25 For a detailed statement of the post-mortem appearances in general paralysis compare Spitzka's Insanity, pp. 218-243; Beiträge zur pathologischen Anatomie und zur Pathologie der Dementia Paralytica, von Dr. Franz Tuczek; Die Progressive Paralyse der Irren, von Dr. E. Mendel; Lehrbuch der Gehirnkrankheiten, von Dr. C. Wernicke, iii. pp. 536-541. Westphal's classical work is not referred to, as his latest views and others of interest are given in a report of a discussion by the German Association of Alienists in the Allgemeine Zeitschrift für Psychiatrie, iv. 1883, pp. 634-638 and 648-654. In the third number of the Neurol. Centralblatt, Mendel reports an autopsy of a patient diagnosticated to have melancholia, who died a violent death, where he thought that he found evidence of the early stage of general paralysis in moderate opacity of the pia mater, with nodules as large as a pin's head in both parietal regions, and in slight indications of diffuse interstitial inflammation of the cortex, the blood-vessels in the frontal convolutions being extensively filled with white blood-corpuscles.
In the majority of cases there is pachymeningitis, often extensive and excessive, with hemorrhages, but which may be no more than is quite commonly found in persons dying of phthisis or chronic nephritis. There is also, usually, leptomeningitis, with adhesions to the cortex, especially of the anterior and antero-lateral portions, so firm that the arachnoid cannot be removed without tearing off portions of the brain; but it is sometimes scarcely observed, and may be no more than is found in persons dying simply of old age. The pia may be in places thickened, opaque, and without adhesions. Ependymitis is usual.
In the terminal stage of general paralysis there is well-marked atrophy (with compensatory serous effusion), which is, as a rule, most marked in the cortex of the brain, but which is of varying degrees in its different portions. Rarely there is scarcely any atrophy of the cortex. The central portion of the brain may be of leathery consistence, but usually shows marked sclerosis, which also may affect its different portions and the different ganglia very differently. The changes resulting from inflammatory, degenerative, and atrophic processes are general and profound.
An opinion is beginning to obtain that general paralysis is primarily a disease of the small cerebral blood-vessels, functional or vaso-motor; and Meynert holds that the transition line between that stage, which he considers curable, and organic disease may be recognized clinically.
In general paralysis, as in other mental diseases, the nervous discharge is accompanied by a greater disturbance in the structure of the gray substance of the brain, a more extensive decompounding of it, and consequently by a more complete exhaustion of nervous force than in healthy mental processes. Longer periods of rest and improved nutrition are therefore necessary to restore healthy function. In general paralysis, as in all other mental diseases dependent upon destructive disease of the brain, there is not only decompounding, but decomposing and disintegrating, of the structure of the brain.
Posterior spinal sclerosis is frequently found. If alone or predominating over sclerosis of the lateral columns of the cord, the knee-jerk is abolished if the morbid process has gone far enough. If descending degeneration of the lateral columns is chiefly found, and is sufficiently advanced, the knee-jerk is increased. At least one of these forms of sclerosis exists in the vast majority of cases.
There is also a distinctly syphilitic disease of the smaller cerebral arteries, together with a diffuse parenchymatous and interstitial encephalitis of syphilitic origin. At present we have no means of differentiating it at the autopsy from general paralysis following a subacute or chronic course, except inferentially from the presence of other evidences of syphilis. It is not always possible, therefore, to distinguish between syphilis and a syphilitic diathesis as the chief factor in diffuse encephalitis.
DIAGNOSIS.—Although a well-marked case of general paralysis is unmistakable, the diagnosis in the early stages or in obscure cases may be extremely difficult. The varying degrees in which the various portions of the cortex, medullary portion, and different ganglia of the brain may be involved in the morbid process naturally give rise to a great variety in the symptoms, mental and physical, sensory and motor, emotional and intellectual, and in the relative preponderance of one or another in individual cases. The usual symptoms of any form of mental disease may for a time obscure the dementia which sooner or later must appear in general paralysis, and which, as has already been said, is the only mental symptom universally present in all cases. This mental impairment must also be associated with progressive muscular loss of power, although the relation of the two symptoms to each other, the degree to which a given amount of the one leads to a fair inference of a certain amount of the other, is liable to the greatest variation, the range of which can only be learned by observation and experience. There is a certain quality to the dementia, as already described, which is often sufficient of itself to establish the diagnosis with a practised physician.
The early mental symptoms may simulate those of cerebral neurasthenia, in which the patient thinks that there is decided mental impairment, although there is no progressive dementia. The tremor in neurasthenia is greater and more universal than in the stage of general paralysis with which it might be confounded, and the subjective symptoms are much more prominent.