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.