Histopathology 16: Lower GI Flashcards
A 2 year old boy with down syndrome presents with symptoms of constipation with overflow diarrhoea and vomiting. There are signs of abdominal distension.
What is the most likely diagnosis ?
Hirschsprung’s disease
Where does Volvulus tend to occur in children? Where does it occur in adults ?
Children= small bowel Adults = Sigmoid colon
Which organism causes pseudomembranous colitis ?
C.difficile
antibiotics kill commensal bacteria and allow C.diff to flourish. It’s endotoxins cause Pseudomembranous colitis
List 5 features of Crohn’s disease ?
Transmural inflammation Skip lesions Non-caseating granulomas Cobblestone mucosa Can affect anus to mouth
List 5 features of Ulcerative colitis ?
Involves rectum and Colon but not small bowel
Inflammation confined to the mucosa
Inflammation is continuous, no skip lesions
Backwash ileitis- terminal ileum gets involved
Can cause toxic megacolon
List 3 skin lesions seen in Crohn’s ?
Erythema multiforme
Erythema nodosum
Pyoderma gangrenosum
List 3 familial syndromes characterised by polyps ?
Familial adenomatous polyposis
Peutz-jeghers syndrome
Hereditary non polyposis colorectal cancer (HNPCC)
Name 2 subtypes of FAP ?
Gardner’s syndrome
Turcot syndrome
List 5 extra-intestinal manifestations of Gardner’s syndrome ?
Multiple Osteomas of the skull and mandible
Epidermal cysts
Desmoid tumours
Dental carries/ unerrupted supernumerary teeth
Post surgical mesenteric fibromatoses
List 3 features seen in carcinoid syndrome ?
- Flushing
- Diarrhoea
- Bronchoconstriction / tachycardia
Which test is used to diagnose carcinoid syndrome ?
- 24 hour urine 5-HIAA
Which paediatric disease presents with up to 100 hamartomatous polyps in children <5 years old ?
Juvenile polyposis
List 3 features of peutz-jeghers syndrome ?
- multiple hamartomatous polyps
- freckles around mouth
- mucocutaenous hyperpigmentation
Which staging system is used to stage colorectal cancer ?
-Duke’s staging
Which tumour marker identifies colorectal cancer ?
CEA
list 3 congenital disorders of the lower GI tract
atresia/ stenosis
duplication
imperforate anus
where do 90% of diverticuli occur
left colon
therapy for pseudomembranous colitis
metronidazole or vancomycin
at what sites do ischaemic colitis/ infarction occur
segments in 'watershed' zones splenic flexure (SMA and IMA), rectosigmoid (IMA and IIA)
list causes of ischaemic colitis
arterial occlusion
venous occlusion
small vessel disease - DM, cholesterol, emboli, vasculitis
low flow states - shock, haemorrhage
obstruction - hernia, intussusception, adhesions
list some extra-intestinal features of crohns disease
arthritis
uveitis
stomatitis
skin - PG, EM, EN
list 3 complications of UC
severe haemorrhage
toxic megacolon
adenocarcinoma
list some extra-intestinal features of UC
arthritis myositis uveitis/iritis EN, PG PSC
list 3 polyps - non neoplastic tumours of the colon and rectum
hyperplastic
inflammatory (pseudo-polyps)
hamartomatous (juvenile, peutz jeghers)
list 3 neoplastic polyps of the colon and rectum
tubular adenoma
tubulovillous adenoma
villous adenoma
list risk factors for the development of cancer from a polyp
size of polyp (>4cm - 455 have invasive malignancy)
proportion of villous component
degree of dysplastic change within the polyp
what is FAP/APC
AD average age of onset = 25 yrs minimum 100 polyps average 1000 chromosome 5q21, APC TS gene nearly 100% develop cancer within 10 years
list features of HNPCC
uncommon AD 1 of 4 DNA MM repair genes involved numerous DNA replication errors early age CC mainly proximal to splenic flexure poorly differentiated and mucinous more common multiple synchronous cancers extra-colonic cancers - endometrium, prostate, breast, stomach
