Acute intestinal obstruction.
Definition of the concept.
Classification (by origin, pathogenesis,
anatomical localization, clinical course).
Methods of diagnostics.
Methods of diagnostics.
Intestinal
obstruction
The impedance to the normal passage of the
bowel contents through the small or large intestine. It is a common cause of
acute abdominal pain.
CAUSES OF OBSTRUCTION
A.
DYNAMIC (mechanical
obstruction)
1.Intraluminal: impacted faeces,
foreign bodies, gallstones, Bezoars.
2.Intramural: tumors, inflammatory
strictures,
According
to site of obstruction its classified as:
B.
Adynamic: (functional obstruction)
1. (paralytic ileus) small bowel
obstruction (SBO)
-high ->early perfuse vomiting, rapid
dehydration
-low->predominant pain, and central
distention; vomiting delayed; multiple central air-fluid levels seen on AXR
2. Pseudo-obstruction -large bowel obstruction (LBO)
early pronounced distension, mild pain,
vomiting, dehydration late e.g.
-carcinoma
-diverticulitis or volvulus
3.
Mesenteric vascular occlusion.
OBSTRUCTION
CAN ALSO BE DIVIDED INTO:
Simple: blockage without
interfering with vascular supply
Strangulation: significant impairment of
blood supply most commonly associated with hernia, volvulus, intussusception,
mesenteric infarction, adhesions/Bands
-surgical emergency
Closed
loop obstruction: bowel is obstructed at both the proximal and distal end
Pathophysiology.
Irrespective
of etiology or acuteness of onset:
Proximal
to obstruction
Increased
fluid secretion à abdominal
distention
Accumulation
of gas à abdominal distention
Increased
intraluminal pressure
Vomiting
Dehydration
Dilatation
of bowel
Reflex
contraction of smooth muscle à colicky pain
Increased
peristalsis to overcome obstruction à increased bowel
sounds
If
obstruction not overcome à bowel atony
Decreased
reabsorption with time and flaccidity to prevent vascular damage from high
pressure
Distal
to obstruction: nothing is passed & bowel
collapse à constipation.
Symptoms
The
four cardinal features of intestinal obstruction:
-abdominal pain
-vomiting
-distension
-constipation
Vary
according to: -
location of obstruction
Duration of obstruction
underlying pathology
intestinal ischemia
Abdominal pain
-
colicky in nature, around the umbilicus in SBO while in the lower
abdomen in LBO
- if it becomes continuous, think about
perforation or strangulation.
- does not usually occurs in paralytic
ileus.
Vomiting
-starts early in SBO and late in LBO
-As obstruction progresses vomitus alters
from digested food to faeculent due to enteric bacterial overgrowth
Distension
-more with lower obstruction
Constipation
-more with lower or complete obstruction
- constipation is either absolute (no
feces or flatus)
cardinal feature of complete Int.obst.
or relative (flatus passed).
¨ it does not apply in
-Richter’s Hernia
-Gallstone obstruction.
-mesenteric vascular occlusion.
- obstruction associated with pelvic
abscess.
-diarrhea may be present with partial
obstruction
Dehydration
¨ More common in
small bowel obstruction.due to repeated vomiting .
¨ Secondary
polycythemia due to raised B.urea & hematocrit.
Pyrexia
¨ Onset of ischemia.
¨ Intestinal
perforation.
¨ Inflamation
associated with int. obst.
Symptoms.
In
strangulation:
¨ severe constant abdominal pain
¨ fever
¨ tachycardia
¨ tenderness with rigidity/rebound
tenderness.
¨ Shock
Clinical examination.
General
examination-
Vital signs
Signs of dehydration –tachycardia,
hypotension
dry
mucus membrane, decreased skin turgor, decreased urine output
Inspection
distension, scars, peristalsis,
masses, hernial orifices
Palpation
tenderness, masses, rigidity
Percussion
tympanic abdomen
Auscultation
high pitched bowel sound or silent abdomen
*Examine
rectum for mass, blood, feces or it may be empty in case of complete
obstruction
Investigation
¨ Hemogram - WBC
(neutrophilia-strangulation)
¨ Hyper kalemia,
hyperamylasemia & raised LDH may be associated with strangulation.
¨ Plain AXR
¨ Sigmoidoscopy
(carcinoma, volvulus)
¨ Contrast x-ray
¨ CT abdomen.
X-ray abdomen
When distended by gas:
¨ Jejunum is characterized
by valvulae conniventes (completely pass across the width & regularly
placed)
¨ Ileum is
featureless.
¨ Caecum is shown by
rounded gas shadow in RIF.
¨ Colon shows
haustral folds.
¨ Fluid level appears
later than gas shadow
¨ Two fluid level in
small bowel considered normal.
¨ No. of fluid level
is proportional to degree of obstruction and distal site in small bowel.
¨ Colonic obstruction
does not commonly give rise to small bowel fluid level unless advanced.
¨ Associated with
large ammount of gas in caecum.
¨ Ba-follow through
is contraindicated in acute intestinal obstruction.
Treatments
¨ Three main
measures-
- GI drainage
- Fluid
&Electrolyte replacement
- Relief of obstruction,
usually surgical
Conservative:
-Nasogastric aspiration by Ryles tube
-NPO
-urinary catheter
-check temp. and pulse 2 hourly
-abdominal examination 8 hourly
-Broad spectrum antibiotics initiated early- reduce
bacterial overgrowth.
• Some cases will
settle by using this conservative regimen, other need surgical intervention.
• Surgery should be
delayed till resuscitation is complete unless signs of strangulation and
evidence of closed-loop obstruction.
• Cases that show
reasons for delay should be monitored continuously for 72 hours in hope of
spontaneous resolution e.g. adhesions with radiological findings but no pain or
tenderness
• “The sun should not
both rise and set” in cases of unrelieved obstruction.
Indication for surgery:
- failure of conservative management
- tender, irreducible hernia
- strangulation
¨ If the site of
obstruction is unknown; laparotomy assessment is directed to-
-The site of obstruction.
-The nature of obstruction.
-The viability of gut.
¨ The site of
obstruction can be determined by caecum
Surgical treatment
Operative
decompression required-if
dilatation of bowel
loops prevent exposure, bowel wall viability is compromised, or if subsequent
closure will be compromised.
Savage’s decompressor used within
seromuscular purse-string suture.
Or large-bore NG tube maybe used for
milking intestinal contents into stomach.
*Once
obstruction relieved, the bowel is inspected for viability, and if non-viable,
resection is required.
Indication of non-viability
1.absent peristalsis
2.loss of normal shine
3.loss of pulsation in mesentery
4.green or black color of bowel
¨ If in doubt of
viability, bowel is wrapped in hot packs for 10 minutes with increased oxygen
and reassessed for viability.
¨ Resection of non-viable
gut should be done followed by stoma.
¨ Sometimes a second
look laparotomy is required in 24-48 hours e.g. multiple ischemic areas.
OBSTRUCTION
BY ADHESION AND BAND
¨ Most common cause
of intestinal obstruction.
¨ Peritoneal
irritation results in local fibrin production, which produce adhesions.
BANDS
¨ Congenital: obliterated
vitelli intestinal duct.
¨ A string band
following previous bacterial peritonitis.
¨ A portion of
greater omentum adherent to parietals.
Causes of adhesions:
¨ Abdominal operation:
anastomosis, raw peritoneal surfaces
¨ Foreign
material: talc, starch, gauze, silk
¨ Infection: peritonitis, T.B.
¨ Inflammatory
conditions: crohn’s disease.
¨ Radiation enteritis.
Prevention
¨ Good surgical
technique.
¨ Washing the
peritoneal cavity with saline to remove the clots.
¨ Minimizing contact
with gauze.
¨ Covering the
anastomosis & raw peritoneal surfaces.
Treatment
¨ Usually
conservative treatment is curative.
(i.v. rehydration & nasogastric
decompression)
¨ It should not be prolonged
beyond 72 hrs.
Surgery
¨ Division of band.
¨ Minimal adhesiolysis.
Treatment of
recurrent obstructions due to adhesions.
¨ Repeat adhesiolysis
alone.
¨ Noble’s plication:
adjacent intestinal coils (15-20 cm) are sutured with serosal sutures.
¨ Charles-Phillips
trans-mesenteric plication.
¨ Intestinal intubation:
intraluminal tube insertion via a WITZEL jejunostomy or gastrostomy.
¨ When a portion of
small intestine is entrapped in one of retroperitoneal fossae or in a
congenital mesentric defect.
Sites of internal herniation:
¨ Foramen of Winslow.
¨ A hole in mesentry
/ transverse mesocolon.
¨ Defects in broad
ligaments.
¨ Congenital/ acquired
diaphragmatic hernia.
¨ Duodenal
retroperitoneal fossae- Lt. paraduodenal & rt. Duodenoojejunal.
¨ intersigmoid fossae.
¨ It is uncommon in
the absence of adhesions.
¨ Treatment: to release
the constricting agent by division.
Intramural
obstruction by gallstone stones
¨ It tends to occur
in elderly.
¨ Erosion of large
gallstone into duodenum.
¨ Present with
recurrent obstruction.
¨ X-ray: small bowel
obstruction with air in biliary tree.
-may show a radio opaque gall stone.
¨ Treatment:
laparotomy & removal /crushing of stone.
Food
¨ After partial
/total gastrectomy.
¨ Unchewed food can cause obstruction.
¨ Treatment similar
to gall stone.
BEZOARS
¨ Trichobezoars
¨ Phytobezoars
WORMS
¨ Ascaris
lumbricoides
¨ Frequently follows
initiation of antihelminthic therapy.
¨ Eosinophilia/worm
with in gas filled bowel loops.
¨ Laparotomy.
¨ In older children
intussusception is usually associated with
a lead point – meckel’s
diverticulum, polyp, & appendix.
¨ Adults: always with a lead point.- polyp, submucosal lipoma/
tumor.
¨ It is composed of
three parts:
-Entering/ inner tube(Intussusceptum)
- Returning/ middle tube
-Sheath/ outer tube(intussuscipiens)
¨ It is an example of
strangulating obstruction with impaired
blood supply of inner layer.
¨ It may be
ileoileal(5%); ileocolic(77%); ileo-ileo-colic(12%); colocolic (2%) &
multiple.
Clinical
features
¨ Severe colic pain.
¨ vomitting as time progress
¨ blood & mucus (the ‘redcurrent’ jelly
stool).
¨ Abdominal
lump(sausage shaped)
¨ Emptiness in RIF(the sign of Dance).
¨ Death may occur
from bowel obstruction or peritonitis
secondary to gangrene.
Radiography
¨ Plain X-ray Abd.:
Bowel obstruction with absent caecal shadow gas in ileo-ileal & ileo-colic
cases.
¨ Ba-enema: the claw
sign in ileocolic & colocolic cases.
¨ CT scan in
equivocal cases of ileo-ileal intussusception.
(small bowel mass may be revealed)
Differential
Diagnosis
¨ Acute
enterocolitis: faecal matter/ bile is
always present.
¨ Henoch-schoenlein
purpura.
¨ Rectal prolapse:
projecting mucosa can be felt in continuity with perianal skin
Treatment
¨ Theraputic Ba-enema
: -in infants.
- unlikely to succeed in lead points.
- contrindications: peritonism,
prolonged
history (> 48 hrs.).
Operative
¨ After resuscitation
;Laparotmy with reduction.
¨ Cope’s method.
¨ Irreducible/
gangrenous intussusception: excision of mass & anastomosis.
Duodenal atresia
•
Occurs in 1 in 10,000 live births
•
Site of obstruction is most
commonly in 2nd part of duodenum
•
Proximal duodenum become
hypertrophied
•
50% are associated with
polyhydramnios
•
60% of such pregnancies are
complicated or end prematurely
•
Can often be diagnosed with
antenatal ultrasound
•
30% of babies with duodenal
atresia have Down's syndrome
•
Other associated
abnormalities are cardiac anomalies, malrotation and biliary atresia
•
Postnatally presents with
bilious or non-bile stained vomiting
•
X-ray may show a
'double-bubble' and no gas within the bowel
Management
•
A nasogastric tube should be
passed
•
Intravenous fluid
resuscitation should be given
•
Major cardiac and other
defects should be excluded
•
Duodenoduodenostomy should
be performed when resuscitated
Other atresias
•
Atresias of the small bowel and colon are
less common
•
Often associated with
polyhydramnios
•
Bilious vomiting and
distension are key features
•
x-ray will show dilated
bowel and a gas-free rectum
•
A nasogastric tube should be
passed
•
Intravenous fluid
resuscitation should be given
•
At operation, dilated
proximal bowel should be resected or tapered
•
A primary anastomosis may be
possible
Hirschsprung,s
Disease
•
Due to absence of autonomic
ganglion cells in Auerbach's plexus of distal large intestine
•
Commences at internal
sphincter and progresses for variable distance proximally
•
Affects 1 in 5000 live
births
•
Male : female ratio 4:1
•
Some appear to be due to
autosomal dominant inheritance
•
75% cases confined to
recto-sigmoid
•
10% cases have total colonic
involvement
Clinical features
•
80% present in neonatal
period with delayed passage of meconium
•
Followed by increasing
abdominal distension and vomiting
•
Accounts for 10% of neonatal
intestinal obstruction
•
Child is at increased risk
of enterocolitis and perforation
•
Occasionally presents with
chronic constipation in infancy
Diagnosis
•
Barium enema - Contracted
rectum, cone shaped transitional zone and proximal dilatation
•
Anorectal manometry - No
recto-sphincteric inhibition reflex on rectal distension
•
Rectal biopsy shows:
–
Absent ganglion cells in submucosa
–
Increased
acetylcholinesterase cells in muscularis mucosa
–
Increased unmyelinated
nerves in bowel wall
Treatment
•
Initial defunctioning stoma
to relieve obstruction
•
Bypass of affected segment -
Duhamal or Soave bypass
•
Excision of aganglionic
segment - Swenson procedure
Meconium ileus
•
Commonest cause of neonatal
intraluminal intestinal obstruction
•
80% cases are associated
with cystic fibrosis
•
Cystic fibrosis occurs in 1
in 2000 live births
•
Inherited as an autosomal
recessive trait
•
Viscid pancreatic secretions
cause autodigestion of pancreatic acinar cells
•
Resulting meconium is
abnormal and putty-like in consistency
•
Meconium becomes inspissated
in the lower ileum
•
There is a microcolon
•
Presents with bilious
vomiting and distension usually on first day of life
•
Passage of meconium is
delayed
•
Meconium filled loops of
bowel may be palpable
•
X-ray may show a
'ground-glass' appearance, especially in the right upper quadrant
Management
•
Gastrografin enemas may be
successful in 50% of patients
•
If unsuccessful, surgery
will be required
•
Limited resection and
stomas may be required
complications
•
Peritonitis from bowel
perforation secondary to over-strenuous attempts at reduction of volvulus or
intussusception
•
Misdiagnosis of an ileus
secondary to intra-abdominal infection as large bowel obstruction, with
consequent delay in treatment
•
Intra-abdominal abscess from
anastomotic leakage
•
Pneumonia from aspiration
during emesis
•
Dehydration
•
Electrolyte disturbance
Sigmoid Volvulus
•
Twisting of loop of
intestine around its mesenteric attachment site may occur at various sites in
the GI tract
•
Most commonly: sigmoid &
cecum
•
Rarely: stomach, small
intestine, transverse colon
•
Results in partial or
complete obstruction
•
May also compromise bowel
circulation resulting in ischemia
•
Sigmoid volvulus most common
form of GI tract volvulus
•
Accounts for up to 8% of all
intestinal obstructions
•
Most common in elderly
persons (often neurologically impaired)
•
Patients almost always have
a history of chronic constipation
Pathophysiology
•
Redundant sigmoid colon that
has a narrow mesenteric attachment to posterior abdominal wall allows close
approximation of 2 limbs of sigmoid colon à twisting of sigmoid colon around
mesenteric axis
•
Other predisposing factors
–
Chronic constipation
–
High-roughage diet (may
cause a long, redundant sigmoid colon)
–
Roundworm infestation
–
Megacolon (often due to
Chagas dz)
–
Peak age > 50 yrs.
–
Second largest group Ã
children
•
Torsion usually
counterclockwise ranging from 180 – 540 degrees
•
Luminal obstruction
generally at 180 degrees
•
Venous occlusion generally
at 360 degrees à gangrene & perforation
Signs
and symptoms
May present as abdominal emergency
•
Acute distension
•
Colicky pain (often LLQ)
•
Failure to pass flatus or
stool (constipation is prevailing feature)
•
Vomiting is late sign
Physical
examination
•
Tympanitic abdomen
•
Abdominal distention
•
+/- palpable mass
Diagnosis
•
Abdominal plain films
usually diagnostic
–
Inverted U-shaped appearance
of distended sigmoid loop
•
Largest and most
dilated loops of bowel are seen with volvulus
–
Loss of haustra
–
Coffee-bean sign à midline
crease corresponding to mesenteric root in a greatly distended sigmoid
•
Sigmoid volvulus – bowel
loop points to RUQ
•
Cecal volvulus – bowel loop
points to LUQ
–
Dilated cecum comes to rest
in left upper quadrant
–
Bird’s-beak or bird-of-prey
sign à seen on barium enema as it encounters the volvulated loop
•
CT scan useful in assessing
mural wall ischemia
Differential
Diagnosis
•
Large bowel obstruction due
to other causes à sigmoid colon CA
•
Giant sigmoid diverticulum
•
Pseudoobstruction
Complications
1.
Colonic ischaemia
2.
Perforation
3.
Sepsis
Treatment
•
Derotation
& decompression by barium enema or with rectal tube, colonoscope, or
sigmoidoscope if no signs of bowel ischemia or perforation
–
Laparoscopic derotation or
laparotomy +/- bowel resection
–
Cecopexy à suture fixation
of bowel to parietal peritoneum may prevent recurrence
–
Recurrence rate after
decompression alone à 50%
Intestinal Pseudo-obstruction
•
The term intestinal
pseudo-obstruction is used to indicate a syndrome characterized by a clinical
picture suggestive of mechanical obstruction in the absence of any demonstrable
evidence of such an obstruction in the intestine
•
Based on clinical
presentation, pseudo-obstruction syndromes can be divided into acute and
chronic forms
•
Acute colonic
pseudo-obstruction is a clinical condition that appears with symptoms, signs,
and radiological findings similar to those of acute large bowel obstruction,
without any apparent mechanical cause
•
Frequency: Recent studies
involving more than 13,000 orthopedic and burn patients documented the
prevalence of acute colonic pseudo-obstruction to be 0.29%
•
Acute colonic
pseudo-obstruction generally develops in hospitalized patients and is
associated with a variety of medical and surgical conditions
•
The most commonly associated
conditions include trauma, pregnancy, cesarean delivery, severe infections, and
cardiothoracic, pelvic, or orthopedic surgery
•
Most recent reports now
indicate the mean age to be in the seventh and eighth decades of life
•
the male-to-female ratio
(1.5-4:1)
•
The mortality rate in medically treated
patients has been documented to be 14%; in surgically treated patients, 30%.
•
The most serious
complication of colonic pseudo-obstruction is perforation of the cecum. The
reported incidence of cecal perforation is 3-40%, and the associated mortality
rate is 40-50%.
•
Pathophysiology remains
unknown
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