Infection may .spread from the tym panic cavity in four directions: (1) upward through the vault, (2) outward through the external table of the proc ess. (3) downward mainly through the lower wall of the mastoid cells, and (4) backward along the groove of the mas toid sinus. Infection spreads, not only throngh necrotic perforations, but also along the lymph- and blood-vessels of the osseous eanaliculi. An unusual mode is through the groove of the trans verse sinus and the foramen lacerum posterius. Quervain (Sem. Me'd., Aug. 20. '97).
Case of neglected middle-ear disease in which a large necrotic focus was found immediately beneath the groove for the attachment of the tentorium, midway between the hiatus Fallopii and the aqueductus vestibuli, communicating with a focus in the left side of the cere bellum. Bacteriological and histological examination revealed the staphylococcus pyogenes albus, staphylococcus cereus flavus, and the bacterium vulgare (pro tens vulgaris). A. P. Ohlmacher (Cin einnati Lancet-Clinic, Sept. 4, '97).
Prognosis. — Brain-abscess is almost always, if not always, inevitably fatal if treated otherwise than surgically. The duration is variable. The acute cases generally terminate within a week or ten days in death. The slow incapsulated variety may extend over months and even years, the patient dyim,, filially from exhaustion or perhaps suddenly from rupture of the abscess-sac.
Analysis of 169 cases in which pus in some form was present in the brain; only 11 recoveries occurred, all of which were operative cases. In 10 other cases the pus was evacuated, either by opera tion or spontaneously. Every case not operated upon died, while more than 50 per cent. of those in which the skull was trephined recovered. This emphasizes forcibly the imperative necessity for operative interference in all eases of cerebral abscess. Frank Allport (Jour. Amer. Med. Assoc., Oct. 22. to Dec. 24, '92).
The prognosis of cerebral abscess due to ear disease after operation is not as good as might be expected. because these abscesses are not infrequently multiple (20 per cent.) and on account of the difficulty in making a correct dia2.nosis. A number of these abscesses run a latent course. Occasionally the symptoms are few and of a passing character. Again,
the patient is sometimes seen in the last stages of the disease, when the abscess has burst through to the surface of the brain or into the ventricles. Even when the patient has been under observation in hospitals diagnostic mistakes are pos sible. When the abscess is accompanied by other intraeranial complications a correct diagnosis may be out of the question. Grunert (Berl. klin. Woch., Dec., '96).
The course of an otitic cerebral ab scess is regularly acute or subacute. In many cases pus opens into the ventricles or on the meninges after some days or weeks, and proves fatal. It is not rare, however, that the course is slow and that the purulent formation ceases, and the virulence of the infection may then be so light that a limiting wall will form. If the cerebral tissue surrounding the ab.scess is in nearly a normal condition, ab.sorption can occur. The membrane limiting the purulent focus may underg,o calcareous degeneration. Iloepke (La Prat. MCA., June 15, 1900).
Prognosis based on statistics of 195 cases of brain-abscess due to middle-ear disease, ISO of which warrant the fol lowing conclusions: Out of 106 cases in which the brain was explored through the squamous temporal, 40, or 37.7 per cent., recovered. Of 64 that were ex plored through the mastoid region, 31, or 43.4 per cent., recovered. Of 10 cases in which the brain was exposed, both through the tegmen antri and through the squamous temporal, 8, or SO per cent., recovered. Hammerschlag (Monats. f. Ohrenh., Jan., 1901).
Examination of the fundus shows that in intracranial suppuration following ear diease neuritis or choked disk is rare, unless a combination of suppurative foci exist. From a prognostic point of view, changes in the papilla are of no value. As a rule. there is a distinct retro gression of the inflammation several days after the pus has been evacuated. Bnt even if it should persist or increase, the outlook is no less favorable. O. _Kerner (Deutsche Arch. f. klin. Med., N-ol. lxxiii. 1902).
Every brain case should be explored where the symptoms are focal regard less of the supposed pathological lesion. H. C. Gordinier (Amer. Jour. of Insan ity, Jan., 1903).