Intestinal Obstruction - Types, C/F & Management

his topic - Intestinal Obstruction is very important for final year MBBS - Students & the Medical Officers, as it is one of the commonest causes of Acute Aabdomen. The PPT - contains the classification, common causes, clinical features & management aspects of Intestinal Obstruction. Also, highlights the differentiating features of Plain X-ray abdomen of Small & Large Bowel Obstruction. 

1. Prof. U.Murali.
Intestinal
Obstruction

2. 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.

3. 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.

4. 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

5. 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

6. 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

8. 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.

10. ◼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

12. 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.

13. 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

15. 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

16. 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.

18. 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.

20. 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.

21. 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.

22. 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

24. 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

25. 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

27. 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

28. 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

29. 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

30. 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

31. 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.

32. 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.

33. 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.

35. Volvulus
Prof. U.Murali.

36. 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)

37. 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

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

39. 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

40. 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.

41. 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.

42. 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.

44. Paralytic Ileus
Prof. U.Murali.

45. 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

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

48. 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.

49. Adhesions & Bands
Prof. U.Murali.

50. 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.

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

52. 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

53. 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

55. 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.

57. 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.

58. References

59. 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.

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

61. 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.

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

63. 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.

64. 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.

65. 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.