(gastro) gastrointestinal disorders & infections

Question 1

what do elevated CRP and WCC indicate?

Answer 1

indicate an infective/inflammatory process

Question 2

what does an elevated creatinine indicate?

Answer 2

usually (acute) kidney injury

Question 3

what are the main differential diagnoses for infectious diarrhoea?

Answer 3

Clostridium difficile
Klebsiella oxytoca
Clostridium perfringens
Salmonella spp

Question 4

what are the main differential diagnoses for non-infectious diarrhoea?

Answer 4

antibiotics side effect

post-infectious irritable bowel syndrome

haemorrhoids

inflammatory bowel disease

microscopic colitis
ischaemic colitis

coeliac disease

Question 5

for a patient that presents with the following, what is the most appropriate next investigation?

• day 4 post-surgery, on antibiotics, with new-onset diarrhoea, generalised tenderness
• investigations show:
  ↑ed WCC & CRP indicating an inflammatory/infective process + has an acute kidney injury indicating dehydration

a) stool sample for C.diff toxin
b) stool culture
c) imaging (AXR)
d) endoscopy
e) all of the above

Answer 5

a, b and c

a) stool sample for C.diff toxin = to investigate most likely differential
b) stool culture = to rule out other possible causes
c) imaging (AXR) = to look for dilated bowel loops or subdiaphragmatic air
d) UNLIKELY - as if the diagnosis is pretty clear form the above investigations, will not do an invasive diagnostic test after

Question 6

why is an endoscopy not really used to investigate differentials unless specifically required?

Answer 6

as if the diagnosis is pretty clear form the above investigations, will not do an invasive diagnostic test to confirm

(= endoscopy increases perforation risk significantly)

Question 7

describe the following scan

Answer 7

normal abdominal X-ray

Question 8

how is C. diff infection managed?

Answer 8

infection control
- move patient into side rooms, isolate

discontinue inciting antibiotic agents
- stop abx causing the problem and start on oral/IV vancomycin or metronidazole

control dehydration
- fluid rehydration, nutrition

Question 9

what are dry oral mucosa and skin turgor indicative of?

Answer 9

dehydration

Question 10

how is C. diff classified in terms of severity?

Answer 10

non-severe infection
= WCC < 15, creatinine < 150

severe infection
= WCC > 15, creatinine > 150

fulminant colitis
= severe infection + either hypotension or shock/ileus/signs of toxic megacolon

Question 11

what are the indications for non-severe C. diff infection?

Answer 11

WCC < 15, creatinine < 150

Question 12

what are the indications for severe C. diff infection?

Answer 12

WCC > 15, creatinine > 150

Question 13

what are the indications for fulminant colitis?

Answer 13

severe infection AND either hypotension/shock/ileus/signs of toxic megacolon

Question 14

what is fulminant colitis?

Answer 14

= C.diff colitis with significant systemic toxic effects and shock

Question 15

how is non-severe C. diff infection managed?

Answer 15

antibiotic therapy with oral vancomycin or fidaxomicin or metronidazole

role of faecal microbiota transplantation (FMT)

Question 16

how is severe C. diff and fulminant colitis infection managed?

Answer 16

antibiotic therapy

supportive care

close monitoring

early surgical consultation (in case symptoms worsen and require immediate surgical intervention)

Question 17

what does the following AXR indicate and why?

a) toxic megacolon
b) small bowel obstruction
c) large bowel obstruction
d) ileus

Answer 17

dilated small bowel loops and dilated large bowel

= approx 8-9cm wide + looks like transverse colon

so toxic megacolon (!!)

Question 18

what is toxic megacolon?

Answer 18

swelling and inflammation spread into the deeper layers of your colon

colon stops working and widens and can even rupture in severe cases

Question 19

what is ileus?

Answer 19

lack of movement somewhere in the intestines that leads to a buildup and potential blockage of food material

= can lead to obstruction and can occur as a side effect of surgery

Question 20

what is the first-line treatment for fulminant colitis with toxic megacolon?

Answer 20

medical therapy with antibiotics and supportive management (rehydration)

usually transfer to ITU for invasive monitoring (fluid resuscitation & ionotropic support)

Question 21

what is fluid resuscitation?

Answer 21

replenishing bodily fluid lost through sweating, bleeding, fluid shifts or other pathologic processes

Question 22

when is a patient fluid resuscitated?

Answer 22

when they have lost significant amounts of fluid that needs to be replenished

(e.g. when patient is NBM, severe diarrhoea, sever vomiting, hypovolaemia due to blood loss)

Question 23

what is ionotropic support?

Answer 23

inotropic support to stabilise circulation and to optimise oxygen supply

(negatively inotropic agents = weaken force of muscular contractions; positively inotropic agents = increase strength of muscular contraction)

Question 24

when is ionotropic support given?

Answer 24

acute conditions where there is low cardiac output (e.g. congestive heart failure, MI, cardiogenic shock post-surgery)

= to prevent tissue hypoperfusion

Question 25

for a patient with toxic megacolon, what are the indication for surgery?

Answer 25

colonic perforation

necrosis or full-thickness ischaemia

intra-abdominal hypertension or abdominal compartment syndrome

clinical signs of peritonitis or worsening abdominal exam despite adequate medical therapy

end-organ failure

Question 26

what is abdominal compartment syndrome?

Answer 26

when the abdomen becomes subject to increased pressure reaching past the point of intra-abdominal hypertension

Question 27

how can end-organ failure occur for a patient with toxic megacolon?

Answer 27

increasing abdominal pressure

= increased abdominal dysfunction
= fluid/oedema collection
= no available space for fluid to go into as organs cannot continue expanding
= increasing pressure on organs leads to end-organ failure

Question 28

why is abdominal compartment syndrome an emergency?

Answer 28

leads to increasing abdominal pressure which can compress organs leading to abdominal organ failure

Question 29

besides fulminant colitis, what other type of colitis is linked to C. diff infection?

Answer 29

pseudomembranous colitis

Question 30

what is pseudomembranous colitis?

Answer 30

infection of the bacterium C. diff which manifests as yellow-white plaque formation in the mucosa

Question 31

what is characteristic of pseudomembranous colitis?

Answer 31

characteristic yellow-white plaques that form pseudomembranes on the mucosa
= manifestation of severe colonic disease

Question 32

how is pseudomembranous colitis diagnosed?

Answer 32

w a flexible sigmoidoscopy

Question 33

when would IV vancomycin be given preferentially over oral vancomycin?

Answer 33

for an acutely unwell patient who cannot fully absorb the vancomycin orally due to

a) severe diarrhoea
b) obstruction due to building oedema

Question 34

differentiate between pseudomembranous and fulminant colitis

Answer 34

both caused by severe C. diff infection but pseudomembranous usually also presents with characteristic yellow-white plaques on the mucosa

Question 35

how is pseudomembranous colitis confirmed?

Answer 35

confirmed on endoscopy +/- biopsy

Question 36

what are some possible differentials for infectious, blood diarrhoea?

Answer 36

Clostridium difficile
Shigella
E. Coli
Salmonella spp

Question 37

what does the following endoscopy result suggest?

‘continuous, left-sided inflammatory changes and histology confirms chronic inflammation with no granulomas

Answer 37

continuous, left-sided, no granulomas

= ulcerative colitis

Question 38

what management options are there for ulcerative colitis?

Answer 38

steroids (prednisolone, hydrocortisone = short-term)

5-ASA (aminosalicyclates)

immunosuppressants (azathioprine, methotrexate)

biologics (in severe cases e.g. anti-TNF)

Question 39

can steroids be prescribed long term?

Answer 39

rarely but probably not, the side effects can be very harmful (osteoporosis, diabetes, acne, hirsutism etc)

Question 40

how is the severity of ulcerative colitis categorised?

Answer 40

different scopes including clinical disease activity index, Montreal classification and Trulov & Witt scores

mild
moderate
severe

Question 41

what is mild ulcerative colitis?

Answer 41

4 x bowel movements/day

no systemic toxicity

normal ESR/CRP

mild symptoms

Question 42

what is moderate ulcerative colitis?

Answer 42

> 4x bowel movements/day

mild anaemia

mild symptoms

minimal systemic toxicity

nutrition maintained

no weight loss

Question 43

what is severe ulcerative colitis?

Answer 43

> 6 bowel movements/day

severe symptoms

systemic toxicity

significant anaemia

increased ESR/CRP

weight loss

Question 44

which immunosuppressants are usually given to treat ulcerative colitis?

Answer 44

azathioprine

methotrexate

Question 45

if ulcerative colitis worsens despite management, how is it approached?

Answer 45

repeat bloods (FBC, LFT, renal profile, CRP, etc)

educate patients on side effects of new drugs they need to take (azathioprine, methotrexate, biologics maybe)

imaging to rule out complications

Question 46

which blood test is essential before administering azathioprine for ulcerative colitis?

Answer 46

TPMT (thiopurine S-methyltransferase)

= essential for metabolising azathioprine and a deficiency in TPMT can cause azathioprine buildup to dangerous levels