Inflammatory bowel disease: SAQ

This boy presents the classic insidious picture of paediatric Crohn disease: months of fatigue and diarrhoea without overt bleeding, growth faltering with a fall in height centile and delayed puberty, iron deficiency anaemia, raised inflammatory markers with hypoalbuminaemia, and perianal skin tags as the easily missed diagnostic clue. The right lower quadrant tenderness and raised faecal calprotectin point to terminal ileal and colonic inflammation. [1]

Question 1 (10 marks)

Outline the diagnostic workup you would arrange for this child, including the endoscopic procedures and the supporting investigations. [1]

The diagnosis follows the ESPGHAN revised Porto criteria. Ileocolonoscopy with biopsies taken from every segment, including the terminal ileum, is the minimum diagnostic procedure, and upper gastrointestinal endoscopy is also performed at diagnosis in all suspected paediatric IBD, because isolated upper-gut Crohn disease is common in children and is missed by colonoscopy alone. Upper endoscopy may be omitted only when both endoscopy and histology of the ileum and colon are completely normal, which is not the case here. [1]

Supporting blood and stool tests complement rather than replace endoscopy. A full blood count confirms the iron deficiency anaemia, C-reactive protein and erythrocyte sedimentation rate confirm ongoing inflammation, and albumin reflects the nutritional deficit. Coeliac serology with total immunoglobulin A excludes a common mimic, and stool studies exclude infection. Faecal calprotectin, already markedly raised, confirms intestinal inflammation and supports the threshold for endoscopy. Thiopurine methyltransferase activity or genotyping should be checked early if azathioprine maintenance is contemplated. [1]

Cross-sectional imaging complements endoscopy. Magnetic resonance enterography is the preferred modality for assessing small-bowel Crohn disease, strictures, fistulae, and abscesses, and avoids the radiation burden of computed tomography. Pelvic magnetic resonance imaging is indicated for the perianal disease to delineate any fistula or abscess before treatment. Together these define the disease location, behaviour, and extent that drive the induction and maintenance plan. [1]

Question 2 (10 marks)

Describe your management plan for this child, including induction and maintenance of remission and how you would protect his growth. [2]

Induction of remission in paediatric Crohn disease favours exclusive enteral nutrition as first-line in many centres. A nutritionally complete liquid formula is given as the sole nutrition for six to eight weeks, inducing remission in a high proportion of children while simultaneously correcting the malnutrition and hypoalbuminaemia and avoiding the growth-suppressing effects of corticosteroids. This is particularly appropriate in this boy, whose growth faltering and delayed puberty make a growth-sparing induction strategy preferable. Corticosteroids are an effective alternative where exclusive enteral nutrition fails or is refused but are never used for maintenance. [2]

Maintenance therapy relies on an immunomodulator, most often azathioprine at a typical dose of 2 to 3 mg per kg per day, guided by thiopurine methyltransferase status, for steroid-dependent or relapsing disease. A multicentre trial showed that adding 6-mercaptopurine to corticosteroids in newly diagnosed Crohn disease improved the maintenance of remission. Anti-TNF biologic therapy with infliximab or adalimumab is reserved for moderate to severe disease refractory to or dependent on corticosteroids and immunomodulators, and is used earlier to achieve mucosal healing and protect growth. The goal throughout is steroid-free remission with normal growth and mucosal healing. [3]

Growth is protected by early and effective control of the inflammation, correction of nutritional deficits with iron and dietitian support, avoidance of prolonged corticosteroid exposure, and regular monitoring of height velocity and pubertal staging. Surgery, such as bowel-sparing resection for stricturing or penetrating disease, is a defined part of the pathway rather than a failure of medical therapy, and growth typically improves markedly afterwards. The plan is delivered by a multidisciplinary team with structured transition planning as he approaches adult care. [2]