Bronchiectasis and other infective diseases of the lungs are less common causes of cerebral abscess, which is usually single, and may occur in any part of the brain.
"Manual of Surgery Volume Second: Extremities--Head--Neck. Sixth Edition."
Alexander Miles Alexis Thomson
The principle is exactly the same as that by which patients suffering from Bronchiectasis avail themselves of the help of gravity and get rid of the nocturnal accumulation of material in their dilated bronchi.
"Psychotherapy"
James J. Walsh