Lower GI Flashcards
how does volvulus affect different age groups
Children: small bowel
Elderly: sigmoid colon
explain how diverticular disease occurs
high intraluminal pressure > herniation of bowel mucosa through weak points in the bowel wall
what can cause acute colitis
infection
drug/toxin
chemo/radiotherapy
What bacterium causes pseudomembranous colitis
C diff
explain the aetiology behind pseudomembranous colitis
C diff is commensal in the gut, kept under control by other bacteria
Course of ANTIBIOTICS kills off other bacteria
C diff is unopposed > produces toxin > colitis
What antibiotics trigger pseudomembranous colitis
3Cs
ciprofloxacin
clindamycin
cephalosporin
hgow do you detect C diff toxin
toxin stool assay
what are symptoms of pseudomembranous colitis
explosive watery diarrhoe
How do you treat pseudomembranous colitis
STOP causative antibiotic
Metronidazole / vancomycin > fidaxomicin > daecal transplant
What are causes of ischaemic collitis
occlusion (arterial/venous)
small vessel disease (DM, hypercholesteraemia, vasculitis)
low flow states (CCf, hhaemorrhage, shock)
Explain Chron’s disease effect on GI tract
- entire GI tract, mouth to anus
- mainly around large bowel, terminal ileum
- skip lesions
- transmural inflammation
- non-caseating granulomas
- THICK WALL, narrow lumen
- COBBLESTONE mucosa
Explain UC effect on GI tract
- ONLY affects rectum and colon (+ backwash ileitis)
- continuous lesions
- superficial ulcers, confined to mucosa
- bowel thickness in normal
- shallow ulcer
- regenerating mucosa forms pseudopolyps
what is a polyp
protrusion from bowel wall
what are three types of neoplastic polyps (i.e. can develiop into tumour)
Tubular adenoma
Vollpis adenoma
What is mode of inheritance of FAP
AD
Explain FAP
large numbers of adenomatous polyps by age of 25
will very likeluy develop cancer
what is the gene responsible for FAP
APC tumour suppressor gene on 5q21
How do you manage FAP
preventative panproctocolectomy
WHat is Gardner’s syndrome
Same as FAP, with extraintestinal manifestations (oseoma, epidermoid cyst, desmoid tumour, dental caries)
What is mode of inhritance of HNPCC
AD
explain HNPCC
No polyps
but very high risk of developing calcer regardless
what is the most common type of colorectal cancer
ADENOCARCINOMA
what staging is used for colorectal adenocarc
Dukes /TNM
what are symptoms of chron’s
intermittent diarrhoea, pain, fever
what are symptoms of UC
bloody diarrhoea with mucous
crampy abdo pain relieved by defecation
what other disease is UC associated wiht
PSC
what is carcinoid syndrome
tumour of enterochromaffin cell origin produced 5-HT (serotonin)
where is carcinoid syndrome tumours found
bowel
also lung, ovaries, testes
what are symptoms of carcinoid
bronchoconstriction
flushing
diarrhoea
what are symptoms of carcinoid crisis
life threatening vasodilation hypotension tachycardia bronchoconstriction hyperglucaemia
what IX for carcinoid
24h urine 5-HIAA
what MX for carcinoid
octreotide (somatostatin analogue)
WHo do hamartomatous polyps occur in
children under 5
what are sx of hamartomatous polyps
bleeding (in rectum)
what syndrome are hamartomatous polyps seen in
Peutz-Jeghers syndrome
Explain Peutz-Jeghers syndrome
multiple polyps
mucocutaneous hyperpigmentation
freckles around the mouth, palms, soles
increased risk of intusseption and malignancy
what antigen marker can be used to monitor colorectal cancer
CEA
what staging can you use for colon cancer
Dukes
