Intestinal Obstruction - Types, C/F & Management

Prof. U.Murali.
Intestinal
Obstruction

Learning Objectives
◼ Define, Classify & Causes of Intestinal Obstruction.
◼ Outline the pathogenesis of Intestinal obstruction.
◼ Describe the C/F, investigations and treatment of
Dynamic Intestinal Obstruction.
◼ Discuss about – Volvulus, Paralytic ileus & Adhesive
obstruction.

Definition
◼ The normal flow of intestinal
contents sometime gets
interrupted and blocked by a
mechanical (or) functional
obstruction, causing impaired
motility resulting in an acute
abdomen.

Classification – I O
Etiopathology
• Dynamic
• Adynamic
Type
Duration
• Acute – SI
• Chronic
• Acute on
chronic – LI
• Sub-acute
Site
• Prox.SB
• Distal SB
• Large bowel
Origin
• Congenital
• Acquired

Dynamic Obstruction - Causes
Outside – wall
[Extramural]
• Bands /
Adhesions
• Hernia
• Volvulus
• Intussusception
In the wall
[Intramural]
• Stricture
• Malignancy
Inside - lumen
• F. Impaction
• Foreign bodies
• Bezoars
• Gallstones
Physical barrier preventing the progress of intestinal contents

Dynamic Obstruction - Causes
Outside – wall
[Extramural]
• Bands /
Adhesions
• Hernia
• Volvulus
• Intussusception
In the wall
[Intramural]
• Stricture
• Malignancy
Inside - lumen
• F. Impaction
• Foreign
bodies
• Bezoars
• Gallstones
Physical barrier preventing the progress of intestinal contents

Intestinal Obstruction - Types, C/F & Management

Adynamic Obstruction
◼ In which there
is no
mechanical
obstruction;
peristalsis is
absent (or)
inadequate.
◼ Paralytic Ileus &
Pseudo-
obstruction.
◼ P. Ileus – Peristalsis may be
absent – secondarily to
neuromuscular failure in the
mesentery.
◼ Pseudo-obstruction – The
peristalsis may be present
in non-propulsive form.
◼ In both forms, mechanical
element is absent.

◼ Adhesions commonly cause small bowel
obstruction than large bowel.
◼ Small Bowel Obstruction
 80% of intestinal obstruction is in small
bowel.
 80% of small bowel obstructions are due
to benign cause.
◼ Large Bowel Obstruction
 70% of large intestine obstruction is due
to malignancy. Other 30% is due to
volvulus; diverticulitis, inflammatory
cause like tuberculosis, etc.
◼ Mortality is 3% in obstruction without
strangulation; 30% in obstruction with
strangulation.
◼ Recurrent obstruction is more common in
adhesions.
Causes - I. Obstruction

I. Obstruction – Nature & Presentation
◼ Classic Quartet
 Abdominal Pain
 Distension
 Vomiting
 Absolute Constipation
◼ Complete
 SBO – All 4 features {+}
 LBO – Lack of
preceding symptoms
◼ Incomplete {Partial /
Subacute}
 Symptoms & Signs are
intermittent
◼ Simple – In which the
blood flow is intact.
◼ Strangulated – In which
there is interference to
blood flow.
◼ Closed-loop – Both ends
are obstructed.

Pathogenesis – I O – Proximal
Changes Proximal to bowel obstruction
Intestinal obstruction
I
Increased peristalsis
I
Becomes vigorous
I
Obstruction not relieved
I
Peristalsis ceases
I
Flaccid, paralyzed, dilated bowel.
2 FACTORS - DISTENSION
◼ GAS -
Overgrowth – aerobic & anerobic org. → gas
Majority : nitrogen (90%) and H2S
◼ FLUID - Composed of various digestive
juices

I O – Reasons For
Dehydration
• Reduced oral intake
• Def. Intest.
absorption
• Losses – Vomiting
• Seq. in bowel lumen
• Transudation of fluid
into the peritoneal
cavity
Systemic Problems

Pathogenesis – I O – Site
Changes at the Site of obstruction
Initially venous return is impaired
I
Congestion & oedema of bowel wall - Occurs
I
Later arterial supply is jeopardized
I
Loss of shininess / blackish discoloration / loss of peristalsis
I
GANGRENE
I
Perforation
I
Bacteria and toxins migrates into the peritoneum
I
PERITONITIS.

Pathogenesis – I O
Closed loop obstruction
Obstruction in the large bowel
I
Ileo-caecal valve is competent &
pressure increases in the caecum
I
Stercoral ulcer in the caecum
I
Gangrene
I
Perforation
I
Peritonitis (Faecal)
◼ This also occurs – when bowel is obstructed at both
the proximal & distal points.
◼ Distension is principally confined to the closed loop.

I. Obstruction – C /F
◼ Pain :
 Pain is the first symptom to
develop which is sudden and
severe.
 Initial colicky pain suggests
obstruction and eventual
diffuse persistent pain
suggests strangulation.
 It is colicky in nature and
usually centered on the
umbilicus (small bowel) or
lower abdomen (large bowel).
◼ Vomiting :
 The more distal the
obstruction, the longer the
interval between the onset of
symptoms & the appearance
of nausea and vomiting.
 In jejunal obstruction, it is
early and persistent.
 In ileal obstruction, it is
recurrent occurring at an
interval; initially bilious later
feculent.
 In large bowel obstruction,
vomiting is a late feature.

I. Obstruction – C /F
◼ Distension :
 In the small bowel the
degree of distension is
greater if more distal the
lesion.
 VIP may be seen in thin
patients.
 Distension is a later
feature in colonic
obstruction and is
enormous.
◼ Constipation :
 This may be classified as
absolute (i.e., neither feces nor
flatus is passed) or relative
(where only flatus is passed).
 Absolute constipation is a
cardinal feature of complete
intestinal obstruction.

Clinical Features – I O
High S B
• Pain – colicky –
intermittent
• Vomiting – early –
profuse - bilious
• Distension - minimal
• No constipation initially
Low S B
• Pain – predominant at
mid abdomen
• Vomiting – delayed
• Distension – central &
moderate
• Step ladder peristalsis
seen
• Constipation – at later
period
Large Bowel
• Pain is mild – lower
abdomen
• Vomiting is late
• Distension – early &
pronounced
• Constipation – may
start early
Colicky abd.pain / Vomiting / Distension / Absolute Constipation

Other Features – I O
Others
• Fever
• Dehydration
• Features of toxemia
• Abdominal tenderness
• Bowel sounds – High-pitched
• Per-rectal exam – Empty
Strangulated
• Constant severe pain
• Features of shock
• Rebound tenderness
• Guarding / Rigidity
• Absence of bowel sounds

Investigations – I O - Imaging
• Straight segments
– Central placed –
lie transversely
• Jejunum – concertina
(or) ladder effect –due
to valvulae
conniventes
• Distal Ileum –
smooth/featureless
• Caecum – rounded
gas shadow - RIF
• Others – shows
haustral folds –
irregularly placed –
do not have
indentations placed
opp. one other
Plain X-ray abdomen – Erect / Supine view
Small Bowel Large Bowel

Other Features & Investigations – I O
Other X-ray
Features
• N - 3 fluid levels – seen
- stomach, duodenum,
terminal ileum /caecum
• Proximal the obstruction
– lesser the air fluid
level
• Vice versa - Distal
• Fluid levels appear later
than gas shadows
• More fluid levels –
advanced obstruction
Investigations
• Blood tests
• Sr. electrolytes
• U/S - abdomen
• CT – abdomen
• Barium meal &
enema -
contraindicated

Treatment – I O
Principles of Treatment
• Decompression of Obstructed gut
• Fluid & Electrolyte replacement
• Relief of Obstruction
• Surgical intervention – In most cases
Principles of Surgery
• Assessing the site of obstruction
• Nature of obstruction
• Viability of the gut
• Probable cause – Treat accordingly

Difference – Viable & Non-viable
Features Viable Non-viable
- Circulation
- General appearance
- Int. musculature
- Peristalsis
- Dark color becomes lighter
/ Visible pulsation – over
mesenteric arteries
- Shiny
- Firm
- May be observed
- Dark color remains / No
pulsation seen
- Dull & lusterless
- Flabby & Friable
- No peristalsis

Treatment – Resuscitative measures
◼ N P O
◼ Monitor – Vital signs
◼ Ryle’s Tube aspiration
◼ IV – Fluids – NS / RL
◼ I / O – chart
◼ Antibiotics
◼ Catheterization
◼ Abd. girth measurement

Surgical Treatment
◼ Adequate exposure is best achieved by a midline
laparotomy incision.
◼ Next assessment is directed to –
 Site of obstruction
 Nature of obstruction
 Viability of gut
◼ The obstruction is identified by finding the
junction of dilated proximal and collapsed distal
bowel. The obstruction is relieved.
◼ Following relief of obstruction, the viability of
the involved bowel should be carefully
assessed.
◼ If in doubt, the bowel should be wrapped in hot
packs for 10 minutes and then reassessed.
◼ Any uncertainty about the bowel viability,
resection and anastomosis should be the option.
◼ Later, a good peritoneal wash is given, and
abdomen is closed in layers.

Surgical Treatment
◼ Type of Surgical procedure depends
upon –
 Division of adhesions.
 Resection / Excision.
 By-pass.
 Proximal decompression.
◼ In critically unwell patient,
consideration should be given to
resecting the necrotic bowel and
raising both residual ends as
stomas.
◼ Laparoscopic approach is being now
common may be useful in relieving
the obstruction.

Surgical Treatment
◼ Small bowel obstruction is treated usually
by resection of the lesion (or) strangulated
bowel + anastomosis [exact site & length –
noted].
◼ In case of right-sided colonic obstruction,
right hemicolectomy with ileocolic
anastomosis is done.
◼ In case of left-sided colonic obstruction, left
hemicolectomy(resection) and Colo-colic
anastomosis is done with a de-functioning
colostomy(right-sided transverse) which is
closed after 6 weeks.
◼ Obstruction due to rectosigmoid growth
with patient being severely ill-Hartmann's
operation can be done to save the life of the
patient wherein distal stump after removal of
the growth is closed, proximal colon is
brought out as end colostomy.

Volvulus
◼ It is the twisting (or) axial rotation of portion of
bowel about its mesentery.
◼ If the twisting is >360° - results in vascular
occlusion of the mesentery – resulting in
ischaemia & gangrene.
◼ The rotation = clock / (or) anticlockwise.
◼ 15% of Large bowel obstruction is due to
volvulus.
 Sigmoid ~ 65% - anticlockwise
 Cecum ~ 30% - clockwise
 Transverse colon ~ 4%
 Splenic Flexure
◼ Volvulus of small intestine (midgut), volvulus
neonatorum, gastric volvulus are another
volvulus which can occur.
TYPES
◼ Primary - secondary to cong. malrotation of
gut / cong. bands. E.g.: VN / CV / SV.
◼ Secondary – is due to rotation of a segment
of bowel around an acquired adhesion (or)
stoma. (more common variety)

Sigmoid Volvulus
Features
• Common in Eastern
Europe & Asia.
• Anticlockwise rotation
• Often seen – males &
old age.
Others
• High fiber diet.
• Chronic constipation &
laxative abuse.
• Ch. psychotropic drug
usage.
Pre-disposing Factors

Sigmoid Volvulus
Common in D / D
• Ogilvie's Syndrome.
• Faecal Impaction.
• Ca. R S region.
• Ileo-sigmoid knotting.
• Idiopathic megacolon.

Sigmoid Volvulus - Presentation
• sudden onset, severe pain,
early vomiting. (younger)
• insidious onset, slow
progressive course, less
pain, late vomiting. (old)
Fulminant
Indolent
• F O - LBO
• Gross abd. distension –
Tympanic abdomen
• Absolute constipation
Clinical
Features

Sigmoid Volvulus – Investigations
◼ Plain X-ray abdomen –
diagnostic – 70-80%
- ‘Omega sign’ / ‘Coffee-
bean’ (or)
- ‘Bent-inner tube’ sign.
◼ Contrast enema – ‘Birds beak’ /
‘bird of prey’ / ‘ace of spades’ - sign.
◼ CT – scan – ‘whirl pattern’.
◼ Basic Blood tests
◼ Sr. electrolytes.

Sigmoid Volvulus – Treatment
◼ Decompression:
- Sigmoidoscope (or) flatus tube inserted into
rectum / pt. passes flatus & faeces --> successful.
◼ If de-rotation does not occur --> E. Laparotomy.
◼ Manual de-rotation & check viability.
◼ Viable → Sigmoidopexy.
◼ Gangrenous → Paul-Mickulicz procedure
(or) Hartmann’s operation.
◼ If conditions are good, resection [sigmoid
colectomy] & anastomosis can be done.

Caecal Volvulus
◼ Caecum is the second common site (clockwise) (C
for C) - 30%.
◼ It is common in females, present as acute intestinal
obstruction.
◼ Caecal bascule is the presence of constricting band
across the ascending colon (Bascule--French-see-
saw and balance).
◼ Caecum will be markedly distended and found in
the center of the abdomen. It is due to lack of
fixation of the caecum-mobile caecum.
◼ Caecal volvulus is the commonest cause of large
bowel obstruction in pregnancy.
◼ X-ray shows round gas shadow in right iliac region.
CT scan is very useful. Barium enema is also
helpful.
◼ Resection and anastomosis (surgery) is the only
treatment.

Paralytic Ileus
Prof. U.Murali.

Paralytic Ileus - (Adynamic I O)
• State in which there
is failure of
transmission of
peristaltic waves
due to
neuromuscular
failure. i.e-
Auerbach’s &
Meissner’s plexus.
Definition
◼ Postoperative – usual & self-limiting.
◼ Infection – localized / generalized.
◼ Reflex ileus -
 Spinal injury / ≠ ribs
 Retroperitoneal hemorrhage
 Plaster jacket application
◼ Metabolic
 Uraemia
 Hypokalemia / Hypomagnesemia
◼ Drugs
 Antidepressants
 Antipsychotics
 Anticholinergics
Varieties

Paralytic Ileus – C / F & Investigations
• X-ray
abdomen –
FO - IO
• Sr. electrolytes -
K
Investigations
◼ No Bowel sounds.
◼ No passage of flatus.
◼ Marked abdominal distension.
◼ Dull pain & not colicky in nature.
◼ Effortless vomiting.
Occurs 72 hours after Laparotomy

Paralytic Ileus – Treatment
◼ Trt follow – certain principles:
- To identify the primary cause & treated
- Proper decomp. – relieve distension
- Fluid & electrolyte management
- Abdominal girth assessment
◼ If P I – prolonged, CT – scan – most
effective investigation.
◼ Laparotomy – likely in – 2 situations:
 Persisting - Bowel inactivity > 7 days
 Bowel activity recommences after
surgery then stops again.

Adhesions & Bands
Prof. U.Murali.

Adhesions – A S B O
◼ Adhesions & Bands are the most
common cause of I O.
◼ Adhesions start to form within
hours of surgery.
◼ P O - adhesions giving rise to IO
usually involve the SB - lower small
bowel and less commonly involve
the large bowel.
◼ Sources – Peritoneal irritation –
local fibrin production – produces
adhesion between bowel surfaces.

Adhesions – Types & Causes
Types
• Type I – Fibrinous / Flimsy
- Occurs early & gets
resolved completely.
• Type II – Fibrous / Dense
- Occur later, persists &
precipitate IO.
Causes

Adhesions – A S B O
• Pain abdomen-
recurrent / episodic
• Distension/vomiting
• Constipation
• Reduced BS
• Old scars - seen
• Tenderness - scar
• Blood tests
• Sr - Electrolytes
• X-ray - abdomen
• U/S - abd
• CT – scan
C / F Investigations

Adhesions – Treatment
◼ Initially treat conservatively provided there are no
signs of strangulation, but no longer than 72
hours.
◼ At operation, divide only the causative
adhesion(s) & limit dissection – using fingers.
◼ Repair serosal tears; invaginate (or resect)
doubtful areas.
◼ Laparoscopic adhesiolysis is becoming popular
with less recurrent adhesion rate and gives good
results.
◼ Instilling drugs –
 Hyaluronidase
 Steroids – hydrocortisone
 Streptomycin / Streptokinase
 Anticoagulants / Antihistamines /
NSAIDS
 Silicone / Dextran
◼ Washing – PC – Saline – 8-10 liters
◼ Gentle handling the bowel
◼ Minimizing contact with gauze
◼ Covering raw surfaces
◼ Careful placing of drains
Prevention

Bands
◼ These are dense fibrous strings attached
from one portion of the abdomen to
another area or bowel causing entrapment
of intestines leading into obstruction and
often dangerous strangulation.
◼ Common causes are vitello-intestinal duct,
Ladd's band, omental band, postsurgical
fibrous band, tuberculous band.
◼ Clinical features are like of intestinal
obstruction.
◼ Management is release of the band either
through laparoscopy (or) through
laparotomy.

To Summarize
◼ Definition & Classification of IO.
◼ Pathophysiology of IO.
◼ C/F of IO at its various level of obstruction in the GIT.
◼ Investigations & Treatment aspects of IO.
◼ Volvulus – Types / C/F & treatment of SV + CV.
◼ PI & ASBO – Causes, types, C/F & management.

Question time
◼ Define Intestinal Obstruction [IO] and Classify them.
◼ Outline the pathophysiology of IO.
◼ Mention the C/F of IO at various levels/sites of GIT.
◼ Differentiate viable bowel from non-viable one.
◼ Enumerate 3 predisposing factors & 3 imaging findings of sigmoid volvulus.
◼ Identify 4 causes of paralytic ileus and ASBO.
◼ Write the surgical treatment aspects of SBO & LBO.
◼ Compare & Contrast – SBO vs LBO – via Plain X-ray abdomen.

Causes of paralytic ileus include all, except –
◼ a) Spinal cord injury.
◼ b) Hypocalcemia.
◼ c) Hypomagnesemia.
◼ d) Uremia.

One of the following is true regarding adhesive intestinal
obstruction –
◼ a) Avoid surgery for initial 48 - 72 hours.
◼ b) Never operate.
◼ c) Immediate operation.
◼ d) Operate after minimum 10 days of conservative
treatment.

Absolute constipation is most likely to occur in –
◼ a) Fecal impaction.
◼ b) Richter’s hernia.
◼ c) Obstructed enterocele.
◼ d) Mesenteric vascular occlusion.

A 40 years old male was brought to the emergency with history of
multiple episodes of colicky abdominal pain, bilious vomiting with no
passage of feces and flatus. X-ray abdomen was done [is shown below].
On the basis of the x-ray, the site of obstruction is most likely at –
◼ a) Pyloric.
◼ b) Jejunal.
◼ c) Ileal.
◼ d) Colonic.

Which of the following statement about volvulus is false?
◼ a) More common in psychiatric patients.
◼ b) SV is more common than CV.
◼ c) Volvulus of caecum is more common in women.
◼ d) Lower GI-scopy is contraindicated in SV.

One of the following statement is false regarding
intestinal obstruction –
◼ a) In low small bowel obstruction vomiting is the earliest symptom.
◼ b) In high small bowel obstruction distension is minimal.
◼ c) In large bowel obstruction distension is early.
◼ d) In high small bowel obstruction vomiting is the earliest symptom.

Intestinal Obstruction - Types, C/F & Management

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