Histopath lower GI Flashcards
Hirschsprung’s disease - what is it? Dx?
What is seen on barium enema
- Absence of GANGLION CELLS in myenteric plexus
- Dx with biopsy
- Barium enema shows constricted segment
Which part of the colon is GIT is affected by volvulus in infants vs elderly?
Infants - small bowel
Elderly - sigmoid
4 Causes of acute colitis?
Drugs - esp abx
Infection
Chemo/radio therapy
Causes of ischemic colitis
- Small vessel disease (DM, vasculitis)
- Low flow (shock, haemorrhage)
- Arterial/venous OCCLUSION
- Obstruction
Common affected areas of GIT in ischemic colitis
“watershed areas”
i.e, splenic flexure, rectosigmoid
Causes of lower GI obstruction
- Adhesions
- Volvulus
- External mass
- Herniation
Diff btw Crohns’ and UC for epidemiology?
Crohn’s usually teens
UC is 20-25yo
Aetiology of IBD
unknown
?Infection ?host immunity issue
Diff btw CD and UC pathophysiology?
CD - transmural, skip lesions, mouth to anus, non-caveating granulomas
UC - proximally from anus, mucosa affected,
Histology of Crohns’
- Non-caseating granulomas
- Linear ulcers
- cobblestone appearance
Sx of IBD
IDA - fatigue Blood in stool Diarrhoea Mucus Pain Fever
Extra GI manifestations of IBD
- Skin: pyoderma gangrenous, erythema nodosum, clubbing
- Eyes: uveitis, conjunctivitis
- Joints
- Liver - PSC (UC)
Major complication of UC
Toxic megacolon - Damage to muscular propia with disruption to neuromuscular function –> chronic dilatation
Which IBD condition is associated with greatly increase risk of adenocarcinoma?
UC
Diverticulitis - how can it complicate?
Fistula
Gross perforation
Obstruction due to fibrosis
Pathophysiology of diverticular disease
Low fibre diet –> High intraluminal pressure –> outpouchings of weak areas of bowel
Commonest non-neoplastic polyp?
Hyperplastic polyp
Which kind of polyp do we worry about and why
Adenoma - risk of developing adenocarcinoma
What is an adenoma?
Excess epithelial proliferation + dysplasia
Classification of adenomas?
Tubular
Villous
or tubulovillous
Risk factors for adenomas to develop into adenocarcinomas?
Size of polyp
Degree of differentiation
High proportion of villous change
CRC - age affected? what type is 98% of them?
60-79 years
(if <50yo, consider familial cause)
Adenocarcinomas
Causes of CRC
Smoking, alcohol, obesity, low fibre diet, familial syndromes
IBD
Dukes staging of CRC
A: mucosa B1: muscularis propria B2: transmural invasion (no LNs) C1: muscularis + LNs C2: transmural invasion + LNs D: distant mets
Mutation in APC gene
Familial adenomatous polyposis
HNPCC - what is it?
AD mutation in DNA repair genes
present with adenocarcinoma at <50yrs
