GI

Question 1

What are the differences in the processes of a stomach ulcer and a duodenal ulcer?

Answer 1

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

Question 2

What is nutcracker oesophagus?

Answer 2

Pain on swallowing, there is a higher than normal squeeze pressure

Question 3

What happens to the oesophagus in scleroderma?

Answer 3

Weak LOS, loss of peristalsis and severe oesophagitis

Question 4

What are the 2 motility phases in the gut and small intestine?

Answer 4

interprandial period and fed state

Question 5

How does non-typhoidal salmonella cause diarrhoea?

Answer 5

Invasion of the enterocyte and inflammation

Question 6

What are the primary and secondary effects of non-typhoidal salmonella?

Answer 6

q1- Nausea, diarrhoea, fever, abdominal cramps

2- Endocarditis and osetomyelitis

Question 7

What increases the risk of diarrhoea?

Answer 7

Gut microflora and gastric acid

Question 8

What are some microbial factors for spread?

Answer 8

Invasiveness, toxins, attachment, infectious dose

Question 9

What are some host factors that will determine microbial invasion.

Answer 9

Genotype, age, personal hygiene, gastric acid/physical barriers, intestinal mobility, microflora, immunity, intestinal receptors.

Question 10

What are some causes of osmotic diarrhoea?

Answer 10

Orlistat, acarbose, laxatives, antacids, pancreatic insufficiency, short bowel syndrome, inflammatory disease, digestive enzyme deficiencies

Question 11

What numbers would indicate a hepatocellular injury?

Answer 11

transaminases >150U/L ALP<200U/L

Question 12

What numbers would show cholestasis?

Answer 12

ALP>180U/L, GGT> 100U/L, ALT<150U/L

Question 13

How does bacteria cause diarrhoea and give e.g.s

Answer 13

Invasion and toxins e.g. shigella, salmonella, E.coli

Question 14

How do viruses cause diarrhoea?

Answer 14

Local invasion, cytopathic effects and cell destruction- norovirus

Question 15

How doe Protozoals like giardia cause diarrhoea?

Answer 15

Invasion and secretory products (damage the tissue and alter secretions)

Question 16

What mechanisms can cause diarrhoeal disease?

Answer 16

• CL- and fluid secretion
• Interruption of fluid absorption by enterocytes in SI
• Loss of intestinal epithelia, increasing permeability
• Enterotoxins loosen binding sites between cells.

Question 17

What do SCFA do?

Answer 17

e.g. acetic acid, propanoic, butyrate
increase cell proliferation in whole gut
promote water absorption and prevent osmotic diarrhoea
inhibit growth of pathogenic bacteria

Question 18

What makes up 99.9% of the gut normal flora?

Answer 18

Strict anaerobes

Question 19

What factors control the composition of gut flora?

Answer 19

Physiochemical (pH, O2 tension, nutrient supply)
Host-bacteria (saliva, bile, gastric acid, immune system)
microbe - microbe interactions (toxic metabolites)

Question 20

What are some harmful products produced by gut flora?

Answer 20

hydroxy fatty acids - toxic to mucosa
Secondary bile acids - carcinogens and increased risk of gall stones.
H2S- toxic to colonic cells

Question 21

What conditions present with hypotension and tachycardia?

Answer 21

Dehydration, sepsis, shock, pregnancy, blood loss, inflammation

Question 22

Give examples of some gut flora

Answer 22

Lactobacillus, bifidobacterium, clostridium, escherichia coli

Question 23

How does H.pylori go on to cause gastric cancer?

Answer 23

Gastritis–> Atrophic gastric hypocholrydia –> Dysplasia and cancer. (risk factors effect progression such as male and smoker)