Editing Acalculous cholecystitis (section)

== '''Imaging''' ==

* USS first-line
** >4mm wall thickness
** Sonographic Murphy's sign
** Pericholecystic fluid/subserosal oedema
** However, most critically unwell patients in ICU will have at least one abnormal GB finding on USS, so the specificity is questionable (84% have one abnormal findings, and 57% have three or more)
* CT second-line - also excludes other causes
** Gas in GB wall or lumen, lack of GB wall enhancement, and oedema around the GB have the highest specificity (99, 95 and 92% respectively) but all have poor sensitivity
* HIDA scan is diagnostic if a third-line study is required, but can have a false positive result
** Failure to opacify the GB at one hour is a positive test
** Specificity 58-88%