Acute suppurative meningitis, purulent exudate: This is an example of the widespread, purulent exudate that may be found in overwhelming, acute meningitis due to a pyogenic organism. The exudate is confluent over many portions of the hemisphere and microscopically is composed of neutrophils and fibrin. The photograph also shows the tendency for exudate to be most prominent along cortical venous channels. Thrombosis of cortical veins is sometimes found secondary to thrombophlebitis. Although edema is present to some degree in the underlying brain, death usually ensues from the overwhelming infection rather than as a consequence of cerebral swelling.