Session 9- Infections And Emergencies

Question 1

What vitamin does the gut micro biome produce?

Answer 1

Vitamin K

Question 2

Bacteria in the colon produce 3 main fatty acids, Butyrate, Acetate and Propionate. What are the functions of these?

Answer 2

Butyrate- Energy source for colonocytes that regulate gut environment

Acetate- involved in cholesterol metabolism

Propionate- Helps satiety (feeling full)

Question 3

Name 4 Gram negative and 1 Gram positive bacterial infections of the Gut

Answer 3

Negative-
Salmonella
Campylobacter
Shigella
E- Coli

Gram positive-
Clostridium Difficile

Question 4

How can Salmonella lead to lymphoid hyperplasia?

Answer 4

Salmon enters enterocytes by endocytosis. Move to Submucosa where they are taken up by macrophages. They’re then taken to the reticuloendothelial system where they multiply causing the hyper plasia.

They then re enter the gut from the liver.

Question 5

Describe the pathophysiology of Shigella gastroenteritis?

Answer 5

Commonly effects children. Invades Large intestine colonocytes. It spreads killing colonocytes and forming abscesses in mucosa. You get bloody and mucus diarrhea

ShigelLAAAAA… LARGE INTESTINE

Question 6

Describe the pathophysiology of enterotoxigenic E-Coli?

Answer 6

Common cause of travellers diarrhoea. Bacterial adheres to enterocyte and produces enterotoxins. This causes hyper-secretion of Cl ions causing water to enter the gut lumen causing watery diarrhoea.

Question 7

Describe the pathophysiology of C. Difficle?

Answer 7

A spore forming bacillus spread faecal-orally. They can colonise in the gut and release 2 toxins.
Toxin A- an enterotoxin causing hyper secretion and inflammation

Toxin B- Cytotoxin

Antibiotics can lead to proliferation.

Complications are pseudomembranous colitis and Toxic megacolon.

Question 8

Describe the pathophysiology of Rotavirus?

Answer 8

Common cause of gastroenteritis in Under 5s (easily spread). Adults rarely effected. Causes vomiting and fever. Diarrhoea follows due to chloride secretion, SGLT1 disruption and reduced brush border enzyme function (last 2 leading to malabsorption and therefore osmotic forces). Treat by managing hydration

Question 9

What is the most common viral gastroenteritis?

Answer 9

Norovirus. Many strains so no immunity. Similar pathophysiology to Rotavirus.

Question 10

Name 3 parasitic gastroenteritis?

Answer 10

Cryptosporidium

Giardia lambia

Entamoeba

Question 11

Describe 2 common causes of bowel obstruction in children and 2 in adults?

Answer 11

Children:
Intussuseception- part of gut telescopes into adjacent area
Intestinal Atresia

Adults-
Adhesions
Incarcerated hernia

Question 12

What are the 2 most common places for Acute Mesenteric Ischaemia?

Answer 12

The splenic flexure (SMA and IMA watershed)

Rectosigmoid junction (IMA and Hypogastric watershed)

Question 13

What is the most common area for a gastric ulcer?

Answer 13

Lesser curve and antrum

Question 14

What is the most common location for an abdominal aortic aneurysm?

Answer 14

Infrarenal

Question 15

How can liver cirrhosis lead to ascites?

Answer 15

1. Portal Hypertension- Increased hydrostatic pressure in the veins draining the gut
2. Decreased Liver function- Decreased albumin production, therefore decreased intravascular oncotic pressure resulting in net movement of fluid into the peritoneal cavity