pathology of the small intestine Flashcards
symptoms of small intestine pathology
pain nausea and vomiting symptoms of nutrient deficiency loss of appetite/loss of weight diarrhoea constipation fever
fever as a symptom
infection related pathology
signs of small intestinal pathology
tenderness abdominal distension palpable mass haemorrhage peritonitis/systemic infection
haemorrhage as a sign in small intestine pathology
haematemasis/malena
anaemia/positive faecal occult blood
investigations for small bowel pathology
physical examination
imaging - xray, U/S, CT, MRI
lab tests - stool for microbiology, blood for serology
endoscopy
hernia
hernia - when a loop bwel gets stuck in a defect in the abdominal wall and becomes incarcerated and vascular supply becomes compromised usually leading to ischaemia
adhesions
adhesions - fibrosis usually in a surgical area causing bpowel to stick together abnormally obstructing the lumen of the bowel
vovlolus
volvolus - bowel loops on itself and causes luminal obstruction and compromise of the blood supply
intussusception
intussusception - more common in children, telescoping of bowel through itself effecting the lumen and the blood supply
small bowel obstruction requires
hernia, adhesions, volvolus and intussusception all require surgical intervention to correct themselves
meckle’s diverticulum
remnant vitaline duct
viteline duct should regrew but it doesn’t
rule of 2 in meckle’s diverticulum
2% of the population
within 2 feet (60cm) of the ileocaecal valve
2 inches ling
x2 as common in males
are most often symptomatic by age 2 - only approx 4% are ever symptomatic
ischaemia of the small bowel
can happen due to obstruction
thrombosis/emboli can cause it
congestion of blood causes it to look red
coeliac disease
gluten sensitive enteropathy
chronic disorder of the digestive tract
an inability to tolerate glaidinn, the alcohol soluble fraction of gluten
underdiagnosed
immunological response to gliadin in coeliac disease
endogenous tissue transglutamidase (TTG) converts gliadin from a neutral to a negatively charged protein
in some people this induces IL-15 in enteric epithelium, leading to proliferation of NK cells and expression of cell surface markers on epithelial cells that cause T cells to attack them
antiglaidin antibodies are frequently found in untreated patients as is IgA to smooth muscle endomysium and TTG
inflammatory mediated damage to enteric epithelial cells, with T cell infiltration, atrophy of villi in small bowel and loss of absorptive surface leads to mal digestion and malabsorption of many nutrients
triggers of coeliac disease
triggers are unknown - genes may play an important role
pathology og coeliac disease
inflammatory mediated damage to enteric epithelial cells, with T cell infiltration, atrophy of villi in small bowel and loss of absorptive surface leads to mal digestion and malabsorption of many nutrients
morphological changes in pathology of coeliac disease
loss of villous height- atrophy
lymphocytes entering epithelial cells and causing damage
more mitotically active epithelial cells as they are trying to regenerate
due to increases mitosis - crypt hyperplasia
tissue translgutaminase
tTG
turns gliadin into negatively charged protein
in coeliac patients this leads to cascade of immune signalling leading to epithelial damage
IL-15 causes expression of proteins recruiting NK cells causing cell damage
may also activate B cells to produce antibodies
clinical features of coeliac disease
chronic but variable diarrhoea steatorrhea abdominal bloating and cramps flutulence and borborygmus weight loss fatigue
complications of coeliac disease
anaemia bleeding disorders osteopeniaa seizure disorders and neuromusclular irritation due to hypocaalcaemia growth restriction/failure to thrive amenorrhoea infertility skin disorders - dermatitis herpetiformis risk of malignancy
diagnosis of coeliac disease
clinical history, serology, endoscopy, histology
serology for diagnosis of coeliac disease
anti-tissue transglutaminase antibody
anti-modified or deaminated gliadin antibodies (AGA)
anti-endomysial antibodies (EMA)
anti-reticulin antibodies (ARA)
coeliac disease differential diagnosis
other food intolerance/allergies Crohn's diseases topical sprue infections - giardiasis, helicobacter, cryptoosporidium, viruses drug reactions - NSIADS, chemotherapy immune system abnormalities
tropical sprue
causes similar histological changes to coeliacs
only in tropical countries
coeliac disease management
strict lifelong gluten free diet
vitamin and mineral supplements
antti-inflammatory agents for severe intestinal injury
close clinical follow up and management for complications
autoimmune enteropathy
x-linked disorder characterised by severe persistent diarrhoea
seen often in young children
intestinal epithelial damage from anti-enterocyte and anti-globlet cell antibodies
leads to small intestinal atrophy
severe familial form termed IPEX results from gremlin mutation of FOXP3 gene
common variable immunodeficiency
one of the most common symptomatic primary immunodeficiencies
characterised by los levels of circulating immunoglobulins
both genetic and sporadic forms
symptoms vary widely and across body systems
GI symptoms of common variable immunodeficiency
abdominal pain, bloating, nausea, vomiting, diarrhoea and weight loss
signs of malabsorption
small bowel histology of common variable immunodeficiency
may appear normal or show non-specific damage
plasma cells are reduced or absent
giardia
protozoan infection associated with malabsorption and chronic diarrhoea
spread by a feacal contamination of water
present on the surface of the mucosa but does not invade the tissue
malignancies
adenocarcinoma
neuroendocrine tumours
gastrointestinal stromal tumours
lymphoma
GIST
gastrointestinal stromal tumour
composed of mesenchymal cells
metastatic melanoma
common metastasis to the small intestine
may cause intussusception
