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examination of the fluid was called for, were in favour of encephalitis lethargica in
15, tuberculous meningitis in 21, other forms of meningitis in 11; and assisted
diagnosis of disease of the mastoid bone or accessory nasal sinuses in 5, gross cerebral
lesions such as abscess and tumor in 7, disorders of the cerebral circulation (haemorrhage
congestion and thrombosis, etc.), in 11, cerebral degeneration in 6, neurosyphilis
of the brain and spinal cord in 14, disordered mental states in 5,meningismus
and other conditions in which the brain was unaffected in 10 cases.
Encephalitis Lethargica.—Nineteen specimens of cerebro-spinal fluid from
fifteen cases were examined. The cases included 7 males and 8 females, whose
ages ranged from 14/12 years to 53 years. As is usually found in the majority of
cases of encephalitis the fluid was practically normal in composition, thus in ten
cases it was clear, transparent and colourless, with total protein content under
•02 per cent., free from excess of globulin, dextrose in normal trace of .7 per cent.,
or occasionally slightly increased in amount, and the cell count was under 5 per
c.m.m. In four specimens there was turbidity or slight opalescence, with fine clot
formation, or flocculi of fibrin and cells in two, and a cell count ranging from
5 to 10 up to 22,90 and 226 per c.m.m., and consisting almost entirely of lymphocytes.
In the two specimens with high cell counts and fibrin formation there was also an
excess of globulin—and protein amounting to .07 and .2 per cent.; whereas the 19
specimens showed a range of total protein varying from .005 to .2 per cent. with an
average of .037 per cent., as compared with the normal .01-.02. In five specimens
traces of blood were present, usually visible only on centrifugation, the films from
the blood-cell-deposit showing little, if any, increase in the number of lymphocytes.
As a result of examination of the fluid it was possible in all cases to support
the diagnosis of encephalitis or post-encephalitis which had been put forward on
clinical grounds, whereas in 6 cases the alternative, or only diagnosis made, of tuberculous
meningitis was clearly contra-indicated in favour of encephalitis. This
was ultimately confirmed by the subsequent course of 15 cases, which resulted
in recovery in five, death in four (one complicated by diabetes) and the development
of post-encephalitic sequelae, such as altered mental states and Parkinsonian
symptoms, in six.
Owing to the varied clinical manifestations of encephalitis lethargica, its
differentiation from other cerebral conditions is often a matter of very considerable
difficulty. It is common to find that during prevalence of the disease, cases of cerebral
tumour, abscess, haemorrhage, meningitis and disordered mental states have been
mistaken for encephalitis and notified as such. It is, therefore, unfortunate that
as a rule the changes in the composition of the fluid are too slight to give material
help in diagnosis. Even in tuberculous meningitis, unless tubercle bacilli have
been definitely found, doubt may arise, especially in children, as to whether the
changes shown by the fluid are due to meningitis or to unusual constituents resulting
from encephalitis, e.g., turbidity or opalescence, excess of protein, lymphocyte
increase in the cell content, and the presence of fine threads of fibrinous or occasionally
colloid material clot, without tubercle bacilli being found (v. two cases of encephalitis
mentioned above and two cases of tuberculous meningitis referred to later).
Somewhat similar abnormalities in appearance and composition of the cerebrospinal
fluid in certain cases of encephalitis have been described in a paper read
before the Pathological Society of Great Britain in January, 1925, by G. S. Williamson,
who attributed the changes to the inflammatory process involving the ependyma,
or lining membrane of the ventricles, and causing a catarrhal ependymitis.
Tuberculous meningitis.—Twenty-three specimens of fluid from 21 cases of
this variety of meningitis were examined, 11 females and 10 males, aged 2-25.
21 specimens were sent from 19 patients at St. James' Hospital and one each from
Fulham and St. Pancras Hospitals. The appearance was clear and colourless in
11, light straw-coloured in 1, slightly turbid in 6, and blood was present in variable