Clostridium difficile

Question 1

What type of bacteria is Clostridium difficile (C diff)?

Answer 1

Gram positive rod

Question 2

How can C diff produce harmful effects in the gut?

Answer 2

produces an exotoxin which causes intestinal damage leading to a syndrome called pseudomembranous colitis

Question 3

What is the name of the condition that can develop as a result of C diff infection?

Answer 3

pseudomembranous colitis

Question 4

What causes a C diff infection to develop?

Answer 4

when normal gut flora are suppressed by broad spectrum antibiotics

Question 5

What are 2 types of broad spectrum antibiotics most commonly responsible for causing C diff infection?

Answer 5

1. Clindamycin
2. 2nd and 3rd generation cephalosporins (cefuroxime, cefotaxine, ceftriaxone)

Question 6

In modern times which antibiotics are the leading cause of C diff?

Answer 6

2nd and 3rd generation cephalosporins

Question 7

In addition to antibiotics, what other drug poses a risk factor for C diff infection?

Answer 7

proton pump inhibitors

Question 8

What are 8 features of clostridium difficile infection?

Answer 8

1. Diarrhoea - watery, can be bloody
2. Abdominal pain/cramps
3. Nausea
4. Signs of dehydration e.g. dry mucous membranes, tachycardia, oliguria
5. Fever
6. Loss of appetite and weight loss
7. Raised white blood cell count (WCC)
8. Toxic megaclon - if severe

Question 9

What is a feature on AXR consistent with colitis?

Answer 9

thumb-printing, loss of bowel wall architecure

Question 10

What causes thumb-printing in colitis?

Answer 10

large bowel wall thickening usually caused by oedema, related to an infective or inflammatory process

normal haustra become thickened at regular intervals appearing like thumbprints projecting into the aerated lumen

Question 11

What is meant by toxic megacolon?

Answer 11

potentially lethal complication of IBD or infectious colitis characterised by total or segmental nonobstructive colonic dilatation plus systemic toxicity

Question 12

What are the 4 steps in the PHE severity scale for C diff?

Answer 12

mild, moderate, severe, life-threatening

Question 13

What defines mild C diff infection?

Answer 13

normal WCC

Question 14

What defines moderate C diff infection?

Answer 14

raised wCC (<15 x 10⁹ /L)

typically 3-5 loose stools per day

Question 15

What defines severe C diff infection? 4 options

Answer 15

• Raised WCC >15 x 10⁹ /L or
• an acutely increased creatinine (>50% above baseline) or
• a temperature >38.5 or
• evidence of severe colitis (abdominal or radiological signs)

Question 16

What are 3 aspects of life-threatening C diff infection?

Answer 16

1. Hypotension
2. Partial or complete ileus
3. Toxic megacolon, or CT evidence of severe disease

Question 17

How is a diagnosis of C diff infection made?

Answer 17

by detecting Clostridium difficile toxin (CDT) in the stool

Question 18

How useful is C diff antigen for diagnosing C diff infection?

Answer 18

this only shows exposure to the bacteria rather than current infection

Question 19

What is the first-line treatment for Clostridium difficile infection (if mild to moderate)?

Answer 19

oral metronidazole for 10-14 days

Question 20

What are 2 drug options if C diff is severe or not responding to metronidazole?

Answer 20

• oral vancomycin
• fidaxomicin

Question 21

What is the disadvantage of using oral vancomycin to treat C diff infection?

Answer 21

recurrent infection occurs in around 20% of patients, increasing to 50% after their second episode

Question 22

In which patients is fidaxomicin a particularly good treatment options for?

Answer 22

patients who are not responding, particularly those with multiple co-morbidities

Question 23

What drugs should be used to treat life-threatening C diff infections?

Answer 23

combination or oral vancomycin and IV metronidazole

Question 24

What is a newer therapy that is not yet in widespread use but can be used to treat C diff infection?

Answer 24

bezlotoxumab - monoclonal antibody which targets C diff toxin B

Question 25

What are 6 risk factors for developing C diff infection?

Answer 25

1. Treated with broad-spectrum antibiotics
2. Have had to stay in healthcare setting e.g. hospital or care home for a long time
3. Over 65 years old
4. Have certain underlying conditions e.g. IBD, cancer, kidney disease
5. Weak immune system e.g. diabetes, HIV, chemo, steroids
6. Are taking a proton pump inhibitors (PPI)

Question 26

What is one more modern viable option for treating recurrent Clostridium difficule infection?

Answer 26

faecal transplant

Question 27

What are 2 factors limiting the ues of faecal transplant to treat C diff infection?

Answer 27

1. Potential transmission of infectious agents to recipient
2. Alteration of the gut microbiome given its far reaching effects on human health and disease

Question 28

What are 2 drugs that should be avoided in the treatment of C diff infection and why?

Answer 28

1. Anti-diarrhoeal agents
2. Narcotic drugs

anti-peristaltic effects and toxin entrapment can predispose to toxic megacolon

Question 29

What causes the pseudomembrane of pseudomembranous colitis?

Answer 29

massive colonic inflammation characterised by pseudomembrane of immune cells, mucus and necrotic tissue

Question 30

What are 3 severe complications of CDI overall?

Answer 30

1. Pseudomembranous colitis
2. Colonic distension ie toxic megacolon
3. Systemic toxicity and manifestations of systemic inflammatory response syndrome

Question 31

What appearance of the bowel is virtually diagnostic of C diff infection?

Answer 31

pseudomembranous colitis

Question 32

What are 5 features of the systemic inflammatory response syndrome which may occur as a complication of CDI?

Answer 32

1. Leucocytosis (>35)
2. Rising serum lactate levels (>5)
3. Hypotension requiring vasopressor therapy
4. Acute renal failure
5. Respiratory distress