BOF: 32
A 63-year-old male presents
with a 6-day history of diarrhoea and lower abdominal pain. He is known to have
COPD and has had several courses of antibiotics recently for what his GP thought
were infective exacerbations.
On examination the patient
looks unwell, he is febrile (temp 39°
C) dehydrated, tachycardic and his blood pressure is low. His abdomen is
distended and tender, no lumps palpable, bowel sounds are heard and not
exaggerated.
Which of the following
investigations would be most appropriate in this patient?
a)
Plain x-ray abdomen
b)
Stool microscopy and culture
c)
CT scan of the abdomen
d)
Colonoscopy
e)
Unprepared flexible sigmoidoscopy
Answer:
e)
The history and examination
suggest the patient has an acute inflammatory condition of his bowel. With the
history of antibiotic treatment the likely cause is pseudomembranous colitis due
to Clostridium difficile rather than an infective colitis. Idiopathic
inflammatory bowel disease such as ulcerative colitis is unlikely as the history
is too short. Ischaemic colitis usually has a much more dramatic onset.
The best way to make a quick
diagnosis would be to perform an unprepared flexible sigmoidoscopy and directly
view the mucosa. As the patient has diarrhoea it is likely that the distal colon
is involved. This should be sufficient to make a diagnosis and biopsies could be
taken to provide histological confirmation.
Colonoscopy would be unwise in
the setting of an acutely inflamed colon, as this would increase the risk of
perforation.
CT scanning would show
inflammation of the colon but the type of colitis would be unclear.
Plain x-ray would be useful in
detecting toxic mega colon and may sometimes show thumb printing in colitis but
these changes are not specific.
Stool microscopy and culture
are unhelpful but toxin assay would point to the diagnosis.
Last Updated: 16/04/06
