Mental disturbances in tuberculous meningitis.

Ever since tuberculous meningitis was first defined as a specific disease (Whytt, 1768) it has been recognized that disturbances of the mind form an integral part of the clinical picture. As the disease progresses, so these disturbances increase until the illness closes in coma and death. Thus the classical descriptions of the disease insist on apathy, irritability, and insidious changes in personality as among the chief characteristics of the early stages of the illness. Whytt himself, writing of children, says: " Their spirits being low they incline mostly to lie in bed, although they are more often disposed to watching than sleep ". Trousseau (1868) says: "Sadness setting in unaccountably is a premonitory sign of great value in a child"; while Osler (1892) states specifically that " the personality may completely change ". Towards the end of the prodromal phase the mental changes deepen to semi-stupor or frank delirium, usually described as either hysterical (Gowers, 1893) or as delirium tremens (Barlow, 1899). The prominence of the mental symptoms is reflected in the discussions of the differential diagnosis. Two conditions often confused with tuberculous meningitis were hysteria and typhoid fever. Both typhoid fever and tuberculous meningitis are characterized by headache, fever, and delirium, and the likeness between the two is still acknowledged by the use of the term " the typhoid state" in modern accounts of general tuberculosis (Go,v an,d Bodley Scott; 4950). In doubtful cases the point at issue was Wvhether the delirium should be asii5ed*sinpty to general toxaemia or to direct cerebral insult. Wilson (1844), writing of acute rheumatic lever, had urged that " it be remembered in4batt9tme&t D '&ad symptoms ' incidental to this as to other forms of acute disease, that the brain may be unsettled by many influences that do not originate within the brain itself". Gowers (1893) recognized both general and local