Paediatrics: Inflammatory bowel disease

Inflammatory bowel disease

Includes Crohn’s disease (CD) and ulcerative colitis (UC). UK incidence is 75.2/100,000/yr. CD is twice as common as UC. The cause is unknown, although there is a recognized genetic disposition.

Ulcerative colitis

•   Involves colon only.

•   Rectal (proctitis) is most common or may extend continuously up to involving the entire colon (pancolitis).

•   Terminal ileum may be affected by ‘backwash ileitis’.

Crohn’s disease

•   May affect any part of GI tract, but terminal ileum and proximal colon are commonest sites of involvement.

•   Unlike UC, bowel involvement is non-continuous (‘skip’ lesions).

Presentation

Symptoms

•   Anorexia, weight loss, lethargy.

•   Abdominal cramps.

•   Diarrhoea +/– blood/mucus, urgency and tenesmus (proctitis).

•   Fever.

GI signs

•   Aphthous oral ulcers.

•   Abdominal tenderness.

•   Abdominal distension (UC > CD), right iliac fossa (RIF) mass (CD).

•   Peri-anal disease (CD), i.e. abscess, sinus, fistula, skin tags, fissure, stricture.

Non-GI signs and associations

•   Fever.

•   Finger clubbing.

•   Anaemia.

•   Skin: erythema nodosum; pyoderma gangrenosum.

•   Joints: arthritis; ankylosing spondylitis.

•   Eyes: iritis; conjunctivitis; episcleritis.

•   Poor growth.

•   Delayed puberty.

•   Sclerosing cholangitis.

•   Renal stones.

•   Nutritional deficiencies, e.g. vitamin B_I2.

Complications

•   ‘Toxic’ colon dilatation (UC > CD).

•   GI perforation or strictures.

•   Pseudopolyps (apparent “polyps” resulting from inflammation).

•   Massive GI haemorrhage.

•   Colon carcinoma (UC: 50% risk after 10–20yrs disease).

•   Fistula involving bowel only or bowel and skin, vagina, or bladder (CD).

Abscesses (CD).

Investigations

• Blood: FBC; ESR/CRP (i); U&E; LFT; albumin (d); blood culture; serum iron (d); vitamin B₁₂ and folate (d).

• Serum serological markers: ASCA (anti-Saccharomyces cerevisiae antibodies, better for CD); p-ANCA (perinuclear antineutrophil cytoplasmic antibody, better for UC).

• Stool M,C&S: (infectious colitis can mimic CD/UC).

• Endoscopy: colonoscopy to determine extent and pattern of abnormal mucosa and intestinal biopsy (UC histology: crypt abscesses, mucosal inflammation only, goblet cell depletion; CD: crypt abscesses granulomas, transmural inflammation); upper GI endoscopy (CD).

• Radiology: barium radiology/ultrasound (CD: mucosal ‘cobblestone’ appearance, ulceration, dilatation, narrowed segments, fistula, ‘skip’ lesions; UC: mucosal ulceration, haustration loss, colonic narrowing +/– shortening).

Treatment

Supportive treatment 

If severe, e.g. bowel rest, IV hydration, PN. 

Drug treatment

• Mild to moderate disease: oral 5-aminosalicylic acid (ASA) dimers, e.g. mesalazine, may be useful to induce and maintain colonic disease remission in UC. ASA or corticosteroid enemas are effective for treating rectal disease. Dietary treatment may be useful to induce remission (see Dietary treatment).

• Moderate to severe disease: induce remission with oral prednisolone or IV methylprednisolone, 1–2mg/kg/day until condition improved (<2wks) then wean over 6–8wks.

• Antibiotics: e.g. ciprofloxacin or metronidazole, may also be useful.

• Maintenance treatment, or to treat resistant active disease: immunomodifiers, e.g. azathioprine, ciclosporin, tacrolimus, methotrexate, or infliximab (anti-TNF antibody).

Dietary treatment

Polymeric/elemental diets are useful to induce remission (CD>UC), but the relapse rate is high. Dietary supplementation often required to mini-mize poor growth and correct specific nutritional deficiencies, e.g. vitamin and mineral supplements. Involve a paediatric dietitian.

Surgery

• UC: total colectomy and ileostomy, and later pouch creation and anal anastomosis, cures UC. There is 10–20% complication rate, e.g. pouchitis.

• CD: local surgical resection for severe localized disease, e.g. strictures, fistula, may be indicated, but there is a high re-operation rate as inflammation recurrence is universal.

Prognosis

UC and CD are marked by relapse and remission. Patients can have very good quality of life with current therapy. Poor prognostic factors include extensive disease, frequent remissions, and young age at diagnosis