Empyema

An empyema (/ˌɛmpaɪˈiːmə/; from Ancient Greek ἐμπύημα (empúēma) 'abscess') is a collection or gathering of pus within a naturally existing anatomical cavity.

Empyema occurs in: Chest X-rays or computed tomography (CT) scans can reveal the presence of fluid within the pleural space and help assess its characteristics.

Once a fluid-filled cavity has been identified, it is often partially or fully drained with a needle, so that the fluid may be analyzed.

Blood tests may also be performed, which can identify both an elevated neutrophil count, which is indicative of an infection, or bacteremia.

[2] In addition to CT, suspected cases of empyema in and around the brain are often subjected to more rigorous neuroimaging techniques, including MRI.