Memorandum on encephalitis lethargica.

Date:
1921
Catalogue details

Licence: Public Domain Mark

Credit: Memorandum on encephalitis lethargica. Source: Wellcome Collection.

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    bility may be accompanied by catalepsy. Various degrees of. stupor have been noted: . The condition may be one of Gee coma with open eyes, total lack of facial expression “and inability to be roused. More commonly the condition 1s not so grave, but the patients are in a profound sleep from which they can be aroused to answer questions or to partake of food. When undisturbed they quickly lapse again into stupor. Certain patients resent being roused and display intense irritability or utter moaning cries when touched. The duration of the stupor is very variable. It may last for only two or three days or more often may persist for two to five or even ‘eight weeks. Periods of remission may occur in the course of the malady. The outset of coma, although grave, does not always imply a fatal issue. Many patients display extreme emotion and are “ childish ’’ in demeanour. Case Mortality. Considered generally, and taking foreign experience into account, the case mortality of encephalitis lethargica since 1917 may be given as between 20 and 50 per cent. Recent inquiries regarding 500 cases notified in 1919 show that exactly half proved fatal. The true case mortality can, however, only be satisfactorily assessed when the mild or abortive cases referred to below are more fully recognised and reported. Sequelee. Recovery is generally gradual and tedious chiefly on account of the great prostration and muscular weakness that are so common. The chief sequele hitherto observed are :— — (1) An alteration in the mental condition. (2) The persistence of cranial nerve palsies. : (3) Myoclonus :—sudden, shock-like muscular spasms of limbs, sometimes also of diaphragm and larynx. (4) The subsequent appearance of paralysis, apparently of. spinal cord origin. | (5) Athetosis :—slow and irregular twisting movements, usually of fingers and wrist. (6) Symptomatic paralysis agitans. Some of these after effects, such as loss of memory, defects of speech, and changed mental disposition have been found to persist for 12 months or more after the attack. : Differential Diagnosis. It is desirable to keep the following diseases in at when diagnosing encephalitis lethargica -—Acute poliomyelitis, polio- encephalitis (Strumpell’s type), tuberculous meningitis, cerebro- spinal meningitis, cerebral syphilis, typhoid fever, diphtheritic paralysis, renal disease (uraemia), botulism; functional disorder,
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