Infectious Diarrhoea

Question 1

What is diarrhoea?

Answer 1

Subjective

Fluidity and frequency

Question 2

What is Gastro-enteritis?

Answer 2

Objective

3 + loose stools a day
Accompanying features

Question 3

What is dysentery?

Answer 3

Obvious

Large bowel inflammation with bloody stools

Question 4

What is the epidemiology of gastro-enteritis?

Answer 4

Contamination of food
Poor food storage
Travel related infections (salmonella)
Person-to-person spread (norovirus)

Question 5

What are the Defences against enteric infections?

Answer 5

Hygiene
Stomach acid
Normal gut flora
Immunity

Question 6

What are the clinical features of diarrhoeal illness?

Answer 6

Non-inflammatory / secretory (cholera)

Inflammation (dysentery)

Mixed picture (C. diff)

Question 7

What can cause non-inflammatory / secretory diarrhoea?

Answer 7

Cholera
Increased cAMP = Cl loss with Na and K = massive water loss
Frequent watery stools with pain
T = re-hydration therapy

Question 8

What can cause Inflammatory diarrhoea?

Answer 8

Dysentry
Inflammatory toxin damage and mucosal destruction

Pain and fever
Antimicrobials may be needed but rehydration is often sufficient

Question 9

How do you assessing the patient with diarrhoea?

Answer 9

Duration 
Risk of food poisoning
Assess hydration
Features of inflammation
I = stool and blood culture, renal function, FBC and scans if pain

Question 10

What happens in fluid and electrolyte loss?

Answer 10

Can be severe

Hyponatraemia and hypokalaemia

Question 11

What are some differential diagnosis for diarrhoea?

Answer 11

Inflammatory bowl disease
spurious diarrhoea
Carcinoma
Sepsis outside the gut

Question 12

What is the treatment of gastro-enteritis?

Answer 12

Rehydration

• Oral with salt/sugar solution
• IV saline

Question 13

What is campylobacter gastroenteritis?

Answer 13

7 days incubation
Stools negative in 6w
Pain can be severe
Post-infection sequelae

Specialised culture (jejuni and coli)
Stool molecular and antigen detection

Question 14

What is salmonella gastroenteritis?

Answer 14

<48h onset
10 days diarrhoea
20% have positive stool at 20/52 (enteritidis and typhimurium)
Post infections irritable bowel

Question 15

What can E. coli O157 cause?

Answer 15

Infection from person-to-person
Frequent bloody stools
Produces shiga (also shigella) toxin which can get into blood = haemolytic anaemia and renal failure + thrombocytopenia

Treatment is supportive

Question 16

When should antibiotics be given?

Answer 16

Indicated in gastroenteritis for

• Immunocompromised
• Severe sepsis or invasive infection
• Chronic illness

Question 17

What are the 4 C antibiotics?

Answer 17

Cephlasporin
Clindomycin
Co-amoxiclav
Ciprofloxacin

Question 18

How do you treat C. diff?

Answer 18

Metronidazole
Oral vancomycin
Stool transplants
Surgery may be required