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					Abdominal Pain and Bowel
      Obstruction
      Mike Goodwin
      CRASH Course
      October, 2010
Abdominal Pain - Approach
 History
 Physical
 Labs
 Imaging
 Provisional Dx
History
 PQRST AAA etx
 But don’t forget
    PSx

    Bowel/Gyne/Urol ROS
Physical Exam
 Complete
 General appearance/vitals/H+N/Chest
 Abdo:
   Rigidity

   Rebound

   Guarding

   IPPA

   DRE / Pelvic / Groin / Flank-CVA
Labs
   Everyone:
     CBC, lytes BUN Cr

     LFT, Bili, Amylase/Lipase, lactate

     Urinalysis

     Urine Preg
Imaging
 AXR
   3-views

   Free air

   Distended bowel/air-fluid

   Calcifications (panc or kidney/ureter)

 US
   If GS disease suspected

   Lower abdo pain in female
Imaging
   CT Abdo
     Test of choice for most patients

     Protocols to minimize contrast
      nephropathy
Bowel Obstruction: Overview

  History
  Etiology
  Pathophysiology
  Clinical presentation
  Imaging
  Management
  Special considerations
Causes of Small Bowel Obstruction
            in Adults
   Lesions Extrinsic to the Intestinal
    Wall

   Lesions Intrinsic to the Intestinal
    Wall

   Intraluminal/Obturator Obstruction
     Lesions Extrinsic to the Intestinal
                  Wall
   Adhesions (usually postoperative)
   Neoplastic
      Carcinomatosis

      Extraintestinal neoplasms

   Hernia
      External (e.g., inguinal, femoral, umbilical,
       or ventral hernias)
      Internal (e.g., congenital defects such as
       paraduodenal, foramen of Winslow, and
       diaphragmatic hernias or postoperative
       secondary to mesenteric defects
   Intra-abdominal abscess
          Lesions Intrinsic to the Intestinal
                        Wall
   Congenital
                                 Traumatic
      Malrotation
                                    Hematoma
      Duplications/cysts

   Inflammatory                    Ischemic stricture
      Crohn’s disease           Miscellaneous
      Infections                  Intussusception

          Tuberculosis            Endometriosis

          Actinomycosis           Radiation
          Diverticulitis            enteropathy/stricture
   Neoplastic
      Primary neoplasms

      Metastatic neoplasms
Intraluminal/Obturator Obstruction

   Gallstone

   Enterolith

   Bezoar
   Common causes of small bowel
obstruction in industrialized countries.
     Pathophysiology
   Early: Increased motility & contractility



    • Bowel dilation, fluid/lytes accumulate in lumen
    and bowel wall




    • Third spacing, intravascular volume depletion
       Bowel obstruction



Increased intraluminal pressure




 Decreased mucosal blood flow



    Progressive Ischemia



     Perforation & Peritonitis
Clinical Diagnosis
   History
     Colicky abdominal pain

     Nausea / vomiting

     Abdominal distension

     Failure to pass flatus / feces
Physical Examination
   Vitals: Tachycardia, hypotension
   Abdomen:
     Distension

     Surgical scars

     Bowel sounds, increased or decreased

     Localized tenderness / rebound / guarding
       suggests strangulation
     Hernia exam (ventral, groin, etc)

   Rectal exam:
     Rectal masses

     Blood – suggesting ischemia, malignancy
Radiology
   Plain Abdo X-Rays
     Confirm Diagnosis

     Localize obstruction to small bowel or
      colon
     Evidence of complete or incomplete
Plain X-ray Features

   Dilated Small Bowel (>3 cm)
   Multiple air-fluid levels
   Colonic gas pattern
      Normal / Dilated (Ileus or partial
       obstruction)
      Absence of gas c/w complete obstruction

   *Thickened bowel wall
   *Pneumatosis intestinalis

           *Suggests ischemia/strangulation
Plain X-rays
   Lappas et al 2001
   Review of 12 AXR findings with SBO
   Findings:
   Combination of
      Air-fluid levels of different heights in the

       same bowel loop
      Mean air-fluid level diameter of 2.5 cm or

       greater
   Most predictive of a high-grade partial or
    complete SBO
       AXR Disadvantages
 20-30% false negative rate
 Does not localize site of obstruction
 Does not establish etiology of
  obstruction
CT Scan
 95% sensitive
 96% specific
 95% accurate in determining the
  presence of complete or high-grade
  SBO
 Shows site and cause of obstruction in
  95% of instances
 Less accurate for partial SBO (50%
  some studies)
            CT for SBO
 CT performed with IV and PO contrast
 High-grade SBO seen even with no
  contrast
 Lesser grades of obstruction seen with
  PO contrast
 IV contrast for assessment of bowel wall
  for signs of edema or ischemia.
CT Findings in Patients with Small Intestinal
                Obstruction

    Type of Obstruction             Findings
Simple obstruction,       Proximal bowel dilatation
partial or complete       Discrete transition zone
                          with collapsed distal small
                          bowel
                          No passage of oral
                          contrast beyond the
                          transition zone
                          Little gas or fluid in colon
CT Findings in Patients with Small Intestinal
Obstruction
   Type of Obstruction             Findings
Closed-loop obstruction
Bowel   Wall Changes     U-shaped,     distended,
                          fluid-filled bowel loop
                          Whirl sign
                          Beak sign
Mesenteric   Changes     Radial distribution dilated
                          bowel loops
                          Thickened mesenteric
                          vessels converging toward
                          point of obstruction
CT Findings in Patients with SBO
    Type of Obstruction             Findings
Strangulated Obstruction
Bowel Wall Changes        Bowel  wall thickening
                           Target sign
                           Pneumatosis intestinalis
                           Dec. bowel wall
                           enhancement
Mesenteric   Changes      Blurring of mesenteric
                           vessels
                           Obliteration of mesentery
                           and vessels
                           Engorgement of
                           mesenteric vasculature
Other                     Ascites
When to Order CT?
 Clinical presentation or abdominal films
  nondiagnostic
 Hx of abdominal malignancy
 Immediate postsurgical patients
 Patients who have no history of
  abdominal surgery
Barium / Contrast Studies
 History of recurring obstruction
 Low-grade mechanical obstruction
 Defines the obstructed segment and
  degree of obstruction
        Gastrograffin Swallow in
        Adhesive SBO, Cochrane
             Review, 2004
   Diagnostic
      Gastrofraffin seen in the cecum on AXR
       within 24 hours predicts resolution
      Sensitivity of 0.96, specificity of 0.96

   Therapeutic
      Hospital length of stay 2-3 days shorter in
       non-operative patients
      Studies prospective, non-blinded
    Simple Versus Strangulating
            Obstruction
 Classic signs:
    Fever

    WBC inc

    Constant Abdo pain

 But no parameters reliably detect
  strang.
 CT findings detect late ischemic
  changes
    Treatment – Nonoperative
   Fluid resuscitation
      IV resuscitation with isotonic saline

      Electrolyte replacement

      Monitor urine output

   Tube decompression
      Empties stomach

      Reduces aspiration risk

      No benefit to long intestinal tubes

   In partial obstruction: 60-85% success rate
Treatment - Operative
 Complete obstruction
  Generally mandates operation

  Some have argued for
   nonoperative approach in
   selected patients
  12-24hr delay of surgery is safe

  >24hr delay is unsafe
     Operative Technique
 Dependent on underlying problem
 Adhesive band: Lysis of adhesions
 Incarcerated hernia: manual reduction
  and closure of defect
 *Presence of hernia with SBO
  mandates OR
 Malignant tumors: Difficult challenge
    Diverting stoma

    Resection / anastamosis

    Enteroenterostomy
    Intestinal Viability at Surgery
 Release obstructed segment
 Place in warm sponge x 15-20 minutes
 If normal colour and peristalsis: return to
  abd
 Doppler probe adds little to clinical
  judgment (Bulkley, 1981)
 Fluorescein may be useful in difficult
  cases
 “Second look” in 24 hrs if questionable
  viability or if clinically deteriorates post-op
Laparoscopy in Acute SBO?
   Criteria:
     Mild distension
     Proximal obstruction

     Partial obstruction

     Anticipated single-band obstruction

     No matted adhesions /
      carcinomatosis
    Special Considerations:
     Recurrent Adhesions
 Multiple agents have been tried, none
  successful
 Hyaluronate-based membrane shown to
  reduce severity of adhesion formation
  (Becker, 1996; Vrigland, 2002)
 No studies yet to show reduction in
  obstruction
Special Considerations:
Recurrent Adhesions
 So far, best evidence to prevent
  adhesions is good surgical technique:
 Gentle handling of bowel
 Avoid unnecessary dissection
 Exclusion of foreign material from
  peritoneum
 Adequate irrigation / removal of debris
 Place omentum around site of surgery
     Special Considerations: Acute
         Post-op Obstruction
   Obstructive symptoms after an initial return of
    bowel function and resumption of oral intake
   Technical complication versus adhesions
   CT scan useful to evaluate for complications:
      Anastamotic leak

      Narrow anastomosis

      Internal hernia

      Obstruction at stoma

   Early reoperation may be indicated
Acute Adhesive Postoperative
        Obstruction
 Difficult to distinguish from ileus
 Incidence 0.7%
 Highest incidence on small intestine
  (3% – 10%)
 Present as early as POD 4
 Usually partial SBO
 CT preferred modality
Acute Postoperative
Obstruction (Adhesive)
 80% spontaneous resolution of
  symptoms
 4% of patients required more than 2
  weeks of treatment
 SBO after laparoscopy: suspect hernia
  at trocar site
    Surgery for Malignant Bowel
    Obstruction in Advanced
    Gynaecological and Gastrointestinal
    Cancer
   Cochrane Review:2004
   Role of surgery controversial
   No firm conclusions from many retrospective
    case series
   Control of symptoms varies from 42% to over
    80
   Rates of re-obstruction, from 10-50%, though
    time to re-obstruction was often not included
   Continues to be a challenging problem
Steroids in Advanced Gyne/GI
Cancer With SBO
   Cochrane Review of prospective data (89
    patients)
   Trend, not statistically significant, for
    resolution of bowel obstruction using
    corticosteroids
   No statistically significant difference in
    mortality
   NNT 6
   Morbidity associated with steroids appears
    low
         Summary


Guidelines for Operative and
   Nonoperative Therapy
Emergent Operation
 Incarcerated, strangulated hernia
 Peritonitis
 Pneumatosis
 Pneumoperitoneum
 Suspected / proven strangulation
 Closed-loop obstruction
 Complete bowel obstruction
Urgent Operation
 Progressive bowel obstruction after
  conservative measures started
 Failure to improve with conservative
  therapy in 24-48 hours
 Early post-op technical complications
  (not adhesions)
Operation Usually Delayed
Safely
 Postoperative adhesions
 Immediate post-op obstruction
  (adhesive)
 Acute exacerbation of Crohn’s dx,
  diverticulitis, radiation enteritis
 Chronic, recurrent partial obstruction
Large Bowel Obstruction
 Cancer
 Cancer
 Cancer (>90%)
 Other things
   Sigmoid Volvulus (5%)

   Diverticular Disease (3%)
Large Bowel Obstruction
 Approach
   Contrast Enema

 CT Abdo
 Treat underlying cause
Acute Pseudo-Obstruction
   Common ward consult
   Predisposing
    Conditions:
       Surgery
       Trauma
       Infection
       Cardiac (CHF/MI)
       Neurological (PD, SCI,
        MS, AD
       Metabolic (↓K/Na)
Ogilvie’s Syndrome
Meds Assoc w/Ogilvie’s   Ogilvie’s Initial Tx:
 Narcotics               Correct fluid and lyte
 Anticholinergic         NPO/NG
 TCA                     Rectal tube
 Chlorpromazine          Limit offending
 Levodop                  medications
 Ca++ blockers
 Clonidine                 >80% success
Ogilvie’s Treatment
Neostigmine             Colonoscopy
 2 mg IV                If neostigmine fails
 Atropine at bedside    Decompression
 Monitored bed
 Patient supine, on    Surgery
  bedpan                Last resort; rarely
 90% success rate        needed
                         If ischemia/perforation

				
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posted:11/25/2011
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