinsic bowel lesions Congenital anomalies (Pediatric) Atresia Stenosis Bowel duplication

Mechanical ileus 2. Strictures Inflammatory Bowel Disease (e.g. Crohn's Disease) Colon Cancer Intussusception Children: Usually idiopathic Adults: 95% have underlying mechanical cause AIDS may predispose to Intussusception Gallstones that have entered the bowel lumen More common in those over age 65 years Bezoar Barium Ascaris infection Tuberculosis Actinomycosis Diverticulitis

Mechanical ileus C. Extrinsic bowel lesions Adhesion Abdominal or pelvic surgery Presence of peritonitis or trauma Hernia (higher risk for strangulation) Inguinal hernia (direct ,indirect) Internal hernias via mesenteric defects Obturator hernia More common in emaciated elderly women

Mechanical ileus D. Idiopathic Intestinal Obstruction 3. Small bowel volvulus Rare compared to colon volvulus More common in Africa, Middle East and India Occurs in intestinal malrotation or adhesions D. Idiopathic Intestinal Obstruction 1. See Bowel Pseudoobstruction

Mechanical ileus III. Symptoms Frequent and recurrent Generalized Abdominal Pain Duration: Seconds to minutes Character: Spasms of crampy abdominal pain Frequency Intermittent pain initially Every few minutes in proximal obstruction Constant pain suggests ischemia or perforation

Mechanical ileus B. Stool passage Initially may be present despite complete obstruction Later, obstipation (no stool) in complete obstruction C. Symptoms more severe in proximal obstruction Proximal obstruction Severe, colicky abdominal pain Constant pain suggests ischemia or perforation Develops over hours and occurs every few minutes Bilious Emesis Mild abdominal distention

May occur at any point in length of small bowel Where? May occur at any point in length of small bowel

Mechanical ileus Distal obstruction Develops over days and becomes progressively worse Emesis may occur and is brown and feculent Significant abdominal distention

Mechanical ileus IV. Signs Bowel sounds Tender abdominal mass Initial: High pitched, hyperactive bowel sounds Later: hypoactive or absent bowel sounds Tender abdominal mass Closed loop Bowel Obstruction may be palpable Abdominal distention and tympany on percussion Indicates distal obstruction Rectal examination for blood

How does it present? Symptoms: Colicky abdominal pain, nausea, vomiting, and obstipation. Continued passage of gas and/or stool beyond 12 hours after onset of symptoms is characteristic of partial rather than complete obstruction. Signs: Abdominal Distention (Greater the farther distal the obstruction) and hyperactive, high pitched bowel sounds. Laboratory Findings: Intravascular volume depletion (consist of hemoconcentration and electrolyte abnormalities) Mild leukocytosis. Features of Strangulated Obstruction (Bowel Infarction): Acute Abdomen,Tachycardia, localized abdominal tenderness, fever, marked leukocytosis, and acidosis. Serum levels of amylase, lipase, lactate dehydrogenase, phosphate, and potassium may be elevated.

The diagnosis is usually confirmed by Radiology How is it diagnosed? Evaluation Goals: Distinguishing mechanical obstruction from ileus Determining the etiology of the obstruction Discriminating partial from complete obstruction Discriminating simple from strangulating obstruction. History: Prior abdominal operations Presence of abdominal disorders (cancer or IBD) Last BM and Flatus Pediatrics - Ingestion of foreign body Physical Exam: Meticulous Search for Hernias (inguinal and femoral) Rectal Exam to look for gross or occult blood. The diagnosis is usually confirmed by Radiology

Mechanical ileus V. Radiology: Flat and upright (or decubitus) abdominal X-Ray Sensitivity: 60% (up to 90%) Typical findings of Bowel Obstruction Bowel distention proximal to obstruction Bowel collapsed distal to obstruction Upright or decubitus view: Air-fluid levels Supine view findings Sharply angulated distended bowel loops Step-ladder arrangement or parallel bowel loops

Abdominal series Radiograph of the abdomen in a supine position Radiograph of the abdomen in an upright position Radiograph of the chest in an upright position. Most Specific Finding: The Triad Dilated small-bowel loops (>3 cm in diameter) Air-Fluid levels on upright films Paucity of air in the colon. Sensitivity is 70 to 80%. Specificity is low, because ileus and colonic obstruction have similar appearing findings. Despite some limitations, Plain films remain an important study because of their widespread availability and low cost.

Small Bowel Gas Pattern Centrally located Soft tissue across entire lumen Colon Gas Pattern Peripheral Located Mostly not overlapping Haustra markings

Mechanical ileus c .String of pearls sign (specific for obstruction) Series of small pockets of gas in a row d. Pseudotumor Sign Bowel loop filled with fluid (resembles mass)

Mechanical ileus VI. Radiology MRI Abdomen (93% Test Sensitivity for SBO cause) CT Abdomen (88% Test Sensitivity for SBO cause) Adjunct to plain XRay to identify obstruction site Findings Intussusception Volvulus Extraluminal mass (e.g. abscess, neoplasm) Closed loop obstruction Strangulated bowel

Flat Abdominal Film Dilated Loops of Small Bowel No Air in Colon or Rectum

Upright Abdominal Film Air - Fluid Levels Dilated Small Bowel

Computed Tomographic (CT) scanning Study preformed with oral and IV contrast. Findings: Discrete transition zone with dilation of bowel proximally and decompressed distally Intraluminal contrast that does not pass beyond the transition zone Colon containing little gas or fluid. Strangulation: Suggested by thickening of the bowel wall, pneumatosis intestinalis (air in the bowel wall), portal venous gas, mesenteric haziness, and poor uptake of intravenous contrast into the wall of the affected bowel. Offers a global evaluation of the abdomen. Important when intestinal obstruction represents only one possible diagnosis in all acute abdominal conditions. Sensitivity 80 to 90% (More sensitive the higher grade obstruction) Specificity 70 to 90%

Dilated Loops of Small Bowel with Air-Fluid levels Area of non-dilated small bowel. Absence of Air in the Colon.

Pneumatosis Intestinalis Dilated Loops of SB Air in Wall of SB No Air in Colon

Mechanical ileus VII. Differential Diagnosis Adynamic Ileus Bowel Pseudoobstruction Ischemic bowel (superior mesenteric syndrome) Gastroenteritis Cholelithiasis Cholecystitis Pancreatitis Peptic Ulcer Disease Appendicitis Myocardial Infarction Pregnancy

Mechanical ileus VIII. Management: Conservative Therapy Fluid replacement Bowel decompression Nasogastric Tube Long intestinal tube (eg. Cantor) offers no advantage Antibiotic Indications (Not for routine use) Surgery planned Bowel ischemia or infarction Bowel perforation Cover Gram Negatives and Anaerobes a. Second-generation Cephalosporin

Mechanical ileus IX. Management: surgical intervention Spontaneous resolution often occurs without surgery Partial small bowel obstruction: 75% Complete small bowel obstruction: up to 50%

Mechanical ileus Predictors of resolution without surgery Early postoperative bowel obstruction Adhesive obstruction (prior laparotomy) Crohn's disease Indications for surgery Inadequate relief with Nasogastric tube placement Persistant symptoms >48 hours despite treatment (strangulation) Neoplasms

Mechanical ileus X. Complications Intestinal Ischemia or infarction Bowel necrosis, perforation and bacterial peritonitis Hypovolemia Complications of surgical intervention if needed XI. Prognosis: Recurrence of obstruction due to adhesions Risk after first episode: 53% Risk after more than one episode: 83%

New Aspect in Treatment of Adhesive Ileus 1. Adhesive small bowel obstruction: How long can patients tolerate conservative treatment? World J Gastroenterol 2003 Mar 15;9(3):603-605 Shou-Chuan Shih, Kuo-Shyang Jeng, Shee-Chan Lin, Chin-Roa Kao, Sun-Yen Chou, Horng-Yuan Wang, Wen-Hsiung Chang, Cheng-Hsin Chu, Tsang-En Wang

Method 1. From January 1999 to December 2001, 293 patients with small bowel obstruction due to postoperative adhesions were retrospectively reviewed . 2. Data collected included the number of admissions, type of management for each admission, duration of conservative treatment, and operative findings.

Result 1.Medical treatment:220 Repeated laprotomy:73 2.Period of observation Medically:2-12 days(average 6.9) (until resolution of obstruction) Surgically:1-14 days(average 5.4)(prior to surgery) 3.At surgery, Adhesions were the only finding:46( 63% of surgically, 15.7% of all) Intestinal complication:27(37% of surgically, 9.2% of all) #Fever and leukocytosis greater than 15000/mm3 were prediction of intestinal complications

Conclusion With closely monitoring, most patients with small bowel obstruction due to postoperative adhesions could tolerate supportive treatment and recover well averagely within 1 week although some patients require more than 10 days of observation.

British Journal of Surgery ,3 Jul 2003 2. Laparoscopic compared with conventional treatment of acute adhesive small bowel obstruction British Journal of Surgery ,3 Jul 2003 Volume 90, Issue 9 , Pages 1147 - 1151 C. Wullstein *, E. Gross Chirurgische Abteilung, Allgemeines Krankenhaus Barmbek, Hamburg, Germany

Method Patients with acute SBO treated laparoscopically (LAP; n = 52) and conventionally (CONV; n = 52) were compared in a retrospective matched-pair analysis. Conversions were included in the laparoscopic group.

Result 1.IntraOP major complication: (Perforation ,Hemorrhage ,Injury to mesentery) LAP 15/52 (28.8%) CONV 8/52 (15.4%) p=0.156 2.PostOP complication (Pulmonary, Cardiac, Deep vain thrombosis, Death…) LAP 10/52 (19.2%) CONV 8/52 (40.4%) p=0.032 3.Bowel movement, days after OP LAP 3.5 CONV 4.4 (p=0.001) 4.Days of hospital stay LAP 11.3 CONV 18.1 (p=0.001)

Conclusion Laparoscopic treatment of acute SBO was feasible in about half of these patients. Postoperative recovery was improved after laparoscopic procedures but the risk of intraoperative complications increased . Laparoscopic management of acute SBO seems justified in patients with fewer than two previous laparotomies but should not be offered to other patients because of the unacceptably high risk of intraoperative bowel perforation.

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