Gallbladder and bile duct pathologies are the most frequent causes of right upper quadrant pain (1,2). Among these, acute cholecystitis is one of the first diagnostic considerations.
Acute cholecystitis consists of inflammation of the gallbladder, being in up to 95% of cases secondary to gallstones (3). Acute calculous cholecystitis is more common in women, although the clinical picture may be more severe in men and patients with other comorbidities.
Its pathophysiology is intuitive:
- Emptying of the gallbladder is compromised by an obstructive gallstone
- There's bile salts accumulation
- Bile salts damage and inflame the gallbladder mucosa.
This progressive inflammation restricts blood flow to the gallbladder wall, and bacterial infection may occur in up to 66% of cases (5).
Classic acute cholecystitis US findings are:
- Presence of gallstones
- Thickening of the gallbladder wall
- Positive Murphy's sign
- Presence of perivesicular fluid or perivesicular inflammatory changes.
Most of the previously described findings can also be found on CT, although the presence of gallstones may be underestimated. However, CT may be performed in some patients when signs and symptoms are equivocal and when US assessment is limited and does not allow a complete diagnosis (6).
When assessing acute cholecystitis complications, the sensitivity of US falls and CT gains diagnostic confidence (7, 8). In addition, complicated acute cholecystitis is sometimes managed differently from classic acute cholecystitis, so knowing whether or not complications are present is important from a radiological, clinical and surgical point of view.
Among the complications of acute cholecystitis we find:
- Gangrenous cholecystitis.
- Perforated cholecystitis.
- Emphysematous cholecystitis.
- Haemorrhagic cholecystitis.
Other chronic complications of cholecystitis include:
- Mirizzi syndrome
- Xanthogranulomatous cholecystitis.
- Gallstone ileus and bile-digestive fistula.
In addition, due to the pro-inflammatory state, there is an increased thrombotic risk that can affect the portal vein and its branches, in a phenomenon known as septic pylephlebitis (9).