Wounds of the Brain.—Incised wounds of the brain usually result from sabre-cuts, hatchet blows, or circular saws. A portion of the scalp and cranium may be raised along with a slice of brain matter, and in some cases the whole flap is severed. The extent of the injury, the conditions under which it is received, and the liability to infection, render such wounds extremely dangerous.
Punctured wounds may be inflicted on the vault by stabs with a knife or dagger, or by other sharp objects, such as the spike of a railing. More frequently a pointed instrument, such as a fencing foil, the end of an umbrella, or a knitting needle, is thrust through the orbit into the base of the brain. Occasionally the base of the skull has been perforated through the roof of the pharynx, for example, by the stem of a tobacco-pipe. All such wounds are of necessity compound, and the risk of infection is considerable, particularly if the penetrating object is broken and a portion remains embedded within the skull. The infective complications of such injuries are described later.
Bullet wounds have many features in common with punctured wounds. There is more contusion of the brain substance, disintegrated brain matter is usually found in the wound of entrance, and the bullet often carries in with it pieces of bone, cloth, or wad, thus adding to the risk of infection.
Aseptic foreign bodies, especially bullets, may remain embedded in the brain without producing symptoms.
The treatment of punctured wounds consists in enlarging the wounds in the soft parts, trephining the skull, and removing any foreign body that may be in it, purifying the track, and establishing drainage.
After-effects of Head Injuries
Various after-effects may follow injuries of the head. Thus, for example, chronic interstitial changes (sclerosis) may spread from an area of cicatrisation in the brain; or softening may ensue, either in the form of pale areas of necrosis (white softening) or of hæmorrhagic patches (red softening). The symptoms vary with the area implicated. Adhesions between the brain and its membranes may produce severe headache and attacks of vertigo, especially on the patient making sudden exertion.
After a head injury, the patient's whole mental attitude is sometimes changed, so that he becomes irritable, unstable, and incapacitated for brain-work—traumatic neurasthenia. In some cases self-control is lost, and alcoholic and drug habits are developed.
Traumatic epilepsy may ensue as a result of some circumscribed cortical lesion, such as a spicule of bone projecting into the cortex, the presence of adhesions between the membranes and the brain, a cicatrix in the brain tissue leading to sclerosis or a hæmorrhagic cyst in the membranes or cerebral tissue.
The convulsive attacks are of the Jacksonian type, beginning in one particular group of muscles and spreading to neighbouring groups till all the muscles of the body may be affected. The convulsions may begin soon after the injury, for example, when the cause is a fragment of bone irritating the cortex; in other cases it may be several years before they make their appearance. The onset is usually sudden, and the “signal symptom”—for example, jerking of the thumb, conjugate deviation of the eyes, or motor aphasia—indicates the seat of the lesion. At first the attacks only recur at intervals of, it may be weeks or months, but as time goes on they become more and more frequent, until there may be as many as forty or fifty in a day. Sometimes the patient loses consciousness during the fit; sometimes he remains partly conscious. In course of time the same degenerative changes as occur in other forms of epilepsy ensue: certain groups of muscles may become paralysed; the patient may pass into a state of idiocy, or into what is known as the “status epilepticus,” in which the fits succeed one another without remission, the breathing becomes stertorous, the temperature rising, the pulse becoming very rapid; finally coma supervenes, and the patient dies.