Diseases of GI Tract - Gastroenteritis and Antibiotic Associated Colitis (24)

Question 1

Commensal flora of gut

Answer 1

• Faecal flora metabolic capacity = liver

- Anaerobic bacteria (Bacteroides outnumber E.coli)

Question 2

What are the beneficial effects of commensal flora of gut?

Answer 2

Metabolism, colonisation, resistance and antibody induction

Question 3

Bottle-fed baby

Answer 3

Adult microflora

Question 4

Breast fed baby

Answer 4

Bifidobacteria

Question 5

Most common commensal flora of gut

Answer 5

Bactericides and prevotella

Question 6

Obligate anaerobes

Answer 6

Clostridia, bifidobacteria

Question 7

Facultative anaerobes

Answer 7

Enterobacteriacea, enterococci

Question 8

Bacterial causes

Answer 8

Salmonella, Shigella, E.coli, Campylobacter, Vibrio cholerae, C.diff, Staph aureus, Bacillus cereus

Question 9

Parasitic (protozoa) causes

Answer 9

Entamoeba hist, Giardia lambila, Cryptosporidium

Question 10

Viral causes

Answer 10

Norovirus, Rotavirus

Question 11

Presenting complaint

Answer 11

Acute onset, vomiting, diarrhoea (frequency, mucous, blood), abd pain, fever

Question 12

Complications

Answer 12

Dehydration, renal failure, haemolytic uraemia syndrome, toxic megacolon, Guillain-Barre syndrome, Salmonella

Question 13

Investigations

Answer 13

• Bloods (FBC, U&E, CRP, cultures)
• AXR
• Stool (Ova, parasites and cysts OCP, microscopy culture and sensitivity MC&S, C.diff toxin CDT, viral PCR)

Question 14

Viral gastroenteritis caused by

Answer 14

Norovirus (commonest gut infection UK)

Question 15

Symptoms of viral gastroenteritis

Answer 15

Diarrhoea and projective vomiting

Question 16

Transmission of viral gastroenteritis

Answer 16

Aerosols (air particles)

Question 17

How long does viral gastroenteritis last?

Answer 17

24-48 hours

Question 18

Parasitic gastroenteritis caused by

Answer 18

Cryptosporidium, Giarda, Entamoeba etc

Question 19

Who is Cryptosporidium infection most common in?

Answer 19

Children

Question 20

Transmission of Cryptosporidium

Answer 20

Waterborne (oocysts resistant to Cl- disinfectants)

Question 21

Presentation of Cryptosporidium

Answer 21

Watery diarrhoea

Question 22

Bacteria gastroenteritis caused by entertoxin production

Answer 22

Vibrio cholerae, E.coli (ETEC/VTEC), C.perfringens, Bacillus cereus, C.diff

Question 23

Bacteria gastroenteritis caused by adherence

Answer 23

Shigella sonnei/flexneri, E.coli (EAEC), Campylobacter jejuni, Salmonellae

Question 24

What toxin is produced by E.coli?

Answer 24

Shiga

Question 25

Which toxin is the 'model' toxin?

Answer 25

Cholera

Question 26

Types of Salmonella

Answer 26

S. typhi, S. paratyphi, S.enteritidis, S.typhimurium

Question 27

Salmonella causes..

Answer 27

Food poisoning, typhoid and paratyphoid

Question 28

Treatment

Answer 28

Avoid antibiotics may increase duration of salmonella and worsen E. Coli HUS

Question 29

When do you use antibiotics?

Answer 29

Very young and old, campylobacter and invasion (positive blood cultures)

Question 30

Organisms that causes antibiotic-associtaed diarrhoea

Answer 30

C. diff, C.perfringens, S.aureus, Candida, Klebsiella, Salmonella

Question 31

Symptoms of antibiotic-associated diarrhoea

Answer 31

Mild diarrhoea > toxic megacolon/perforation/shock

Question 32

How does antibiotic associated diarrhoea come about?

Answer 32

Disruption of gut microflora > change in metabolism > overgrowth of pathogenic organism

Question 33

High risk antibiotics of CDI

Answer 33

Cephalosporins and Clindamycin

Question 34

Medium risk antibiotics of CDI

Answer 34

ampicillin/amoxycillin co-trimoxazole macrolides fluoroquinolones

Question 35

Low risk antibiotics of CDI

Answer 35

``` aminoglycosides metronidazole anti-pseudomonal penicillins + β- lactamase inhibitor Tetracyclines rifampicin vancomycin ```

Question 36

CDI therapy

Answer 36

Oral metronidazole/vancomycin

Question 37

New CDI therapy

Answer 37

Oral fidaxomicin