Intestinal obstruction
By:
Dr. Wasfi M Salayta
Definition
• Any condition interferes with normal
propulsion and passage of intestinal contents.
• Can involve the small bowel, colon or both
small and colon as in generalized ileus.
Classification
• Cause of obstruction : mechanical or
functional ( Ileus ).
• Duration of obstruction: acute or chronic.
• Extent of obstruction : partial or complete
• Type of obstruction : simple or complex
(closed loop and strangulation) .
Mechanical obstruction
• There is physical blockage of intestinal lumen which due to:
1.
2.
3.
Intramural : congenital-tumor-hematoma-inflammatory
Extramural : adhesion-volvulus-hernia –abscess-hematoma
Lumen obstruction: stone-meconium-foreign body- impaction
(stool-worm-barium)
• This mechanical obstruction can be partial ( lumen narrowed
but allow transit some content) or complete ( lumen totally
obstruction) this classify to
A.
B.
C.
simple obstruction (no vascular impairment)
closed loop ( both ends are obstructed e.g volvulus)
strangulation obstruction
Functional obstruction
 These obstructions secondary to factors cause either
paralysis or dysmotility of intestinal peristalsis.
 Postoperative ileus is the most common form of functional
bowel obstruction.
 Postoperative ileus present to some extent after most
intra-abdominal operation
 Postoperative ileus correlates with degree of surgical
trauma and type of operation ,so patients operated on for
radiation enteropathy-chronic obstruction or sever
peritonitis has more prolong P.O.I
 Different anatomic segments of GIT also recover at
different rates after manipulation and trauma :
1.
2.
3.
Small bowel within hours after operation.
Stomach may take 24-48 hr .
Colon 3-5 days post op.
This should be differentiated from early postoperative
mechanical bowel obstruction:
Occurs within the first 6 weeks post operation
Acute adhesions are responsible cause > 90%
 other causes are:
Internal herniation
intra-abdominal abscess
intramural hematoma
anastomatic edema and leak
 Difficult to differentiate by clinical presentation and X-ray so contrast
study and CT scan helpful to differentiated between them
Epidemiology
 1% of all hospitalization
 3% of emergency surgical admissions
 More frequent in female patients because of gynecological-obstetric
and pelvic surgical operations are important etiologies for post
operative adhesions
 Adhesion is the most common cause of intestinal obstruction
 80% of bowel obstruction due to small bowel obstruction and the
most common causes are adhesion—hernia---neoplasm while 20%
due to colon obstruction and the most common cause is CR-cancer
60-70% while 30% are diverticular disease and volvulus
 Mortality rate range between 3% for simple bowel obstruction to 30%
when there is strangulation or perforation
 Recurrent rate vary according to method of treatment if conservative
12% while the operation treatment recurrent rate 8-32%
Path physiology
o Patho-physiology of bowel obstruction incompletely
understood
Bowel distension-decreased absorption-intralumial
hypersecrtion and alteration in motility are found but yet
the mechanisms are responsible not clear.
In opposite to old explaination that pathophysiology of
obstruction decreases in blood flow responsible for these
changes , recently these changes in part related to
increase in blood flow in association with intramural
inflammatory reaction ( strong evidence suggests this
inflammatory reaction plays key role).
Recent data show mucosal production of reactive oxygen
metabolites which modulate not gut motility but also
permeability may be one important mediator of some
changes seen in simple bowel obstruction.
Etiology
Mechanical bowel obstruction:
A. Small bowel obstruction:
1.
2.
3.
4.
5.
Adhesion 60%
Hernia 20%
Neoplasm 5%
Volvulus 5%.
Others: IBD-GALL STONE-FOREIGN BODY-INTUSSUSCEPTION.
B. Large bowel obstruction :
1.
2.
3.
4.
Cancer 60%.
Diverticular disease 15%.
Volvulus 15%.
Others: hernia –fecal impaction-inflammatory.
Etiology
Functional bowel obstruction: three types
A. Vascular occlusion ileus.
B. Spastic ileus. ( intestine remain contracted and no
propulsive) causes are:
1.
2.
3.
Uremia.
Porphyria.
Heavy metal poison.
C. Adynamic or inhibition ileus :
1.
2.
3.
4.
5.
Post operation mostly after abdominal surgery
Metabolic causes: DKA- hyponateremia-hypokalemia –
hypomagnesaemia.
Drugs: morphine –TCA-antacid-anticonvulsant.
Intra-abdominal inflammation—sepsis—occult wound
infection.
Pneumonia—renal stone—retroperitoneal hematoma--fracture spine and ribs
Diagnosis
History and physical examination:
1. Four cardinal symptoms (pain-vomiting-distension and
obstipation).
2. Proximal obstruction earlier symptoms with prominent
vomiting and less distension. While vomiting uncommon
in colon obstruction till late stage
3. Location and characteristic of pain differentiate between
mechanical obstruction and ileus which sever –cramp and
localized in mid of abdomen in mechanical while diffuse
and mild in ileus.
4. Examination :
o Vital signs.( PR-Temp-BP)
o Hydration status.
o Abdominal and rectal examinations
Diagnosis
Laboratory :
CBC: increase PCV (dehydration ) and increase in WBC.
KFT: increase in BUN and creatinine .
Lactate concentration-amylase-lactic dehydrogenase
useful but not sensitive in evaluations of bowel
obstruction especially to rule out necrosis
Serum concentration of phosphate--intestinal fatty acid
binding protein and isoforms of creatine
phosphokinase (isoform B): identify presence of
intestinal cell necrosis but the specificity and sensitivity
still note accurate.
ABG: metabolic and respiratory acidosis.
Diagnosis
Radiological :
A. Upright CXR with supine and upright abdominal
radiographs:initial imaging study.
1.
2.
CXR :
1. Detect extra-abdominal condition present with bowel
obstruction e.g. pneumonia.
2. Presence of pneumoperitoneum indicates perforated viscus.
Abdominal X-RAY
Small bowel considered dilated when diameter more than 3
cm while proximal colon 9 cm and the sigmoid 5 cm.
Dilated small bowel tend to be in the central portion of
abdomen recognized by presence plicae circularis.
Dilated colon tend to be in the periphery of abdomen and
recognized by haustral marking.
Can be diagnostic in 50-80% of patients
The cause of bowel obstruction can often determined
1. Presence of pneumobilia suggest G.S ileus.
2. Sigmoid and cecal volvulus produce pathognomnic
images.
Diagnosis
 Contrast studies:
Indications are controversial.
Identify site and often the cause of obstruction.
Differentiate between colonic and distal small bowel
obstruction
Differentiate between ileus-partial and complete obstruction.
Computed tomography:
o Recently become valuable in B.O especially when plain films
failed in diagnosis or suspect strangulation.
o Sensitivity 93% and specificity 100%
o Accuracy 94% in diagnosis of BO
Treatment
A. Resuscitation.
B. Conservative treatment
1.
2.
3.
4.
Previous surgery.
Incomplete obstruction.
Advanced malignancy.
Uncertain diagnosis.
C. Indications for surgery
1.
2.
3.
4.
5.
Generalized or localized peritonitis.
Perforation.
Irreducible hernia.
Palpable mass.
Virgin abdomen.
6.
Closed loop
7.
Failure to improve.
Thank You