Severe colitis

Severe colitis - a patient who is septic due to colitis

• 'Toxic megacolon' is a complication of severe colitis - does not need to have a 'megacolon' to meet diagnostic criteria for severe or fulminant colitis
• 'Severe' or 'fulminant' colitis is probably clearer terminology than talking about 'megacolon', since the disease can be just as severe without dilation
• The underlying cause doesn't change the treatment much, once you get beyond medical management

Aetiology (any inflammatory condition of the colon)

• Commonly:
  • Ulcerative colitis flare
  • C diff-associated colitis
• Also:
  • Crohn disease flare
  • Infectious colitis
    • Salmonella
    • Shigella
    • Campylobacter
    • Yersinia
    • CMV
    • Entamoeba histolytica
    • Cryptosporidium
  • Ischaemic colitis
  • Chemotherapy
  • Colonoscopy
  • Barium enema
  • Drugs that slow colonic motility

Pathogenesis

Severe colitis

• • Toxic systemic response results from bacterial translocation - as the mucosa sloughs, the endotoxins within the bowel lumen are absorbed, leading to sepsis

Toxic megacolon

• • Complication/progression of fulminant colitis (not a precisely defined disease, but in general it means severe inflammation of colon with systemic toxicity)
  • Thought to be a result of severe colon inflammation associated with release of inflammatory mediators that induce colonic smooth muscle relaxation and inhibit colon motility (ileus/pseudo-obstruction). There may also be a direct impact on the myenteric plexus, but this is not conclusive yet.
  • Can extend transmurally
  • Dilation may be exacerbated by any other factor predisposing to pseudo-obstruction - electrolyte disturbances, opiates, anticholinergics/antimotility agents, antidepressants, barium enemas, colonoscopy

Presentation

• Be aware that patients may not appear unwell, because they are often young and fit
• Differentiate toxic megacolon from pseudo-obstruction by the presence of systemic toxicity

Diagnostic criteria

Acute severe colitis - use Truelove and Witts diagnostic criteria (from 1955, but still useful)

• • CRP >12 is said to be equivalent to ESR >30
  • 'Severe' requires >6 bowel actions and continuous bloody stool, along with either fever or tachycardia, and 4/6 in total
  • 'Mild' is only given when none of the criteria are met

Fulminant colitis

• • Bloody stools >=10/day, accompanied by abdominal pain and distension, in addition to meeting criteria for 'severe colitis'

Toxic megacolon

• • Fulminant colitis and radiographic distension of transverse colon >6cm or caecum >9cm
  • Alternative diagnostic criteria of Jalan (1969) for toxic megacolon:
    • Radiographic dilatation of colon to >6cm
    • Plus three or more of
      • Fever >38
      • HR> 120
      • WCC >10.5
      • Anaemia
    • Plus one of dehydration, mental changes, electrolyte disturbances, hypotension

Investigation

• AXR/CT
• Sigmoidoscopy should be limited to rectosigmoid to reduce risk of perforation
  • Looking for pseudomembranes - C diff

Management approach:

• Treat underlying cause
• Monitor for megacolon
• Review at day 3 to predict treatment failure
• Consider early salvage surgery or biologics

Management of severe colitis

Medical - successful in 60-70%. Expect significant response within 3 days.

• • Stool cultures and CDT
  • Treat underlying cause
    • For IBD, give 100mg QID IV hydrocortisone
  • Immediate aggressive supportive management
  • No evidence for NGT
  • Frequent patient repositioning and mobilisation might be helpful
  • Complete bowel rest
  • IVF and electrolyte replacement
  • Stop meds that affect bowel function
  • DVT prophylaxis
  • PPI
  • Broad spectrum ABX, adapted to underlying aetiology. Not necessary in inflammatory colitis in some cases, but worth giving for severe colitis.
  • Monitoring with serial AXR to look for toxic megacolon/perforation
  • Consider sigmoidoscopy with biopsies for CMV

Surgical

• • Timing is crucial - delay can lead to perforation or ACS
    • Don't be fooled by a benign abdo exam - by the time they develop peritoneal signs it is usually too late to avoid perforation
    • Severe/fulminant colitis operation can be done the next day, while if operating because toxic and unwell, should do it overnight
  • Absolute indications
    • Toxic megacolon with progressive dilatation (see separate section below)
    • Uncontrolled haemorrhage
    • Development of complications such as free perforation
    • General clinical deterioration
    • Lack of improvement in 48-72 hours
  • The surgery is subtotal colectomy with end ileostomy, or sometimes Hartmann procedure, depending on regions involved
    • Divide distal sigmoid - probably ok to leave a bit of length above the true peritoneal reflection, to both make it easier to reverse in future and allow the stump to be sutured up to anterior abdominal wall
    • Probably take greater omentum along with the transverse colon to make the dissection easier
    • No need to do an oncologic resection
    • Be very gentle with the colon to avoid perforation
    • Can sometimes be done laparoscopically apparently, but this is hard if the bowel is dilated, not recommended
    • Do not resect rectum, no matter how inflamed it looks - it usually responds to medical therapy after the colectomy
    • Commonly complicated by rectal stump blow-out, resulting in pelvic abscess. Traditionally, can be avoided by leaving a very long rectal stump and incorporating this into the fascial closure of the midline laparotomy wound, to cause a controlled mucous fistula rather than a deep pelvic infection. Modern teaching is that this is unnecessary, but the risk of blowout is real, so oversew the staple line with PDS and leave a rectal catheter in situ for several days. If the rectal stump is so friable that it cannot be stapled at all, bring it out to skin as a true mucus fistula.
    • Restoration of intestinal continuity can take place after 3 months and after the patient is back onto maintenance therapy and preferably off immunosuppressants. Do not do a primary anastomosis.
  • Post-op
    • ICU
    • Leave rectal tube to about day 5
    • Clear fluids as tolerated, light diet day 1
    • IV steroids until diet is re-established, if they are on it, then weaning dose orally
    • Many biologics can be stopped immediately post-op
    • Consider extended VTE prophylaxis for IBD

Management of toxic megacolon

• Initial supportive medical therapy as above, which can avoid an operation in 50% of patients
• Close multidisciplinary manage with experienced gastroenterologist
• Timing of surgery varies with underlying aetiology
• Absolute indications for surgery at any time:
  • Frank intra-peritoneal haemorrhage
  • Life-threatening bleeding or increasing transfusion requirements
  • Worsening systemic toxicity
  • Worsening colonic dilatation
• IBD
  • Hydrocortisone 100mg QID IV. If deterioration, re-image looking for complications.
    • After 48-72 hours, if no improvement, switch to infliximab or upadacitinib or cyclosporine (cyclocporine is only evidence-based in UC and should only be given to those who cannot have infliximab)
    • Surgeons usually recommend surgery if no improvement in colon after 24-48 hours
  • If no improvement after second-line therapy for 72 hours, recommend surgery
• C diff
  • See separate topic