What are the features of Giardia infection?
- Waterborne protozoal infection
- Associated with immunodeficiency
- Treated with metronidazole
What are the features of C. difficile?
- Often prior to treatement with antibiotics (e.g. Clindamycin)
- Causes elimination of gut commensals and overgrowth of toxin producing C. difficile
- Diagnosed by finding toxin in the stool
- Treated with vancomycin
What causes Whipple's disease and how is it diagnosed?
- Infection by Tropheryma
- Diagnosed on biopsy of duodenum - PAS positive macrophages
What are the features of Entamoeba Histolytica Infection?
- Intestinal amebiasis may involve any part of the bowel
- Small foci of necrosis that progress to ulcers
- Flask-shaped ulcer with narrow neck and broad base
- May metastasize to the liver
What does M. Tb do to the GIT?
- Granulomatous inflammation with confluent granulomas, usually with caseous necrosis
- Loss of crypts
- Fibrin and acute inflammatory cells present
- Endoscopic findings include strictures, ulcers and mucosal hypertrophy
What is tropical sprue a histological mimic of and how is it treated?
- Coeliac disease
- Treat with tetracycline
What are the features of Coeliac disease?
- Diagnosed on duodenal biopsy whilst on gluten-containing diet
- Histology supports other features (coeliac-assocated antibodies, HLA-DQ2 and/or DQ8, response to gluten exclusion)
What are the histopathological features of coeliac disease?
- Villous atrophy
- Crypt hyperplasia
- Increased number of intraepithelial lymphocytes
- Increased numbers of plasma cells in lamina propria
What are the features of ulcerative colitis?
- Peak age of onset 15-25
- Gradual onset of chronic bloody diarrhoea >4 motions per day
- Rectum always involved
- Inflammation confined to mucosa and submucosa of large intestine
- Crypt architectural distortion (irregular)
- Crypt abscess (≥4 neutrophils in a crypt)
- Complications include acute toxic dilatation, perforation and increased risk of carcinoma of the colon
What are the features of Crohn's disease?
- Commonly presents 15-35 years
- Commoner in smokers
- Can affect any part of gut from mouth to anus
- Commonly affects terminal ileum
- Inflammation commonly transmural
- Granulomas are diagnostic
- Mutations in NOD-2 are associated
- Fistulae between the intestine and other intestinal loops, skin, bladder, vagina
What are the features of diverticular disease of the colon?
- Principally affects sigmoid colon
- Low roughage diet causes constipation and high sigmoid luminal pressure – herniation of mucosa through weaknesses in muscle coat of sigmoid
- Presents with left iliac fossa pain
- May perforate, fistulae into bladder or bowel, bleed, or obstruct bowel
What are the causes of ischaemia of the gut?
- Mesenteric artery or vein thrombosis
- Mesenteric artery embolus
- Hypotension (watershed infarction)
- Strangulated hernia
How is gut ischaemia diagnosed?
- Endoscopy will show petechial haemorrhages, oedematous and fragile mucosa, segmental erythema, scattered erosion, longitudinal ulcerations, sharply defined segment of involvement