The circumference of the skull may continue to increase for some length of time after birth. Sometimes the enlargement takes place in successive stages, each increment being accompanied by brain symptoms. Spontaneous evacuation of the cerebral fluid through the nose, has rarely-, if ever, been observed in children.
The prognosis of congenital hydrocephalus depends primarily on the severity of the condition. In milder cases, in which the ical symptoms are not too nounced, there is more hope of recovery and especially of lectual development than in a case of e xcessi ve hydrocephalus i n which walking is greatly delayed and the mental functions are manently impaired. A large portion of these children die soon after birth or in early childhood. The treatment of alus is not encour4,ing. In view of the favorable results obtained with iodides and mercury in many varieties of acquired alus, these remedies should be tried in conge ni t a I cases. Various operations have been devised for the purpose of diminishing the quantity of fluid or preventing its re-accumulation, Different methocls of puncturing the ventricles, followed by- the injection of iodine or the insufflation of sterilized air, the application of permanent external drainage and, finally, the establishment of a permanent nication between the ventricles of the brain and the meningeal space or the external integument have been tried in the hope of plishing the above result. The pressure bandages which at one time were extensively employed have now been practically abandoned and are used only as part of the after-treatment following tion of the fluid. There can be no doubt that cases of hydrocephalus have been improved by repeated lumbar puncture, but permanent results are extremely rare and the effect of the procedure in most cases is only temporary. Acute cerebral manifestations with the symptoms of a recent meningitis are not rare after evacuation of large quantities of fluid and are probably due to speedy re-accuniulation of serum. Never theless, especially in CEO.,CS of increasing pressure, as, for example. when inflammation of the optic nerve goes on to atrophy, lumbar puncture should be tried; but as in some cases the communication between the ven tricles of the brain and the spinal canal is closed, the operator should not be surprised if he fails to obtain a considerable flow of cerebrospinal fluid.
Ifydromicrocephalus or hydranencephalus (Cruveilhier; is the term used to designate a rare malformation in which the external skull is diminished in size instead of enlarged, and the Urfa n itself is repre sented by a watery cyst.
The condition is apparently due to the collection of hydrocephalic flui d at a time when tbe cerebral cortex is still in the initial stages of its development.
The medulla oblongata and small portions of the basal ganglia nifty in such cases represent the sole remains of the brain. In spite of t hese marked alterations clinical symptoms may be wanting. In a case de scribed b y Zappert an d Ilitschniann, although the child lived 11 days, deficiency of the brain had not been suspected.
7. Hypertrophy of the brain is an alteration of the brain mani festing itself by excessive weight and increase in bulk. The convolu tions are flattened, and the ventricles are usually totally obliteraled (Schick) or they may occasionally be dilated (Anton). The micro scopic findings are normal; occasional persistence of the thymus gland in adult individuals and aplasia of the adrenal boles are notable features. The skull is sometimes, but not always, enlarged; the shape, however, is not that of hydrocephalus. The bones of the skull are thin and porous.
This hypertrophy of the brain is at the present time regarded by most authorities as a congenital condition, it being doubtful whether it can occur as the result of external injuries (lead poisonings, Barthez and Rilliet). It is possible that heredity is a feature in the etiology.
The conffition does not necessarily cause symptoms. Indeed, it is difficult to draw the line between normal and pathological size of the brain, for we know that many persons of great mental powers have extremely heavy brains. Quite often the existence of a cerebral anomaly is only discovered at autopsy. When symptoms rire present they are due to the pressure of the skull on the surface of the brain. The most important are convulsions., which may go on to the status epilepti eus and arc brought on through reflex irritation (auditory and visual impressions). Intelligence is sometimes diminished; in severe cases deep coma, with protracted convulsions, and death occur. There are no local brain symptoms. It is worthy of note that the morbid syrup touis as a rule do not develop until after the first year of life, because up to that time the skullcap is soft enough to yield to the internal press ure. From hydrocephalus, which may present very similar symptoms, the condition according to Schick can usually be differentiated by the negative result of lumbar puncture (due to the absence or diminution of the cerebrospinal fluid).