CHANGES IN THE CSF AND THEIR RELATION TO THE ETIOLOGY OF THE DISEASE AND THE AGE AT ONSET

Summary At the time of onset of the disease the cell content of the CSF was usually higher in mumps meningoencephalitis than in meningoencephalitis of other origin. The difference was particularly striking among children. After the first 2 weeks of the disease no difference was found between the two groups in the children series, while adults with mumps meningo‐encephalitis at this stage had a lower cell‐count than the remainder. At onset as well as during the later course of the disease the total protein content of the CSF was higher in adults with meningoencephalitis not related to mumps than in those with mumps meningo‐encephalitis. During the initial stage of the disease a pronounced increase was noted in the relative concentration of the CSF albumin which thereby exceeded that of serum. At the same time the other protein fractions of the CSF were decreased. During the further course the pattern gradually became normal although the relative gamma‐globulin concentration was above normal for some time afterwards. The abnormalities in the electrophoretic pattern of the CSF protein are probably due to disturbed meningeal permeability. During the initial stage of the disease serum albumin may pass into the CSF space more readily than the remaining serum protein fractions. The increase in the gamma‐globulin concentration during the later course of the disease might be explained by a relative retardation of the re‐absorption to the blood stream.