Week 101: Diarrhoea

Question 1

What are the signs of clinical dehydration?

Answer 1

⇒	Appears to be unwell/deteriorating
⇒	Altered responsiveness (e.g. irritable/lethargic)
⇒	Sunken eyes
⇒	Tachycardia
⇒	Tachypnoea
⇒	Reduced skin turgor

• Decreased urine output
• Dry mucous membranes

⇒ Symptoms of the hand indicate shock

Question 2

What are the signs of clinical shock?

Answer 2

• Decreased level of consciousness
• Pale or mottled skin
• Cold extremities
• Tachycardia
• Tachypnoea
• Weak peripheral pulses
• Prolonged capillary refill time
• Hypotension (decompensated shock)

⇒ Symptoms of the hand indicate shock

Question 3

How is diarrhoea caused in severe acute malnutrition (SAM)?

Answer 3

Higher levels of potassium are excreted from the cells than normal which leads to diarrhoea

Question 4

What fluid management would you use for shock?

Answer 4

• 20ml/kg in 30 minutes
• Repeat if still in shock
• Then move to maintenance fluid

Question 5

Maintenance fluid post shock?

Answer 5

• 0.9% saline

- 100ml/kg/day

Question 6

Maintenance fluid (not post shock)?

Answer 6

• 0.9% saline

- 50ml/kg/day

Question 7

Maintenance fluid in children?

Answer 7

⇒ 4-2-1 rule

• 4: first 10kg, 4ml/kg/hour
• 2: next 10kg, 2ml/kg/hour
• 1: more weight, 1ml/kg/hour

Question 8

What is the calculation to work out electrolytes in the stool?

Answer 8

290 - 2(concentration (Na+K))

• 290 is the normal osmolality of blood

Question 9

How does osmotic diarrhoea work?

Answer 9

• Electrolytes are absorbed normally
• Other things malabsorbed
• Little Na and K excretion
• Normal osmolality

⇒ Caused by malabsorption (coeliac disease)

Question 10

How does secretory diarrhoea work?

Answer 10

• Damage to membrane leads to a loss of Na and K
• Low answer to calculation, low osmolality

⇒ Mainly caused by infection

Question 11

How to tell the difference between osmotic and secretory diarrhoea?

Answer 11

• Osmotic diarrhoea stops when eating stops

- Secretory diarrhoea continues regardless

Question 12

What are the drugs that can cause diarrhoea?

Answer 12

• Antibiotics
• NSAIDs
• Digoxin
• Lipase inhibitor
• Magnesium

Question 13

What is the leading cause of gastroenteritis worldwide?

Answer 13

Rotavirus

Question 14

What causes infant diarrhoea?

Answer 14

Rotavirus

Question 15

What causes an outbreak of diarrhoea in a hospital amongst staff?

Answer 15

Norovirus

Question 16

What is the most likely cause of diarrhoea amongst patients in a hospital?

Answer 16

Clostridium difficile

Question 17

What is the most likely cause of diarrhoea after a barbecue?

Answer 17

Campylobacter

Question 18

What is the most likely cause of diarrhoea after raw eggs?

Answer 18

Salmonella

Question 19

What is the most likely cause of diarrhoea after working on a farm in the US?

Answer 19

EHEC

Question 20

What is the most likely cause of diarrhoea after working on a farm in a developing country?

Answer 20

ETEC

Question 21

What is the most likely cause of diarrhoea due to war or water?

Answer 21

Cholera

Question 22

What are the most likely causes of diarrhoea after travelling?

Answer 22

Giardiasis

ETEC

Question 23

What is the most likely cause of diarrhoea amongst elderly/hospitalised/antibiotic using?

Answer 23

Clostridium difficile

Question 24

What is the main sign of giardiasis?

Answer 24

Cysts in the faeces

• It is spread by cysts in faeces
• Cysts are not always present

Question 25

What are the pharmacological treatments of diarrhoea?

Answer 25

⇒ Loperamide - Opioid antagonist - Receptors in bowel - Gives gut more time to absorb fluid ⇒ Oral rehydration solution - Dioralyte - WHO oral rehydration spoon

Question 26

What is the difficulty with tachypneic patients?

Answer 26

- Getting rid of too much CO2 - Leads to respiratory alkalosis - Body can't compensate

Question 27

How would you treat respiratory alkalosis?

Answer 27

- iv Ringer's Lactate | - iv Hartman's Lactate

Question 28

What are the differences between crystalloids and colloids?

Answer 28

⇒ Crystalloid - Small molecules - Can cross semi-permeable membranes - E.g. sodium chloride ⇒ Colloid - Large molecules - Can expand fluid in blood cells - Increase blood pressure - E.g. albumin

Question 29

What is the main organism that colonises the duodenum?

Answer 29

⇒ Giardia | - Won't find giardia anywhere else

Question 30

What is the main function of the jejunum?

Answer 30

Food absorbed

Question 31

What is absorbed in the distal ileum?

Answer 31

- Bile acids | - Vitamin B12 with intrinsic factor

Question 32

What are the main immune cells in the ileum?

Answer 32

Payer's Patches

Question 33

What are goblet cells?

Answer 33

Goblet cells contain clear mucin granules, mucous secretion serves a protective role Denser in proximal intestine, sparser on villus tip

Question 34

What are absorptive cells?

Answer 34

Have well adapted microvilli, found in small intestine

Question 35

What are crypt cells?

Answer 35

Smaller with fewer less developed microvilli than absorptive cells, have narrow apices Found in the small intestine

Question 36

What are paneth cells?

Answer 36

Found at the base of the crypt villi Contain eosinophilic secretory granules More common in the ileum than the jejunum Probably involved in intestinal barrier function

Question 37

What are m cells?

Answer 37

M cells are found over Peyer's Patches Rapidly transport luminal macromolecules and some microorganisms by transcytosis Probably important for processing and presenting antigens to the mucosal immune system

Question 38

Where is food absorbed?

Answer 38

In the jejunum

Question 39

What are Peyer's Patches?

Answer 39

Immune cells found in the ileum

Question 40

What is submucosa?

Answer 40

Contains blood vessels, connective tissue lymphatics, and lymphoid aggregations

Question 41

What is the main organism that colonies the duodenum?

Answer 41

Giardiasis

Question 42

Embryologically, what divisions of the embryo form the gastrointestinal system?

Answer 42

Foregut, midgut, hindgut, mesenteries

Question 43

What does ectoderm make?

Answer 43

``` Hair Retina Outer layer of skin Central nervous system Outer lining of everything Enteric nervous system (neural tube) Extrinsic innervation ```

Question 44

What does the mesoderm make?

Answer 44

``` Muscle Bone Organs Mesentery Connective tissues Blood vessels ```

Question 45

What does endoderm make?

Answer 45

``` Lining of the gut Secretory cells of the GI tract Inner linings (including respiratory tract) Epithelium Glands ```

Question 46

What is diarrhoea?

Answer 46

3 or more loose or watery stools in a 24-hour period