2.  DEFINITION
 CLASSIFICATION
 CAUSES
 SYMPTOMS
 EXAMINATION
 INVESTIGATION
 PSEUDO-OBSTRUCTION
 MANAGEMENT
 SURGERY : INDICATION
 DISCHARGE
 TAKE HOME MESSAGES

3. DEFINITION
Any form of impedance to the
normal passage of bowel content
through small or large intestine

4. CLASSIFICATION
• Partial vs complete
• Mechanical vs non-mechanical (functional)
• Simple vs strangulated
• Acute, subacute, acute on chronic, chronic

5. CAUSES
• ELDERLY – carcinoma, diverticulitis, sigmoid
volvulus
• ADULT – hernia, adhesion, carcinoma
• PAEDIATRICS – intussusception, congenital
hypertrophic pyloric stenosis, atresia
(duodenum, ileum), meconium obstruction,
volvulus neonatorum

6. CAUSES
SMALL BOWEL
OBSTRUCTION
LARGE BOWEL
OBSTRUCTION
Intraluminal Intussusceptions
Gallstone
Constipation
Intramural Crohn’s disease
Radiation stricture
Adenocarcinoma
Adenocarcinoma
Diverticulitis
IBD stricture
Radiation stricture
Extramural Adhesion
Hernia
Peritoneal
carcinomatosis
Volvulus

7. SYMPTOMS
• Abdominal pain – true colic
• Vomiting – high small bowel  greenish, bile-
stained; low small bowel  brown / faeculent
vomit
• Distension
• Constipation
• Signs of strangulation – pain more marked

8. EXAMINATION
• Dehydrated, in pain, tachycardic
• Toxic-looking, high temperature, hypotension
(might suggestive of strangulation)
• Distended, visible peristalsis, scar, hernia orifice
• Tender, abdominal mass
• Strangulation – tenderness more marked,
guarding, rebound tenderness
• Bowel sound
• PR exam – mass, faeces, blood

9. INVESTIGATION
• AXR
• FBC: Hb  anaemic (ca); PCV  dehydration;
TWBC  strangulation
• RP: dehydration, AKI, electrolyte imbalance
• ABG: alkalosis  proximal obstruction; acidosis
 strangulation
• USG: to differentiate mechanical obstruction &
paralytic ileus
• Colonoscopy
• CT scan: level of obstruction, causes, sign of
strangulation

10. SMALL BOWEL
OBSTRUCTION
LARGE BOWEL
OBSTRUCTION
PARALYTIC ILEUS
Abdominal pain Colicky Colicky Minimal or absent
Vomiting Early, may be bilious Late, may be faeculent Present
Constipation + + +
Other +/- visible peristalsis +/- visible peristalsis
Bowel sounds Normal, increased
Absent if secondary ileus
Normal, increased
Absent if secondary ileus
Decreased or absent
AXR Proximal distension (> 3
cm) + no colonic gas
Air-fluid levels
‘Ladder’ pattern
Proximal distension (> 6
cm) + distal
decompression
Air-fluid levels
‘Picture frame’
appearance
No small bowel air (if
ileocaecal valve
competent)
Air throughout small
bowel & colon

16. PSEUDO-OBSTRUCTION
PARALYTIC ILEUS
• Temporary paralysis of myenteric plexus
• Causes: Post-operatives, intra-abdominal sepsis,
electrolyte disturbances, medications (opiates,
anaesthetics, psychotrophics)
• In post-op, normally resolves after 1 – 3 days
OGILVIE’S SYNDROME
• Acute pseudo-obstruction
• Causes:Trauma, infection, cardiac (MI, CHF), disability
(bedbound, paraplegia), drugs
• AXR: caecal dilatation
• Mx :Tx underlying cause

17. MANAGEMENT
• DECOMPRESSION: NG tube
• FLUID & ELECTROLYTE
- Fluid replacement  NG tube loss
- Correct electrolytes  daily RP
- Input/output charting  CBD
- CVP monitoring
• ANALGESIC

18. SURGERY: INDICATIONS
• Tumor, hernia
• Failed conservative management
• Peritonitis
• Adhesion colic not resolved

19. DISCHARGE
• BO + passing flatus
• Tolerating orally
• Haemodynamically stable
• Abdominal distension resolves, bowel sound
normal
• RP normal

20. TAKE HOME MESSAGES
• Define - impedance to the normal passage of bowel
content
• 4 cardinal symptoms of IO: pain, vomiting,
distension & constipation
• Common complication – electrolite imbalance (hypo
k) and metabolic asidosis
• Bowel dilation : >3 cm small bowel , > 6 cm large
bowel
• Adequate resuscitation & hydration
• Common causes of obstruction in adult : carcinoma

21. REFERENCES
• Browse’s IntroductionToThe Symptoms And
Signs of Surgical Disease. Browse NL, Black J,
Burnand KG,ThomasWEG.
• Principle and Practice of Surgery. Garden OJ,
Bradbury AW, Forsythe J.
• Toronto Notes 2011