The pathologic changes in this disorder consist not only of meningeal infiltrates but also of inflammation and fibrosis of small arteries (Heubner arteritis), which lead to narrowing and, finally, occlusion. Most of the infarctions occur in the distal territories of mediumand small-caliber lenticulostriate branches that arise from the stems of the middle and anterior cerebral arteries. Most characteristic perhaps is an internal capsular lesion, extending to the adjacent basal ganglia. The presence of multiple small but not contiguous lesions adjacent to the lateral ventricles is another common pattern. Small, asymptomatic lesions are often seen in the caudate and lenticular nuclei. Several of our patients have had transient prodromal neurologic symptoms.
The neurologic signs that remain after 6 months will usually be permanent but adequate treatment will prevent further vascular episodes. If repeated strokes occur despite adequate therapy, one should consider the possibility of nonsyphilitic vascular disease of the brain.
Paretic Neurosyphilis (General Paresis, Dementia Paralytica)
The general setting of this form of cerebral syphilis is long-standing meningitis hence, with tabes, it is a form of tertiary syphilis. As remarked above, some 15 to 20 years usually separate the onset of general paresis from the original infection. The history of the disease is entwined with many of the major historical events in neuropsychiatry. Haslam in 1798 and Esquirol at about the same time first delineated the clinical state. Bayle in 1822 commented on the arachnoiditis and meningitis, and Calmeil, on the encephalitic lesion. Nissl and Alzheimer added details to the pathologic descriptions. The syphilitic nature of the disease was suspected by Lasegue, by Fournier, and by others before Schaudinn’s and Hoffman’s discovery of the spirochete; it was finally confirmed by Noguchi in 1913. Kraepelin’s monograph General Paresis (1913) is one of the classic reviews (see Merritt et al for these and other historical references).
Once a major cause of various forms of mental illness, accounting for some 4 to 10 percent of admissions to asylums (hence the term “general paresis of the insane,” or GPI), general paresis is now seen less frequnetly. Because syphilis is acquired mainly in late adolescence and early adult life, the middle years (35 to 50) are the usual time of onset of the paretic symptoms. There have not been many cases of this process in patients with HIV; possibly the immunodeficiency has altered the biologic reaction to the organism.
The clinical picture in its fully developed form includes progressive dementia, dysarthria, myoclonic jerks, action tremor, seizures, hyperreflexia, Babinski signs, and Argyll Robertson pupils. However, greater importance attaches to diagnosis at an earlier stage, when few of these manifestations are conspicuous. The insidious onset of memory defect, impairment of reasoning, and reduction in executive function—along with minor oddities of deportment and conduct, irritability, and lack of interest in personal appearance—are not too different from the general syndrome of dementia outlined in Chaps. 20 and 38, especially of the frontotemporal variety. One can appreciate how elusive the disease may be at any one point in its early evolution. Indeed, with the currently low index of suspicion of the disease, diagnosis at this predemented stage is more often accidental than deliberate.