Acute Infectious Diarrhoea

Question 1

Definition

Answer 1

Consistency: Loose, watery stools
Frequency: ≥ 3 times in 24h period
Duration: < 14 days

Question 2

Types

Answer 2

1) Non-inflammatory

2) Inflammatory

Question 3

Etiology

Answer 3

Non-inflammatory:
Usually viral

Inflammatory:
Usually invasive & toxin-producing bacteria

Question 4

Pathophysiology

Answer 4

Non-inflammatory:
More likely to promote intestinal secretion, without significant disruption in intestinal mucosa

Inflammatory:
More likely to disrupt intestinal mucosa –> tissue invasion & distruction
May lead to impaired ability to absorb nutrients
Inflammation (cytokine response)

Question 5

Severity

Answer 5

Non-inflammatory:
Generally milder

Inflammatory:
Generally more severe

Question 6

Mode of transmission

Answer 6

Fecal-to-oral

Question 7

Sources of infectious diarrhoea

Answer 7

1) International travel
2) Food/water borne
3) Exposure to infected animal/feces
4) Recent antimicrobial use

Question 8

Microbiology

Answer 8

May be caused by bacteria/virus/parasite

Bacteria:
Camplylobacter
C. difficile
Salmonella
Shigella 
Shiga toxin producing E. coli
Yersinia
Vibrio

Question 9

Clinical presentation

Answer 9

Mild/Common symptoms:

1) Fever
2) Abdominal pain
3) N/V

More severe symptoms (more common with bacteria):

1) Fecal evidence of inflammation e.g. mucous in stools
2) Bloody stools

Question 10

Indication for diagnostic testing

Answer 10

1) Immunocompromised
- Test & carry out empiric therapy when patient first presents

2) Severe diarrhoea & not responding to treatment
- Severe: Fever + Bloody/Mucoid stools +/- Severe abdominal cramping/tenderness
- Carry out empiric treatment first
- Test if patient does not respond

Question 11

Diagnostic test

Answer 11

Test: Stool culture & PCR
Test for:
1) Campylobacter
2) Shigella
3) Salmonella
4) C. difficile
5) Shiga toxin producing E. coli
6) Yersinia

Question 12

Need to treat

Answer 12

Most cases are self-limiting & do not require antibiotic treatment (supportive treatment sufficient)

Indication for antibiotics:

1) Immunocompromised host
2) Signs of sepsis
3) Severe disease
- Fever + Bloody/Mucoid stools +/- Severe abdominal cramping/tenderness

Question 13

Supportive treatment

Answer 13

1) Appropriate hydration

2) Anti-diarrhoea agents

Question 14

Choice of antibiotics

Answer 14

1st Line:
Ceftriaxone
- Higher prevalence of resistance to Ciprofloxacin in SG
- May not be able to take orally if patient has N/V

Alternative
Ciprofloxacin
- Alternative in penicillin allergy

Question 15

Duration

Answer 15

3-5 days

- May extend (depending on patient response) in bacteremia, extra-intestinal infections, immunocompromised

Question 16

Dosing

Answer 16

Ceftriaxone
- IV 2g q24h

Ciprofloxacin
- PO 500 mg BD

Question 17

Monitoring

Answer 17

Clinical improvement

• Symptom resolution e.g. decrease in frequency
• If persistent, further workup might be needed (e.g. assess for other causes of symptoms