The initial site of infection is usually the pharyngeal or tonsillar tissue. The bacteria invade these tissues, causing an inflammatory response. Histologically, this can be observed as acute inflammation characterized by the infiltration of neutrophils, tissue edema, and necrosis. As the infection progresses, the bacteria can invade the nearby internal jugular vein, leading to thrombophlebitis. The thrombus formed in the vein can break off and disseminate to other organs, causing septic emboli.
