A 65-year-old man presented with abdominal pain, vomiting, and constipation. Examination showed a hugely distended abdomen with visible peristalsis and previous laparotomy scar. Imaging showed dilated small bowel loops. The patient had signs of dehydration. This document discusses intestinal obstruction, including its types, causes, clinical features, investigations, and management. Conservative management includes decompression with a nasogastric tube and IV fluids, while surgery is indicated for complications like strangulation.

1. Brigadier Dr.
Khaled Elkholy
MD, MRCS, MSc

2. A 65y old man presented to the
A&E with
 Attacks of colicky abdominal pain associated with
repeated vomiting and absolute constipation
 On examination, the abdomen is hugely distended
showing visible peristalsis with a long midline scar of
previous laparotomy
 The patient is tachycardic and dehydrated with
disturbed electrolytes
 AXR showed dilated small bowel loops

4. Definition
 The normal flow of
intestinal contents is
interrupted

5. Classifications of IO:
 Type of obstruction
 Mechanical (dynamic)
 Functional (adynamic)
 Time of presentation
 Acute
 Chronic
 Extent of obstruction
 Partial
 Complete
 Pathological nature of
obstruction
 Simple mechanical
 Strangulation
 Paralytic ileus

6. Mechanical (dynamic)
 Peristalsis is working
against a mechanical
obstruction
Extramural Intramural Intraluminal
• Adhesions
• Hernias
• Volvulus
• Tumours
• Congenital
anomalies 
atresia
• Intussuscepti
on
• Neoplasm
• Stricture
• Gallstone
ileus
• Fecal
impaction
• FB  bezor
• Traumatic
intraluminal
hematoma

7. Functional (adynamic)
 Atony of the intestine
with loss of normal
peristalsis in the absence
of mechanical
obstruction e.g. ileus
 Peristalsis present in a
non-propulsive form e.g.
MVO or pseudo-
obstruction

8. Commonest causes
 Strangulated hernias 
most common cause of
SBO in children
 Adhesions  most
common cause of SBO in
adults
 Cancer colon  most
common cause of LBO

9. Cardinal clinical features of acute
obstruction
 Abdominal pain
 Distension
 Vomiting
 Absolute constipation

10. Features according to level of obstruction
 High small bowel obstruction
 Vomiting  early & profuse 
rapid dehydration
 Distension  minimal
 Few fluid levels on AXR
 Low small bowel obstruction
 Pain  predominant
 Central distension.
 Vomiting  delayed.
 Multiple central fluid levels on
AXR
 Large bowel obstruction
 Distension  early + marked
 Pain  mild
 Vomiting & dehydration  late
 The proximal colon and
caecum are distended on AXR

11. General examination
Signs of dehydration
 Tachycardia
 Oliguria
 Dry tongue
 Hypotension

12. Abdominal examination
 Inspection
 Distension
 Scars
 Visible peristalsis
 Hernia
 Palpation
 Mass
 Tenderness
 Percussion
 Tenderness
 Hyper-resonance
 Auscultation
 ↑Bowel sounds
 Silent
 Rectal examination
 Empty
 Blood
 Fecal mass

13. Clinical features of strangulation
 Constant pain
 Tenderness + rebound
tenderness
 Rigidity
 Shock
 Toxicity

14. Investigations
 CBC
 Urea & creatinine
 S. electrolytes
 AXR
 Ultrasound
 CT scan

15. Radiological features of obstruction
 SBO
 Straight segments that are generally
central and lie transversely
 No gas is seen in the colon
 Jejunum  Valvulae conniventes
 Pass across the width of the bowel
 Regularly spaced, giving a
‘concertina’ or ladder effect
 Ileum  featureless
 Caecum – a distended caecum  a
rounded gas shadow in the RIF
 Large bowel, except for the caecum 
haustral folds (unlike VC)
 Spaced irregularly
 Do not cross the whole diameter of
the bowel
 Do not have indentations placed
opposite one another

16. MCQ
The following features are present in SBO except
 Distension
 Vomiting
 Dehydration
 Diarrhoea
 Hyperkalemia
 Dilated bowel loops on AXR

17. Preoperative management (drip & suck)
 NGT
 Free drainage + 4-hourly
aspiration /continuous
or intermittent suction.
 Decompression
proximal to the
obstruction
 Reduce risk of
aspiration
 IV fluids
 Antibiotics
 Urinary catheter

18. Surgery
Indications for early surgical
intervention
Principles of surgical
intervention for obstruction
 Obstructed or strangulated external
hernia
 Internal intestinal strangulation
 Acute obstruction
Management of:
 The segment at the site of
obstruction
 The distended proximal bowel
 The underlying cause of obstruction

19. Differentiation between viable and non-viable
intestine
Viable Non-
viable
Circulation • Dark color
becomes
lighter
• Mesentery
bleeds if
pricked
• Dark colour
remains
• No bleeding
if mesentery
is pricked
Peritoneum Shiny Dull & lustreless
Intestinal
musculature
• Firm
• Pressure
rings may or
may not
disappear
• Peristalsis
may be
observed
• Flabby, thin
& friable
• Pressure
rings persist
• No
peristalsis

20. Conservative treatment
 Adhesions  drip & suck
 Ileo-caecal
intussusception 
hydrostatic effect of
barium enema
 Sigmoid volvulus 
rectal tube
 Fecal impaction 
enema

21. MCQ
In the treatment of dynamic bowel obstruction
 Conservative management is the only option
 Non-viable bowel should be resected during the
operation
 Volvulus can be treated conservatively
 Drip and suck is tried in adhesive intestinal
obstruction
 Fecal impaction should be treated operatively
 Intussusception should be treated operatively

22. A 10 months old child presented to
the A&E with
 Episodes of screaming and drawing up of the legs lasting
for 1-2min and recurs every 15-20min
 The condition is associated with Pallor + sweating +
retching
 Vomiting which is bile-stained
 Initially, the passage of stool was normal, but now the
patient is passing blood and mucus PR
 Hx of recent respiratory tract infection
 On examination, the right iliac fossa felt empty with
Sausage-shaped mass palpated in the right hypochondrium

23. Most commonly in children

24. Definition
 Segment of the gut
(intussusceptun) becomes
invaginated within an
immediately adjacent
segment (intussuscepiens)
 Usually proximal into
distal
 An example of a
strangulating obstruction
as the blood supply of the
inner layer is usually
impaired

25. Aetiology
 Peak between 5-10 months
 ~90% idiopathic  ?
• Upper respiratory tract
infection
• gastroenteritis
 >2 years  a pathological
lead point in 1/3
 Adult  lead point usually
a polyp (e.g. Peutz–Jeghers
syndrome), a submucosal
lipoma or other tumour.

26. Types
 Ileo-ileal
 Ileo-colic (ileo-caecal)
In most children
 Ileo-ileo-colic
 Colo-colic  common in
adults

27. Symptoms
Early
 Intermittent colicky pain
 Screaming and drawing up
of the legs
 Pallor + sweating +
retching
 Vomiting
 Episodes 1-2min every 15-
20min
 Redcurrant jelly stool
Late
 Symptoms of peritonitis &
IO

28. Signs
 Examination between episodes of
colic
 Abdomen is not initially distended
 Emptiness in the right iliac fossa
(sign of Dance)
 Sausage-shaped mass
 PR
 Blood-stained mucus
 Apex palpable / protrude from the
anus  in extensive ileocolic or
colocolic
 Unrelieved 
 Progressive dehydration
 Abdominal distension
 Gangrene  peritonitis

29. Imaging in intussusception
 AXR 
 IO
 Absent caecal gas in
ileocolic
 Soft tissue opacity in
children
 Barium enema  the claw
sign in ileocolic I
 US  high sensitivity in
children  typical
doughnut appearance of
concentric rings in
transverse section
 CT  in equivocal cases

30. Pneumatic or hydrostatic reduction
 Successful 
 free reflux of air or barium into
the small bowel
 resolution of symptoms &
signs
 Contraindicated if
 Signs of peritonitis or
perforation
 Known pathological lead point
 Profound shock
 >70% can be reduced non-
operatively
 10% recurrence

31. Surgery
 Radiological reduction failed
or contraindicated
 Transverse right-sided
abdominal incision
 Gently compress the most distal
part of the intussusception
toward its origin
 The last part of the reduction is
the most difficult
 Resection & 1ry anastomosis 
 Irreducible intussusception
 Infarction
 Lead point

32. MCQ
Intussusception
 Most common in children
 Always secondary to intestinal pathology, e.g. polyp,
Meckel’s diverticulum in infants
 Ileo-colic is the least common
 Can lead to an ischaemic segment
 Pneumatic reduction is usually successful in children
 Laparotomy is always required

33. A 70y old black male present to
the A&E with
 Recurrent attacks of abdominal pain associated with
absolute constipation
 The patient complained of nausea but no vomiting is
experienced
 On examination, the abdomen is distended hugely,
tympanitic on percussion with exaggerated bowel
sounds
 AXR showed the coffee-bean sign

35. Definition
 Twisting or axial rotation of a
portion of bowel around its
mesentery
 When complete it forms a closed
loop of obstruction with resultant
ischaemia secondary to vascular
occlusion
 May involve
 Sigmoid colon  commonest in
adults
 Small intestine
 Caecum
 Stomach
 Neonatal midgut volvulus
secondary to midgut malrotation is
life-threatening

36. Sigmoid volvulus
 Predisposing factors 
 Symptoms
 Large bowel obstruction
 initially intermittent
 Abdominal distension 
early & progressive sign
 Hiccough & retching
 Vomiting occurs late
 Constipation is absolute
 In elderly  chronic form

37. AXR  Coffee-bean sign or Omega sign Ὠ

38. Barium study

39. CT Scan

40. Treatment
 Flexible sigmoidoscopy or
rigid sigmoidoscopy +
flatus tube
 Laparotomy
 Untwisting of the loop +
per anum decompression
 Viable  fixation of the
sigmoid colon to the
posterior abdominal wall
 inexperienced hands
 Resection  preferable
Hartmann’s procedure +
subsequent re-
anastomosis

41. MCQ
Volvulus
 May involve the sigmoid colon only
 Neonatal midgut volvulus secondary to midgut
malrotation is life-threatening
 The commonest spontaneous type in adults is caecal
volvulus
 Sigmoid volvulus can be relieved by decompression per
anum
 Surgery is required to prevent or relieve ischaemia

42. A 50y old lady presented to the
A&E with
 Abdominal colicky pain
 Nausea and vomiting
 Absolute constipation
 Distension
 Tachycardia
 Dry tongue
 History of repeated laparotomies, the last one was rwo
years ago for perforated DU

43. Most common cause of intestinal obstruction in developed
countries

44. Common causes of intra-abdominal
adhesions
1. Ischaemic areas • Sites of
anastomoses
• Vascular occlusion
2. Foreign material Talc, gauze, silk
3. Infection Peritonitis, T.B.
4. Inflammatory
conditions
Crohn’s disease
5. Radiation
enteritis

45. Bands
 Congenital, e.g.
obliterated vitello-
intestinal duct
 String band following
previous bacterial
peritonitis
 Portion of greater
omentum, usually
adherent to the parietes

46. Prevention of adhesions
Factors that may limit
adhesion formation include:
 Good surgical technique
 Washing of the peritoneal
cavity with saline to
remove clots, etc.
 Minimising contact with
gauze
 Covering anastomosis and
raw peritoneal surfaces

47. Treatment of adhesive obstruction
 Initially treat conservatively
provided there are no signs of
strangulation; should rarely
continue conservative
treatment for longer than 72
hours
 At operation, divide only the
causative adhesion(s) and
limit dissection
 Cover serosal tears
 Invaginate (or resect) areas of
doubtful viability
 Laparoscopic adhesiolysis 
in chronic cases

48. MCQ
Prevention of intraoperative adhesions can be
done by
 Good surgical technique
 Copious irrigation with saline
 Curetting the bowel with gauze
 Excising omentum
 Avoid using powdered gloves

49. The ward nurse asked you to review a
postoperative patient complaining of
 Abdominal distension and absolute constipation
 The patient vomited twice
 No abdominal pain is felt
 On examination, abdominal tenderness is mild and no
bowel sounds are heard on auscultation
 AXR  showed dilated small bowel loops with
multiple fluid levels

51. Definition
 Failure of transmission of
peristaltic waves secondary
to neuromuscular failure
i.e. in the myenteric
(Auerbach’s) and
submucous (Meissner’s)
plexuses
  accumulation of fluid
and gas  distension,
vomiting, absence of bowel
sounds & absolute
constipation

52. Causes
 Postoperative: a variable duration
of 24–72
 Intra-abdominal sepsis: localised
or generalised ileus
 Reflex ileus: following
 # Spine or ribs
 Retroperitoneal hge
 Plaster jacket
 Metabolic:
 Uraemia
 Hypokalaemia
 Diabetic ketoacidosis
 Drugs in high doses:
 Anticholinergics e.g. probanthine
 Tricyclic antidepressants

53. Clinical features
 72 hours after laparotomy:
 no bowel sounds
 flatus.
 Abdominal distension 
more marked &
tympanitic.
 Pain is not a feature
 Vomiting  if no NGT
 AXR  gas-filled loops of
intestine + multiple fluid
levels

54. Prevention
 Correction of biochemical
disturbances
 Gentle handling of bowel
 Nasogastric suction
 Restriction of oral intake
 Electrolyte balance
 Enhanced recovery
programme with early
introduction of fluids and
solids

55. Treatment
 1ry cause must be
removed
 Drip & Suck
 Rarely, in resistant
cases:
 Adrenergic blocking
agent + cholinergic
stimulation, e.g.
neostigmine (the
Catchpole regimen)
 Laparotomy  to
exclude a hidden cause
& facilitate bowel
decompression

56. MCQ
Paralytic ileus
 Is functional and not mechanical
 Usually postoperative
 Pain is predominant
 Distension is present
 Bowel sounds are present
 Is due to neuromuscular failure
 Usually treated surgically

57. You was asked to review a patient with
known retroperitoneal sarcoma
showing
 Massive abdominal distension and respiratory distress
 Abdominal pain, nausea and vomiting
 Tympanitic abdomen and sluggish intestinal sounds
 AXR showed dilated colon from the caecum to the
splenic flexure
 Single-contrast water-soluble barium enema showed no
mechanical cause of LBO

59. Definition
 Obstruction, usually of
the colon, that occurs in
the absence of a
mechanical cause or
acute intra-abdominal
disease

60. Factors associated with pseudo-
obstruction
Idiopathic
 Metabolic
 Diabetes: intermittent porphyria
 Acute hypokalaemia
 Uraemia
 Myxodoema
 Severe trauma (especially to the lumbar spine and
pelvis)
 Shock
 Burns
 Myocardial infarction
 Stroke
Septicaemia
 Retroperitoneal irritation
 Blood
 Urine
 Enzymes (pancreatitis)
 Tumour
 Drugs
 Tricyclic antidepressants
 Phenothiazines
 Laxatives
 Secondary gastrointestinal involvement
 Scleroderma
 Chagas’ disease

61. Colonic pseudo-obstruction
 Acute (Ogilvie’s syndrome) or
chronic
 AXR  colonic obstruction +
marked caecal distension 
??Caecal perforation
 Absence of a mechanical cause
requires urgent confirmation by
 Colonoscopy
 single-contrast water-soluble
barium enema
 CT
 Colonoscopic decompression 
recur in 25%  further colonoscopy
+ flatus tube
 Colonoscopy fails or unavailable 
 Tube caecostomy
 Subtotal colectomy and ileorectal
anastomosis.

62. MCQ
Colonic pseudo-obstruction
 Is called Ogilvie’s syndrome in chronic cases
 AXR shows dilated large bowel
 Single-contrast water-soluble barium enema is used to
exclude mechanical cause
 Colonoscopy is used for colonic decompression
 Surgery is not an option for treatment