Editing Crohn's disease (section)

== '''Complications''' ==

=== Localised peritonitis ===

* Presentation with local guarding, RIF pain and fevers suggests contained micro-perforation
* Once CT has excluded abscess, medical management should be undertaken with one month of antibiotics (initially IV)
* The role of steroids is controversial - those already on them can continue, but those not on them would probably have a higher rate of complication with steroids
* Non-responders or recurrent episodes warrant resection

=== Perforation and abscess ===

* Perforations can occur anywhere in GIT - secondary to either penetrating ulcer or upstream from a stricture
** Caecal perforation occurs in setting of LBO secondary to colonic stricture - needs subtotal colectomy with end ileostomy
** Focal perf secondary to segmental disease - needs either segmental resection and primary anastomosis or Hartmann's. Can be associated with a fibrosing stricture, which may need resection.
* Free perforation and generalised peritonitis
** Uncommon (more common to have a fistula to another viscera, or contained abscess)
** Resect the segment of involved bowel, with a primary anastomosis if there is minimal contamination, and an ostomy if generalised peritonitis is present or the patient has compromised immune system or nutrition (reverse in 4-6 weeks)
* Abscesses are especially common in caecum/ileum secondary to micro-perforation - can be intraperitoneal, extraperitoneal, or intra-mesenteric
** Initial management
*** Antibiotics - ciprofloxacin and metronidazole first-line
*** Percutaneous drainage if possible (step up to surgical drainage if not)
**** Well-defined abscesses <3cm may be treated medically
*** Stop/reduce steroids and immunomodulators (involve gastro)
*** Optimise nutrition for planned resection - TPN vs EEN
*** Wait 3-5 days for improvement
**** >90% of cases improve with drainage, others require elective bowel resection (better outcome if you can get them through to elective procedure in a clean field)
** Subsequent management:
*** Either semi-elective resection of the involved segment in 5-7 days (classical approach) or medical treatment with immunomodulators
**

=== Obstruction ===

* Much more common in CD than UC - intermittently - can be inflammatory/fibrotic stricture, but can also be adhesive due to previous surgery
* Aetiology
** Secondary to an acute exacerbation of active disease
*** Typically improve with medical management (IV corticosteroids)
** Secondary to chronic fibrosing lesions (most patients with complete SBO fall into this group)
*** Most commonly TI
*** Trial non-op - often partial obstruction
**** No benefit to steroids - often require surgery - complete obstruction often requires resection
**** If doubt over presence of acute inflammation, can do faecal calprotectin
*** Look to intervene if no improvement in 48 hours, according to Schein
**** Operation of choice is segmental resection and primary anastomosis
**** Consider stricturoplasty - when bowel resection is inappropriate due to risk of short bowel syndrome in patients with extensive fibro-stenotic disease, or in patients with multiple short-segment strictures over a longer area of bowel, several previous bowel resections, and in those with chronic fibrous obstruction. Complication and recurrence rates are comparable to resection with anastomosis in this setting.
****
**** Endoscopic dilation - initial success rate 90% for fibrotic strictures however 75% of patients require further dilation
**** Needle-knife stricturotomy can also be used - not widely-accepted yet
**** Large bowel strictures, particularly UC, raise concern for malignancy. Do a full oncologic resection if operating in this setting. Stricturoplasties are not recommended in colon.

=== Bleeding ===

* Large-volume bleeding is rare to be truly caused by IBD - consider alternatives such as PUD
* Can get erosion into a vessel from a CD ulcer, particularly duodenal CD
* If small bowel, may need resection with primary anastomosis
* Duodenal bleeding can usually be treated endoscopically, with duodenotomy and oversewing of the bleeding area as a backup
* Initial management
** Resus
** ?saline-adrenaline enemas
** NGT with gastric lavage (?UGIB) -> gastroscopy +/- colonoscopy
** Consider CT angio
** Surgery if continued haemorrhage despite 6+ units pRBC, or other indications

=== Toxic megacolon ===

* Occurs in Crohn colitis and UC
* Marked colonic dilation, abdominal tenderness, fever and leucocytosis
* See separate topic

=== Bowel cancer ===

* Carcinomas typically arise at sites of chronic inflammation, especially TI
* Epidemiology
** OR 100 for small bowel cancer compared to normal population, but absolute risk still low
** 2.2% risk at 25 years since diagnosis
* Pathophysiology
** Follows standard dysplasia sequence
** Risk related to extent of small bowel involvement and duration of disease
** Small bowel adenocarcinoma associated with CD behaves aggressively - strong probability of extracellular mucin
** Mucinous-appearing anal fistulas and ileal areas of adhesion/retraction should always be closely examined by a pathologist to evaluate for dysplasia or malignancy
* Presentation
** Suspect in patients who develop a change in their clinical status, such as an obstruction that fails to resolve with usual treatments
** Diagnosis rarely made pre-operatively
* Poor prognosis due to frequent late detection

=== Ureteral obstruction ===

* Occurs secondary to ileocolic disease with retroperitoneal inflammatory compression
* Aim to treat the primary ileocolic disease surgically, which is usually adequate
* Less likely to work with longstanding disease - may require ureterolysis +/- stenting