1. Clinical features of volvulus Volvulus of the small intestine
This may be primary or secondary and usually occurs in the
lower ileum. It may occur spontaneously
particularly following the consumption of a large volume of
vegetable matter, or secondary to
adhesions passing to the parietes or female pelvic organs.

2. Caecal volvulus
This may occur as part of volvulus neonatorum or de novo and
is usually a clockwise twist. It is more common in females in
the fourth and fifth decades and usually presents acutely with
the classic features of obstruction. Ischaemia is common. At
first the obstruction may be partial, with the passage of flatus
and faeces. In 25 per cent of cases, examination may reveal a
palpable tympanic swelling in the midline or left side of the
abdomen. The volvulus typically results in the caecum lying
in the left upper quadrant. The diagnosis is not usually made
preoperatively.

3. Sigmoid volvulus
The symptoms are of large bowel obstruction. Presentation varies
in severity and acuteness, with younger patients appearing
to develop the more acute form. Abdominal distension is an
early and progressive sign, which may be associated with hiccough
and retching. Constipation is absolute. In the elderly, a
more chronic form may be seen. In some patients, the grossly
distended torted left colon is visible through the abdominal
wall.

4. Radiological features of obstruction (on plain
x-ray)
The obstructed small bowel is characterised by straight
segments that are generally central and lie transversely.
No/minimal gas is seen in the colon
The jejunum is characterised by its valvulae conniventes,
which completely pass across the width of the bowel and
are regularly spaced, giving a ‘concertina’ or ladder effect
Ileum – the distal ileum has been piquantly described by
Wangensteen as featureless
Caecum – a distended caecum is shown by a rounded gas
shadow in the right iliac fossa
Large bowel, except for the caecum, shows haustral folds,
which, unlike valvulae conniventes, are spaced irregularly,
do not cross the whole diameter of the bowel and do not
have indentations placed opposite one another

5. Gas-filled small bowel loop; patient supine.

6. Fluid levels with gas above; ‘stepladder pattern’
Fluid levels with gas above; ‘stepladder pattern’. Ileal obstruction by adhesions.

7. The CT scan is now used very widely to investigate all forms
of intestinal obstruction. It is highly accurate and its only limitations
are in diagnosing ischaemia. It is important to remember
that even with the best imaging techniques, the diagnosis of
strangulation remains a clinical one.
Impacted foreign bodies may be seen on abdominal radiographs.
It is noteworthy that gas-filled loops and fluid levels in
the small and large bowel can also be seen in established paralytic
ileus and pseudo-obstruction. The former can, however,
normally be distinguished on clinical grounds, whereas the latter
can be confirmed radiologically. Fluid levels may also be seen in
non-obstructing conditions such as gastroenteritis, acute pancreatitis
and intra-abdominal sepsis.

8. Imaging in intussusception
A plain abdominal field usually reveals evidence of small or
large bowel obstruction with an absent caecal gas shadow in
ileocolic cases. A soft tissue opacity is often visible in children.
A barium enema may be used to diagnose the presence of an ileocolic
intussusception (the claw sign), but does
not demonstrate small bowel intussusception. An abdominal
ultrasound scan has a high diagnostic sensitivity in children,
demonstrating the typical doughnut appearance of concentric
rings in transverse section. CT scan is currently considered the
most sensitive radiologic method to confirm intussusception,
with a reported diagnostic accuracy of 58–100 per cent. The
characteristic features of CT scan include a ‘target’ or ‘sausage’-
shaped soft-tissue mass with a layering effect, mesenteric vessels
within the bowel lumen are also typical.

9. ‘Claw’ sign of iliac intussusception.

10. Imaging in volvulus
In caecal volvulus, radiological abnormalities are identifiable
in nearly all patients, but are often non-specific, with caecal
dilatation (98–100 per cent), single air-fluid level (72–88
per cent), small bowel dilatation (42–55 per cent) and
absence of gas in distal colon (82 per cent) reported as the
most common abnormalities. A barium enema may be used to confirm the diagnosis if there are no concerns about
ischaemia, with an absence of barium in the caecum and a
bird beak deformity. CT scanning is replacing barium enema
as the imaging of choice in these less urgent cases.

11. • In sigmoid volvulus, a plain radiograph shows massive
colonic distension. The classic appearance is of a dilated loop
of bowel, the two limbs are seen running diagonally across
the abdomen from right to left, with two fluid levels seen,
one within each loop of bowel (if an erect film is taken).
• In volvulus neonatorium, the abdominal radiograph shows
a variable appearance. Initially, it may appear normal or
show evidence of duodenal obstruction but, as the intestinal
strangulation progresses, the abdomen becomes relatively
gasless.

12. TREATMENT OF ACUTE INTESTINAL OBSTRUCTION
There are three main measures used to treat acute intestinal obstruction.
Treatment of acute intestinal obstruction
Gastrointestinal drainage via a nasogastric tube
Fluid and electrolyte replacement
Relief of obstruction
Surgical treatment is necessary for most cases of intestinal obstruction but should be delayed until resuscitation is complete,
provided there is no sign of strangulation or evidence of closed-loop obstruction.The first two steps are always necessary before attempting the
surgical relief of obstruction and are the mainstay of postoperative management..

13. Principles of surgical intervention for obstruction
Management of:
The segment at the site of obstruction
The distended proximal bowel
The underlying cause of obstruction

14. Supportive management
Nasogastric decompression is achieved by the passage of a
non-vented (Ryle) or vented (Salem) tube. The tubes are
normally placed on free drainage with 4-hourly aspiration, but
may be placed on continuous or intermittent suction. As well
as facilitating decompression proximal to the obstruction, they
are essential to reduce the risk of subsequent aspiration during
induction of anaesthesia and post-extubation.

15. The basic biochemical abnormality in intestinal obstruction
is sodium and water loss, and therefore the appropriate replacement
is Hartmann’s solution or normal saline. The volume
required varies and should be determined by clinical haematological
and biochemical criteria.
Antibiotics are not mandatory but many clinicians initiate
broad-spectrum antibiotics early in therapy because of bacterial
overgrowth. Antibiotic therapy is mandatory for all patients
undergoing surgery for intestinal obstruction.

16. Surgical treatment
The timing of surgical intervention is dependent on the clinical
picture. There are several indications for early surgical intervention.
Summary box 70.12
Indications for early surgical intervention
Obstructed external hernia
Clinical features suspicious of intestinal strangulation
Obstruction in a ‘virgin’ abdomen

17. The classic clinical advice that ‘the sun should not both rise
and set’ on a case of unrelieved acute intestinal obstruction was
based on the concern that intestinal ischaemia would develop
while the patient was waiting for surgery. If there is complete
obstruction, but no evidence of intestinal ischaemia, it is reasonable
to defer surgery until the patient has been adequately
resuscitated. Where obstruction is likely to be secondary to
adhesions, conservative management may be continued for up
to 72 hours in the hope of spontaneous resolution.

18. • the site of obstruction; • the nature of the obstruction;
If the site of obstruction is unknown, adequate exposure is
best achieved by a midline incision. Assessment is directed to:
• the site of obstruction;
• the nature of the obstruction;
• the viability of the gut.
In cases of small bowel obstruction, the first manoeuvre is to
deliver the distended small bowel into the wound. This permits
access to the site of obstruction. The small bowel should
be covered with moist swabs and the weight of the fluid-filled
bowel supported such that the blood supply to the mesentery is
not impaired.

19. Operative decompression should be performed whenever
possible. This reduces pressure on the abdominal wound reducing
pain and improving diaphragmatic movement. The simplest
and safest method is to insert a large bore orogastric tube and
to milk the small bowel contents in a retrograde manner to the
stomach for aspiration. All volumes of fluid removed should be
accurately measured and appropriately replaced. It is important
to ensure that the stomach is empty at the end of the procedure
to prevent postoperative aspiration.

20. The type of surgical procedure required will depend upon the cause of obstruction – division
of adhesions (enterolysis), excision, bypass or proximal
decompression.
Following relief of obstruction, the viability of the involved
bowel should be carefully assessed .

21. Differentiation between viable and non-viable intestine.
Viable Non-viable
Circulation Dark colour becomes Dark colour remains
lighter
Visible pulsation in No detectable
mesenteric arteries pulsation
General appearance Shiny Dull and lustreless
Intestinal musculature Firm Flabby, thin and
friable
Peristalsis may be No peristalsis
observed
Viable Non-v lighter

25. Treatment of adhesive obstruction
Initially treat conservatively provided there are no signs of
strangulation; should rarely continue conservative treatment
for longer than 72 hours
At operation, divide only the causative adhesion(s) and limit
dissection
Repair serosal tears; invaginate (or resect) areas of doubtful
viability
Laparoscopic adhesiolysis in the hands of advanced
laparoscopic practitioners

26. Treatment of recurrent intestinal obstruction caused by adhesions
Several procedures may be considered in the presence of recurrent
obstruction including:
• repeat adhesiolysis (enterolysis) alone;
• Noble’s plication operation;
• Charles–Phillips transmesenteric plication;
• intestinal intubation.

27. Postoperative intestinal obstruction
Differentiation between persistent paralytic ileus and early
mechanical obstruction may be difficult in the early postoperative
period. Mechanical obstruction is more likely if the patient
has regained bowel function postoperatively which subsequently
stops. Obstruction is usually incomplete and the majority settle
with continued conservative management. Postoperative intraabdominal
sepsis is a potent cause of postoperative obstruction;
CT scanning with oral contrast is of particular value in the
assessment of the postoperative abdomen. A water-soluble contrast
agent (50–100 mL) by mouth with a delayed plain abdominal
x-ray is also of value .

28. Treatment of intussusception
In the infant with ileocolic intussusception, after resuscitation
with intravenous fluids, broad-spectrum antibiotics and
nasogastric drainage, non-operative reduction can be attempted
using an air or barium enema.
Successful reduction can only be accepted if there is free reflux
of air or barium into the small bowel, together with resolution
of symptoms and signs in the patient. Non-operative reduction
is contraindicated if there are signs of peritonitis or perforation,
there is a known pathological lead point or in the presence of
profound shock. Surgery is required when radiological reduction has failed
or is contraindicated.

29. Acute intestinal obstruction of the newborn
Neonatal intestinal obstruction has many potential causes.
Congenital atresia and stenosis are the most common.

30. TREATMENT OF ACUTE LARGE BOWEL OBSTRUCTION
Large bowel obstruction is usually caused by an underlying
carcinoma or occasionally diverticular disease, and presents in
an acute or chronic form. The condition of pseudo-obstruction
should always be considered and excluded by a limited contrast
study or CT scan to confirm organic obstruction.
After full resuscitation, the abdomen should be opened
through a midline incision. Care should be taken to ensure that
the loss of tamponade of the abdominal wall does not lead to
increased caecal distension and rupture (this starts with splitting
along the line of the taenia coli on the antimesenteric border).

31. Distension of the caecum will confirm large bowel involvement.
Identification of a collapsed distal segment of the large bowel
and its sequential proximal assessment will readily lead to identification
of the cause. As surgery for malignant bowel cancer is
technically challenging, wherever possible a suitably trained surgeon
should perform the procedure. When a removable lesion is
found in the caecum, ascending colon, hepatic flexure or proximal
transverse colon, an emergency right hemicolectomy should
be performed.

32. A primary anastomosis is safe if the patient’s
general condition is reasonable. If the lesion is irremovable (this
is rarely the case), a proximal stoma (colostomy or ileosotomy
if the ileocaecal valve is incompetent) or ileotransverse bypass
should be considered. Obstructing lesions at the splenic flexure
should be treated by an extended right hemicolectomy with ileodescending
colonic anastomosis. For obstructing lesions of the left colon or rectosigmoid junction,
immediate resection should be considered unless there are
clear contraindications

33. Treatment of caecal volvulus
At operation, the volvulus is usually found to be ischaemic
and needs resection. If, viable, the volvulus should be reduced.
Sometimes, this can only be achieved after decompression of
the caecum using a needle. Further management consists of fixation
of the caecum to the right iliac fossa (caecopexy) and/or caecostomy. Recurrence of volvulus after caecopexy has been
reported in up to 40 per cent of cases.

34. Treatment of sigmoid volvulus
Flexible sigmoidoscopy or rigid sigmoidoscopy and insertion of
a flatus tube should be carried out to allow deflation of the gut.
The tube should be secured in place with tape for 24 hours and
a repeat x-ray taken to ensure that decompression has occurred.
Successful deflation, as long as ischaemic bowel is excluded, will
resolve the acute problem.

35. In young patients, an elective sigmoid colectomy is required.
It is reasonable not to offer any further treatment following
successful endoscopic decompression in the elderly as there is
a high death rate (~80 per cent at two years) from causes other
than recurrent volvulus. In elderly patients with comorbidities
and recurrent episodes of volvulus, the options are resection
or two point fixation with combined endoscopic/percutaneous
tube insertion (gastrostomy tubes are frequently used for this
purpose). Failure results in an early laparotomy, with untwisting
of the loop and per anum decompression .

37. When the bowel is viable, fixation of the sigmoid colon to the
posterior abdominal wall may be a safer manoeuvre in inexperienced
hands. Resection is preferable if it can be achieved safely. A Paul–Mikulicz procedure is useful, particularly if there
is suspicion of impending gangrene ; an alternative
procedure is a sigmoid colectomy and, when anastomosis
is considered unwise, a Hartmann’s procedure with subsequent
reanastomosis can be carried out.

39. CHRONIC LARGE BOWEL OBSTRUCTION
The symptoms of chronic intestinal obstruction may arise from
two sources – the cause and the subsequent obstruction.
The causes of obstruction may be organic:
• intraluminal (rare) – faecal impaction;
• intrinsic intramural – strictures (Crohn’s disease, ischaemia,
diverticular), anastomotic stenosis;
• extrinsic intramural (rare) – metastatic deposits (ovarian),
endometriosis, stomal stenosis;
or functional:
• Hirschsprung’s disease, idiopathic megacolon, pseudoobstruction.

40. The symptoms of chronic obstruction differ in their predominance,
timing and degree from acute obstruction. In functional
cases, the symptoms may have been present for months or years.
Constipation appears first. It is initially relative and then absolute,
associated with distension. In the presence of large bowel
disease, the point of greatest distension is in the caecum, and
this is heralded by the onset of pain. Vomiting is a late feature
and therefore dehydration is less severe. Examination is unremarkable,
save for confirmation of distension (which can be
profound) and the onset of peritonism in late
cases. Rectal examination may confirm the presence of faecal
impaction or a tumour.

41. Principles of investigation of possible large bowel obstruction
In the presence of large bowel obstruction, a single contrast
water-soluble enema or CT should be undertaken to exclude
a functional cause.
Functional disease requires colonoscopic decompression in
the first instance and conservative management. Intestinal perforation
can occur in patients with functional obstruction.
Those at risk have such gross distension that the abdomen is
rigid on palpation

42. ADYNAMIC OBSTRUCTION Paralytic ileus
This may be defined as a state in which there is failure of transmission
of peristaltic waves secondary to neuromuscular failure
(i.e. in the myenteric (Auerbach’s) and submucous (Meissner’s)
plexuses). The resultant stasis leads to accumulation of fluid
and gas within the bowel, with associated distension, vomiting,
absence of bowel sounds and absolute constipation.

43. Varieties • Postoperative. A degree of ileus usually occurs after any
The following varieties are recognised:
• Postoperative. A degree of ileus usually occurs after any
abdominal procedure and is self-limiting, with a variable
duration of 24–72 hours. Postoperative ileus may be
prolonged in the presence of hypoproteinaemia or metabolic
abnormality (see below).
• Infection. Intra-abdominal sepsis may give rise to localised or
generalised ileus.
• Reflex ileus. This may occur following fractures of the spine
or ribs, retroperitoneal haemorrhage or even the application
of a plaster jacket.
• Metabolic. Uraemia and hypokalaemia are the most common
contributory factors.

44. Clinical features
Paralytic ileus takes on a clinical significance if, 72 hours after
laparotomy:
• there has been no return of bowel sounds on auscultation;
• there has been no passage of flatus.
Abdominal distension becomes more marked and tympanitic.
Colicky pain is not a feature. Distension increases pain from the
abdominal wound. In the absence of gastric aspiration, effortless
vomiting may occur. Radiologically, the abdomen shows gasfilled
loops of intestine with multiple fluid levels (if an erect film
is felt necessary).

45. Management
Nasogastric tubes are not required routinely after elective intraabdominal
surgery. Paralytic ileus is managed with the use of
nasogastric suction and restriction of oral intake until bowel
sounds and the passage of flatus return. Electrolyte balance must
be maintained. The use of an enhanced recovery programme
with early introduction of fluids and solids is, however, becoming
increasingly popular.

46. • If a primary cause is identified, this must be treated.
Specific treatment is directed towards the cause, but the following
general principles apply:
• If a primary cause is identified, this must be treated.
• Gastrointestinal distension must be relieved by
decompression.
• Close attention to fluid and electrolyte balance is essential.
• There is no place for the routine use of peristaltic stimulants. Rarely, in resistant cases, medical therapy with a
gastroprokinetic agent, such as domperidone or erythromycin
may be used, provided that an intraperitoneal cause has been
excluded.

47. • If paralytic ileus is prolonged, CT scanning is the most
effective investigation; it will demonstrate any intraabdominal
sepsis or mechanical obstruction and therefore
guide any requirement for laparotomy. Otherwise the decision
to take a patient back to theatre in these circumstances
is always difficult. The need for a laparotomy becomes
increasingly likely the longer the bowel inactivity persists,
particularly if it lasts for more than 7 days or if bowel activity
recommences following surgery and then stops again.

48. Factors associated with pseudo-obstruction
Metabolic
Diabetes
Hypokalaemia
Uraemia
Myxodoema
Intermittent porphyria
Severe trauma (especially to the lumbar spine and pelvis)
Shock
Burns
Myocardial infarction
Stroke
Idiopathic
Septicaemia
Postoperative (for example, fractured neck of femur

49. Secondary gastrointestinal involvement
Retroperitoneal irritation
Blood
Urine
Enzymes (pancreatitis)
Tumour
Drugs
Tricyclic antidepressants
Phenothiazines
Laxatives
Secondary gastrointestinal involvement
Scleroderma
Chagas’ disease

50. Small intestinal pseudo-obstruction
This condition may be primary (i.e. idiopathic or associated
with familial visceral myopathy) or secondary. The clinical
picture consists of recurrent subacute obstruction. The diagnosis
is made by the exclusion of a mechanical cause. Treatment
consists of initial correction of any underlying disorder.
Metoclopramide and erythromycin may be of use.

51. Colonic pseudo-obstruction
This may occur in an acute or a chronic form. The former, also
known as Ogilvie’s syndrome, presents as acute large bowel
obstruction. Abdominal radiographs show evidence of colonic
obstruction, with marked caecal distension being a common
feature. Indeed, caecal perforation is a well-recognised complication.
The absence of a mechanical cause requires urgent
confirmation by colonoscopy or a single-contrast water-soluble
barium enema or CT. Once confirmed, pseudo-obstruction
requires treatment of any identifiable cause.

52. If this is ineffective,
intravenous neostigmine should be given (1 mg intravenously),
with a further 1 mg given intravenously within a few minutes
if the first dose is ineffective. During this procedure, it is best
to sit the patient on a commode. ECG monitoring is required
and atropine should be available. If neostigmine is not effective,
colonoscopic decompression should be performed.

53. Caecal perforation
can occur in pseudo-obstruction. Abdominal examination
should pay attention to tenderness and peritonism over the
caecum and as with mechanical obstruction, caecal perforation
is more likely if the caecal diameter is 14 cm or greater. Surgery
is associated with high morbidity and mortality and should be
reserved for those with impending perforation when other treatments
have failed or perforation has occurred.
Rarely, an endoscopically placed tube colostomy is used as a
vent for patients with those with a chronic unremitting condition.