The role of - General Surgery Residency Program
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Transcript The role of - General Surgery Residency Program
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
Malrotation
Duplications/cysts
Inflammatory
Crohn’s disease
Infections
Tuberculosis
Actinomycosis
Diverticulitis
Neoplastic
Primary neoplasms
Metastatic neoplasms
Traumatic
Hematoma
Ischemic stricture
Miscellaneous
Intussusception
Endometriosis
Radiation
enteropathy/stricture
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
Simple obstruction,
partial or complete
Findings
Proximal
bowel dilatation
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
Mesenteric
Changes
U-shaped,
distended,
fluid-filled bowel loop
Whirl sign
Beak sign
Radial
distribution dilated
bowel loops
Thickened mesenteric
vessels converging toward
point of obstruction
CT Findings in Patients with SBO
Type of Obstruction
Strangulated Obstruction
Bowel Wall Changes
Mesenteric
Other
Changes
Findings
Bowel
wall thickening
Target sign
Pneumatosis intestinalis
Dec. bowel wall
enhancement
Blurring of mesenteric
vessels
Obliteration of mesentery
and vessels
Engorgement of
mesenteric vasculature
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
Narcotics
Anticholinergic
TCA
Chlorpromazine
Levodop
Ca++ blockers
Clonidine
Ogilvie’s Initial Tx:
Correct fluid and lyte
NPO/NG
Rectal tube
Limit offending
medications
>80% success
Ogilvie’s Treatment
Neostigmine
2 mg IV
Atropine at bedside
Monitored bed
Patient supine, on
bedpan
90% success rate
Colonoscopy
If neostigmine fails
Decompression
Surgery
Last resort; rarely
needed
If ischemia/perforation