DISEASES OF THE BRAIN - the preceding chapter a general outline has been given of the very large class of symptoms which must be investigated in inquiring into conditions of disease in the brain, and at first sight their number and variety seem to present almost insurmountable difficulties ; but in reality it is not so ; in any given case, we are rather left in the dark by the absence of trustworthy evidence of the state of the brain, than bewildered by the number of ob jective and subjective phenomena; thus, when the mental func tions are deranged, we lose all aid to be derived from the sensa tions of the patient; in some cases one symptom (e. g., paralysis) stands alone, in others there is scarcely anything to indicate the existence of disease beyond the presence of pain, which we know may be exaggerated, or may depend simply on disturbance of other organs.
We cannot too often recur to these important principles—(1) to inquire in every possible way into the history of the case; (2) to examine most carefully the condition of other organs, and search for the existence of other diseases; if these two points be neglected, correct diagnosis is almost impossible ; if properly attended to, they not only lead us in the right direction when we fail to get at the exact truth, but they also enable us to avoid many errors. The next step is to consider the various important lesions of the brain, and ascertain whether the case under inves tigation adapt itself to any one of these not overlooking the pos sibility of insanity and simple functional disturbance, which, with all their complex associations, belong distinctly to diseases of the brain.
The primary division is into those with and those without a febrile state. Acute diseases of the encephalon in adults seldom arise spontaneously, or without previous derangement of health; hence the importance of the history of the case. We may thus be enabled to exclude "head symptoms" occurring in the course of some other acute disease; it is only necessary to guard against being misled by a vague assertion of the existence of fever, when this was but the first step in the progress of inflammation. The
history also conveys very important information with reference to the recurrence of headache, to pain or discharge from the ear, to previous loss of power, or attacks of convulsions in genuine cases of disease of the brain, or to cough and emaciation as pre ceding tubercular meningitis; in either case inflammatory action, when present, is, as it were, engrafted in old standing disease, and this is its most common course; on the other hand, it is some times developed suddenly in a person who had previously enjoyed perfect health, with great febrile disturbance, severe pain in the head, vomiting, and constipation ; or it is announced in a more unmistakable manner by the coexistence of convulsion. Here we shall learn that symptoms of affection of the brain were among the earliest phenomena of disease, and we are thus assured that this organ has not become secondarily affected in the course of some other febrile disorder.
The importance of the information obtained from this prelimi nary inquiry can hardly be overrated, in so far as it serves to point out the association of the tubercular diathesis, either by the previous condition of the patient himself, or his hereditary ten dency to scrofula or consumption. It may also greatly assist us in forming a judgment as to the exact seat of the disease, whether in the membranous or in the substance of the brain, because we learn from experience that meningitis is apt to be produced by disease of bone in the internal ear and the sinuses of the nares ; or by caries or fracture of some other portion of the skull ; by syphilitic nodes of the pericranium, or by injury of the scalp, especially when terminating in suppuration ; on the other hand, inflammation of the substance of the brain, when not dependent on over-stimulation of the organ, or upon scrofulous deposit, is more commonly excited by the pressure of an old apoplectic clot, or by the progress of chronic disease, traces of which are to be found very often in the past history of the individual.