Transcript Presentation, diagnosis and management of

Presentation, diagnosis and
management of bowel
obstruction
Mr Alastair Moses
Consultant Surgeon
NHS Tayside
Pathophysiology
• Any part of the GI tract may become
obstructed and present as an acute
abdomen.
• Dilatation of bowel proximal to obstruction
with air and fluid.
• Peristalsis is disrupted.
• The manner of presentation depends on
the level of obstruction.
Pathophysiology: level of
obstruction
• Upper small bowel obstruction:
Can present acutely within hours of onset
with large volumes of gastric, pancreatic
and biliary secretions regurgitated into the
stomach and vomited.
Pathophysiology: level of
obstruction
• Distal small bowel / large bowel
obstruction:
Can present with colicky abdominal pain and
distension. Vomiting (possibly ‘faeculent’)
can occur subsequently.
Symptoms of intestinal obstruction
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Vomiting
Pain
Constipation
Large bowel obstruction
Incomplete obstruction
Symptoms of intestinal obstruction:
vomiting
• The more proximal the obstruction, the
earlier vomiting develops.
• Can occur even if nothing is taken by
mouth: GI secretions continue to be
produced –
Saliva, gastric , pancreatic, bile, small
intestine (up to several litres per day).
Symptoms of intestinal obstruction:
vomiting
•
Nature of vomitus gives clues to the level
of obstruction:
- Semi-digested food eaten a day or two
previously (no bile) suggests gastric
outlet obstruction.
- Copious bile-stained fluid suggests
upper small bowel obstruction.
Symptoms of intestinal obstruction:
vomiting
•
Nature of vomitus gives clues to the level
of obstruction:
- Thicker, brown, foul-smelling vomitus
(‘faeculent’) suggests a more distal
obstruction.
[Faeculent vomitus contains altered small
bowel contents, not faeces].
Symptoms of intestinal obstruction:
pain
•
Distension of the bowel caused by
swallowed air and intestinal fluid
secreted proximal to an obstruction
causes pain.
•
Intermittent episodes of colicky pain
occur as peristalsis attempts to
overcome the obstruction.
Symptoms of intestinal obstruction:
constipation
•
Propulsion of bowel contents is arrested.
•
Bowel gas is absorbed distal to the
obstruction.
•
‘Absolute constipation’ (neither faeces or
flatus passed rectally) is pathognomonic
of bowel obstruction.
Symptoms of intestinal obstruction:
large bowel obstruction
•
Symptoms tend to develop more
gradually in large bowel obstruction due
to the large capacity of the colon and
caecum and their absorptive activity.
Symptoms of intestinal obstruction:
large bowel obstruction
•
If the ileo-caecal valve remains
competent (50% cases) backward flow of
accumulated bowel contents is
prevented .
•
The thin walled caecum progressively
distends with swallowed air and
eventually may rupture: ‘closed loop
obstruction’.
Symptoms of intestinal obstruction:
large bowel obstruction
•
If the ileo-caecal valve becomes
incompetent (50% cases) the small
bowel distends, delaying the onset of
symptoms.
Symptoms of intestinal obstruction:
incomplete obstruction
•
If the bowel is only partially obstructed,
the clinical features may be less clearly
defined.
•
Vomiting may be intermittent and bowel
habit erratic.
Symptoms of intestinal obstruction:
incomplete obstruction
•
Chronic incomplete obstruction leads to
gradual hypertrophy of the muscle of the
bowel wall proximally.
•
Peristaltic activity in this hypertrophic
muscle is responsible for bouts of colicky
pain which can be more prominent than
in complete obstruction.
Physical signs of intestinal
obstruction
• Dehydration (dry mouth, loss of skin turgor and
elasticity)
• Abdominal distension
• Visible peristalsis
• Relative lack of abdominal tenderness
(obstruction with tenderness may indicate bowel
strangulation)
Physical signs of intestinal
obstruction
• Obstructing abdominal mass may be
palpable
• On percussion the centre of the abdomen
tends to be resonant due to gaseous
distension
• Groins must be examined for an
obstructing hernia
Physical signs of intestinal
obstruction
• Bowel sounds are traditionally described
as high-pitched and tinkling. In practice
they may be absent at the time of
auscultation, echoing (cavernous quality),
or may sound like water lapping against a
boat.
Investigation of suspected bowel
obstruction
• Most useful initial investigation is a supine
abdominal X-ray:
• Bowel proximal to the obstruction is
distended with gas.
• Erect abdominal films are no longer part of
routine clinical practice (multiple air fluid
levels).
Investigation of suspected bowel
obstruction
• Distended small bowel loops tend to lie in
a central position and have valvulae
coniventes.
• Distended large bowel tends to lie in its
anatomical position and has haustra coli.
Investigation of suspected bowel
obstruction
• Initial plain abdominal X-ray is often
followed by CT scan of abdomen to look
for the cause of obstruction.
• A ‘cut off’ will be observed between dilated
proximal and collapsed distal bowel at the
site of obstruction.
Principles of management of
intestinal obstruction
• Initial management is ‘drip and suck’.
• Nil by mouth.
• Insert IV cannula and send blood for: urea &
electrolytes.
• Resuscitate with IV fluids, replacing electrolyte losses.
• Pass a nasogastric tube to decompress the stomach.
Mechanical causes of bowel
obstruction
• Adhesions or bands: congenital or
resulting from previous abdominal surgery
or peritonitis.
Mechanical causes of bowel
obstruction
•
Incarcerated external hernias:
1.
2.
3.
4.
5.
6.
Inguinal
Femoral
Umbilical
Paraumbilical
Ventral
incisional.
•
Internal hernias.
Mechanical causes of bowel
obstruction
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Volvulus of large or small bowel:
A mobile loop of bowel rotates causing
obstruction at its neck.
Mechanical causes of bowel
obstruction
•
Tumours
1. Gastric cancer blocking the pylorus
2. Small bowel tumours (rare)
3. Large bowel cancer
Mechanical causes of bowel
obstruction
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Inflammatory strictures:
1. Crohn’s disease
2. Diverticular disease
These obstructions are usually incomplete.
Mechanical causes of bowel
obstruction
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Bolus obstruction:
1.
2.
3.
4.
Food bolus
Impacted faeces
Impacted ‘gallstone ileus’ (rare)
Trichobezoar (rare)
Mechanical causes of bowel
obstruction
•
Intussusception: a segment of bowel wall
becomes telescoped into the segment
distal to it.
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Usually initiated by a mass in the bowel
wall: enlargement of lymphatic tissue or
tumour.
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Common in children.
Bowel strangulation
• Strangulation occurs when a segment of
bowel becomes trapped so that its lumen
becomes obstructed (incarcerated) and its
blood supply compromised (strangulated).
• If strangulation is not relieved this will
progress to infarction and perforation.
Bowel strangulation
• Pain over a hernia suggests possible
strangulation and is a sign requiring urgent
surgical intervention.
• Can occur in external hernia or volvulus.
Adynamic bowel obstruction
• Paralytic ileus
• Pseudo-obstruction