Acute Suppurative Encephalitis.
Acute inflammation of the brain terminating in the formation of pus may be a focal or circumscribed process, in which single or multiple areas are af fected; or it may be a diffuse process affecting large areas of the cortex, often with implication of the adjacent mem branes, or larger or smaller areas of the brain-substance may be involved, often including the lining membrane of the ventricles. The majority of cases of abscess of the brain are inflammatory in origin, so that acute suppurative en cephalitis in its circumscribed or focal form is practically synonymous with cerebral or encephalic abscess. Certain cases of abscess may occur without any evidence of an inflammatory genesis. They are, however, due to necrotic soft ening and do not come under considera tion here, as they are considered under CEREBRAL ABSCESS. Practically, in flammation of the brain, in its suppura tive form, occurs as a focal or diffuse disease, and the former is clinically ab s.cess of the brain, while the latter is most common as a diffuse meningo-en cephalitis. These affections, although closely allied, for clearness of descrip tion will be considered separately.
(A) Acnte Focal Suppurative En cephalitis.
Synonyms.—Abscess of the brain; en cephalic abscess. (See CEREBRAL AB SCESS.
(B) Acute Diffuse Suppurative En cephalitis.
Definition.—Diffuse suppurative en cephalitis, as. the term irnplies, is a dif fuse infective inflammation involving large areas of the brain, often with coin cident involvement of its membranes., and resulting in pus-formation.
symptoms of this con dition are those of cerebral irritation and compres:,--ion of large and irreg,ular areas of the brain. The signs present point to a septic process. The pulse, tempera ture, and respiration are irreg-ularly af fected: sudden variations in all three frequently occur. Chills or rigors may be a marked feature. The symptoms in addition which are present in whole or in part in such cases are dull and deep pain in the head, stupor with attacks of delirium, irreoular local or general convulsions or paralysis., optic neuritis,
various forms of aphasia, ansthesias or parmsthesias of irregular distribution, oculomotor palsy, various disorders of vision, or of other special senses. accord ing to the region of brain involved. The patient may die within a few days. or a week, especially in cases due to severe head-wounds, fractures, or lacerations of the brain-subs-tance. In such cases an extensive leptomeningitis is commonly present in addition. In other ca_ses the acute symptoms pa.ss away and leave the patient in a condition of great torpidity. with pain in the head, spastic or chronic paralytic phenomena, occasional con vulsions and progressive los.s of function in those parts supplied by the affected part of the brain. In some cases patient:. may linger for months with hopeless mental deterioration, extensive motor and sensory paralysis, and partial or complete destruction of some of the spe cial senses. Death in these cases finally results from exhaustion.
Etiology.—This: form of suppurative encephalitis follow's, at times, severe in juries, or it may be a complication or a sequence of one of the acute infectious. diseases.. It has. the same general eti ology as the focal form of suppurative encephalitis, already referred to. It is never primary.
Pathology. — Post-mortem examina tion reveals large areas of disorganized, pulpy, soft, or even semifluid consistence of the affected portion of the brain. The adjacent membranes are likely to be in volved, and may be softened, deeply con gested, and covered with purulent exu date, which may also fill up the sulci and large fissures of the organ. In cases running. a subacute course. the mem brane may be considerably thickened. with breaking down of their cerebral surfaces. Microscopically there is the pus-cell, massing of leucocytes around the borders of the process. dilated ves sels and periyascular s.paces. and within the area of utter destruction are seen compound ,granule-cells, granular debris.