Diarrhoea

Question 1

What are the 4 different types of diarrhoea

Answer 1

• Osmotic/malabsorptive diarrhoea
• Secretory diarrhoea
• Inflammatory/infectious diarrhoea
• Motility disorders

Question 2

Describe Osmotic/malabsorptive diarrhoea

Answer 2

šIt results from the presence of unabsorbed or poorly absorbed solute (magnesium, sorbitol, and mannitol) in the intestinal tract that causes an increased secretion of liquids into the gut lumen

Question 3

Give an example of an secretory diarrhoea

Answer 3

Cholera toxin

Question 4

In osmotic diarrhoea the diarrhoea ____ when the patient fasts

Answer 4

Stops

Question 5

In secretory diarrhoea the diarrhoea ____ when the patient fasts

Answer 5

does not stop

Question 6

Describe secretory diarrhoea

Answer 6

šThere is an altered transport of ions across the mucosa, which results in increased secretion and decreased absorption of fluids and electrolytes from the GI tract

Question 7

Give an example of an osmotic diarrhoea

Answer 7

Laxative abuse

Question 8

Describe inflammatory diarrhoea

Answer 8

Diarrhoea occurs because of damage to the intestinal mucosal cell so that there is a loss of fluid and blood

In addition, there is defective absorption of fluid and electrolytes.

Question 9

Name the bacterium that causes inflammatory diarrhoea

Answer 9

Salmonella, E. coli, Campylobacter

Question 10

Name the viruses that causes inflammatory diarrhoea

Answer 10

rotaviruses, coronaviruses, norovirus

Question 11

Name the protozoa that causes inflammatory diarrhoea

Answer 11

Cryptosporium, Giardia

Question 12

Describe motility disorders that cause diarrhoea

Answer 12

Increased motility, decreased transmit time/motility

Can lead to bacterial overgrowth

Question 13

Give examples of motility disorder diarrhoea

Answer 13

Diabetic, post-vagotomy and hyperthyroid diarrhoea

Question 14

Concentration of bacteria in the small intestine is smaller than in the large intestine.

What prevents the bacteria from colonising the small intestine

Answer 14

• Gastric acid
• Bile acids
• Propulsive motility
• Pancreatic enzymes

Question 15

What is the pH of the large intestine

Answer 15

pH 4.5- 7

Question 16

Are the bacteria in the large intestine aerobic or anaerobic?

Answer 16

99% are anaerobic (not reuqiring oxygen)

Question 17

What is the function of gut bacteria?

Answer 17

• Ferment carbohydrate
• Produce short chain fatty acids – many actions and influences
• Reduce colonic pH
• Inhibit pathogens
• Produce a range of vitamins

Question 18

Define fermentation

Answer 18

Anaerobic metabolism of carbohydrate and protein in human colon by the microbiota

Question 19

Which carbohydrates does the gut microbiota fementate?

Answer 19

• Resistant starch
• Non starch polysaccharides
  
  • Wheat bran, oat fibre, other cereals, pectins, glucans
• Sugar alcohols
• Non absorbed oligosaccharides and sugars
  
  • prebiotics

Question 20

What is the product of the fermentation of carbohydrate and protein

Answer 20

Short chain fatty acids (SCFA)

Question 21

What is the function of short chain fatty acids formed from the fermentation of carbohydrates and proteins

Answer 21

• Promote colonic absorption – reduce diarrhoea
• Provide energy, influence hormone release affecting satiety -Obesity

•Protect gut mucosa- IBD and cancer

•Influence lipid metabolism in different ways - coronary heart disease

Question 22

Contrast the reabsorption of water in the large and small intestine

Answer 22

• In the SI, you absorb a lot of water by cotransported with electrolytes
• In the LI, it is the SCFA. Few electrolytes present so it’s the SCFA in the LI that drives the absorption of water
• High fibre diets- large increase in stool output, because the flora are used to carbohydrate and protein food.

Question 23

Give examples of short chain fatty acids

Answer 23

1. Acetate
2. Propionate
3. Butyrate

Question 24

Describe acetate

Answer 24

• 60% of the total number of SCFA formed.
• Main SCFA to reach systemic blood
• Used for energy
• May increase hepatic lipogenesis
• May influence satiety but may increase energy salvage from food.

Question 25

Describe propionate

Answer 25

* 2^nd most important short chain fatty acid * Seems to influence the release of hormones in the gut that effect the lectin, gut mobility and Influence insulins sensitivity * Inhibits cholesterol synthesis. * Inhibits lipid synthesis * Increases insulin sensitivity

Question 26

Colonic pH is ____ by colonic fermentation

Answer 26

Reduced

Question 27

Why is it important that the pH of the large intestine is more acidic

Answer 27

* inhibits harmful enzymes * 7 alpha hydroxylase * precipitates harmful molecules * Bile acids, sterols, fatty soaps * Inhibits colonic cell proliferation * Increases colonic calcium and magnesium absorption * Inhibits pathogens and may influence other bacteria

Question 28

Define the term "probiotic"

Answer 28

Live microorganisms which when administered in adequate amounts confer a health benefit on the host.

Question 29

Name the vitamins that are formed by the colonic bacteria

Answer 29

Vitamin K and B12

Question 30

Which gases produced by the colonic bacteria add to flatus

Answer 30

Carbon dioxide, hydrogen gas, and methane

Question 31

Which virus is the most frequent viral cause of severe gastroenteritis in infants and children

Answer 31

Rotavirus

Question 32

When seeing a patient with diarrhoea, the most important investigation is?

Answer 32

A clear history

Question 33

When treating someone with gastroenteritis, the most important management is

Answer 33

Rehydration

Question 34

Which important vitamin is made and absorbed in the large intestine?

Answer 34

Vitamin K

Question 35

Viral gastroenteritis is the most common. Viral gastroenteritis is highly contagious. Name the 3 most common viruses that can cause viral gastroenteritis

Answer 35

Rotavirus Norovirus Adenovirus is a less common cause and presents with a more subacute diarrhoea

Question 36

Describe E.coli in regards to its ability to cause gastroenteritis

Answer 36

Escherichia coli (E. coli) is a normal intestinal bacteria. Only certain strains cause gastroenteritis. It is spread through contact with infected faeces, unwashed salads or water. E. coli **0157** produces the **Shiga** **toxin**. This causes abdominal cramps, bloody diarrhoea and vomiting. The Shiga toxin destroys blood cells and leads to haemolytic uraemic syndrome (HUS). The use of antibiotics increases the risk of haemolytic uraemic syndrome therefore antibiotics should be avoided if E. coli gastroenteritis is considered.

Question 37

Enterohaemorrhagic E coli (EHEC) is: A) Gram negative B) Gram positive

Answer 37

A) Gram negative

Question 38

Describe the clinical signs of E.coli gastroenteritis

Answer 38

Blood often present Abdominal pain

Question 39

Which viral gastroenteritis has a high rate in children and often seen spread in nurseries

Answer 39

Rotavirus

Question 40

What is the typical culprit of E.coli gastroenteritis

Answer 40

Beef, pork, unwashed veg

Question 41

Describe Campylobacter Jejuni

Answer 41

* Gram negative bacterium * Symptoms include: * Blood often present * Severe abdominal pain * Nausea but rarely vomiting * fever * Cause is often under cooked poultry * Mechanism is INFLAMMATORY * Associated with Guillain-Barre syndrome or reactive arthritis

Question 42

Describe Salmonella

Answer 42

* Gram negative bacterium * Clinical symptoms include: * Nausea * Abdominal pain * fever * Cause is often under cooked poultry * Asymptomatically shed for on average 5 weeks- people who work in healthcare or food handling job is required to be tested before going back to work to prevent spread during asymptomic stage

Question 43

Describe Clostridium Difficile

Answer 43

* Gram positive bacterium * Clinical signs: * High WCC (leucocytosis) * Fever * Often seen in hospital and care homes * Can result in toxic mega colon- very dilated colon

Question 44

The typical exam patient develops symptoms soon after eating leftover fried rice that has been left at room temperature. It has a short incubation period after eating the rice and they then recover within 24 hours.. Which kind of pathogen has caused this diarrhoea

Answer 44

**Bacillus Cereus** The typical course is vomiting within 5 hours, then diarrhoea after 8 hours, then resolution within 24 hours.

Question 45

Describe Staphylococcus Aureus

Answer 45

can produce enterotoxins when when growing in food such as eggs, dairy and meat. When eaten these toxins cause small intestine inflammation. This causes symptoms of diarrhoea, perfuse vomiting, abdominal cramps and fever. These symptoms start within hours of ingestion and settle within 12-24 hours. It is not actually the bacteria causing the enteritis but the staphylococcus **enterotoxin**.

Question 46

What is the management of Clostridium difficle

Answer 46

šStop or change causative antibiotics, give ORAL Metronidazole +/ Vancomycin as per local guidance. A faecal transplant can be used to restore gut flora in recurrent infection

Question 47

Name four organisms which commonly cause blood diarrhoea

Answer 47

* Escherichia coli* * Shigella species* * Salmonella species* * Campylobacter species*

Question 48

Name the two types of inflammatory bowel disease

Answer 48

**ulcerative colitis** and **Crohn's disease**

Question 49

What are the most common causes of chronic diarrhoea

Answer 49

1. Lactose intolerance 2. Celiac disease 3. Inflammatory bowel disease 4. Irritable bowel disease

Question 50

Describe crohns disease

Answer 50

* Can affect any part of the GI tract from mouth to anus * The lesions are not continous * It affects all layers of the gut wall * The goblet cells appear normal * It causes inflammation of the GI, which can lead to abdominal pain (in the right quadrant), severe diarrhea, fatigue, weight loss and malnutrition.

Question 51

Describe ulcerative colitis

Answer 51

* UC is caused by the inflammation and ulceration of the inner lining of the colon and rectum (the large bowel). * In Colitis, ulcers develop on the surface of the bowel lining and these may bleed and produce mucus- causing bloodly stools. * The inflammation affects only the rectum and colon. * The inflamed colon is less able to absorb the liquid and this can lead to a larger volume of watery stools. Also, because the colon cannot hold as much waste as normal, very frequent bowel movements (six or more a day) may occur * `The lesions are continous through the colon and rectum * Depletion of goblet cell numbers