Standard of Care Conference: Intra-Abdominal Infections Michael Seneff M.D.

Standard of Care Conference:
Intra-Abdominal Infections
Michael Seneff M.D.
Associate Professor Anesthesiology & Critical Care Medicine
The George Washington School of Medicine
Goals of “Standard of Care”
• Identify disease processes frequently requiring surgical
evaluation and intervention
• Review the recent literature concerning diagnosis, management,
and operative treatment
– focus on areas of controversy or diverse clinical
practice
• Present findings to the faculty and residents to develop a datadriven standard practice
• Diseases reviewed of interest to multiple specialties- including
ED, GI, Critical Care, ID
• Appendicitis, small bowel obstruction (SBO), pancreatitis, biliary
disease, diverticulitis
Acute Appendicitis
Introduction
The inflammation of the appendix is the most common cause of acute
abdomen in young adults.
Most frequently performed urgent abdominal operation
Incidence
Relatively rare in infants
Common in childhood and early adult life reaching a peak incidence in the
teens and early 20s.
Etiology
Luminal obstruction by a faecolith or a stricture
Proliferation of bacteria
Occasionally obstruction to the lumen of the appendix may be due to a
tumour of the caecum appendicitis
Appendicitis: Diagnosis
• WBC
– single value not reliable to diagnose appendicitis
– serial WBC used w/ serial exam useful in equivocal
cases
• CT scan
– best value if used only after surgical examination
– best with PO/ IV/rectal contrast, 5 mm cuts through
lower abdomen/pelvis
– no prospective, randomized trials
– focused helical scan w/ rectal contrast only may be
sufficient compared to triple-contrast scan
Appendicitis: Antibiotics
• Antibiotics
– single dose of pre-operative antibiotics warranted
– duration of antibiotics for perforated appy not
defined -> minimum of 5 days vs. clinically guided
decisions
• retrospective studies support discontinuing abx when
WBC nl and < 3% bands, tol POs, temp < 38 for 24 h
• 24 hours for resectable infection (ie gangrenous)
• may switch to PO abx when tolerating diet
Appendicitis: Operative Approach
• Operative management
– lap appy -> decreased pain, decreased LOS,
decreased wound infections, fewer unestablished
diagnoses
– open appy -> decreased intra-abdominal abscess
formation, lower operative costs w/ open appy
– intraoperative cultures are of no utility
– copious irrigation (NS vs. abx solution not defined)
– literature suggests that both simple and complex
appendectomy wounds may be closed primarily
Appendicitis: Perforation
• Perforated appendicitis
– perforated appendix w/ peri-appendiceal mass treated
non-operatively w/ IVF, IV abx
• worsening exam requires abscess drainage or operation if
perc drainage fails
• may change to PO abx when afebrile 24 h, tol diet
– perforated appendix w/out mass
• non-operative failure in 5%, 6 % recurrence in 6 months
• complications in 10%
– interval appendectomy if recurrent appendicitis,
persistent abd pain; colonoscopy if over 50
ANSWER:
E. Go straight to surgery
Ultrasonography
Transverse abdominal US demonstrates a
noncompressible mixed echotexture mass in the RLQ
consistent with appendiceal abscess/phlegmon.
Acute Appendicitis on CT
The arrow points to an
area of soft tissue
induration within the
retrocecal fat. There is
a rim like area of higher
attenuation within this
area that is fluid filled.
An axial slice of a CT scan done with intravenous and oral contrast
that is compatible with a diagnosis of acute appendicitis. The
presence of rupture cannot be excluded.
Appendicitis Protocol
SUSPECTED APPENDICITIS
surgical assessment
appendicitis
OR for appy, single
appendicitis
pre-op dose IV abx
diagnosis unclear
long time course
CT scan
perforation w/ abscess
or mass
perforation
IV abx,
supportive care
simple
gangrenous
perforated
worsening exam
no improvement
abscess drainage
no abx
24 hr abx
abx until afebrile
24 hrs, WBC < 10
all abx may be changed to oral when tol POs
improve
improve
PO abx
1-2 wks
colonoscopy if > 50 yrs
interval appendectomy
PRN rx
Biliary Disease: Antibiotics
• Antibiotics
– biliary colic patients do not need prophylactic
antibiotics EXCEPT diabetics and immunosuppressed
patients
– most patients with acute cholecystitis can be
adequately managed with a single preoperative dose
– gangrenous cholecystitis warrants 24 hours post-op abx
– more complex patients (perforated cholecystitis,
cholangitis) require longer duration post-op abx
– abx should cover bile pathogens and achieve good MIC
in bile -> Zosyn is drug of choice
Biliary Disease: Operative Choices
• Timing of surgery
– urgent LC (<48 hours after symptom onset) is associated w/
better outcomes (conversion, hospital stay, complications)
– cholecystostomy tube provides an alternative in pts not able
to tolerate an operation
• Common bile duct stones
– very high-risk patients should undergo ERCP
– patients at moderate risk, decreasing LFTs should have IOC
at time lap chole
– others can be safely treated with LC without imaging of
biliary tract (i.e. LFTs rapidly normalize)
Biliary Disease: Management Issues
• Postoperative LFTs
– 24 hour tests frequently show spurious elevations
– no data supporting use of LFTs as screening test for
complications
• Asymptomatic gallstones
– diabetics with asymptomatic cholelithiasis can be
managed expectantly
– cirrhotics are clearly at high risk and should be
operated on early when sx develop in Childs A/B
– data is not clear on transplantation patients and
recommendations tend to be center specific; however,
early operation when sx develop is warranted
Biliary Colic Protocol
SUSPECTED BILIARY COLIC
(episodic postprandial pain, nl LFT, nl WBC, no fever)
USG
gallstones, nl CBD
no gallstones
assess infection risk
low
no pre-op abx
high (DM, immunosuppressed)
single dose abx pre-op
OR for elective lap chole
abnormal sx, prolonged stay?
no
no LFTs, routine F/U
further eval
(EGD, CT,
GB ejection)
yes
LFTs, further eval
Acute Biliary Disease Protocol
SUSPECTED CHOLECYSTITIS
(abd pain > 8 h w/ RUQ tenderness, + WBC/fever, + nl LFTs)
USG
cholecystostostomy tube
poor surg candidate
uncomp acute cholecystitis
?
no gallstones
gallstones
comp acute cholecystitis
(CBD < 5 mm, LFTs nl)
symptomatic CBD stone + pancreatitis
(CBD > 5 mm, > 2 LFTs elev.)
(CBD < 5 mm, > 2 LFTs elev.)
single dose abx pre-op
further eval
(HIDA, CT)
ERCP
single dose abx pre-op
single dose abx pre-op
single dose abx pre-op
OR lap chole
OR lap chole w/ IOC
normal/edematous GB
no abx
OR lap chole
gangrenous GB
24 hr
OR lap chole w/ CBDE
perforated GB
abx
2-5 days abx
abnormal sx, prolonged stay?
no
no LFTs, routine F/U
yes
LFTs, further eval
Acute Cholecystitis2
• Thickened gallbladder wall or edema
• Pericholecystic Fluid
• Sonographic Murphy’s Sign
Acute Cholecystitis
Slide 1 U/S of GB pathology
Slide 2 CT scan of GB pathology
Slide 3 CT scan of GB complications
Slide 4 Contrast studies of bile ducts
Figure 1. Acute cholecystitis
Bortoff G A et al. Radiographics 2000;20:751-766
©2000 by Radiological Society of North America
Figure 11. Transient increased attenuation in the liver adjacent to the gallbladder in a patient
with pathologically proved acute cholecystitis
Bortoff G A et al. Radiographics 2000;20:751-766
©2000 by Radiological Society of North America
Figure 14. Hemorrhagic cholecystitis
Bortoff G A et al. Radiographics 2000;20:751-766
©2000 by Radiological Society of North America
Figure 15. Hepatic abscess related to acute cholecystitis
Bortoff G A et al. Radiographics 2000;20:751-766
©2000 by Radiological Society of North America
Conclusions
• LC compared with OC has decreased pain and
disability without an increase in morbidity or mortality
• LC is more cost-effective
• Outcome of LC influenced by expertise of surgeon
• ASA scale useful but difficult to classify all patients
• Percutaneous cholecystostomy useful alternative in
ASA IV, V patients BUT 50% still require surgery15
• Conversion from laparoscopic to open cholecystectomy
should not be viewed as a complication
• Conversion must occur if anatomy is obscured or
excessive bleeding occurs18
Diverticulitis: Diagnosis
• Imaging studies
– not required for clinical diagnosis
– CT scan test of choice -> 95% sensitivity
• use if diagnosis unclear, empiric medical management has
failed, unusual presentation, immunocompromised patients
• “diverticular abscess” may be perforated colon cancer in
>20%
– no role for endoscopy in the acute setting
– contrast enemas may enlarge perforation
Diverticulitis: Management
• Medical therapy
– outpatient treatment w/ PO abx if maintaining oral
intake clear liquids
– severe pain, ileus need inpatient admission
• NPO, IVF, IV abx -> change to oral abx when tolerating
POs
• total antibiotic course 7-10 days
• Colonoscopy 6 weeks after resolution of acute
episode
Diverticulitis: Complicated Disease
• Diverticulitis with intra-abdominal abscess
– 50% improve on antibiotics alone, 14-day course
– percutaneous drainage if no improvement in 72 hours
or sooner if clinically deteriorating
– single catheter for multiloculated collection vs
multiple catheters for septated abscesses
• > 2 catheters -> likely need for surgery
• > 50 cc after 1st 24 hours -> c/w fistula
– no resolution 72 hours after drainage -> surgery
Diverticulitis: Operative Indicators
• Indications for operative intervention
–
–
–
–
–
–
–
diffuse peritonitis
unresolving obstruction
fistula
symptomatic stricture
failure medical therapy
recurrent attacks -> elective operation
immunosuppression
• 30% of patients w/ recurrent attacks will require
surgery
Diverticulitis: Operative Approaches
• Operative options
– single-stage for Hinchey I,II (pericolonic abscess or
larger abscess) ->
• abscess drainage, resection, primary anastamosis
– two-stage for Hinchey III, IV (purulent peritonitis,
feculent peritonitis)
• drainage, removal diseased segment, colostomy
• re-anastamosis and takedown colostomy at second
operation
– no role for three-stage operation
Hinchey Classification Scheme
Hinchey 1 - peri-diverticular
abscess within the
mesocolon
Hinchey II - distant (pelvic,
retroperitoneal) abscess
Hinchey III - generalized
purulent peritonitis
Hinchey IV – generalised
faecal peritonitis
Jacobs D. N Engl J Med 2007;357:2057-2066
Who needs operation?
• Hinchey I - conservative
• Hinchey II distal or large abscess > 4cm:
CT drainage
– Less than 10% of Hinchey I and II need
operation
• Hinchey III – usually operation
• Hinchey IV – always operation
CT Scans of the Colon in Four Patients with
Diverticulitis of Varying Severity
56-year-old woman admitted for first episode of acute diverticulitis. Transverse CT scan shows
concentric wall thickening (arrow) of descending colon with area of adjacent fatty infiltration
(arrowheads). Patient underwent 10 days of IV antibiotic treatment and was discharged home free of
symptoms. Patient relapsed 2 months later; she was readmitted to hospital for new antibiotic
treatment and scheduled for elective surgery.
48-year-old man admitted for acute diverticulitis. Axial CT scan shows wall thickening
of horizontal aspect of sigmoid colon (arrowheads). Bubbles of extraintestinal gas (< 5
mm diameter) (arrow) are seen in area of fat infiltration. Diverticulitis resolved with
nonoperative treatment.
76-year-old woman admitted for first episode of acute diverticulitis. She underwent
nonoperative treatment with IV antibiotics. Her general condition improved initially,
but she relapsed 8 days after admission. She underwent sigmoidectomy 3 months
later. Transverse CT scan shows thickening (arrowheads) of wall of horizontal
aspect of sigmoid colon with associated local fat infiltration (arrow).
89-year-old man admitted for first episode of acute diverticulitis. Transverse pelvic CT scan shows thickened
wall of distal sigmoid colon with narrowed lumen, filled by thin strip of intraintestinal contrast media
(arrowhead). Cavity containing air–fluid level corresponding to abscess (arrow) is located adjacent to
thickened sigmoid segment. Patient underwent IV antibiotic treatment, and abscess was drained under CT
guidance. General condition improved, and patient was discharged home 2 weeks later with normal clinical
examination and normal WBC. Three months later, he was readmitted to hospital with perforation of sigmoid
colon and massive pneumoperitoneum seen on CT examination (not shown). He underwent emergent
sigmoidectomy with colostomy (Hartmann procedure) and died soon after surgery.
85-year-old woman admitted for acute diverticulitis. She recovered with antibiotic therapy
and had no recurrence of diverticulitis. CT scan shows free peritoneal fluid (arrows) in right
paracolic gutter and in mesosigmoid; infiltration of perisigmoid fatty tissue (arrowheads) is
also shown.
Summary
• Most people in the Western World will develop
diverticulae
• Most will remain asymptomatic
• The most serious complication is fecal perforation
(stercoral ulcer-43% mortality) – most likely to
occur at first attack
• After first attack of complicated diverticulitis 10%
recur in the first year – then 3% per year
Diverticulitis Protocol
peritonitis
free perf
immunosuppressed
ACUTE DIVERTICULITIS
home on PO abx
POs
no POs
7-10 day total
OR (1 or 2 stage)
fistula
admission, IVF, IV abx
no
improvement
free air
no collection
CT scan
failure to
improve 72
hours
improved
clears, PO abx
no abscess
14-day total
abscess
improved
deterioration
continue IV abx
deterioration
perc drainage
failure to
improve 72
hours
OUTPATIENT COLONOSCOPY AT 6 WEEKS
Pancreatitis: Definitions
• Simple acute pancreatitis
– 80% of cases of pancreatitis
– mild, self-limited course that resolves w/ supportive
care
• Complicated acute pancreatitis
– 20% of cases
– develop severe, potentially life-threatening disease
characterized by variable amounts of pancreatic
necrosis
• high risk for MSOF, infection of pancreatic necrosis, death
Pancreatitis: Diagnosis
• Laboratory tests
– serum amylase most
commonly used, usually
elevated w/in 24 hrs of
symptoms
– amylase is NOT specific
for pancreatitis -> may be
high with cholecystitis,
SBO, ischemic bowel,
appendicitis and PUD
– degree of elevation does
NOT correlate w/ severity
of disease
Pancreatitis: Diagnosis
• CT scan most sensitive
• Pancreatic changes
– parenchymal enlargement
and edema
– necrosis
• Peri-pancreatic changes
– blurred fat planes
– thickened fascial planes
– fluid collections
• Non-specific findings
– pleural effusion, ascites
– mesenteric edema, ileus
Pancreatitis: How Severe?
• Multiple scoring and grading systems aimed at
predicting outcome
– Ranson criteria most famous, predicts mortality
– Imrie, Kummerle, Bank classifications
– Acute Physiology and Chronic Health Evaluation
(APACHE II) illness grading system
– Simplified Acute Physiology Score (SAPS II) ->
score correlates w/ risk MSOF, mortality
• A comparative evaluation of these systems failed
to demonstrate any significant differences in
overall accuracy
Pancreatitis: How Severe?
Non-gallstone associated pancreatitis:
Age > 55 yrs
Hct fall > 10%
WBC > 16,000 cells/mm3
BUN elevation > 5 mg/dL
Blood glucose > 200 mg/dL
Serum calcium < 8 mg/dL
Serum LDH > 350 IU/L
Arterial pO2 < 60 mm Hg
AST > 250 U/dL
Base deficit > 4 mEq/L
Estimated fluid sequestration > 6L
Gallstone associated pancreatitis:
Age > 70 yrs
Hct fall > 10%
WBC > 18,000 cells/mm3
BUN elevation > 2 mg/dL
Blood glucose > 200 mg/dL
Serum calcium < 8 mg/dL
Serum LDH > 400 IU/L
Arterial pO2 < 60 mm Hg
AST > 250 U/dL
Base deficit > 5 mEq/L
Estimated fluid sequestration > 6L
.
Pancreatitis: How Severe?
•Patients w/ < 3 Ranson criteria have no mortality
•50 % of patients w/ 3-4 Ranson indicators require
ICU care
•Patients w/ meeting 7 or more Ranson criteria have
very high mortality
Number
% requiring ICU
% mortality
0-2
0%
0%
3-4
50%
15%
5-6
100%
50%
>6
100%
>50%
Pancreatitis: How Severe?
• Serum markers
– 2 studies assessed CRP and LDH -> discrimination
b/w mild and severe acute pancreatitis possible in
84% (CRP > 120 mg/dL, LDH > 270 mg/dL)
– IL-6 levels increase 24-36 hours earlier than CRP
• during 1st 24 hours after onset of disease, IL-6 levels had
sensitivity of 100% and specificity of 86% in predicting the
severity of acute pancreatitis
• CT scan to identify pancreatic necrosis
– defined by non-enhancement of gland as defined by
Hounsfield units and/or pancreas to aorta ratio
Pancreatitis: Timing of Feeding
• Randomized trials of NGT, somatostatin,
anticholinergics and antacids have FAILED to
demonstrate any difference in duration of illness or
complication rate
• Concept of “pancreatic rest” has historically led to
recommendation of NPO
– if eating provokes pain or is not tolerated, then keep
NPO and consider parenteral nutrition
– in biliary pancreatitis, eating may provoke another
episode -> recommend NPO or clears at most until OR
Pancreatitis: Timing of Surgery
• When to operate in gallstone pancreatitis?
– prospective study of patients w/ gallstone pancreatitis
• patients randomized to early operation (w/in 24 hrs) vs. late
operation (after normalization of enzymes and CT)
• no difference found b/w the groups in terms of length of stay,
morbidity, or mortality
– several retrospective studies confirm that timing of
surgery does not affect outcome
• Operation should include IOC
– data supports using ERCP only for failure to clear CBD
during operation rather than as a pre-operative tool
Pancreatitis: Is Necrosis Infected?
• Infected pancreatic necrosis is most reliably determined by
CT- or USG-guided FNA with Gram staining and culture
of the aspirate
– Gram stain has proven a reliable early indicator of pancreatic
infection w/ positive Gram stain almost always followed by
positive culture
• CT scan w/ air bubbles around necrosis is also diagnostic
• No good data to compare routine vs. selective guidedFNA in patients w/ pancreatic necrosis
– most authors reserve FNA for patients w/ clinical signs of
infection
– others advocate routine FNA in patients w/ complicated disease
as infection may be manifested only by low grade temp
Pancreatitis: Is Necrosis Infected?
• Demonstrated risk factors for infection include
extent of necrosis, severity of pancreatitis, and
duration of disease
– recent study found infection in 31% of 226 patients
with documented pancreatic necrosis
• highest rate of infection was found in patients with > 50%
necrosis (42% infection)
– risk of infection increases
during course of disease,
jumping from 23 % to 36%
to 71% in 1st 3 weeks
– infection increases w/ Ranson’s
score (0-1=5% vs. >5= 58%)
Pancreatitis: Sterile Necrosis
• Several studies in the past decade have
demonstrated that sterile pancreatic necrosis can be
managed non-operatively without mortality
– one study employed selective guided-FNA in patients
w/ documented necrosis who remained persistently
febrile or developed new fever later in hospital course
– results contradicted belief that necrosis w/ organ failure
was an absolute indication for surgery
• Conversely, multiple publications confirm that
debridement of sterile pancreatic necrosis does
NOT improve the clinical course these patients
Pancreatitis: Antibiotics
• Antibiotic prophylaxis in sterile pancreatic
necrosis remains an area of some controversy
– based on belief that pancreatic tissue levels of abx can
prevent colonization of pancreas after gut translocation
– animal studies supported this concept
– flawed 1970s study w/ ampicillin showed no difference
– 7 clinical trials in last decade
•
•
•
•
decreased mortality w/ cefuroxime
decreased rate pancreatic infection and MSOF w/ imipenem
meropenem = imipenem
no benefit w/ ofloxacin/metronidazole
Pancreatitis: Antibiotics
• Recent meta-analysis showed positive benefit
of antibiotic in reducing mortality
– limited to patients w/ severe pancreatitis who received
broad-spectrum abx able to achieve pancreatic tissue
levels
• Cochrane Database review of randomized
trials (2003)
– evidence that prophylactic IV antibiotic therapy for 1014 days decreases both risk of superinfection and
mortality in patients with severe pancreatitis w/ proven
pancreatic necrosis
Pancreatitis: Antibiotics
• Conclusions
– clinical studies have demonstrated that use of
prophylactic IV antibiotics in pancreatic necrosis
decreases both infection of the necrosis and mortality
– advocates favor imipenem and meropenem for their
penetration into pancreatic tissue
– duration of therapy remains debatable
– Powell et al argued that sample size of 322 patients
would be required to detect 50% reduction in infection
• larger study would be needed to detect reduction in mortality
– selective gut decontamination may be alternative
Pancreatitis: Infected Necrosis
• Literature supports surgical debridement of
devitalized tissue and drainage of infected
collections for any patient w/ infected necrosis
– inadequate data concerning IR techniques as an
alternative to surgery
– laparoscopic techniques has been reported but there are
no trials comparing laparoscopic vs. open approaches to
operative debridement
Gallstone-induced pancreatitis in 27 year-old woman
Transverse CT scan obtained with intravenous and oral contrast material reveals a
large, edematous, homogeneously attenuating (73-HU) pancreas (1) and
peripancreatic inflammatory changes (white arrows). Although the attenuation
values are low, there is no pancreatic necrosis. Calcified gallstones are seen in
gallbladder (black arrow). 2 = liver (140 HU).
47-year-old man with severe pancreatitis
Fluid collection replacing pancreatic body and tail
57-year-old man with acute necrotizing
pancreatitis and severe back pain
Large region of unenhancement (necrosis) involving most of body
and tail of pancreas. Inflammatory fluid is present in anterior
pararenal space. Note ascites around liver.
50 year-old woman with acute pancreatitis (1st view)
Transverse CT scans obtained with intravenous and oral contrast material reveal an encapsulated
fluid collection associated with liquefied necrosis (large straight arrows) in the body of the
pancreas. The head, part of the body, and the tail of the pancreas are still enhancing (small
straight arrows). N = liquefied gland necrosis, S = stomach.
50 year-old woman with acute pancreatitis (2nd view)
Transverse CT scans obtained with intravenous and oral contrast material. The head, part of
the body, and the tail of the pancreas are still enhancing (straight arrows). Residual fluid
collections and areas of soft-tissue attenuation (curved arrow) consistent with fat necrosis
are seen adjacent to the pancreas. f = fluid, N = liquefied gland necrosis.
28 year-old man with pseudocyst
Image demonstrates a pseudocyst (arrow) in the tail of the pancreas surrounded by a
thick enhancing wall. The lesion appears heterogeneous with central areas of higher
attenuation, which is suggestive of fresh hemorrhage. Note infiltration (arrowheads) of
the peripancreatic fat.
44 year-old man with acute abdominal pain
hemorrhagic pseudocyst
Axial CT scan obtained with intravenous contrast material demonstrates calcifications
from chronic pancreatitis in the head of the pancreas. A high-attenuation focus of blood
(arrow) is seen within the low-attenuation pseudocyst, a finding that is consistent with
hemorrhage.
Pancreatic abscess containing gas in 54-year-old man
Large fluid collection containing gas bubbles in pancreatic
bed due to abscess complicating acute pancreatitis. Note
infiltration of peripancreatic fat and calcified gallstones.
70 year-old woman with hemorrhagic pancreatitis
CT scan demonstrates hemorrhagic pancreatitis as a heterogeneous mass in the area of
the pancreatic bed (*). Arrow indicates active extravasation (hemorrhage).
Pancreatitis Protocol
PANCREATITIS (based on hx, labs and PE)
admit, NPO, IVF, scoring system, +/- CT scan
mild symptoms +/- CT w/out necrosis
no gallstones
OR for lap chole
w/ IOC
selective guided-FNA
(-) FNA
identify
etiology
failure to clear CBD
(+) FNA
yes
rpt CT
signs of sepsis ?
yes
no
ERCP
CT w/ infected
necrosis
IV abx
USG
gallstones
CT w/ necrosis
early feeds,
supportive care
intensive critical care
OR for
debridement
SBO: Definitions
• Complete SBO
– no egress of intestinal contents past point of
obstruction
– clinically -> no flatus or BM for 12 hours
– radiographically -> no air in the colon
• Partial SBO
– narrowing of lumen w/out complete obstruction
– may be chronic or intermittent problem, often
presenting as pain
– 50- 80% will resolve w/ non-operative management
SBO: Definitions
• Open SBO
– obstructed at one end, transmitting increased
intraluminal pressure proximally
– may be relieved by vomiting or NGT
• Closed loop SBO
– bowel is obstructed at 2 points, cannot decompress
– distention causes rapid rise in intraluminal pressure ->
faster ischemia and perforation
– may be characterized by severe pain w/out emesis
SBO: Definitions
• Simple SBO
– blood supply to bowel is NOT compromised
• Strangulated SBO
– obstruction has embarrassed blood supply to small
bowel
• external compression (hernia)
• twisted mesentery (volvulus)
• increased intraluminal pressure
– simple SBO may become strangulated w/ time
• risk greatest in closed loop, incarcerated hernia, complete
SBO
SBO: Presentation
• Symptoms of pain, nausea, emesis, obstipation
– pain initially diffuse colic -> severe, constant if
progress to ischemia
– may pass flatus +/- stool up to 48 hrs after obstruction
• Exam
– abdominal distention, previous scars, hernias
• Tests
– dehydration (elevated BUN/Cr), electrolyte imbalance
– AXR w/ dilated loops SB, air-fluid levels
– CT w/ dilated loops (air OR fluid), poss transition
SBO: Presentation
AXR
CT Scan
SBO: Etiology
• adhesions
• Crohn’s disease
• incarcerated hernia
• radiation enteritis
• early post-operative
• gallstone ileus
• malignancy
• intussusception
• combination
• foreign body
SBO: Adhesions
• Most frequent cause of SBO in North America,
accounting for 50-70% of all SBO
– post-surgical adhesions
– congenital adhesions
– adhesions secondary to infection/inflammation
• ~15% of patients who undergo abdominal surgery
will have an episode of SBO
– more common after colon, appy, GYN surgery
– 10-30% of patients will have recurrence
SBO: Incarcerated Hernia
• Accounts for approximately 25 % of SBO
– 50% inguinal, 25% femoral
– 20% ventral, 5% other (obturator, Speigelian, etc.)
• Associated w/ higher incidence of strangulation
and morbidity
– review of 405 pts w/ SBO -> 74% w/ adhesions
(9% were strangulated) vs. 8% incarcerated hernia
(33% strangulated)
– review 189 pts > 65 w/ incarcerated hernia
• 48% strangulated, 19% gangrenous requiring resection
SBO: Early Post-Operative
• Initial demonstration of bowel function -> then
development of obstructive symptoms w/in 4-8
weeks of surgery
– attributed to filmy, soft adhesions which regress
spontaneously
– bowel ischemia uncommon
– 80-90% patients resolve w/ non-operative management
– 2/3 will resolve w/in 7 days
SBO: Strangulation
• Strangulation leads to bowel infarction and
perforation
– associated w/ increased mortality -> 5-30% vs. 1% in
simple SBO
• Signs and symptoms
–
–
–
–
continuous pain
fever, tachycardia -> sepsis
peritonitis
elevated WBC, art lactate, amylase
SBO: Goals of Treatment
• Operate on irreversible SBO before strangulation
– prompt operative intervention to reduce need for
resection and morbidity
• Avoid additional abdominal surgery on patients
who would resolve w/ non-operative management
– limit stimulus for future episodes of SBO
• Difficulty lies in determining who needs an
operation and when
SBO: Bowel Compromise?
• Multiple studies have demonstrated that there is
NO RELIABLE INDICATOR of strangulation in
SBO
• Multi-center study of 639 pts w/ SBO
– evaluated for continuous pain, fever, elevated WBC,
palpable mass, peritonitis
– 77 % pts w/ at least one sign had NO strangulation
– 9.8% of pts found to have strangulation had NONE of
these signs
• Retrospective study found SIRS to be the only
reliable sign of bowel strangulation (too late!)
SBO: Partial or Complete?
• CT w/ PO contrast not ideal due to large volume
• Gastrograffin contrast studies can delineate partial
from complete SBO
– hyperosmolar contrast draws fluid into proximal bowel
to dilute contents
– safer than barium in cases of perforation
• Study patients by AXR 24 hours after contrast
– contrast progressed to R colon = partial
– contrast remained in small bowel = complete
SBO: Partial or Complete?
• Choi et al looked at 121 pts w/ simple SBO
– 48 hrs NGT decompression
– if improved, continued observation
– no improvement -> OR vs. gastrograffin study
• 16 pts to OR
• 19 pts had GG study w/ AXR after 24 hrs
• 14 had partial SBO, all resolved (avg 41 hrs)
• 5 had complete SBO -> to OR
– no strangulation, no bowel resection
SBO: Partial or Complete?
• Onoue et al looked at 102 pts w/ simple SBO
– GG contrast 1st 24 hrs -> AXR w/in subsequent 24 hrs
– 92 pts w/ partial SBO -> clears
• 2 pts later required OR for strangulation
• Biondo et al randomized 83 pts w/ simple SBO
– control rx NGT 4-5 days -> 8 to OR (2 SB resections)
– GG study ER, AXR 24 hrs -> 39 partial SBOs
improved, 5 complete SBO to OR (1 SB resection)
• Studies indicate that GG study is reasonable
protocol to distinguish complete vs. partial SBO
SBO: Laparoscopy
• Laparoscopic adhesiolysis 1st described by Bastug
et al in 1991
– since then, various case reports, series, and
retrospective reviews attesting to success of approach
• Laparoscopy shown to decrease incidence,
severity, and extent of post-operative adhesions
when compared to open surgery
• NO prospective, randomized trials comparing
open and laparoscopic lysis of adhesions
– indications and outcomes not well established
SBO: Laparoscopy
• Review of selected series
– conversion: 7- 43% -> dense adhesions, iatrogenic
perforation, bowel necrosis, inability to visualize point
of obstruction, neoplasm
– iatrogenic perforation: 3-18%
– mortality: 0-3%
– reduced LOS, incidence of post-op ileus
• Few established selection criteria
– advanced laparoscopic surgeon
– bowel diameter < 4 cm, NGT decompression
– fewer abdominal operations, partial or chronic SBO
Meckel’s Diverticulum Causing SBO
Meckel’s Diverticulum Causing SBO
50-year-old woman with strangulating small-bowel obstruction and
infarction. Contrast-enhanced CT scan shows dilated and fluid-filled bowel
loops in right flank (i). Small amount of fluid is present in mesentery (m).
50-year-old woman with strangulating small-bowel obstruction and infarction. Contrast-enhanced
CT scan slightly more caudal reveals that wall of ischemic dilated loops is not clearly visible
(white arrowheads), and proximal collapsed loops enhance normally (black arrowheads). Patient
underwent surgery 24 hr later; she had complete volvulus of distal meter of small bowel caused
by tight adhesive band. One meter of necrotic small bowel was resected
54-year-old man with history of appendectomy, aortic surgery, and previous laparotomy for
adhesive bands. Unenhanced CT scan shows dilated and fluid-filled jejunal loops (j). Veins
in adjacent mesentery are enlarged (arrowheads).
54-year-old man with history of appendectomy, aortic surgery, and previous laparotomy for
adhesive bands. Unenhanced CT scan reveals fluid in mesentery around congested veins (m).
Note pseudothickening of bowel wall (arrowheads) caused by transverse scanning of Kerckring's
folds. Gas bubbles in intestinal lumen (arrow) must not be confused with pneumatosis. Also note
large amount of fluid in pelvis. Patient was immediately treated by nasogastric suction and fully
recovered without surgery
85-year-old woman with reversible ischemia. Contrast-enhanced CT scan shows signs of mechanical
obstruction of small bowel with dilated and fluid-filled loops in left fossa iliaca (i). Note fluid in mesentery
(m) and congestion of small mesenteric veins (arrowheads). Wall of segment of small bowel is barely visible
(arrows). Small gas bubble is present in unenhanced loop. Patient underwent surgery same day and had
surgical evidence of ischemic bowel due to secondary volvulus. After devolvulation, ischemic bowel
regained normal coloration and resection was not necessary. Patient left hospital 7 days after admission.
67-year-old woman with thrombosis of superior mesenteric vein who presented with clinical
signs of intestinal obstruction. Contrast-enhanced CT scan reveals thrombus (arrowhead) in
superior mesenteric vein. Second portion of duodenum (d) and proximal jejunum (i) are dilated
and fluid-filled
67-year-old woman with thrombosis of superior mesenteric vein who presented with clinical
signs of intestinal obstruction. Contrast-enhanced CT scan more caudal shows absence of
enhancement (white arrowheads) of dilated jejunal loop, and more proximal loop enhances
normally (black arrowheads). Note that nonenhancing loop has no evidence of wall thickening.
67-year-old woman with thrombosis of superior mesenteric vein who presented with clinical
signs of intestinal obstruction. Contrast-enhanced CT scan more caudal than B. Jejunal loops
have thickened wall with reduced enhancement (arrowheads). Mesentery (m) is hazy. Patient was
treated medically with anticoagulant therapy and had uneventful evolution. Months later she
developed fibrotic stricture but did not undergo surgery
65-year-old man with history of allergy to iodine contrast agent. Unenhanced CT scan shows
dilated and fluid-filled small-bowel loops (i) occupying left flank. Mesentery (m) is hazy because
of presence of triangular-shaped fluid adjacent to dilated loops
65-year-old man with history of allergy to iodine contrast agent. Unenhanced CT scan 3 cm more
cephalad than A reveals presence of congested mesenteric veins (arrowheads). Surgery
performed 6 hr later confirmed diagnosis of strangulation. It was caused by internal hernia, and
1.20 m of necrotic bowel was resected
SBO Protocol
SBO (based on hx, labs, PE, flat + upright AXR)
NPO, NGT, IVF, Foley in ER
CT w/out transition
or closed loop
non-contrast CT, admit
CT w/ closed loop
incarcerated hernia
peritonitis
signs of sepsis
24 hrs w/ NGT, IVF
deterioration
improve
no change
D/C NGT, clears
well
adv diet
120 cc GG, AXR at 24 hrs
contrast R colon
contrast in SB only
OR
fail
`