© 1930 The Royal College of Psychiatrists
Problems of Pyretotherapy in Paralytic Dementia
Wonford House Hospital, Exeter
ABSTRACT
In the series of cases under consideration it was found that changes occurred in the bone-marrow and blood in paralytic dementia, which showed that the leucopoietic functions were impaired and that the leucocyte reserve was diminished. In untreated cases there was a definite leucopenia.
When leucocytosis was stimulated the intensity of the neutrophilic reaction varied inversely with the stage to which the paralytic dementia had advanced.
Under the same conditions the Schilling index rose in direct proportion to the stage of the disease. The rise was most marked in those cases whose decline was accelerated by pyretotherapy, and least marked in those who were benefited.
Six to nine months after treatment by the induction of relapsing fever the Schilling index, in favourable cases, was restored to normal limits after having been at a higher level before treatment. This is in accord with the experience of other writers with regard to the effects of malarial treatment.
The better the condition of the patient after treatment, the nearer did the differential leucocyte count and Schilling index approach the normal, and the converse was equally true.
The changes described above are referable to affection of the reticulo-endothelial system. An analogy has been drawn between paralytic dementia and pernicious anæmia. That syphilis may attack this system is evident from the fact that it may produce a condition clinically resembling pernicious anæmia. Yet this need not always be the case, for the writer detected no appreciable rise in the Schilling index when neutrophilia was artificially induced in syphilitic subjects in whom paralytic dementia was not evident, nor were any signs of impairment of the leucopoietic function detected at autopsy.
It would appear, therefore, that involvement of the reticulo-endothelium by the syphilitic virus constitutes one of the factors which determine whether a given syphilitic subject will develop paralytic dementia. Strength is lent to this hypothesis when it is remembered that the type of subject who develops paralytic dementia is one in whom a scanty history of earlier syphilitic lesions indicates absence of reaction against the infecting organism.
Since involvement of the reticulo-endothelial system is a characteristic of paralytic dementia, it follows that therapeutic measures should take this into account.
In general, pyrexia is associated with a leucocytic reaction resulting in numerical changes in the leucocyte-content of the blood—that is to say, the reticulo-endothelial system takes part in the genesis and control of pyrexia.
Treatment by means of leucogenic infections resulted at first in emphasizing the changes which paralytic dementia produces in the leucopoietic functions. The later effects consisted in the correction of these changes in the cases which derived benefit from the treatment, and in the reverse in those which were unimproved. In other words, pyretotherapy stimulates the resistive function of the reticulo-endothelial system at a time when this function is flagging under the influence of a chronic infection, namely, syphilis.
From the pathological point of view, some writers have found that malaria can convert paralytic dementia into a condition of meningo-vascular syphilis which may even assume a diffuse gummatous nature. Others describe increased reaction on the part of the reticulo-endothelium of the cerebral blood-vessels during the malarial attack, with subsequent restoration of the cortex. It is significant that a therapeutic measure which relieves the depression of the leucopoietic function should either stimulate the cerebral reticulo-endothelium and then restore it nearly to normal, with consequent clinical improvement, or else convert a paretic condition into one of meningo-vascular syphilis.
From the therapeutic point of view the following considerations arise:
- Malarial therapy should be reserved for those cases in which a satisfactory leucocytic reaction has been obtained by means of a preliminary test with a mild leucogenic agent.
- In view of the importance of the reticulo-endothelial disturbance, patients who have derived benefit from malarial treatment should reside for a time at a high altitude in order to stimulate erythropoiesis, in the hope that the closely allied function of leucopoiesis will benefit.
- Prophylactic malarial treatment should be advised for all patients who are known to suffer from syphilis in whom few, if any, secondary or tertiary lesions have been observed.