Infectious colitis

Question 1

What is infectious colitis?

Answer 1

Inflammation of the colon due to bacteria, parasites or viruses.

Question 2

What are the risk factors for infectious colitis?

Answer 2

1. Lack of sanitation 
2. Drinking contaminated water 
3. Antibiotic use 
4. Ulcerative colitis
5. HIV/AIDS/Immunosuppression
6. C.Difficile (causes pseudomembranous colitis) → gram positive rod often encountered in hospital practice:
   - Risk Factors for C.Diff → antibiotics and PPIs
   - Abx most commonly associated = ciprofloxacin, clarithromycin, clindamycin and cephalosporins
   - Can cause perforation or toxic megacolon (hence AXR and CT may be useful)
   - May see yellow plaques on the intraluminal wall of the colon on sigmoidoscopy

Question 3

What bacteria/ parasites usually cause infectious colitis?

Answer 3

CHESS ⇒ campylobacter, haemorrhagic e.coli, entamoeba histolytica, salmonella, shigella 

Question 4

What are the presenting symptoms of infectious colitis?

Answer 4

1. Diarrhoea → may be watery or blood stained
2. Blood & Mucus in stool
3. Lower abdominal pain
4. Malaise & Fever

Question 5

What signs of infectious colitis can be found on physical examianation?

Answer 5

• Diffuse abdominal tenderness
• Abdominal distension
• Bowel sounds are often INCREASED

Question 6

What investigations are used to diagnose/ monitor infectious colitis?

Answer 6

a) C.Diff
1. Stool culture → c.diff toxin can be identified in the stool
- Clostridium difficile antigen positivity only shows exposure to the bacteria, rather than current infection
2. Raised WCC
3. AXR → if severe, can cause toxic megacolon

b) Colonoscopy → visualize colonic inflammation
c) Ask patients about previous travel history

Question 7

How is infectious colitis managed?

Answer 7

1. Hydration to replace lost fluids
2. Loperamide (Anti-Diarrhoeal)
3. Antibiotics (specific antibiotic depends on infectious agent)
   - Clostridium difficile → Oral Vancomycin for 10 days