The rise of AIDS in the 1980s and 1990s has led to an increase in the number of diagnosed cases of neurosyphilis.
Late syphilis consists of ongoing inflammatory disease most likely in the aorta or nervous system (neurosyphilis), the latter occurring in about 10% of patients. The neurosyphilis of the late stage can consist of 1) asymptomatic neurosyphilis, 2) meningovascular syphilis, and 3) parenchymal neurosyphilis which has two forms. One form of parenchymal neurosyphilis consists of general paresis, which occurs about 20 years after infection and includes cognitive impairment, myoclonus, dys-arthria, personality changes, irritability, psychosis, grandiosity and mania. Untreated general paresis leaves the patient a helpless invalid. The second form of parenchymal neurosyphilis is tabes dorsalis with onset 25 to 30 years after initial infection. Tabes features loss of position and vibratory sense, areflexia in lower extremities, chronic pain, ataxia and incontinence.
The original screening test for syphilis is the venereal dis-ease research laboratory (VDRL) test. This test has a significant false-positive rate, especially in the elderly and in patients with addictions and autoimmune disorders (Kaufman, 1990b). The VDRL test may revert to negative after a number of years, and 20 to 30% of patients in the stage of late syphilis have a negative (nonreactive) VDRL result. A more specific test is the fluores-cent treponemal antibody screen, which is positive 95% of the time in neurosyphilis. The false-positive rate for the fluorescent treponemal antibody screen is extremely low, and reversion to a nonreactive state is unlikely. In addition to a positive VDRL result, the CSF in patients with neurosyphilis generally shows pleocytosis.
Dementia secondary to neurosyphilis produces various physical findings in advanced cases. These may include dysar-thria, Babinskiâ€™s reflex, tremor, Argyll Robertson pupils, myelitis and optic atrophy. Although notorious, delusions of grandeur in neurosyphilis are rare. A reactive CSF VDRL result or a positive serum fluorescent treponemal antibody result in a patient with neurological symptoms who cannot document treatment should be treated with appropriate therapy. Penicillin often improves cognitive deficits and corrects CSF abnormalities, but complete recovery is rare.