(gastro) gastrointestinal disorders & infections Flashcards
what do elevated CRP and WCC indicate?
indicate an infective/inflammatory process
what does an elevated creatinine indicate?
usually (acute) kidney injury
what are the main differential diagnoses for infectious diarrhoea?
Clostridium difficile
Klebsiella oxytoca
Clostridium perfringens
Salmonella spp
what are the main differential diagnoses for non-infectious diarrhoea?
antibiotics side effect
post-infectious irritable bowel syndrome
haemorrhoids
inflammatory bowel disease
microscopic colitis
ischaemic colitis
coeliac disease
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
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
why is an endoscopy not really used to investigate differentials unless specifically required?
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)
describe the following scan
normal abdominal X-ray
how is C. diff infection managed?
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
what are dry oral mucosa and skin turgor indicative of?
dehydration
how is C. diff classified in terms of severity?
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
what are the indications for non-severe C. diff infection?
WCC < 15, creatinine < 150
what are the indications for severe C. diff infection?
WCC > 15, creatinine > 150
what are the indications for fulminant colitis?
severe infection AND either hypotension/shock/ileus/signs of toxic megacolon
what is fulminant colitis?
= C.diff colitis with significant systemic toxic effects and shock
how is non-severe C. diff infection managed?
antibiotic therapy with oral vancomycin or fidaxomicin or metronidazole
role of faecal microbiota transplantation (FMT)
how is severe C. diff and fulminant colitis infection managed?
antibiotic therapy
supportive care
close monitoring
early surgical consultation (in case symptoms worsen and require immediate surgical intervention)
what does the following AXR indicate and why?
a) toxic megacolon
b) small bowel obstruction
c) large bowel obstruction
d) ileus
dilated small bowel loops and dilated large bowel
= approx 8-9cm wide + looks like transverse colon
so toxic megacolon (!!)
what is toxic megacolon?
swelling and inflammation spread into the deeper layers of your colon
colon stops working and widens and can even rupture in severe cases
what is ileus?
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
what is the first-line treatment for fulminant colitis with toxic megacolon?
medical therapy with antibiotics and supportive management (rehydration)
usually transfer to ITU for invasive monitoring (fluid resuscitation & ionotropic support)
what is fluid resuscitation?
replenishing bodily fluid lost through sweating, bleeding, fluid shifts or other pathologic processes
when is a patient fluid resuscitated?
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)
what is ionotropic support?
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)
when is ionotropic support given?
acute conditions where there is low cardiac output (e.g. congestive heart failure, MI, cardiogenic shock post-surgery)
= to prevent tissue hypoperfusion
for a patient with toxic megacolon, what are the indication for surgery?
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
what is abdominal compartment syndrome?
when the abdomen becomes subject to increased pressure reaching past the point of intra-abdominal hypertension
how can end-organ failure occur for a patient with toxic megacolon?
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
why is abdominal compartment syndrome an emergency?
leads to increasing abdominal pressure which can compress organs leading to abdominal organ failure
besides fulminant colitis, what other type of colitis is linked to C. diff infection?
pseudomembranous colitis
what is pseudomembranous colitis?
infection of the bacterium C. diff which manifests as yellow-white plaque formation in the mucosa
what is characteristic of pseudomembranous colitis?
characteristic yellow-white plaques that form pseudomembranes on the mucosa
= manifestation of severe colonic disease
how is pseudomembranous colitis diagnosed?
w a flexible sigmoidoscopy
when would IV vancomycin be given preferentially over oral vancomycin?
for an acutely unwell patient who cannot fully absorb the vancomycin orally due to
a) severe diarrhoea
b) obstruction due to building oedema
differentiate between pseudomembranous and fulminant colitis
both caused by severe C. diff infection but pseudomembranous usually also presents with characteristic yellow-white plaques on the mucosa
how is pseudomembranous colitis confirmed?
confirmed on endoscopy +/- biopsy
what are some possible differentials for infectious, blood diarrhoea?
Clostridium difficile
Shigella
E. Coli
Salmonella spp
what does the following endoscopy result suggest?
‘continuous, left-sided inflammatory changes and histology confirms chronic inflammation with no granulomas
continuous, left-sided, no granulomas
= ulcerative colitis
what management options are there for ulcerative colitis?
steroids (prednisolone, hydrocortisone = short-term)
5-ASA (aminosalicyclates)
immunosuppressants (azathioprine, methotrexate)
biologics (in severe cases e.g. anti-TNF)
can steroids be prescribed long term?
rarely but probably not, the side effects can be very harmful (osteoporosis, diabetes, acne, hirsutism etc)
how is the severity of ulcerative colitis categorised?
different scopes including clinical disease activity index, Montreal classification and Trulov & Witt scores
mild
moderate
severe
what is mild ulcerative colitis?
4 x bowel movements/day
no systemic toxicity
normal ESR/CRP
mild symptoms
what is moderate ulcerative colitis?
> 4x bowel movements/day
mild anaemia
mild symptoms
minimal systemic toxicity
nutrition maintained
no weight loss
what is severe ulcerative colitis?
> 6 bowel movements/day
severe symptoms
systemic toxicity
significant anaemia
increased ESR/CRP
weight loss
which immunosuppressants are usually given to treat ulcerative colitis?
azathioprine
methotrexate
if ulcerative colitis worsens despite management, how is it approached?
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
which blood test is essential before administering azathioprine for ulcerative colitis?
TPMT (thiopurine S-methyltransferase)
= essential for metabolising azathioprine and a deficiency in TPMT can cause azathioprine buildup to dangerous levels
