IBS, Crohn's disease and ulcerative colitis — everything you need to know, simply explained
A long-form, plain-language overview of the three most commonly confused gastrointestinal conditions — irritable bowel syndrome, Crohn's disease, and ulcerative colitis. Symptoms, causes, diagnosis, treatment, and lifestyle in one place, accessible to both patients and clinicians.
Topics covered
"IBS, Crohn's, and ulcerative colitis live in the same anatomical neighbourhood but follow three different rules. The patient who understands the rules manages the disease far better than the patient who only follows the prescription."
Show notes
This long-form episode is the SGA's comprehensive plain-language overview of three conditions that account for a huge fraction of GI clinic visits — irritable bowel syndrome (IBS), Crohn's disease, and ulcerative colitis. It is designed to be watchable straight through by patients newly diagnosed with any of the three, and to serve as a teaching reference for medical students and primary-care colleagues.
The opening 25 minutes are on IBS: definition, the four sub-types by stool pattern (IBS-D, IBS-C, IBS-M, IBS-U), the gut-brain axis and visceral hypersensitivity model, the role of stress and diet, and the staged management approach — patient education and reassurance, dietary modification including low-FODMAP, fibre adjustment, antispasmodics, neuromodulators, gut-directed psychological therapies. The segment closes on the red-flag features that must trigger a structured workup rather than a functional label.
The middle 45 minutes cover Crohn's disease and ulcerative colitis in parallel — comparing them at every level. Anatomy and depth of inflammation (UC mucosal/continuous from rectum; Crohn's transmural/segmental mouth-to-anus). Symptoms (UC: bloody diarrhoea, urgency, tenesmus; Crohn's: pain, weight loss, fistulae, perianal disease). Diagnostic workup (calprotectin, CRP, endoscopy, histology, MR enterography). Complications (toxic megacolon and colorectal cancer in UC; strictures, fistulae, abscesses in Crohn's). Extra-intestinal manifestations (joints, eyes, skin, primary sclerosing cholangitis).
The treatment section walks through the full ladder — 5-ASAs, corticosteroids (for induction only), immunomodulators (azathioprine, methotrexate), anti-TNF biologics (infliximab, adalimumab), anti-integrin (vedolizumab), anti-IL-12/23 (ustekinumab), JAK inhibitors, S1P modulators, and the role of surgery in both conditions. Treat-to-target principles, monitoring, and when to step up therapy are framed as clinical decisions the patient and clinician make together.
The closing 30 minutes are practical and life-centred: diet patterns with evidence (Mediterranean, CDED, EEN), sleep and exercise as disease-modifiers, smoking cessation as a high-yield Crohn's intervention, vaccinations on immunosuppression, pregnancy and fertility planning, the importance of medication adherence, and how to build a supportive long-term relationship with an IBD service. The episode closes with a frequently-asked-questions segment addressed directly to patients.