Pathology of Small Bowel Flashcards
types of ischaemia of the small bowel
mesenteric arterial occlusion
non occlusive perfusion insufficiency
usually acute but can be chronic
aetiology of ishcaemia of the small bowel - mesenteric arterial occlusion
mesenteric artery atherosclerosis
thromboembolism from heart (AF)
aetiology of ishcaemia of the small bowel - non occlusive perfusion insufficiency
shock
strangulation obstructing venous return (hernia, adhesion)
drugs (cocaine)
hyper viscosity
describe mucosa of the small bowel
most metabolically active part of bowel wall - most sensitive to effects of hypoxia
pathogenesis of ischaemia if small bowel - mesenteric arterial occlusion
longer the hypoxia the greater the depth of damage to the bowel wall and greater the likelihood of complications
pathogenies of ischaemia of small bowel - non occlusive ischaemia
tissue damage occurs after reperfusion
types of small bowel infarction
mucosal
mural
transmural
complications of ischaemia the small bowel
resolution
fibrosis, stricture, chronic ishcaemia, mesenteric angina and obstruction
gangrene, perforation, peritonitis, sepsis and death
what is Meckel’s Diverticulum
result of incomplete regression of Vitelli-intestinal duct
pathogenesis of Meckel’s Diverticulum
tubular structure, above IC valve
may contain heterotypic gastric mucosa
signs of Meckel’s Diverticulum
asymptomatic;
bleeding
perforation
diverticulitis mimicking appendicitis
tumours of the small bowel
primary - rare
secondary - common (ovary, colon and stomach)
primary tumours of the small bowel
lymphomas
carcinoid tumours
carcinomas
lymphomas of small bowel
rare all non Hodkins in type
pathology of lymphomas of small bowel
maltomas (B cell) derived
enteropathy associated T-cell lymphomas (associated with Coeliac disease)
treatment for lymphomas of small bowel
surgery and chemotherapy
carcinoid tumours of small bowel
most commonly found in appendix
small, yellow, slow growing tumours
locally invasive
pathology of carcinoid tumours of small bowel
can cause intussusception, obstruction
produces hormone like substances if metastases to liver producing flushing and diarrhoea
describe carcinoma of small bowel
associated with Crohn’s disease and Coeliac disease
presents late
pathology of carcinoma of small bowel
identical to colorectal carcinoma in appearance
metastases to lymph nodes and liver occurs
describe appendicitis
common cause of acute abdomen
commoner in children but occurs in adults
symptoms of appendicitis
vomiting
abdominal pain
right iliac fossa tenderness
increased white cell count
aetiology of acute appendicitis
unknown faecoliths (dehydration) lymphoid hyperplasia parasites tumours (rare)
pathology of appendicitis
acute inflammation (neutrophils) involving muscles coat (mural)
mucosal ulceration
serosal congestion, exudate
pus in lumen
complications of appenditics
peritonitis rupture abscess fistula sepsis and liver abscess
what is coeliac disease
abnormal reaction to constituent of wheat flour, gluten
pathology of coeliac disease
effects small intestine;
damaging enterocytes - reducing absorptive capacity, loss of villous structure, loss of surface area, flat duodenal mucosa
aetiology of coeliac disease
gliadin (component of gluten);
tissue injury as bystander effect
IEL and CD8 T cell mediated
metabolic effects of coeliac disease
malabsorption
reduced intestine hormone production
what substances does malabsorption affect
fats sugars amino acids water electrolytes
what does malabsorption of fats lead to
steatorrhea
what does reduced intestinal hormone production lead to
reduced pancreatic secretion and bile flow (CCK) - leading to gallstones
complications of malabsorption
weight loss anaemia abdominal bleeding failure to thrive vitamin deficiencies T-cell lymphomas of GI tract increased risk of small bowel carcinoma gallstones ulcerative-jejenoilleitis
