GI Flashcards
What are the differences in the processes of a stomach ulcer and a duodenal ulcer?
Stomach: Severe inflammation results in gastric mucous degradation and disruption of tight junctions.
Duodenum: Impaired somatostatin release and so increased gastrin release –> Gastric acid hyper-secretion
What is nutcracker oesophagus?
Pain on swallowing, there is a higher than normal squeeze pressure
What happens to the oesophagus in scleroderma?
Weak LOS, loss of peristalsis and severe oesophagitis
What are the 2 motility phases in the gut and small intestine?
interprandial period and fed state
How does non-typhoidal salmonella cause diarrhoea?
Invasion of the enterocyte and inflammation
What are the primary and secondary effects of non-typhoidal salmonella?
q1- Nausea, diarrhoea, fever, abdominal cramps
2- Endocarditis and osetomyelitis
What increases the risk of diarrhoea?
Gut microflora and gastric acid
What are some microbial factors for spread?
Invasiveness, toxins, attachment, infectious dose
What are some host factors that will determine microbial invasion.
Genotype, age, personal hygiene, gastric acid/physical barriers, intestinal mobility, microflora, immunity, intestinal receptors.
What are some causes of osmotic diarrhoea?
Orlistat, acarbose, laxatives, antacids, pancreatic insufficiency, short bowel syndrome, inflammatory disease, digestive enzyme deficiencies
What numbers would indicate a hepatocellular injury?
transaminases >150U/L ALP<200U/L
What numbers would show cholestasis?
ALP>180U/L, GGT> 100U/L, ALT<150U/L
How does bacteria cause diarrhoea and give e.g.s
Invasion and toxins e.g. shigella, salmonella, E.coli
How do viruses cause diarrhoea?
Local invasion, cytopathic effects and cell destruction- norovirus
How doe Protozoals like giardia cause diarrhoea?
Invasion and secretory products (damage the tissue and alter secretions)
What mechanisms can cause diarrhoeal disease?
- CL- and fluid secretion
- Interruption of fluid absorption by enterocytes in SI
- Loss of intestinal epithelia, increasing permeability
- Enterotoxins loosen binding sites between cells.
What do SCFA do?
e.g. acetic acid, propanoic, butyrate
increase cell proliferation in whole gut
promote water absorption and prevent osmotic diarrhoea
inhibit growth of pathogenic bacteria
What makes up 99.9% of the gut normal flora?
Strict anaerobes
What factors control the composition of gut flora?
Physiochemical (pH, O2 tension, nutrient supply)
Host-bacteria (saliva, bile, gastric acid, immune system)
microbe - microbe interactions (toxic metabolites)
What are some harmful products produced by gut flora?
hydroxy fatty acids - toxic to mucosa
Secondary bile acids - carcinogens and increased risk of gall stones.
H2S- toxic to colonic cells
What conditions present with hypotension and tachycardia?
Dehydration, sepsis, shock, pregnancy, blood loss, inflammation
Give examples of some gut flora
Lactobacillus, bifidobacterium, clostridium, escherichia coli
How does H.pylori go on to cause gastric cancer?
Gastritis–> Atrophic gastric hypocholrydia –> Dysplasia and cancer. (risk factors effect progression such as male and smoker)
