28438747 Intestinal Obstruction
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Transcript of 28438747 Intestinal Obstruction
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INTESTINALOBSTRUCTION
MSU Medical Students.
Batch 2.Group 2.
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CONTENTS
Definition
Introduction
Etiologies
Categories Pathophysiologiy
Clinical Manifestation
Investigations
Treatment
Complication
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Definition
Intestinal obstruction is a partial or completeblockage of the bowel caused by whether
mechanical or functional obstruction of the
intestines that results in the failure of theintestinal contents to pass through.
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Introduction
Mechanical obstruction is divided into:
a) Obstruction of the small bowel (includingthe duodenum) and
b) Obstruction of the large bowel.
Obstruction may be partial or complete.
a) About 85% ofpartial small-bowelobstructions resolve with non-operative
treatment, whereasb) About 85% ofcomplete small-bowel
obstructions require operation.
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Etiologies
Overall, the most common causes ofmechanical obstruction are adhesions,
hernias, and tumors.
Other general causes are diverticulitis, foreign
bodies (including gallstones), volvulus
(twisting of bowel on its mesentery),
intussusception (telescoping of one segment
of bowel into another and fecal impaction.
Specific segments of the intestine are affected
differently.
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Aetiologies
LOCATION CAUSES
Colon Tumors (usually in left colon)
Diverticulitis (usually sigmoid)
Volvulus (sigmoid or cecum)
Fecal impaction
Hirschprung's disease
Duodenum Adult Cancer of duodenum
Cancer of head of pancreas
Ulcer disease
Neonates Atresia
Volvulus Bands
Annular pancreas
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LOCATION CAUSES
Jejunum and Ileum Adult Hernias
Adhesions (common)
Tumors Foreign body
Meckel's diverticulum
Crohn's disease (uncommon)
Ascaris infestation
Midgut volvulus
Intussusception by tumor (rare)
Neonates Meconium ileus
Volvulus of malrotated gut
Atresia
Intussusceptiom
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Categories
Complete or Partial
Mechanical versus Functional
Small versus Large intestine Acute, Sub-Acute, Chronic
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Mechanical vs. Functional
A. Mechanical
1. Extraluminal: adhesions (bands of scartissue), hernias, volvulus (twisted bowel),tumours.
2. Intramural: tumors, IBD (e.g Crohns),strictures, paralytic, intussusception(telescoping bowel)
3. Intraluminal (partial or complete): foreignbodies, fecal impaction, gallstones,bezoars, worms
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Mechanical vs. FunctionalB. Functional Paralytic Ileus
Failure of peristalsis to move intestinal contents:adynamic ileus (paralytic ileus, ileus) due to neurologic ormuscular impairment
Accounts for most bowel obstructions
Causes includea. Post gastrointestinal surgery
b. Tissue anoxia or peritoneal irritation fromhemorrhage, peritonitis, or perforation
c. Hypokalemia
d. Medications: narcotics, anticholinergic drugs,antidiarrheal medications
e. Spinal cord injuries, uremia, alterations in electrolytes
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Pathophysiology
1) In simple MECHANICAL obstruction, blockage occurs
without vascular compromise.
2) Ingested fluid and food, digestive secretions, and gas
accumulate above the obstruction.
3) The proximal bowel distends, and the distal segment
collapses.
4) The normal secretory and absorptive functions of the
mucosa are depressed, and the bowel wall becomes
edematous and congested.5) Severe intestinal distention is self-perpetuating and
progressive, intensifying the peristaltic and secretory
derangements and increasing the risks of dehydration
and progression to strangulating obstruction.
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6) Strangulating obstruction is obstruction with
compromised blood flow; it occurs in nearly 25% of
patients with small-bowel obstruction.
7) It is usually associated with hernia, volvulus, and
intussusception.
8) Strangulating obstruction can progress to infarction and
gangrene in as little as 6 h.9) Venous obstruction occurs first, followed by arterial
occlusion, resulting in rapid ischemia of the bowel wall.
10) The ischemic bowel becomes edematous and infarcts,
leading to gangrene and perforation.11) In large-bowel obstruction, strangulation is rare (except
with volvulus).
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12) Perforation may occur in an ischemic segment (typically
small bowel) or when marked dilation occurs.
13) The risk is high if the cecum is dilated to a diameter 13
cm.
14) Perforation of a tumor or a diverticulum may also occur
at the obstruction site.
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Pathophysiology
COLICKY PAIN due to excessive contraction PROXIMAL DISTENSION due to accumulation
of fluid, gas
Impaired absorption of fluid and electrolyte -DEHYDRATION
SEPSIS - bacterial overgrowth due to stasis
Impairment of venous & arterial flow -STRANGULATION, INFARCTION,
PERFORATION
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Clinical Features
Colicky low abdominal
pain
Vomiting
Abdominal distension
Absolute constipation
Others - dehydration,
fever, tachycardia,
oliguria, hypotension,
peritonism
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Manifestations Small Bowel Obstruction
a. Vary depend on level of obstruction and speed ofdevelopment
b. Cramping or colicky abdominal pain, intermittent,intensifying
c. Vomiting
1. Proximal intestinal distention stimulates vomiting
center2. Distal obstruction vomiting may become feculent
d. Bowel sounds
1. Early in course of mechanical obstruction: borborygmiand high-pitched tinkling, may have visible peristaltic
waves2. Later silent; with paralytic ileus, diminished or absent
bowel sounds throughout
e. Signs of dehydration
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Manifestation Large Bowel Obstruction
a. Only accounts for 15% of obstructions
b. Causes include cancer of bowel, volvulus,
diverticular disease, inflammatory disorders,
fecal impaction
c. Manifestations: deep, cramping pain; severe,
continuous pain signals bowel ischemia and
possible perforation; localized tenderness or
palpable mass may be noted
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Investigation
FBC Electrolytes and Urea
Plain supine AXR - dilated SB, central, valvulae
coniventes, air fluid level Contrast X-rays barium/gastrograffin follow-
through/enema
CT scan with oral contrast
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Treatment 1 - Resuscitation
NBM
Fluid replacement - IV fluid
IV antibiotic Correction of electrolyte imbalance
Nasogastric suction
Monitoring - vital signs, fluid balance Adequate analgesia
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Treatment 2 - Surgery
Indications Non-resolving or failure of conservative treatment
Perforation / peritonitis
Underlying disease e.g hernia, crohns, tumour
Avoid in obstruction due to adhesions
High mortality in poorly resuscitated patients
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Treatment 3 Resuscitation
Surgerya. Laparotomy
b. Hemicolectomy- Right / extended right / left
c. Sigmoid colectomy
d. Anterior resection
e. Abdominoperineal resection
f. Hartmanns procedure
g. Colostomy
Staged laparotomy
1, 2 or 3-stage procedures
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Complications
a. Hypovolemia and hypovolemic shock can
result in multiple organ dysfunction (acuterenal failure, impaired ventilation, death)
b. Strangulated bowel can result in gangrene,
perforation, peritonitis, possible septic shockc. Delay in surgical intervention leads to higher
mortality rate
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SBO
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SBO
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SBO
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Intussusception Volvulus
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Large-bowel obstruction. This
chest radiograph demonstratesfree air under the diaphragm,
indicating bowel perforation.
Abdominal (KUB) film of a patient
with obstipation. Dilation of the colon
is associated with large-bowel
obstruction.
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Large-bowel obstruction.
Gastrografin study in a patient
with obstipation reveals
colonic obstruction at the
rectosigmoid level.
Large-bowel obstruction. Contrast
study demonstrates colonic
obstruction at the level of the splenic
flexure, in this case due to carcinoma.
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Large-bowel obstruction.
Abdominal (KUB) radiograph
depicting massive dilation of
the colon due to a cecal
volvulus.
Large-bowel obstruction.
Contrast study of patient with
cecal volvulus. The column of
contrast ends in a "bird's beak"
at the level of the volvulus.
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Large-bowel obstruction.
Massive dilation of the
colon due to a sigmoid
volvulus.
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References
1. Merck Manual Professional
2. eMedicine (http://emedicine.medscape.com)
3. MedlinePlus (http://medlineplus.gov)