Discuss the gross pathology and histopathology of tabes dorsalis and general paresis. In most bacterial infections, the primary site is remote, such as the lung, heart, or bone. The pathogens reach the CNS by hematogenous dissemination. The exudate may extend into the brain parenchyma via perivascular spaces. It may invade the vessel walls causing vasculitis, necrosis or thrombotic occlusion of the lumen.
Meningococcus meningitis has a fulminant variant with a high mortality rate.
The abscess begins as a localized purulent encephalitis. After 2-3 days, the center liquefies. The causative organism of syphilis is Treponema pallidum. AIDS patients and IV drug abusers are at high risk of developing neurosyphilis. Two major forms of parenchymal neurosyphilis are general paresis and tabes dorsalis.