Gallbladder empyema is a complication of acute cholecystitis characterized by extensive pus formation from invading bacteria and distension of the gallbladder, which may lead to life-threatening sepsis in the absence of early therapy. The clinical presentation is not significantly different from acute cholecystitis, comprising fever, chills, and right upper quadrant abdominal pain, as main symptoms. Imaging studies are used to support clinical suspicion.
The inflammation of the gallbladder (mostly due to the presence of a gallstone), known as acute cholecystitis, can further lead to the development of various complications, one of the most important being gallbladder empyema . It is seen in approximately 2-11% of patients who suffer from cholecystitis  and is caused by bacterial superinfection of the bile that is trapped in the gallbladder, leading to pus formation and distension of the gallbladder lumen (together with increased wall thickness)  . For this reason, the term suppurative cholecystitis is often used as a synonym in the medical literature  . Males have shown to be at an increased risk for the development of gallbladder empyema compared to women, whereas diabetes mellitus was also identified as a predisposing factor  . The clinical presentation is largely similar to acute cholecystitis - fever, chills, and pain in the right upper quadrant of the abdomen, which could be accompanied by severe weakness (prostration)  . Symptoms may rapidly develop, and in the setting of sepsis (predominantly caused by gram-negative pathogens) or perforation, the condition might be life-threatening  . For this reason, early recognition is necessary in order to facilitate proper therapy  .
Physicians need to conduct a thorough clinical assessment through a detailed patient history and a comprehensive physical examination. The initial diagnosis of acute cholecystitis should be made based on clinical criteria, and in the setting of very high fever, abdominal pain that is accompanied by rebound tenderness (and a positive Murphy's sign - palpation of the inflamed gallbladder during inspiration that results in pain), as well as poor general condition, can point to gallbladder empyema  . Imaging studies, however, are the cornerstone in visualizing gallbladder empyema and establishing a firm diagnosis   . Abdominal ultrasonography (US), regarded as the first-line study in patients with hepatobiliary system pathology, will be able to identify gallstones, and thus raise valid suspicion, but more advanced methods, such as computed tomography (CT) and magnetic resonance imaging (MRI), may be necessary to make a definite diagnosis   . In addition to gallstones, thickening of the gallbladder wall, distension, and reactive hyperemia are other notable findings on the US and CT . MRI, on the other hand, is a superior method compared to US and CT, as it can discriminate pus and bile on T2-weighed studies, in which case percutaneous needle aspiration of pus and subsequent microbiological investigation might be recommended to reveal the underlying bacterial microorganism responsible for the infection  . Apart from significant leukocytosis, other laboratory findings are nonspecific  .