INFLAMMATION OF THE CENTRAL NERVOUS SYSTEM I. ENCEPHALITIS The study of encephalitis in childhood presents some very difficult problems, some of which still await solution. The difficulty lies in the want of harmony between pathologic findings and clinical experience, in the fact that the symptoms vary not only according to the seat of the disease but also according to the patient's age and, finally, that in childhood recovery' from encephalitis is probably much more frequent than in adults and it is accordingly difficult to establish a diagnosis of encephalitis from existing focal symptoms or retrospectively from autopsy changes discovered at some later period. In view of these facts we s.hall divide the subject loosely into the following subdivisions: interstitial congenital encephalitis (Virchow), encephalitis of infants, and encephalitis of older children. In discussing cerebral infantile palsy we shall have occasion to refer to infantile encephalitis again.
1. Interstitial Congenital Encephalitis as described by Virchow in 1SOff is interesting solely from a pathologic viewpoint and its existence as a clinical entity is very doubtful. According to Virchow the characteristic feature of this form of encephalitis is the presence in the brain of fatty granule cells. which are found either diffusely or in disseminated nests in the cerebrum of newborn infants. Very soon, however, a doubt was raised (Hayern, Jastrowitz, Kramer, Flechsig and others) whether these structures were really pathologic, and it was contended that these fatty granule cells are normal in the brain of the newborn. Other authors (v. Limbeek, Fisch!, Thicinich) are inclined to make a distinc tion between diffuse and circumscribed cellular accumulations aml accord to the latter at least a pathologic significance. From my own quite extensive investigations, which, it is true, have reference to the spinal cord rather than to the brain, I have eome to the conclusion that the fatty granule cells at a certain period of life unquestionably repre sent a normal condition in the. central nervous system of man and ac cumulate in many portions of the brain and spinal cord in a manner quite remarkable. On the other hand T know from personal experience
that small, yellowish foci occur in the brain of newborn infants, and since these foci, according to the investigations of several authors, contain, in a .(lition to the fatty cells, round cell infiltration, changes in the ganglion cells ancl proliferating neurogliar tissue, there can be no doubt that these small foci represent an inflammatory process. it will be advisable in future histologic investigations to pay more attention to other tissue elements that are characteristic of inflammation rather than to the fatty granule cells. We may then expect a solution of the question of Virchow's encephalitis and it may be found that newborn children, particularly immature and debilitated infants, may reaet to general septic processes by the formation of small inflammatory foci in the brain, and that the finding of fatty granule cells is not enough to establish a diagnosis of encephalitis. At all events these findings have a purely pathologic signifieanee, and it is very questionable whether the smaller foci ever coalesce to form large inflammatory areas capable of producing clinical symptoms; it is more probable that such conditions begin as severe and extensive lesions.
2. Acute Encephalitis of Infants.—Investigations by a number of authors (Gaudard, Kast, Jendrassik, Marie, Reymond, Fischl, Ganghofer, Finkelstein and others) have established the occurrence in infants of a clinical picture which begins acutely with violent cerebral symptoms, has a fatal termination and reveals post mortem an extensive inflamma tion of the brain.
The disease is apparently primary and occurs without any ante cedent characteristic infectious disease. it is probably the result of some septic process such as are so frequent at this age. Premature, sickly children arc particularly prone to diseases of this kind. The seat of inflammation is practically always in the cerebrum, particularly in the hemispheres, sometimes in the basal ganglia, and rarely in the pons.