Acute bowel obstuction (lecture mogilevec e.v)

Acute bowell
(intestinal)
obstruction (ileus)

Intestinal obstruction
 Intestinal obstruction is the disturbance
of passage (blockage) which precludes
intestinal contents from moving in the
usual oral to anal progression.
 Obstruction is the most common
surgical disorder of the small intestine.

 There are some pathological processes of
the same type and irrespective of the
cause of disorder in human organism due
to bowel obstruction.
 Terminal early conservative or surgical
removal of functional and objective
morphological problems are most
important in reducing morbidity and
mortality of mechanical intestinal
obstruction and ileus.

Сlassification of acute intestinal
obstruction
 There are four signs in the bases of all
today classifications of acute intestinal
obstruction: origin; method of occurrence;
blood flow state; clinical course.
I. According to origin а) congenital;
b) acquired.

obstruction
II. According to morphofunctional nature
(etiology)
 1. Mechanical obstruction of the intestine
The term mechanical obstruction means that
luminal contents cannot pass through the gut tube
because the lumen is blocked.

obstruction
1. Mechanical obstruction of the intestine
a) In simple obstruction, the intestinal lumen is partially or
completely occluded without compromise of intestinal blood
flow.
 Simple obstructions can be complete, meaning that the
lumen is totally occluded, or incomplete, meaning
that the lumen is narrowed but permits distal passage of
some fluid and air.
 Simple obstruction is most often due to adhesion, groin
hernia, or neoplasm, intraluminal foreign bodies or
gallstones . The hernia can act as a tourniquet, causing a
closed-loop obstruction and strangulation.

obstruction
1. Mechanical obstruction of the intestine
b) strangulated obstruction (volvulus,
“knotformation”, incarceration); In strangulated
obstruction, blood flow to the obstructed segment
is compromised, and tissue necrosis and
gangrene are imminent. Strangulation usually
implies that the obstruction is complete, but some
forms of partial obstruction can also be
complicated by strangulation.
c) mixed forms (adhesions, intussusception)

obstruction (continuation)
2. Description of the previous form contrasts with
neurogenic or functional obstruction, in which luminal
contents fail to pass because of disturbances in gut
motility that prevent coordinated peristalsis from one
region of the gut to the next. This latter form of
obstruction is commonly referred to as ileus in the
small intestine and pseudoobstruction in the large
intestine in the US-medical literature.
 a) adynamic (paralytic);
 b) spastic.

Сlassification of acute intestinal obstruction
(continuation)
III. According to location
1. Obstruction of the small intestine:
 а) proximal obstruction. Proximal, or high, obstructions
involve the pylorus, duodenum, and proximal jejunum.
 b) mid or distal obstruction. Intermediate levels of obstruction
involve the intestine from the mid-jejunum to the mid-ileum.
Distal levels of obstruction arise in the distal ileum, ileocecal
valve, and proximal colon,
2. Obstruction of the large intestine.
 Whereas the most distant, or low, obstructions arise in
regions beyond the transverse colon.
IV. According to clinical course
 а) acute;
 b) chronic.

according to variant of obstruction
Small bowel obstruction:
 strangulated obstruction:
 volvulus
 intussusception
 “knotformation”
 simple obturative obstruction
 adhesion obstruction
 functional(dynamic) obstruction
 early mechanical postoperative obstruction

according to variant of obstruction
Large bowel obstruction
 obturative simple obstruction due to tumors
 volvulus of the large bowel
 obstruction due to torsion at the point of an adhesion
 obstruction due to fecal impaction
 obturative simple obstruction as complication of
diverticulitis
 pseudoobstruction of the large intestine
 obstruction of the large bowel due to rare causes

Frequency of different variants of
acute intestinal obstruction
 Dynamic (neurogenic or functional )
obstruction - 40%;
 Mechanical obstruction – 60%;
 strangulated – 74%;
 obturative (simple) – 26%;
- Adhesion obstruction – 82,5%;
- Volvulus – 12%;
- Intussusception – 3,5%;
- “Knotformation” – 2%.

Causes of the acute intestinal
obstruction
 Predispositional congenital: maldevelopments of
bowels, mesentery and peritoneum (malrotation,
diverticulesis, common mesentery of cecum and ileum,
dolichosigmoid, maldevelopments of diaphragm and
peritoheum with formation fissures and pockets);
 Predispositional aquiered: commissures, cicatrixes
(scars), adhesions, fusions, tumors, inflammatory
infiltrates, hematomas, foreign bodies in the bowel lumen,
functional state of gut connecting with prolonged hunger
and next overeating, chronic inflammatory changes of
bowels;
 Making: acute disorders of motility (hyper- and hypomotor
reactions.

Pathogenetic stages of acute
intestinal obstruction
 I — the stage of acute disorder of intestinal
passage;
 II — the stage of acute disturbances in
transmural intestinal hemocirculation;
 III — the stage of peritonitis.

Morphopathology
 1. Necrotic changes started from mucous
tunic in acute intestinal obstruction. The
underline layers can be nonviable
(devitalized) in macroscopic unchangeable
serous integument.
 2. Significant changes of intestinal wall in
adducting loop are spreading more
proximal than the place of obstruction

Clinical features
(Small bowel obstruction)
 Patients invariably present with abdominal pain. This is usually
crampy or colicky in nature in the early stages and can
progress to severe, constant pain as the process progresses.
 Nausea and vomiting are also quite common findings, as is
the absence of flatus.
 Much emphasis has been placed on the nature of the emesis
suggesting that bilious emesis occurs with proximal
obstruction while feculent emesis occurs in distal obstruction,
but this is not without exception.
 Intestinal obstruction may present with an acute onset of pain
(less than 1 day) such as those with proximal obstruction or a
more indolent course (a few days) such as those associated
with metastatic disease.
 Acuity is related to type (complete or partial) rather than the
location of obstruction.

Clinical features
 Physical examination must include assessment of
vital signs.
 Abdominal examination may reveal distension,
evidence of prior surgery, or incarcerated hernias.
 Abdominal auscultation may reveal high-pitched
bowel sounds with obstruction, though the
presence or absence of bowel sounds is not an
absolute indicator of abdominal pathology.
 Abdominal pain may be elicited with or without
signs of peritoneal irritation.
 A rectal examination should be performed not only
to check for occult blood but also to rule out an
obstructing rectal mass.

Clinical features
(Large bowel obstruction)
 The manifestations of an obstructed colon
can occur insidiously or less often rapidly,
superimposed on chronic complaints.
 Frequently the abdomen distends gradually
and there is progressive constipation and
finally obstipation.
 The severe, crampy abdominal pain
characteristic of small-bowel obstruction is
not a common feature; most patients have
dull, lower abdominal cramps, which may
radiate to the hypogastrium if the ascending
or transverse colon is involved.

Clinical features
 The distended abdomen is tympanitic, and high-
pitched tinkles or more prolonged, low-pitched
peristaltic sounds may be present.
 There is local tenderness in the right lower
quadrant over the cecum if perforation is
impending.
 The rectum tends to feel empty and capacious;
rarely, a rectal tumor is palpable on digital rectal
examination.
 Traces of blood suggest a possible tumor or bowel
ischemia.
 The patient is carefully examined for the presence
of hernias.

Clinical features
 The clinical presentation can be more
fulminant when there is complete
obstruction and/or perforation of the colon.
 Abdominal distension is frequently
pronounced; abdominal tenderness,
guarding and rebound are found.
 Hypovolemia can lead to hypotension and
oliguria.

Laboratory investigations
 All laboratory and radiographic tests must be
interpreted in the context of the history and physical
findings.
 Laboratory tests are helpful in determining the severity
of illness, though they are not specific for small bowel
obstruction (Patients can manifest leukocytosis with
bandemia in cases of intestinal ischemia;
Hemoconcentration can occur with severe volume
depletion; electrolyte abnormalities commonly occur
from protracted vomiting, an elevated level of blood
urea nitrogen signifies intravascular volume depletion
ect.)
 These tests may suggest that obstruction should be
included in the differential diagnosis, though they are
not absolute indicators.

 An abdominal plain film is usually performed in the
upright position.
 Signs of small bowel obstruction include bowel
dilatation proximal to the site of obstruction, air–fluid
levels, paucity of large bowel gas, bowel wall
thickening, a fixed loop, and ground glass appearance
signifying intraluminal fluid.
 In early small intestinal obstruction, however, there
may still be gas in the large bowel due to incomplete
evacuation of contents distal to the point of obstruction.
 Air–fluid levels may suggest small bowel obstruction in
a patient with a consistent history, though this finding
can be present in any illness which decreases bowel
motility resulting in ileus. Plain films can also appear
normal in the setting of small bowel obstruction.

 Barium are administered with timed plain
films to evaluate intraluminal transit.
 This study can show the point of obstruction,
the degree of narrowing in the case of a
partial small bowel obstruction, and
associated mucosal abnormalities.
 It involves an initial bolus of enteral contrast
with subsequent filming to document transit
through the small bowel to the colon.
 When contrast does not reach the colon after
several hours, a complete obstruction must
be postulated.

 Computed tomography (CT) is playing a
growing role in the diagnosis of intestinal
obstruction.
 Signs of obstruction by CT scan include
proximal dilatation with transition point and
closed-loop obstruction with a 'beak' sign.
 Small bowel strangulation can be shown as
circumferential thickening of the bowel wall,
increased small bowel attenuation,
pneumatosis, and 'target sign' secondary to
thickening.

CT scan of a small bowel
obstruction

 Contrast administration is helpful, though
fluid-filled loops of small bowel often act as
their own contrast medium.
 Rectal contrast is useful in ruling out large
bowel obstruction as the etiology of small
bowel obstructive symptoms.
 Current recommendations include utilizing CT
scan in cases where plain films are non-
diagnostic, there is a disparity between
clinical and radiographic findings, there is
postoperative small bowel obstruction, and
cases where neoplasms are suspected.

 CT scans are useful in the diagnosis of
complete as opposed to partial small
bowel obstruction in the postoperative
period, with metastatic disease, in
inflammatory bowel disease, where a
bowel malignancy is suspected, and in
patients with a history of a chronic partial
bowel obstruction.

 Abdominal films provide useful information:
they may suggest or confirm the diagnosis
and site of obstruction, and the degree of
cecal distension can be assessed from
them.

 The site of obstruction and its severity can
be detected with a retrograde contrast
study; the diagnosis of pseudo-obstruction
is also ruled out.
 Computed tomographic (CT) scans are of
value: they may illustrate the transitional
area of colonic obstruction, as well as
extracolonic abnormalities and more subtle
degrees of pneumoperitoneum.

Treatment
(conservative)
 Decompression with a nasogastric or long
intestinal tube and evacuation of intestinal
content;
 Fluid and electrolyte resuscitation,
parenteral nutrition (feeding) with
spasmolytics injection;
 Bilateral paranephral novocaine (procaine)
blokade;
 Siphon enema.

Treatment
(surgical)
 The modern approach to intestinal obstruction and
ileus has paralleled the development of techniques
for safe abdominal surgery.
 The indications for operation of acute intestinal
obstruction are established differentiatedly,
according to the variant of obstruction and terms of
it’s development.
 Preoperative antibiotics to cover bowel and skin
flora should be administered.
1. Anesthesia – intubation narcosis with AVL
2. Approach – midline laparotomy.

3. The goal of the operation and
sequence of actions:
 Elimination of intestinal obstruction;
 Bowel involved in obstruction is carefully examined for
viability. If frankly necrotic, the bowel should be resected.
 Primary anastamosis can then be performed, either with
stapled or hand-sewn techniques. The determinination of
bowel viability can also be aided by intraoperative
inspection after either a waiting period or fluoroscein
injection with Woods lamp detection.
 An intestinal bypass may be necessary in cases of diffuse
metastatic disease. Irrigation is then used to clean the
abdominal cavity.
 Abolition (if it is possible) the main pathology, which is the
cause of acute intestinal obstruction, and reversal the
reason of obstruction recurrence;
 Sanation and drainage of abdominal cavity in cases of
peritonitis presense.

Three major types of operations
are done (large bowel obstruction):
 Three major types of operations are done:
 decompressive procedures such as loop ileostomy;
 colon resections; and
 bypass procedures.
 At times, different types of procedures are
combined.
 Resections are safest done under the following
circumstances: when
 the ileocecal valve is incompetent;
 the obstructed colonic segment can be removed in its
entirety; and
 the bowel can be decompressed to a normal size
without vascular compromise.

Prognosis of treatment acute
intestinal obstruction
 Nonstrangulating obstruction has a death rate of
about 2%; most of these deaths occur in the
elderly.
 Strangulation obstruction has a mortality rate of
approximately 8% if operation is performed
within 36 hours of the onset of symptoms and
25% if operation is delayed beyond 36 hours.

Acute bowel obstuction (lecture mogilevec e.v)

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