Lower GI Tract-Non-Neoplastic Flashcards
Aetiology of peptic ulcers
ACID
H. PYLORI
Genetics
Triggers: certain foods, alcohol, smoking, stress
Rarer: NSAIDS, Crohn’s, steroids, Zollinger Ellison syndrome (carcinoid tumour producing gastrin)
Complications of peptic ulcer disease
Blood loss (vomiting, meleana, anaemia)
Gastric outlet obstruction
Perforation/infection
Malignancy: rare in duodenum, SEEN IN STOMACH
Define coeliac disease
Immunologically mediated chronic inflammatory disease
Intolerance to gliadin part of gluten (storage protein of cereal etc)
Key histology features of coeliac disease
Increased intraepithelial lymphocytes
VILLOUS ATROPHY
Plasmacytosis in lamina propria
Genetics of coeliac?
Specific HLA haplotypes and gerographical clustering
Diagnosis of coeliac disease? (serology, biopsy, clinical)
Serology: Anti TTG, Anti EMA
Biopsy: OGD, villous atrophy
CLinical: GLuten withdrawl: improvement in symptoms
Associations with coeliac disease
Autoimmune diseases with same HLA haplotypes: DM type 1 and hypothyroidism
Dermatitis herpetiformis
WHich cancer is linked to coeliac disease?
Small bowel lymphoma: Enteropathy associated T cell NHL
Poor prognosis
Also increased risks of other GI cancers
Investigations for viral gastroenteritis
Stool culture/PCR
SEE SCBP MICROBIOLOGY FOR DISEASE DETAILS
How does mycobacteria affect the bowel?
TB of the bowel, or atypical infections in small bowel in AIDS patients
Describe Whipple’s disease
Tropheryma whippella (PAS +ve)
found in duodenal biopsy alongside symptoms of malabsorption, joint pain, neurological symptoms
Types of viral gastroenteritis
SRSVS eg Norwalk
Rotaviruses in children
Adenovirus (linked with lymphoid hyperplasia and intusssusception)
Enterovirus: polio, Cox A and B
HIB: cryptosporidiosis, girdia lamblia, CMV, atypical mycobacteria
Examples of protozal GI infections?
Giardia (dirty water)
Cryptosporidia (immunosuppressed pts)
Amoebae colitis (followng trip abroad, may cause life threatening HAEMORRHAGIC ENTEROCOLITIS)
Biopsy diagnosis: Schistosome in a granuloma in a colonic biopsy
Schistosomiasis
Epidemiology of IBD
Adolescents
Second peak in older adults
F>M
Developed world>undeveloped
Aetiology of IBD
Idiopathic: no specific cause identified
Polymorphisms in NOD1 gene linked ot which IBD?
Crohn’s
Granulomas present in which IBD?
Crohn’s
Also has fissure ulceration
Fat wrapping in which IBD?
Crohn’s
Fat around bowel seems to be drawn in
Complications of Crohn’s?
Fistualae
Sinuses
Strictures
Risk of lymphomas with immunosuppression and SCC
Key complications of ulcerative colitis?
Toxic megacolon
Increased risk of colorectal cancer
What causes small bowel ileus?
Atonic small bowel associated with fluid imbalance
Describe Meckel’s diverticulum (2 rule)
2% of population
2 inches long 2 feet proximal to ileocaecal valve
Pathogenesis of appendicitis
Faecolith, foreign body, lymphoid hyperplasia, endometriosis, tumour
Venous outflow compromised, mucosal ulceration, secondary infection and transmural inflammation
Cancers related to appendicitis
Low grade appendiceal mucinous neoplasm (LAMN)
Carcinoid tumours
Where does diverticular disease occur?
These are commonest in the sigmoid colon, but can occur in other parts of the colon, and they occur
between the taenia coli, and are associated with a thickened circular layer of muscularis propria in
between the diverticul
Blood supply to GIT?
Coeliac, superior and inferior mesenteric
SM and IM arteries form arcades
Watershed zones are susceptbile to ischaemia (splenic flexure, junction between SM and IM arteries)
Variations in severity of small bowel ischaemia
Acute arterial insufficiency or venous obstruction: mucosal ulceration
More severe/longstanding lack of supply: typically thin walled, dusky loops of small bowel
Repeated episodes of damage: Iscahemic colitis with strictures
