investigations

Last edited 02/2022

The investigations of choice in cholecystitis are:

• FBC – usually shows leucocytosis
• liver function test – to detect any obstructive jaundice (1)
• abdominal x-ray:
  • can reveal radio-opaque stones in minority of cases
• may show air in the biliary tree
• can rule out intra-abdominal free air – seen in diverticulitis or perforated peptic ulcer (2)

• ultrasound:
  • recommended for any suspected acute cholecystitis
• first-choice imaging method for the morphological diagnosis of acute cholecystitis (3)
• diagnosis of acute cholecystitis is made radiologically when the following are present at the same time:
• thickening of the gallbladder wall (5 mm or greater)
• pericholecystic fluid
• ultrasonographic Murphy’s sign
• pain which occurs when the probe is pushed against the gallbladder
• superior to ordinary Murphy’s sign (3)
• other findings may include: gallbladder enlargement, gallbladder stones, debris echo and gas imaging (3)

• magnetic resonance cholangiopancreatography (MRCP):
  • can obtain images of the whole of the biliary tree and adjacent structures
• small stones can be detected
• recommended if abdominal ultrasound does not provide definitive diagnosis (3)

• CT scan:
  • finding may include: gallbladder distention (41%), gallbladder wall thickening (59%), pericholecystic fat density (52%), pericholecystic fluid collection (31%) (3)
• recommended for diagnosing gangrenous cholecystitis and emphysematous cholecystitis (3)

• radio-isotopic scanning – HIDA scanning:
  • has a sensitivity of 80–90% for acute cholecystitis
• normally outlines the gall bladder and duct system
• if gallbladder is obstructed, cannot take up contrast, hence, not shown
• ‘rim sign’ (a blush of increased pericholecystic radioactivity) is present in about 30% of patients with acute cholecystitis and in about 60% with acute gangrenous cholecystitis (3)
• usually reserved for patients in whom diagnosis is unclear after ultrasonography (4)

Reference:

1. Dawson J. Acute cholecystitis. GPonline 2009
2. Elwood DR. Cholecystitis. Surg Clin North Am. 2008;88(6):1241-52
3. Yokoe M, et al.Tokyo Guidelines 2018: diagnostic criteria and severity grading of acute cholecystitis (with videos). J Hepatobiliary Pancreat Sci. 2018 Jan;25(1):41-54. doi: 10.1002/jhbp.515. Epub 2018 Jan 9. PMID: 29032636.
4. Strasberg SM. Clinical practice. Acute calculous cholecystitis. N Engl J Med. 2008;358(26):2804-11.