In some few cases, and these are the most difficult of diagnosis, the tubercular disease has begun so decidedly in the abdominal viscera, that diarrhoea persists till the head affection has become unquestionable from the presence of coma or convulsion : in other instances an attack of convulsion is the first circumstance that awakens the attention of the mother or nurse to anything being wrong.
The hopelessness of the disorder deprives diagnosis of much of its interest ; yet it is well to be able to warn parents of ap proaching danger, and it is now and then a source of gratification when we can remove apprehension regarding a case which has been looked upon with distrust, and can feel confidence in a pros pect of amelioration.
In the advanced stages. extreme listlessness and unwillingness to be moved,. frequent moaning, great aversion to light and noise, with marked inequality of pulse, followed by stupor, convulsions, paralysis, strabismus, or insensibility of the retinae, and total blindness, sooner or later make the nature of the dis ease only too evident ; their sequence is not always the same, and the more decided symptoms may be postponed till within a day or two of the patient's death. When the disease has been making slow and insidious progress for days before the child is first seen, and the bowels continue relaxed, while the history of the case is either imperfect or incorrect, it is apt to be regarded as an advanced stage of fever: this is the disease with which in all circumstances it is most liable to be confounded, and therefore a few hints may be given for their discrimination. In doubtful cases it is always a favorable sign when the child is seen to watch the attendant as a stranger in the room, when, though listless and unwilling to be disturbed, he is not distressed at being moved ; it is also favorable when there is thirst, and no refusal of fluid nourishment: and, I may add, what seems paradoxical, when delirium and muttering are observed at night. This is explicable enough from the consideration that, if delirium depended on serious lesion of the brain, the other symptoms would be such as to render the case perfectly clear ; it is only when doubt exists that delirium can be thus viewed. Deafness may be to a certain extent re garded among the favorable signs, as it is a common circumstance in fever ; but if it amount to total loss of hearing, it is most unquestionably of evil omen. Blindness is a constant effect of effusion, but it is sometimes difficult to make out whether the child be blind or simply indifferent to surrounding objects : mothers never admit the fact, and the mobility of the pupil can alone be taken as a certain guide.
Heat of head, refusal of fluids, moaning, anxiety of expression, are all un favorable : variableness of pulse is also a very hopeless circumstance ; its acceleration in acute hydrocephalus is constant, but not always great, often less than in fever, sometimes much greater : its occasional increase from slight causes, as well as its unevenness under the finger, are of more value than its absolute frequency : during the period of effusion it is sometimes slow.
Hydrocephalus must be carefully.discriminated from the functional derange ment following on exhaustion, which often so closely simulates it' as to have received the name of the hydrencephaloid disease : the proper place for its consideration is among functional disorders (I 6); the most useful diagnostic mark. in cases where it remains unclosed, is the condition of the fontanelle, which is full and tense in inflammation, hollow and flaccid in exhaustion.
In adults the cases of tubercular inflammation of the brain may be divided into two classes: the one accompanying the early stages of tubercular deposit, when miliary tubercles are evenly distributed through the lungs ; the other attending the advanced stages of phthisis, with vomic,as in the lungs. In their general features there is considerable analogy, but in the early eases the symptoms are more acute, and correspond more closely to those seen in the same disease in childhood ; in the advanced cases the inflammation is of lower type ; the presence of disease in the follicular glands of the intestine renders constipation very rare; vomiting, on the other hand, is of common occurrence. The pulse, so often quick in pbthisis, is always so in this affection of the brain ; the head is hot and painful; night-sweats, if they have previously occurred, have ceased, and, contrary to what is found in childhood, delirium is an early symptom. This subject has been already fully discussed under the head of delirium, to which the student is referred; its presence cannot fail to draw attention to the condition of the brain: it may be accompanied by strabis mus, unequal action of the pupils, or aversion to light and noise, but such signs are more often wanting among adults. Alterations of sensibility and mobility are rarely observed in the early stages.