At an isolated weather station in the central United States, a technician emerges from a small brick shed grasping a balloon. It's not just any birthday party balloon, mind you, but a massive, white sphere more than 5 feet (1.5 meters) in diameter.
Most frequently, the lung abscess arises as a complication of aspiration pneumonia caused by mouth anaerobes. The patients who develop lung abscess are predisposed to aspiration and commonly have periodontal disease.
The germs that cause a brain abscess can reach the brain through the blood. Or, they enter the brain directly, such as during brain surgery. The source of the infection is often not found. However, the most common source is a lung infection. Less often, a heart infection is the cause.