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(3) Water, 2 samples for bacteriological counts.
(4) Blood, complete cell count of a school teacher for evidence of pernicious
anaemia.
VI. Cerebrospinal fluid.—During 1924 a total of 106 specimens of cerebro-spinal
fluid were examined from 100 separate cases, many of which presented difficult and
obscure points and yielded results of considerable interest. The specimens were
sent with a view to help in diagnosis, notably of encephalitis lethargica, the various
forms of meningitis, syphilitic and other affections of the central nervous system.
63 came from the Fulham Infirmary, 27 from St. James Hospital, Balham, 10 from
St. Pancras hospital, one from St Luke's Hospital, Chelsea, and five specimens were
obtained from lumbar puncture of cases visited in consultation with private
practitioners.
The cases may be grouped under the headings set out in the margin as regards
final diagnosis :
Encephalitis
lethargica.
26 specimens of fluid were examined from 23 cases, eventually diagnosed as
probable encephalitis or confirmed as such by their ultimate course. The original
diagnosis of encephalitis on clinical grounds was regarded as probable in 7, and
doubtful in 16, with alternative diagnoses of meningitis in 10, neurosyphilis in 3,
cerebral tumour in 2, and epilepsy in 1.
From examination of the cerebro-spinal fluid it was possible to draw conclusions
in support of encephalitis in 18 cases, and doubtful in five—two of which were complicated
by epilepsy, one by possible cerebral syphilis, and two were subsequently
diagnosed as encephalitis. These conclusions were based on the slight departures
from the normal composition of the cerebro-spinal fluid usually shown in encephalit's,
taken in conjunction with the clinical features of the individual cases. Confirmation
was supplied by their subsequent course, leading to notification in 14 cases and
death in 9, five of which were further confirmed by post-mortem examination. The
puzzling and protean clinical aspects of encephalitis have for some years now been
fully realised and, despite increasing familiarity with this disease, its diagnosis is
still often extremely difficult. With the aid of examination of the cerebro-spinal fluid
in such cases it is usually possible to eliminate meningitis and neurosyphilis. But
in other pathological conditions, such as cerebral haemorrhage, cerebral abscess or
tumour, concussion, and, as in one case to be referred to, of acute ex-ophthalmic
goitre, in which the symptoms of hyperthyroidism simulated those of encephalitis,
the comparatively negative results of examination of the cerebro-spinal fluid may
lead to the mistaken diagnosis of encephalitis, corrected only should there be a postmortem
examination.
Analysis of the results which led to conclusions in favour of encephalitis, in cases
subsequently confirmed as such, showed that in 10 specimens the fluid appeared
to be normal in composition, and in four heavy traces of blood were present, preventing
satisfactory examination. Four showed some turbidity, or opalescence, with
particles of fibrin and collections of the debris of degenerate and dead cells. In five
the presence of lymphocytes in excess of the normal number (2-5 per c.mm.), up
to 30 or 40 per c.mm. were found.
The amount of protein varied from .001 to .08 per cent.,with an average of .027,
i.e., above the normal .01-.02, as measured by Aufrecht's albuminometer. In one
specimen, only, globulin was present in excess, and in all a trace of dextrose was
indicated by the ready reduction of Fehling's solution, apparently in about normal
amount.
The suggested alternative diagnosis of neurosyphilis in three cases was contraindicated
by the negative Wassermann reaction, negative colloidal benzoin or
Lange gold tests, and by the absence of globulin in excess. One case which was
clinically regarded and notified as encephalitis and subsequently developed insanity,
was complicated by evidence obtained from the cerebro-spinal fluid in favour of
cerebral syphilis, namely, positive Wasserman and colloidal benzoin reactions,