Histopath - Lower GI Flashcards
What is Hirschprung’s disease caused by?
Absence of ganglion cells of the myenteric plexus
- distal colon fails to dilate
What presentation is Hirschsprung disease associated with?
Failure to pass meconium within 48h
Which genetic syndrome is Hirschsprung associated with?
Down’s syndrome (2%)
Two types of acute cholitis
Pseudomembranous colitis and ischaemic colitis
*What cause is pseudomembranous colitis associated with?
Clostridium difficile
caused by 3C antibx: Cephalosporins, ciprofloxacin & clindamycin
*Histology for pseudomembranous colitis
Pseudomembrane (membrane like material) formation
Ix for diagnosing pseudomembranous colitis
Toxin stool assay (for exotoxins)
Mx for pseudomembranous colitis
Side room, metronidazole
*What is ischaemic colitis?
Bowel is hypoperfused
oedematous thickening bowel wall, areas necrotic ulceration confined to mucosal layers
Where does ischaemic colitis usually occur?
Watershed zones -
splenic flexure and rectosigmoid
*Causes of ischaemic colitis
Occlusive
- Arterial/venous occlusion
- Small vessel disease: DM, vasculitides
- Obstruction: hernia, volvulus
Hypoperfusion
- CHF
- Haemorrhage
- Shock
Two types of Inflammatory bowel diseases
Crohn’s disease and ulcerative colitis
What part of GI tract is affected in Crohn’s?
Entire GI tract: mouth to anus
(skip lesions)
Inflammation depth for Crohn’s disease
Transmural inflammation
Bowel wall thickness in Crohn’s
Thick bowel wall, narrow lumen
*What feature is pathognomonic of Crohn’s disease?
Non-caseating granulomas
What part of GI tract is affected in Ulcerative colitis?
Rectum and colon
(continuous)
*Inflammation depth for UC?
Inflammation confined to mucosa (superficial)
Bowel wall thickness in UC?
Normal thickness