Intestinal obstruction is a stoppage of intestinal contents that can have many causes. A review found adhesions and volvulus were common causes. Symptoms include severe abdominal pain, vomiting, constipation and distension. Simple obstruction may be treated conservatively but strangulating obstruction requires surgery to prevent tissue death. Proper fluid and electrolyte management is important to prevent complications like shock.

1. Intestinal obstruction

2. Outline
• Definition
• Classification of causes of intestinal obstruction
• Mechanical intestinal obstruction
• Type of mechanical obstruction
• Clinical features
• Differential diagnosis
• Management

3. Definition
• Intestinal obstruction, one of the commonest surgical emergencies, is
a condition in which there is stoppage of the onward passage of
intestinal contents - gas, digestive juices and food.
.

4. Epidermiology
• In a series by Adam Gyadu et al
• Of the 230 records reviewed, 108 patients (47%) had obstructions
due to adhesions, 50 (21%) had volvulus, 22 (7%) had an ileus from
perforation and 14 (6%) had intussusception.
• Hernia incidence reduced from the 1st to the 8th most common
cause of obstruction.
• Patients with intestinal obstruction were older in 2007-2011
compared to those presenting between 1998 and 2003 (p < 0.001);
• conditions associated with older age (e.g. volvulus and neoplasia)
were more frequently encountered .
https://doi.org/10.1159/000438798

5. Causes
• There are several causes but they may broad groups:
• Divided into 2 groups
• 1. Mechanical (or dynamic) ileus, due to mechanical obstruction of the
intestinal canal, is associated with abdominal pain.
• 2. Paralytic (or adynamic) ileus, due to paralysis of the intestinal musculature,
is characterized by the absence of pain

6. Mechanical intestinal obstruction
• Mechanical obstruction is of 3
types:
• 1. Acute, i.e. of sudden onset.
• 2. Chronic, i.e. of slow,
progressive severity.
• 3. Acute-on-chronic, i.e. chronic
obstruction suddenly becoming
acute by the obturation of the
already narrowed intestinal
canal.

7. Acute intestinal obstruction
• It is by far the commonest form and its effects depend to a large
extent on its site and nature.

8. Classification by site of obstruction
• 1. The site of obstruction is its
position relative to the
ampulla of Vater.
• lt may be
• I) High, i.e. relatively near to the ampulla-jejunum
and proximal ileum - with rapid loss of water and electrolytes
• (ii) Low i.e. relatively distant from the ampulla-distal ileum and colon -
with relatively late onset of fluid and electrolyte imbalances but early
onset of distension.

9. Classification by the nature of obstruction
• 2. Nature of obstruction: This may be:
• (i) Simple obstruction. The bowel lumen is occluded of with no
impairment of the blood supply to the bowel, e.g. obstruction due to
intra-abdominal adhesions which may improve on conservative
treatment alone. Other examples are uncommon causes such as ball
of worms, gallstones and bezoars.
• (ii) Strangulation obstruction, e.g. strangulated inguinal hernia,
volvulus or intussusception. In addition to the occlusion of the lumen,
the blood supply to the segment of bowel involved is also cut off.
Pure strangulation without occlusion of the bowel lumen occurs in
mesenteric thrombosis or embolism.

11. Closed loop obstruction.
• Iii.The obstructed loop is "closed"
at both ends so that nothing can
escape from it proximally or
distally.
• The blood supply of the bowel wall
may be impaired.
• Closed loop obstruction occurs in a
pure form in obstruction of the
colon with a competent iliocaecal
valve which allows ideal contents
to enter the calcium but prevents
their backward passage

12. Types of acute intestinal obstruction
• All three types occur in most cases of intestinal obstruction. For
instance, in a strangulated inguinal hernia, constriction of the neck of
the sac causes:
(a) simple occlusion of the lumen.
(b) Strangulation obstruction where there is cutting off of the blood
supply of the loop in the sac
(c) a closed loop obstruction of the segment of bowel in the hernial
sac.

13. Pathophysiology
• For simplicity and clarity this will
be described as it occurs in:
• (i) Simple obstruction.
• (ii) Strangulation obstruction.
• (iii) Closed loop obstruction.

14. Simple obstruction
• In the bowel below the site of obstruction, normal peristal sis and
absorption continue until the contents are absorbed or passed out.
The bowel then collapses.
• Above the obstruction the bowel becomes distended
• Peristalsis is vigorous for several days but if the obstruction is not
relieved, then increasing distension leads ultimately to loss of peristal
tic activity.

15. Distension
• The distension results from accumulation of gases and fluids.
• The gases nitrogen (70%), carbon dioxide (6-9%), oxygen (10%),
hydrogen (1%), methane (1%), hydrogen sulphide (1-10 %) - are
mostly from swallowed air.
• But some are products of putrefaction and fermentation of intestinal
contents by bacteria and some result from diffusion from the blood.
•

16. • The fluids are essentially digestive juices - saliva, gastric juice, bile,
pancreatic and intestinal secretions - which accumulate partly
because of loss of the absorbing surface of the bowel below the
obstruction and partly because of the disordered fluid and electrolyte
transport in the obstructed segment.
• While the rate of absorption of water, sodium and potassium by the
obstructed bowel decreases steadily and ceases by about 12h, the
rate of their secretion by the intestine rises steadily and significantly
with time.

17. Pathophysiology
• The degree of distension depends on the level of obstruc tion.
• In high obstruction, the accumulated fluid soon reaches the stomach and
the patient vomits it out, whereas in low obstruction, there is a bigger
space for the fluid to accumulate and vomiting is late.
• Peristaltic activity increases in an attempt"to remove the obstruction" and
this with the distension, increases the intraluminal pressure considerably
from the normal 2-4mmHg to 10 in the small bowel and up to 25 mmHg in
the colon.
• When the raised intraluminal pressure becomes higher than the venous
pressure, it compresses the veins with resulting venous congestion,
oedema of the wall, and outpour ing of fluid from the plasma into the
lumen of the gut and the peritoneum.

18. Pathophysiology
• The blood supply, especially to the mucosa, may be undermined by
this increased intraluminal pressure with necrosis of patches of the
mucosa.
• It is to be observed that accumulation of fluid increases distension
which in turn leads to secretion of more fluid.
• The distended bowel is also more of permeable. After some days the
distended bowel becomes atonic.
• Distension of the abdomen embarrasses respiration and acidosis or
respiratory failure may set in

19. Problems due to intestinal obstruction
• These are due to vomiting, accumulation of gastrointestinal secretions in
the bowel lumen, sequestration of fluid in the bowel wall and peritoneal
cavity, diminished oral intake and decreased absorption.
• Most of the gastro-intestinal secretions - normally amounting to 7-10 litres
in 24h but increased in obstruction is lost to the body through vomiting
and/or sequestration in the obstructed gut. The fluid secreted into the
obstructed gut has a much higher concentration of potassium and sodium
• These loss results in hypovolaemai , dehydration or shock
• Other electrolyte abnormalities include hyponatraemia ,hypokalaemai
hypochloraemia
• Shock can progress to renal failure

20. Cause of Death
• Death in acute intestinal obstruction may result from any of the following:
• 1.Shock(i) Hypovolaemic Loss of E.C.F. and/or sequestration of blood.(ii)
Endotoxic.
• 2. Dehydration.
• 3. Electrolyte and metabolic imbalance.(i) Hypokalaemia(ii) Hyponatraemia. (iii)
Alkalosis or acidosis.
• 4. Peritonitis.
• 5. Septicaemia
• 6. Renal failure(i) Pre-renal (from dehydration or shock)(ii) Acute tubular necrosis
(from shock).
• 7. Respiratory failure, respiratory acidosis from distension of the abdomen.
• 8. Multiple organ failure.

21. Clinical features
• Cinical Features
• In mechanical obstruction, a distinction must be made early between
simple and strangulating obstruction.
• 1. Pain is the first symptom. It is severe, cramping, rhythmically intermittent
and colicky. In small bowel obstruction, it is central in position. In large bowel
obstruction it is hypogastric. Each spasm of pain waxes rapidly, lasts for
several seconds and more slowly wanes; in between spasms there is relief. In
strangulation, there is a persistent pain between spasms of colicky pain.

22. • 2 Vomiting.
• It is early and profuse in high obstruction but late or absent in low
obstruction.
• The vomitus is at first colourless or greenish, then becomes light
brown.
• In the late stages it is dark brown and faeculent due to bacterial
decom position of the intestinal contents and blood..

23. • 3. Absolute constipation. i.e. failure to pass flatus and faeces is present
from the outset although the patient may pass one or two normal stools as
the bowel below the obstruction empties. In Richter's hernia, however,
faeces and flatus may be passed because the obstruction is not complete.
• 4. Distension. It varies inversely as the vomiting. In low and colonic
obstruction, it is particularly marked.
• In high obstruction with early copious vomiting it is minimal. In small
intestinal obstruction, the distension is in the central abdomen; in colonic
obstruction, it is in the flanks. In volvulus of the sigmoid colon, distension is
very gross and may fill the entire abdomen.

24. • 5. Visible peristalsis may be present. Auscultation reveals increased high-pitched
bowel sounds.
• 6. The hernial orifices and rectum must be examinedas they may be sites of the
obstruction. A femoral hernia in afat patient may escape notice unless specifically
looked for.
• 7. A scar on the abdomen must be looked for as this maysuggest obstruction
secondary to post-operative adhesions.
• 8. Rebound tenderness, tenderness and some guarding due to serosal
hyperaemia or inflammation and a mass are suggestive of strangulation. They are
absent in simple obstruc tion.
• 9. General signs of dehydration, shock and electrolyte imbalance must be sought-
sunken eyes, dry tongue, dry inelastic skin, rapid pulse, low blood pressure and
mental confusion.10. The urine is scanty and highly concentrated
fromhypovolaemia.

25. Investigations
• The plain X ray of the abdomen , Supine and erect view
• BUE AND CR for electrolyte abnormalities

30. Differential diagnosis
• 1. Paralytic lleus following inflammatory processes - acute
appendicitis, cholecystitis, salpingitis, perforated pep tic ulcer,
generalized peritonitis - gives rise to constant pain, tenderness,
rebound tenderness, guarding or rigidity and pyr exia. Bowel sounds
are absent
• 2. Acute pancreatitis. The patient may be collapsed. Tenderness and
guarding are mainly in the upper abdomen. The Vant Zant sign may
be present and an upper abdominal mass may be palpable.

31. • 3. Typhoid perforation. An antecedent history of fever, headache and
diarrhoea is suggestive. Abdominal ten derness and guarding or
rigidity are generalized.
• 4. Severe constipation. Impacted facces can be felt in the rectum and
the condition improves with

32. Treatment
• General Measures
• 1) Correction of Fluid, Electrolyte and Metabolic ImbalancesFluid and
electrolyte deficiencies must be vigorously corrected by the
administration of Ringer's lactate or dextrose/ saline, and dextrose
water. Potassium chloride is added when the urine output is over 30
ml/h. In severe strangulation when a considerable amount of blood
may be sequestered-, blood may be necessary after the initial
administration of crystalloids.
•

33. • Aspirations are replaced with gastrointestinal replacement solution.
Pulse and blood pressure are checked quarter-hourly and the urine
output hourly. C.V.P. is useful.
• Fluid balance chart should be kept and the serum electrolytes and
blood urea checked twice a day.

34. • (ii) Nasogastric decompressionGastric aspiration must be done to
remove swallowed air and intestinal contents which regurgitate into
the stomach.
• This reduc the distension of the bowel thereby minimizing the
intestinal secretion of water and electrolytes. It also prevents
aspiration into the trachea and bronchi during induction of
anaesthesia.
• Respiratory embarrassment is also diminished.

35. • Sedation: Morphine 10-15 mg or Pethidine 100mg should be given to
relieve pain.
• (iv) Antibiotics to combat infection.Growth and spread of bacteria
should be prevented or checked with broad spectrum antibiotics such
as ciprofloxacin or cefuroxime/ceftazidime and metronidazole or
ceftriaxone.
• .

36. • 2. Conservative management
• (i) Simple obstruction of small intestine from adhesions following
operation often responds to conservative management. Operation is
not advised because it often leads to new adhesions.
• But laparotomy should be done if obstruction continues as shown by:
• (a) increase in distension or aspiration.
• (b) worsening of abdominal pain and tenderness, or
• (c) rise in the pulse rate.
• (ii) Acute-on-chronic obstruction of the left colon is often relieved by
repeated enemata and so is initially managed conservatively