Volume 1

Green's Encyclopedia and dictionary of medicine and surgery / edited by J. W. Ballantyne.

Date:
1906-1909
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Green's Encyclopedia and dictionary of medicine and surgery / edited by J. W. Ballantyne. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    sides and may completely disappear, so that, provided post-neiiritic atrophy is not in progress, sight may thus 1)6 saved. Brain—Atrophy, Hypertrophy, Cysts, Inflammations. Atrophy of the Brain . . . 499 Hypertrophy of the Brain . . . 499 Cysts and Cystic Degeneration . . 500 Chronic Progressive Softening . . 500 Encephalitis— Acute 501 Chronic ...... 503 Atrophy of the Brain Atrophy of the brain may be general or local. A limited degree of general atrophy is a senile change, where shrinkage of brain matter is not infrequently associated with a proportionate in- crease in the amount of cerebro - spinal fluid. Apart from this, in some rare cases atrophy of the whole brain occurs, although much more frequently the change is local. Pathological Anatomy.—There is always an increase of connective tissue at the expense of nerve-cells, and the result may be a softer or a liarder brain substance, depending upon the kind of sclerosis which accompanies or is the result of the atrophic process. Etiology.—Atrophy may occur: (1) Before birth, as the result of maternal injury or im- perfect development of the embryonic structures. (2) At birth, as the result of injury to the skull, liEemorrhage causing pressure, or possibly meningeal inflammation. (3) During the first years of life, when atrophy, often partial, is due to defective de- velopment, gradually causing more and more definite alterations in the brain structure. Partial atrophy, while it may affect any part of the brain, more generally occurs in one cere- l)ral hemisphere in whole or part, in the cere- bellum, either one or both lateral lobes, or in the ])ons. There may be atrophy of one part of the l)rain, consequent on, or associated with, a similar condition in another part, as, for example, one cerebral hemisphere and the opposite hemi- sphere of the cereliellum, or one cerebellar hemisphere and the opposite basal ganglia and olivary body. Clinical Features.—While it is unnecessary to refer here to the symptomatology of hereditary cerebellar ataxia, or other more or less defined types of disease associated with atrophy of the l)rain, it is sufficient to remark that intellectual feol)leness is generally coincident with imperfect development. Hemiplegia or vmilateral weak- ness, very freqiiently athetoid movements such ;is post-hemiplegic chorea, inco-ordination, and not uncommonly epilepsy, are associated with a greater or less degree of idiocj'. Occasionally no symptom has resulted in cases where well-marked atrophy existed, but these are both rare and inexplicable. No special treatment can be given other than that based on general principles. Hypertrophy op the Brain This is a subject upon which much discussion has taken j)lace, and many theories have been formulated since Virchow's paper in 1856. Hydrocephalus and neoplasms are not in- cluded under this head, and it is necessary in many cases carefully to distinguish between hydrocephalus and the condition we are con- sidering. Hypertrophy may be local, but is more frequently general. Pathological Anatomy.—Hypertrophy of the brain, as Gowers points out, should mean ^vo- portionate increase in all the constituent parts of which the organ is normally composed. There are many instances of large brains in persons specially endowed with genius and intellectual power, and also in those who are mentally defi- cient. In the former Gowers' definition holds true, but in the latter there is probably an in- crease of neuroglia, as Virchow stated, in excess of nerve-cells and nerve-fibres. There is generally a proportionately greater amount of white matter, and the consistency of the brain is much firmer than normal. In sharp contrast to hydrocephalus there is a diminution in amount of cerebro - spinal fluid, and the brain is anfemic, probably due to in- creased pressure. Etiology.—-It is possible that deficient resist- ing power of the cranium may account for the increasing growth of the brain substance, an,d therefore the greater number of cases occur before the sutures of the skull have ossified, or where ossification is greatly delayed, as in rickets. It is not surprising to find that the condition may run in families for several generations. Clinical Features.—Many symptoms, such as mental enfeeblement, idiocy, fits, headache, mental excitement, followed by temporary coma, have been ascribed to this condition; but, as Gowers rightly jaoints out, they may or may not be associated with it, and it is in his opinion in- correct to place the hypertrophy of brain sub- stance in a causal relationship to the very vary- ing symptoms. Still, many later observers agree in associating these groups of symptoms with the anatomical or pathological condition— hypertrophy of the brain,—and give many con- vincing instances in support of their arguments. Some cases resemble hydrocephalus, others meningitis, and others again merely a greater or less degree of mental apathy, with slow move- ments as in eating or drinking, and still more lethargic thought and sjDcech. In these cases the balance of neuron and neuroglia is certainly not normal, and therefore they may not be accurately described by the