Download Small Bowel Obstruction (SBO)

Highlights of patient’s history
• 53 year old man with longstanding diabetes
mellitus
• One-week illness, characterized by:
– Nausea, for 6 days
– More nausea, vomiting, bloating, and crampy
lower abdominal pain for 1 day
– No BM for 2 days pta and for hospital days 1-5
Highlights of his physical exam
• Temp 98.5, Resp 24 (depth?), BP 157/82,
Pulse 103; tilt test ?
• Oropharynx: slightly dry
• Abdomen: slightly distended; mildly tender
in the “lower abdomen” (RLQ?, LLQ?,
suprapubic region?); “quiet” bowel sounds
– Quiet. adj. making very little sound
Describing bowel sounds
• Frequency
– absent, present, increased (hyperactive)
• Intensity
– normal, loud
• Quality
– high-pitched, musical, tinkling
– normal
– rumbling, gurgling, rushes (borborygmi)
Physician accuracy: bowel sounds
[Gade et al. Scand J Gastro 33:773, 1998]
• Bowel sounds recorded from 4 normals, 6
pts. with obstruction [SBO(4), LBO(2)], and
2 pts. with peritonitis (perforated viscus)
• Recorded sounds from these 12 people were
amplified and transmitted through a dummy
and listened to with a stethoscope by 100
physicians of different specialty and
experience {normal vs. abnormal}
Physician accuracy: bowel sounds
Gade et al. Scand J Gastro 33:773, 1998
• NORMALS (n=400 ratings)
– 25% were called abnormal [75% specificity]
• OBSTRUCTION (n=600 ratings)
– 64% abnormal (69% for surgeons, 50% for GIs)
• PERITIONITIS (n=200 ratings)
– 43% abnormal (50% for surgeons, 25% for GIs)
Conclusion: Our patient’s bowel sounds are certainly
compatible with SBO, LBO, and peritonitis with ileus.
Highlights of laboratory tests
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WBC 15.9, with 94% neutrophils
Glucose 430’s
Anion gap 14; bicarbonate 22
Urine + for glucose and ketones; no UTI
Lactate normal
LFTs, serum lipase/amylase normal
EKG, cardiac enzymes normal
Summary of clinical presentation
(prior to his X-ray studies):
• Middle-aged diabetic man with nausea and
vomiting, constipation, lower abdominal
pain, tenderness, and distention
• Mild diabetic ketoacidosis
DIABETES
?
GI SYMPTOMS
GI Symptoms in Diabetics
OUTPATIENTS*
Constipation
60%
Abdominal pain 34%
Nausea, vomiting 29%
Dysphagia
27%
Diarrhea
22%
Fecal incontinence 20%
None of the above 24%
* Feldman and Schiller. Ann Int Med 1983
INPATIENTS, DKA
“Abdominal pain, nausea
and vomiting are common
and may be caused by the
ketoacidosis, but associated disorders such as
pyelonephritis, pancreatitis, or an acute abdomen
must always be
suspected.”
Williams textbook. Unger and Foster. 1998
Hospital course: days 1-5
• No BMs or flatus production
• Abdominal distention did not resolve and
instead increased despite NG suction
• Diabetic ketoacidosis treated successfully
with insulin, fluids and electrolytes
“ACUTE ABDOMEN”

DKA in a previously
stable diabetic patient
FILM REVIEW:
ADMISSION
ABDOMINAL
FILMS AND OF
ARTERIOGRAMS
Summary of radiological exams
• Plain films: dilated loops of small bowel
and right colon, compatible with LBO or
ileus
• CT: same as above, with probabl”cut off” at
the level of the transverse colon; “probable”
filling defect in SMV; no abscesses or
evidence of diverticulitis/ mass
• Visceral arteriogram: normal vessels; dilated bowel as above
Separating pseudoobstruction from true obstruction
• Ileus of small bowel = intestinal
pseudoobstruction [can mimic SBO]
• Ileus of colon = Ogilvie’s syndrome [can mimic
LBO] and can affect the right side prodominately
• Ileus involving small and large intestine [can also
mimic LBO] 
Conditions that may 
pseudo-obstruction or ileus
• Electrolyte disturbance, esp. hypokalemia
– DKA can be a cause, but should improve with rx of DKA
• Medications that suppress GI transit, especially anticholinergics and opiates
• Neurological disease (CVA, Parkinson’s, dementia, CP),
bedridden, institutionalized
• Severe intra-abdominal inflammatory and infectious
diseases:
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pancreatitis
cholecystitis
diverticulitis
strangulated obstruction
- bowel ischemia/infarction
- bowel or GB perf., incl. perf. ulcer
- appendicitis
- peritonitis
Radiology workup of obstruction
vs. ileus in acutely ill inpatients
• Plain films: is there disproportionate bowel
distention with gas or with gas/fluid levels?
• CT with oral ± rectal contrast: is there a cutoff, transition point or site of blockage?
• Water-soluble contrast enema (e.g.,
diatrizoate meglumine [HyapaqueR,
GastrografinR])*
* barium sulfate enema is relatively contraindicated
Typical SBO
Ileus involving
small and large intestine
Hyapaque enema: complete sigmoid
obstruction in patient with
diverticulitis and obstipation
Hyapaque enema:
complete obstruction to retrograde
dye at the descending colon (Ca)
Differential Diagnosis,
in order of likelihood
• Intestinal Obstruction
– MORE
LIKELY,
BASED
ON
HIS
DRAMATIC XRAY STUDIES and that THIS
IS A CPC “INTESTINAL OBSTRUCTION”
• Ileus
– LESS LIKELY, SINCE NO EVIDENCE FOR
AN UNDERLYING PRECIPITATOR
Intestinal Obstruction (SBO/LBO)
• Common cause for admission to hospital (20% of
acute admissions to surgical services are for SBO)
• SBO and LBO can be either partial or complete
• Strangulation (ischemic infarction of the bowel) is
the most dreaded and lethal consequence
• SBO and LBO have many causes, making a
specific diagnosis of the cause challenging
• Ideal therapy is dictated by knowledge of the
cause, although this is often not known at the time
of surgery
Clinical features of
Intestinal Obstruction
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Crampy abdominal pain in waves (intestinal colic)
Nausea
Bilious or feculent vomiting
Abdominal distention
Constipation with decreased flatus production
High pitched (musical, tinkling) hyperactive
bowel sounds
• Symptoms and signs of intravascular volume
depletion due to external losses, reduced oral
intake, and 3rd space losses into the bowel wall
and/or abdominal cavity
Common causes of SBO/LBO
(SBO)
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(LBO)
Adhesions are most common cause of SBO, but are rare cause of LBO.
Hernia is a common cause of SBO, but rearely LBO.
Neoplasm is most common cause of LBO, and accounts for 10% of SBO.
Volvulus and diverticulitis are common causes of LBO, but rarely SBO.
Miscellaneous causes of SBO/LBO
Atresia/stenosis/ bands
IBD (Crohn’s)
Radiation injury
Ischemic stricture
Endometriosis
Anastomotic stricture
Intussusception
Gallstones
Foreign body/bezoar
Meconium
Meckel’s diverticulum
Intra-abdominal abscess
[Children, young adults] S
[History of fever, diarrhea] S
[History of cancer/XRT] S,L
[Vascular disease] L,S
[Premenopausal female] S,L
[Prior anastomosis] S,L
[Children > adults] S>>L
[Biliary colic;pneumobilia] S
[Ingestion history] S
[Neonate, cystic fibrosis] S,L
[Male, young, recurrences] S
[Fever, chills, ? mass] S>L
Historical/demographic factors
which aid in assessing the
etiology of SBO and LBO
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Age and gender of the patient
History of abdominal or pelvic surgery
History of intra-abdominal disease
History of recent abdominal surgery/trauma
History of abdominal radiotherapy
History of overt rectal bleeding/ weight loss
History compatible with undiagnosed IBD
If obstruction, SBO or LBO?
• Pain before nausea/vomiting is typical in SBO
• History of prior surgery or abdominal trauma
would favor SBO over LBO
• Bilious vomiting favors SBO; feculent vomiting
favors LBO
• No mass on digital exam excludes distal rectal
cause of LBO, but not high rectal/colon obst’n
• Right colon distention on radiographs favors LBO,
especially as there is a distinct cut-off 
• Periumbilical pain (SMA distribution ) favors
SBO, while suprapubic pain favors LBO 
LBO (adults)
• Neoplasms (60%)
– Adenocarcinoma
– Others
• Volvulus (20%)
– sigmoid
– cecal (SBO)
– others are rare
• Diverticulitis with stricture (10%)
– Sigmoid, descending colon
– Cecal
– Others are rare
• Miscellaneous causes (10%)
Annular adenocarcinoma of
the colon, the “apple core”
Sigmoid diverticulitis can
mimic colon cancer
BE: complete retrograde
obstruction at the rectosigmoid
junction due to diverticulitis
Distal small bowel obstruction
2º to cecal volvulus
LBO from sigmoid volvulus
Miscellaneous causes of SBO/LBO
Atresia/stenosis/ bands
IBD (Crohn’s)
Radiation injury
Ischemic stricture
Endometriosis
Anastomotic stricture
Intussusception
Gallstones
Foreign body/bezoar
Meconium
Meckel’s diverticulum
Intra-abdominal abscess
[Children, young adults] S
[History of fever, diarrhea] S
[History of cancer/XRT] S,L
[Vascular disease] L,S
[Premenopausal female] S,L
[Prior anastomosis] S,L
[Children > adults] S>>L
[Biliary colic;pneumobilia] S
[Ingestion history] S
[Neonate, cystic fibrosis] S,L
[Male, young, recurrences] S
[Fever, chills, ? mass] S>L
Final diagnosis
• Most likely: large bowel obstruction due to
adenocarcinoma of the colon
– “He has not seen a PCP in over 4 years and has
never had a colonoscopy.”
• Less likely:
– Diverticular stricture (pro:mom;con:age/history)
– Another 1º colonic malignancy (e.g., lymphoma)
– Sigmoid or (less likely) or cecal volvulus
What was the
diagnostic procedure?
• PREFERRED: Flexible sigmoidoscopy or
colonoscopy following enema preparation
• ACCEPTABLE ALTERNATIVES:
Diatrizoate meglumine (not barium) enema
or CT with rectal contrast
• LESS ATTRACTIVE APPROACH
(at this point -may do later for therapy):
Laparoscopy or exploratory laparotomy
Therapy of Intestinal Obstruction
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MEDICAL
NPO
fluid and electrolyte
support
NG decompression
analgesia p.r.n.
meds. for underlying
disease, if indicated
e.g., steroids for Crohn’s
disease
– 48-72 hour trial with
frequent bedside exams
SURGICAL
– laparoscopy
– laparotomy
OPTIONS INCLUDE:
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adhesiolysis
resection/ anastomosis
stricturoplasty
removal of intraluminal
obturation (FB, stone)
• bypass
• untwist volvlus/ “pexy”
• “open and close”