The common Scenario
A 50 year old gentleman presents
with abdominal pain, distension and
absolute constipation. With
repeated episodes of vomiting.
His vital sign were stable, abdomen
distended with diffuse tenderness
but minimal peritonism. Bowel
Sounds are hyperactive.
The plain abdominal xray was taken
Introduction and Definitions
Accounts for 5% of all acute surgical admissions
Patients are often extremely ill requiring prompt
assessment, resuscitation and intensive monitoring
Obstruction A mechanical blockage arising from a
structural abnormality that presents a
physical barrier to the progression of gut
Ileus is a paralytic or functional variety of
8L of isotonic fluid received by the small
intestines (saliva, stomach, duodenum,
pancreas and hepatobiliary )
2L enter the large intestine and 200 ml excreted
in the faeces
Air in the bowel results from swallowed air ( O2
& N2) and bacterial fermentation in the colon (
H2, Methane & CO2), 600 ml of flatus is released
If mucosal barrier is breached it may
result in translocation of bacteria and
toxins resulting in bactaeremia,
septaecemia and toxaemia.
Obstruction results in:
1. Initial overcoming of the obstruction by
2. Increased intraluminal pressure
4. Lymphatic and venous congestion resulting
in edematous tissues
5. sequestration of fluid into the lumen from the
6. Factors 3,4,5 result in hypovolaemia and
7. Further: localised anoxia, mucosal depletion
necrosis and perforation and peritonitis.
8. Bacterial over growth with translocation of
bacteria and it’s toxins causing bacteraemia
WHAT ARE YOUR OBJECTIVES?
You should be able to address these questions
1. Is this bowel obstruction?
2. Partial or complete obstruction?
3. Site of obstruction?
4. Cause of this obstruction?
5. Is this a complicated or simple obstruction?
The Universal Features
Colicky abdominal pain
If deemed necessary.
distension and it’s
P, BP, RR, T, Sat
vomitus if possible
•Full lung and heart
Supine, Upright and CXR
Colonic and 1-2 small bowel
Check gasses in 4 areas:
3. Free gas under diaphragm
Look for calcification,soft tissue masses,
Look for fecal pattern
Different height in
the same loop
Step ladder pattern
Associated with the following conditions:
Postoperative and bowel resection
Intraperitoneal infection or inflammation
Extra-abdominal: Chest infection, Myocardia infarction
Endocrine: hypothyroidism, diabetes
Spinal and pelvic fractures
Drug induced: morphine, tricyclic antidepressants
Is this an ileus or obstruction
Is there an under lying cause?
Is the abdomen distended but tenderness is not marked.
Is the bowel sounds diffusely hypoactive.
Is the bowel diffusely distended
Is there gas in the rectum
Are further investigasions (CT or Gastrografin studies)
helpful in showing an obstruction.
Does the patient improve on conservative measures
Persistent pain may be a sign of strangulation
Relative and absolute constipation
•? Preexisting change
in bowel habit
•Colicky in the lower
•Vomiting is late
•Cecum ? distended
Distal small bowel
•Pain: central and
•Vomitus is feculunt
•Distension is severe
•May continue to pass
flatus and feacus
•Pain is rapid
•Vomiting copious and
contains bile jejunal
is limited or localized
The Difference between small
and large bowel obstruction
Small BowelLarge bowel
•Central ( diameter 5 cm max)
•Ileum: may appear tubeless
•Peripheral ( diameter 8 cm max)
•Presence of haustration
4. CAUSE OF
Small bowel VS Large bowel obstruction
Causes- Small Bowel
Small Bowel Adhesions
Accounts for 60-70% of All SBO
Results from peritoneal injury, platelet activation
and fibrin formation.
As early as 4 weeks post laparotomy. The majority
of patients present between 1-5 years
Colorectal Surgery 25%
70% of patients had a single band
Readmission in surgically treated patients is 35%
Accounts for 10% of SBO
1. Femoral hernia
2. ID inguinal
4. Others: incisional and internal H.
Site of obstruction is the neck of hernia
The compromised viscus is with in the sac.
Ischaemia occurs initially by venous
occlusion, followed by oedema and arterial
Followed by oedema and arterial compromise.
Attempt to distinguish the difference between:
Strangulation is noted by:
Intussusception is an "internal prolapse" of the bowel
This occurs when a mass or lead point in the bowel is
pulled forward by normal peristalsis
Intussusception is rare in adults, 1-5% of SBO.
Adult intussusception commonly involves a distinct
pathologic lead point, which is malignant in over half of the
Pediatric intussusception is usually due to a benign etiology
and can usually be managed with non-operative reduction.
Symptoms are often chronic; intermittent abdominal pain is
the most common presentation in adults.
The diagnosis is most often made with CT
A "target sign" may be seen on CT on perpendicular view,
while the intussusception will appear as a sausage shaped
mass when the CT beam is parallel to the longitudinal axis.
An increased incidence of intussusception has been
reported in patients with AIDS. This is due to the high
incidence of conditions, such as lymphoid hyperplasia,
Kaposi's sarcoma, and non-Hodgkin's lymphoma.
IBDGall stone IleusIntussusception
Large Bowel Obstruction
1. Carcinoma: The commonest cause, 18% of CA colon
present with obstruction
2. Benign stricture: Due to Diverticular disease, Ischemia,
Inflammatory bowel disease.
3. Volvulus: 1. Sigmoid Volvulus
2. Caecal Volvulus
5. Congenital : Hirschusbrung, anal stenosis and agenesis
•Distinguishing ileus from mechanical obstruction is challenging
•According to Leplac’s law: maximum pressure is at the it’s
maximum diameter. Cecum is at the greatest risk of perforation
Role of CT
Used with iv contrast, oral and rectal contrast
Able to demonstrate abnormality in the bowel wall,
mesentery, mesenteric vessels and peritoneum.
It can define
the level of obstruction
The degree of obstruction
The cause: volvulus, hernia, luminal and mural causes
The degree of ischaemia
Free fluid and gas
Ensure: patient vitally stable with no renal failure and no
previous allergy to iodine
Role of barium gastrografin
As: follow through, enema
Limited use in the acute setting
Gastrografin is used in acute
abdomen but is diluted
Useful in recurrent and chronic
May able to define the level and
Barium should not be used in
a patient with peritonitis
5. IS THIS A SIMPLE
Who suspected complicated
Patients suspected on admission of having
complicated obstruction with
complete or closed-loop obstruction
patients with fever, leukocytosis, tachycardia,
continuous abdominal pain or peritonitis
those who develop these signs and symptoms
during the course of nonoperative Mx.
Closed loop obstruction
Small bowel Large bowel
The primary goals in the initial management of
patients with SBO are to determine:
The degree of volume depletion and metabolic
The severity, cause, extent and location of the
Whether nonoperative management can be
The need for and timing of operative intervention
Adequate intravenous (IV) access should be
obtained for fluid resuscitation. should be given
until the patient makes urine or is clinically
A Foley catheter should be placed to monitor urine
output. If necessary, a central venous catheter or
Swan-Ganz catheter can be inserted
Bowel decompression – NPO +NG tube insertion
Antibiotics are not indicated in the routine.
Patients who indicate the need for surgery should
receive prophylactic antibiotics perioperatively.
The timing of surgical intervention requires careful consideration.
Approximately one-quarter of patients admitted for small bowel obstruction
will require operation. Patients suspected on admission of having
complicated obstruction with complete or closed-loop obstruction, patients
with fever, leukocytosis, tachycardia, metabolic acidosis, continuous
abdominal pain or peritonitis, or those who develop these signs and
symptoms during the course of nonoperative management warrant prompt
surgical exploration . Although prophylactic antibiotics are not routinely
administered for uncomplicated small bowel obstruction, antibiotics may be
warranted for patients with complications (eg, perforation) (table 2) [52-54].
Every patient considered for exploration due to a suspected small bowel
obstruction, whether open or laparoscopically, should be appropriately
resuscitated prior to surgery with IV fluids and have their electrolytes
repleted, as indicated. This is especially important for patients with copious
emesis resulting from more proximal obstruction, obstruction lasting several
days, or obstruction causing large-volume intraluminal fluid sequestration.
These patients may have severe metabolic acidosis, volume depletion, and
electrolyte abnormalities, and need resuscitation prior to operation.
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