ETIOLOGY. -- Extradural haemorrhage may occur with or without fracture of the skull. When the result of fracture, it is caused by the fissure tearing across the meningeal artery or more often one of its branches distributed on the interior of the skull, or a fragment of bone wounding a sinus or the vascular net-work on the cerebral surface.
-The blood that is cx travasated usually coagulates into a firm, granular clot. This clot may be ab sorbed entirely; the serous portions and coloring matter may become absorbed, leaving a fibrinous, buff-colored clot, which may become organized; and finally the exterior of the clot may be come organized, while the interior may contain fluid and disintegrated blood.
PROGNOSIS.—The mortality of these cases treated upon the expectant plan (without operation) is very high. Nies mann reports 147 cases treated expect antly with 131 (S9.1 per cent.) deaths, while of 110 cases operated on only 30 (32.7 per cent.) died, and in the ma jority of the fatal cases the extravasation was not reached and the clot therefore not removed.
—Operative treatment should be resorted to as soon as the diag nosis has been clearly made. The local izing symptoms should determine the spot to be trephined. Kronlein has shown that, in the greater number of cases, the clot will be most easily reached by trephining one inch and a quarter be -hind the external angular process at the upper level of the orbit. If the clot is not found by this opening we may tre phine just below the parietal boss, on the same level with the former opening. The main trunk and the anterior branch of the middle meningeal artery are reached by the anterior opening, and the posterior branch by the posterior open ing. If the clot be discovered it should be removed, enlarging either trephine opening, if necessary, by the rongeur forceps. If the pupil be dilated, show ing that the clot is gravitating down ward toward the base, the trephine open ing should be made near the first point, but about one-half inch lower. After the clot has been scooped out gently, the cavity should be well washed out with freshly boiled water cooled down to blood-heat. If the artery is still bleeding, a semicircular Hagedorn needle armed with catgut should be passed through the dura, under the artery, and out again through the dura on the other side of the artery, and the artery tied. Drainage should be pro
vided and the wound treated antisep tically. A second trephine opening should be immediately made if the first trephine opening does not answer well for drainage in the recumbent posture. (AV. N. Keen.) Subdural Hmmorrhage.—This hmmor rhage generally occurs from the rupture of a number of small vessels, or of one large vessel (especially the middle cere bral), the extravasation being located under the dura mater.
Sviurroms.--The symptoms and treat ment are very much the same, the differ entiation between this and the preceding variety not having yet been made out.
ETIOLOGY.—This hmmorrhage occurs most frequently as a result of depressed fracture. A few cases have been re ported as due to pachymeningitis in terna, which cases should be treated by trephining, evacuation, and drainage.
PATHOLOGY.—The patient often dies from direct injury to the brain. If he recovers, the clot, having produced more or less paralysis, is gradually absorbed, but the brain may not expand to its former position, being permanently de pressed, the site of the injury being sometimes occupied by spongy connect ive tissue, the meshes of which are filled with cerebrospinal fluid, resembling a series of cysts. The paralysis will gradu ally lessen and may almost entirely dis appear, but, after a period of from a few months up to two or three years, epi leptic or other cerebral disturbance may appear and persist throughout life.
- The treatment is the same as for the preceding variety of hmorrhage. The anterior trephine opening, already referred to, if enlarged upward and backward, will give access to the middle cerebral arteries, and, if symptoms indicate intracranial rhage, and no clot is found under the bone on trephining, the dura should be opened and the clot searched for along the fissure of Sylvius, in which the mid dle cerebral lies. If this artery be the source of haemorrhage, the bleeding point must be found and the artery tied. (Keen.) Cerebral hemorrhage. See CEREBRAL HAEMORRHAGE.