Gastroenterology Flashcards
Coeliac disease
Complex immune-mediated disorder triggered by gluten ingestion in genetically predisposed individuals (carrying HLA-DQ2 or HLA-DQ8)
Coeliac disease aetiology
Genetic predisposition – HLA-DQ2 & HLA-DQ8
Gluten exposure – gliadin is particularly implicated
Environmental factors – early-life gluten exposure, infections, changes in gut microbiota & other lifestyle factors
Coeliac disease gastrointestinal symptoms
Diarrhoea – loose, watery or bulky stools
Abdominal pain and bloating
Steatorrhoea – fatty, foul-smelling stools can occur due to impaired fat absorption
N&V – particularly in severe disease
Coeliac disease extraintestinal manifestations
Dermatitis herpetiformis – intensely pruritic, vesicular rash, typically affecting the elbows, knees and buttocks
Fatigue – malabsorption of essential nutrients or anaemia
Iron deficiency anaemia
Weight loss – may occur as a result of malabsorption
Bone pain and fractures – malabsorption of calcium and vitamin D
Peripheral neuropathy – numbing, tingling or burning sensations in the extremities
Coeliac disease investigations
Anti-tTG – most widely used initial screening test for coeliac disease (false negative may occur in patients with selective IgA deficiency)
Anti-endomysial antibodies – may be used when confirmation of the diagnosis is needed
Total serum IgA levels – important to exclude selective IgA deficiency
Duodenal biopsy (gold standard) – villous atrophy, crypt hyperplasia, increased intraepithelial lymphocytes
Coeliac disease management
Gluten free diet
Tissue transglutaminase antibodies may be checked to check compliance with a GF diet
Vitamin supplements
May often have a degree of functional hyposplenism – offered the pneumococcal vaccine
Coeliac disease GI complications
Malabsorption – iron deficiency anaemia, folic acid deficiency, vitamin B12 deficiency, fat-soluble vitamin deficiencies (ADEK) & weight loss
Lactose intolerance – loss of lactase-producing enterocytes
Refractory coeliac disease – persistent symptoms despite strict GF diet
Coeliac disease other complications
Malignancies – enteropathy-associated T-cell lymphomas, small bowel adenocarcinoma
Bone – osteoporosis, osteopenia
Dermatological – dermatitis herpetiformis
Neurological – peripheral neuropathy, gluten ataxia
Reproductive – infertility & adverse pregnancy outcomes (recurrent miscarriages, low birth weight)
Autoimmune conditions – T1DM, autoimmune thyroiditis, Sjogren’s syndrome, autoimmune liver diseases
Crohn’s disease
Chronic inflammatory bowel disease characterised by transmural inflammation that can affect any part of the GI tract from mouth to anus
Crohn’s disease GI clinical features
Abdominal pain – may be localised or diffuse, inflammation involving terminal ileum can cause RIF pain
Diarrhoea – non-bloody diarrhoea, often with increased frequency and urgency (bloody = more severe inflammation or the presence of ulcerations)
Weight loss – nutritional deficiencies, malabsorption, anorexia
Perianal disease – anal fissures, perianal abscesses & fistulas
Oral manifestations – aphthous ulcers can occur on the buccal mucosa, tongue or lips
Obstructive symptoms – strictures, adhesions & bowel obstruction may present as N&V, abdominal distension and constipation
Crohn’s disease extraintestinal manifestations
Arthritis – typically affects large joints (knees, ankles and wrists), axial arthritis
Skin – erythema nodosum presents as painful, raised erythematous nodules on the lower extremities, pyoderma gangrenosum is characterised by rapidly progressing, painful ulcers
Ocular – uveitis, episcleritis
Hepatobiliary – PSC is characterised by inflammation and fibrosis of the bile ducts, cholelithiasis and fatty liver disease
Haematological – anaemia, increased risk of VTE
Crohn’s disease investigations
Blood tests – FBC, CRP, ESR, LFTs, serum albumin, iron studies, vitamin B12 and folate levels, serological markers (ASCA and pANCA) may aid in differentiating CD from UC
Stool tests – cultures, ova and parasite examination & faecal calprotectin (marker of intestinal inflammation) can help differentiate between IBD and other causes
Colonoscopy
CT & MRI
Crohn’s disease histopathological examination
Non-caseating granulomas
Transmural inflammation
Lymphoid aggregates
Crypt architectural abnormalities
Cryptitis/crypt abscesses
Crohn’s disease management
Smoking cessation
Inducing remission – glucocorticoids (oral, topical or IV) generally used, mesalazine is used as second-line; azathioprine may be used as add-on to induce remission, metronidazole for isolated peri-anal disease
Maintaining remission – stop smoking, azathioprine is used first-line, methotrexate is second-line
Surgery for complications
Crohn’s disease GI complications
Strictures – chronic inflammation and fibrosis may lead to narrowing of bowel lumen
Fistulas – abnormal connections between different bowel segments/bowel and other organs
Abscesses
Perianal disease
Malabsorption & nutritional deficiencies
Colorectal cancer – regular surveillance colonoscopy with biopsies is recommended
