When tuberculosis is present it is usu ally also at the base in children, but m9y involve large areas of the pia mater in older subjects, and in adults the vertex is not infrequently the site of the tuber culous deposit. The characteristic post mortem appearance is the tubercle, and the location in which this is most corn monly found is in the pia overlying the crura cerebri, the optic, olfactory, and the point of exit of the third nerve, and also in the membrane as it extends over the corpora quadrigemini. The pia is much thickened, is covered by a grayish white exudate, and the tubercles show as whitish-gray bodies imbedded in the membrane. In size the tubercles vary from exceedingly-minute bodies, hardly discernible macroscopically, to that of the head of a pin or even somewhat larger. The ventricles are distended with a turbid albuminous fluid, and there is thickening and softening of the epcn dyma. The microscope confirms the diagnosis and reveals the existence of numerous obstructions of the smaller arterioles from tubercular deposit, or an obliterating endarteritis. Giant cells may be seen in the perivascular spaces or in the cerebral substance, while the bacillus tuberculosis is seen along the lines of the vessels and in and around the areas of the tubercular deposits. In all cases the bronchial glands should also be examined, since they are frequently a most important factor in the production of the ventricular effusion.
Diagnosis. — The diagnosis of acute hydrocephalus is not difficult when it occurs as the result of meningitis. In such cases the prolonged coma, the irreg ular movements of the muscular system, with the respiratory rhythm, are all sug gestions of the increased intracranial tension due to the ventricular effusion. The subacute cases are, perhaps, the most difficult of recognition, and the condition of the brain may remain un suspected until the graver symptoms ap pear. The cases arising rather abruptly from the pressure of intracranial growths or from enlarged bronchial glands also present many difficulties in the way of early diagnosis, but the appearance of grave signs of cerebral disturbance, the discovery in certain cases of other evi dences of tuberculosis, or of retropharyn geal abscess causing embarrassment to the cerebral circulation, the exclusion of traumatism, the ophthalmoscopical ex amination, and a careful study of the his tory of the illness will often aid in mak ing up an opinion. The very fatal cases which occur in large cities, especially during the course of the diarrhceal dis eases of infants and young children, pre sent few difficulties in their recognition, because the brain-symptoms develop so early and progress so rapidly toward death. In these cases the tendency toward a marked, but most deceptive, re mission of symptoms should be borne in mind. In all cases of acute hydroceph
alus the general wasting of the body is a prominent feature. In cases of long duration the emaciation may become extreme, and contractions occur in the limbs which may be more or less perma nent should recovery take place. The characteristic hydrocephalic aspect is rarely seen in acute hydrocephalus, un less the case should drift into the chronic condition, cases of which are only rarely seen. Cases arising from meningea] hemorrhage usually become chronic, the fluid being encysted between the mem branes of the brain.
Prognosis.—The prognosis of acute hydrocephalus is always bad. The dis ease ends usually in death, or in perma nent mental or physical defects, in the cases which escape death. Probably the syphilitic form is the most hopeful when the condition is suspected early enough to get the patient promptly under the influence of specific remedies. The cases arising from enterocolitis, or any of the acute fevers or other exhausting disease, offer little hope as to recovery, although occasionally a patient will recover. The tuberculous cases are absolutely hopeless, although Jacobi and others have testified to the recovery of two or three cases. Subacute basilar meningitis may cause ventricular effusion and subside, leaving the effusion, which may remain station ary in amount or even lessen in amount so that the symptoms of its presence dis appear; but usually the tendency is for it to increase, and finally, after months or years, the clinical picture of chronic hydrocephalus is produced, should the patient have been a young child, thus admitting of the expansion of the cra nium.
Treatment.—The treatment of acute hydrocephalus is very often that of the primary disease to which the ventricular effusion is only secondary. Sometimes, from the very rapid progress of the case toward a fatal end, treatment can be of little avail. In the majority of cases it is almost hopeless, but in all cases every effort should be made, for occasionally the recovery of one of these cases from a seemingly-hopeless condition will amply repay the untiring care which they all demand.
When the initial symptoms of menin geal irritation appear, should the patient be seen at that early period, absolute rest in a darkened room, prompt vesication behind the ears with cantharidal collo dion, in children, and regular doses of calomel in great amount should be in stituted. If necessary, opium should be given to control the restlessness, prefer ably combined with chloral, and these should be continued in suitable doses so long as the twitchings and spastic muscular condition continue. Irrigation of the bowels should he practiced where there is entcrocolitis as the cause.