An accumulation of pus in a specific area, known as an abscess, is caused by bacteria that have traveled from another location through the bloodstream or lymphatic system. These bacteria can originate from an already existing abscess or an infected wound. An illustration of this phenomenon is the transmission of bacteria from the heart valves to create an abscess in the brain.
An abscess that results from an infected embolus, typically a blood clot, often occurring in the lung or liver. This condition arises in cases of pyemia, which is caused by bacteria producing pus in the bloodstream, or as a complication of subacute bacterial endocarditis.