Other
disorders
Traumatic
rupture
The intestine can be ruptured with or without an external wound —
so-called blunt trauma (Fig. 57.49). The most common cause of this is a blow
on the abdomen which crushes the bowel against the vertebral column or sacrum;
also a rupture is more likely to occur where part of the gut has been fixed, for
example, in a hernia, or where a fixed part of the gut joins a mobile one such
as the duodenojejunal flexure. Here the damage may be retroperitoneal and easily
overlooked.In small perforations the
mucosa may prolapse through the hole and partly seal it, making the early signs
misleading. In addition there may be a laceration in the mesentery. The patient
will then have a combination of intra-abdominal bleeding and release of
intestinal contents into the abdominal cavity, giving rise to peritonitis.
Traumatic
rupture of the large intestine is much less common. In blast injuries of the
abdomen following the detonation of a bomb, the pelvic colon is particularly at
risk of rupture. Compressed air rupture can follow the dangerous practical joke
where an air-line carrying compressed air is turned on near the victim’s anus.
Rupture of the upper rectum
can occur during sigmoidoscopy and occasionally during the placement of rectal
catheters for barium radiology. Traumatic rupture of the colon can occur during
colonoscopy. The most common site is the sigmoid colon where the formation of a
sigmoid loop pushes against the antimesenteric border of the sigmoid colon,
stretching it out and eventually perforating it.
Gun
shot wounds and impalement injuries to the bowel have mote serious consequences
because of the introduction of debris from the patient’s clothing or the
missile itself mixing with the bacteria in the patient’s gut. High-velocity
missiles may cause extensive damage of the bowel over a much wider area than
just the entry and exit wounds.
Treatment
Where rupture is suspected a plain radiograph in the erect or lateral
decubitus position will demonstrate the presence of free air in the peritoneal
cavity or indeed in the retroperitoneal tissues. In almost all cases an
abdominal exploration must be performed and, in many instances, simple closure
of the perforation is all that is required. In others, for example, where the
mesentery is lacerated and the bowel is not viable, resection may be necessary.
In the case of the large intestine small clean tears can be closed primarily, if
there is a large tear with damage to the surrounding structures to the adjacent
mesentery resection, exteriorisation may be used. Much depends on the amount of
intra-abdominal soiling.
In
the case of retroperitoneal portions of the intestine, for example, the
duodenum, perforations can involve the front and back walls and the duodenum in
particular has to be carefully mobilised to check that a concealed tear is not
overlooked. In all cases the abdomen is washed out with saline and
broad-spectrum intravenous antibiotics are given.
Pneumatosis
cystoides intestinalis
This is a rate condition in which gas-filled cysts ate found in the subserosa
or submucosa of the small intestine or colon. They ate usually translucent,
thin-walled, range in size between 1 and 2 cm and contain gas, mainly nitrogen,
but also an increased content of hydrogen, and have a lining of flattened cells.
The cause is not known; there is an association with chronic obstructive
pulmonary disease but an increased local production of intestinal gas is a mote
probable cause. It has been seen in patients with necrotising enteritis,
entetocolitis and diverticulitis. The cysts ate usually symptomless but
occasionally can give rise to intestinal obstruction and rectal bleeding,
diarrhoea or mucus in the stool. The cysts may be recognised at sigmoidoscopy or
seen on plain abdominal films, barium studies (Fig.
57.50) and even CT scans.
Management of the uncomplicated primary disease is conservative. When symptoms
demand treatment the first line is intermittent high-flow oxygen therapy
providing a concentration of 70 per cent continuously for 5 days by nasal
specula. The cysts may also resolve with antibiotic treatment, particularly
metronidazole. In resistant cases maintenance treatment with sulphasalazine may
be helpful.
Enterocutaneous
or faecal fistula
An external fistula communicating with the caecum sometimes follows an
operation for gangrenous appendicitis or the draining of an appendix abscess. A
faecal fistula can occur from necrosis of a gangrenous patch of intestine after
the relief of a strangulated hernia, or from a leak from an intestinal
anastomosis. The opening of an abscess connected with chronic diverticulitis or
carcinoma of the colon frequently results in faecal fistula. Radiation damage is
also another cause of fistula formation. The most common cause of
enterocutaneous fistula is, however, previous surgery. This happens most often
in patients with adhesions following previous operations. Damage to the small
intestine occurs inadvertently during dissection of the adhesions and, because
of an associated subacute obstruction or abscess, the fistula ‘blows’
postoperatively. Enterocutaneous flstulae can be divided into:
• those with a high output, more than 1 litre/day;
• those with a low output, less than 1 litre/day.
They
can also be described anatomically as simple, with a direct communication
between the gut and the skin, or complex, that is, those with one or more tracts
that are tortuous and sometimes associated with an intervening abscess cavity
half-way along the tract.
The
discharge from a fistula connected with the duodenum or jejunum is bile stained
and causes severe excoriation of the skin. When the ileum or caecum is involved
the discharge is fluid faecal matter; when the distal colon is the affected site
it is solid or semisolid faecal matter. The site of leakage and the length of
the fistula can be determined by small bowel enema and barium enema, by
fistulography and most importantly CT of the abdomen will show up any associated abscesses (Fig.
57.51).
Treatment
This can be very challenging in patients with a high-output fistula.
Low-output fistulae can be expected to heal spontaneously, provided there is
no obstruction beyond the fistula opening. Reasons for failure of spontaneous
healing also include:
• epithelial continuity between the gut and the skin;
• the presence of active disease where, for example, there is
Crohn’s disease or carcinoma at the site of the anastomosis or in the tract;
• an associated complex abscess.
The
abdominal wall must be protected from erosion by the use of appliances. The
patient must remain nil by mouth, intravenous nutrition is started and signs of
a decrease in the fistula output are sought. The higher the fistula in the
intestinal tract the more skin excoriation must be expected, and this is worst
in the case of a duodenal fistula. High-output fistulae cause rapid dehydration
and hypoproteinaemia. Vigorous fluid replacement and nutritional support are
essential. The drainage of an intra-abdominal abscess can be life saving. This
can be achieved by either CT-guided drainage or occasionally laparotomy. In
patients with a complex fistula it may be necessary to bring out a defunctioning
stoma upstream of the fistula site, even if this results in a high-output stoma.
Treatment
with a somatostatin analogue (octreotide) may be useful in these cases to
reduce fistula output and stoma output.
Operative
treatment
Operative repair should only be attempted after a trial of conservative
management. The surgery can on occasion be technically extremely demanding and
anastomosis should not be fashioned in the presence of continuing intra
abdominal sepsis or when the patient is hypoproteinaemic.