Inflammatory Bowel Disease

Inflammatory Bowel Disease

1. Crohn's Disease

   • Cause
     • Cause unknown. Assoc: NOD2/CARD15 mutations, high-sugar low-fibre diet, anerobes, mucins, altered cell-mediated immunity, smoking (x3 increased risk), NSAIDS
   • Prevalence
     • 50-100/100,000
   • Signs & Symptoms
     • Symptoms: Diarrhoea, abdo pain, weight loss. With active disease: fever malaise, anorexia. Signs: Aphthous ulcers, abdo tenderness, RIF mass, perianal abcesses/fistulae/skin tags, anal/rectal strictures. Extra-intestinal signs: Clubbing, erythema nodusum, pyoderma gangrenosum, conjunctivitis, episcleritis, iritis, large joint arthritis, sacroiliitis, ank spond, fatty liver, PSC, cholangiocarcinoma, renal stones, osteomalacia, malnutrition, amyloidosis
   • Complications
     • Small bowel obstruction, toxic megacolon, abscess formation, fistulae, perforation, rectal haemorrhage, colonic ca (<than in UC)
   • Investigations
     • Bloods: FBC, ESR, CRP, U&E, LFT, blood culture. If anaemia: serum iron, B12 & red cell folate. Markers of activity: low Hb & albumin, high ESR and CRP. Stool M,C&S: to exclude infectious diarrhoea, Sigmoidoscopy & rectal biopsy: If mucosa looks normal. Small bowel enema/Capsule endoscopy: detects ileal disease. Barium Enema: May show cobblestonning, rose-thorn ulcers, strictures. Colonoscopy: preferred to barium enema to assess disease extent. MRI: pelvic disease
   • Management
     • Mild attacks: Symtomatic but systemically well: Prednisalone 30mg/d for one week then 20mg/d for one month. See in clinic every 2-4 weeks. If symptoms resolve reduce pred by 5mg every 2-4 weeks. Stop pred when parameters normal.
     • Severe attacks:
       • Admit for IV steroids (hydrocortisone). Nil by mouth. IV hydration. Treat rectal disease with topical steroids. Add IV metronidazole if perianal dis/superadded infection (SEs: alc intolerance, irreversible neuropathy). Monitor temp, HR, BP & stool freq/character. Physical examination twice daily. Daily FBC, ESR, CRP, U&E & plain AXR. Consider blood transfusion (if HB<10g/dL) and parenteral nutrition. If improving after 5d transfer to oral pred (40mg/d). If no improvement/deterioration seek surgical advice
     • Perinanal dis: In 50%. MRI and examination under anaesthetic. Tx: Oral antibiotics, immunosuppressants +/- infliximab, local surgery +/- seton insertion.
     • Additional therapies
       • Azathioprine: useful steroid sparing agent. Takes 6-10 weeks to work. Sulfasalazine. Elemental diet: not effective alone in inducing remission. Methotrexate: to induce remission and completely withdraw steroids in pts with refractory dis. Surgery: 50-80% need 1+ op, Never curative, aims are to rest bowel ie with temporary iliostomy or limited resection of worst areas. Bypass/pouch surgery not done due to risk of recurrence. Infliximab: anti-tumour necrosis factor monoclonal antibody. Good to induce remission, may be effective as maintenance therapy.
   • Chronic transmural granulomatous inflammation. Affects any part of gut but favours terminal ileum/proximal colon. Skip lesions (unlike in UC).

2. Ulcerative Colitis

   • Cause
     • Unknown , genetic susceptibility. 3xmore common in non-smokers
   • Prevalence
     • 100-200/100,000
     • Presents 15-30yrs
   • Signs & Symptoms
     • Symptoms: Gradual onset diarrhoea +/- blood/mucus, crampy abdo pain, bowel frequency related to severity of disease. Urgency and tenesmus with rectal dis. Systemic symptoms common during attacks: fever, malaise, anorexia, weight loss. Signs: May be none. In acute severe UC: fever, tachycardia, tender & distended abdo. Extraintestinal signs: clubbing, aphthous ulcers, erythema nodosum, pyoderma gangrenosum, conjunctivitis, episcleritis, iritis, large joint arthritis, sacroiliitis, ank spond, fatty liver, PSC, cholangiocarcinoma, renal stones, osteomalacia, nutritional deficits, amyloidosis
   • Complications
     • Perforation, bleeding, toxic megacolon, venous thrombosis, colonic cancer (15% with pancolitis for 20yrs) surveillance colonoscopy may be used
   • Investigations
     • Bloods: FBC, ESR, CRP, U&E, LFT, blood cultures. Stool M,C&S: to exclude infections. AXR: no faecal shadows, mucosal thickening/islands, colonic dilatation. Erect CXR: Perforation. Sigmoidoscopy: Inflamed friable mucosa. Rectal biopsy: inflammatory infiltrate, goblet cell depletion, glandular distortion, mucosal ulcers, crypt abscesses. Barium enema: loss of haustra, granular mucosa, shortened colon. (never do during acute attack or as a diagnostic test). Colonoscopy: shows disease extent and allows biopsy
       • Indeterminate colitis: IBD that has been fully investigated but stlll not sure whether UC or Crohn’s.
     • Truelove & Witts criteria: Mild UC; <4motions/d, small rectal bleeding, apyrexial, HR<70, Hb>11g/dL, ESR<30mm/h. Moderate UC; 4-6motions/d, mod rectal bleeding, 37.1-37.8 deg, HR 70-90, Hb 10.5-11g/dL. Severe UC; >6motions/d, large rectal bleeding, >37.8 deg, HR>90, Hb<10.5g/dL, ESR >30mm/h.
   • Management
     • Inducing remission: Mild UC; prednisalone + mesalazine. If distal dis use steroid foams or prednisolone enemas. If symptoms improve reduce steroids gradually, if no improvement after 2 weeks treat as mod UC. Moderate UC; prednisolone + 5-aminosalycilic acid + twice daily steroid enema. If symptoms improve reduce steroids gradually, if no improvement after 2 weeks treat as sev UC. Severe UC; admit, nil by mouth, IV hydration, hydrocortisone. Monitor temp, HR, BP, stool freq/character. Twice daily exam documenting distension, bowel sounds, tenderness. Daily FBC, ESR, CRP, U&E, AXR. Consider blood transfusion (Hb <10g/dL) and parenteral nutrition if severe malnourishment. If improving by 5d transfer to oral steroid plus a 5-ASA ie sulfasalazine. If on day 3 CRP>45 or stool frequency >6 consider ciclosporin/infliximab/surgery.
       • Maintaining remission: All 5-ASAs reduce relapse from 80% to 20% at 1 year. Maintenance is continued for life. Sulfasalazine is 1st line but mesalazine and olsalazine as effective and fewer SE’s but more expensive. Azathioprine used as a steroid sparing agent in those with steroid SEs or who relapse quickly when steroids stopped.
       • Topical therapies: Proctitis may respond to prednisolone or mesalazine suppositories. Topical 5-ASAs work better than topical steroids. Procto-sigmoiditis may respond to foams. Retention enemas may be needed in left-sided colitis.
       • Surgery: ~20% will require surgery at some stage. Indications: perforation, massive haemorrhage, toxic dilatation, failure to respond to medical therapy.
     • Additional therapies
       • Novel therapies: Ciclosporin; short course to induce remission if steroid refractory (though nephrotoxic so monitor U&Es), tacrolimus; also in steroid refractory disease, infliximab; may work as a rescue therapy. Transdermal nicotine (though SEs common ie nausea, dizziness)
   • Relapsing and remitting mucosal inflammation. Usually not transmural but may have ulcers. May affect just the rectum (proctitis ~50%) or extend proximally (left sided colitis: ~30%, pancolitis: ~20%). Only in backwash ileitis does it spread proximal to ileocaecal valve