These patients seldom come under the surgeon’s notice until the condition is serious. If they are still conscious, pain is the dominating complaint. This may be aggravated by percussion over the affected region. Rigidity of the sternomastoid on the affected side is a sign of lesion of the sigmoid sinus. Pain elicited by deep pressure in the posterior cervical triangle is also significant. There is mental hebetude, with progressive failure of mental and physical power, as the stupor increases, or coma becomes marked.
Abscess may be often distinguished from infectious thrombosis, as in the latter respirations are quickened and vomiting occurs when the patient is in the upright position.
Vomiting accompanied by cephalalgia is always indicative of intracranial mischief. If it be a special feature throughout the case it may indicate cerebellar lesion. Convulsions are also frequent, but rarely distinctive. They are the result in most cases of secondary irritation of motor areas. Paralysis is the consequence of destructive rather than of irritative lesions.
The ear should be examined, and the use of a probe may give much information.
Brain abscess connected with middle-ear disease will usually be found in the temporosphenoidal lobe, but occasionally occurs beneath the tentorium, in the cerebellum. Many of these cases are connected with self-evident indications of purulent otitis media and mastoid disease, and operation for the latter has often to be combined with the recognition of and suitable treatment for brain abscess. The surgical treatment of mastoid disease will be discussed in separate paragraphs and under a separate heading. Whenever there is any reason to suspect the existence of pus within the cranium the operator should expose the dura by opening above the mastoid; or his operation may already have taken him as far as the sigmoid sinus, in which case, with the dental engine or with other bone-cutting instruments, he may much enlarge the field of operation and thus make access both to the sinus and to the brain itself. An extradural collection of pus may be found within the sinus or above it. Drops of pus may escape as the operator cleans away or even presses apart the granulations. He has often to decide upon further exploration, either to open the sinus expecting to find it filled with disintegrated blood clot and products of decomposition, or to open the dura proper, expose the cortex, and perhaps explore here with the aspirating needle for pus located more deeply. In those cases where evidences of brain abscess are more pronounced, and those of mastoiditis less so, the lateral region of the skull may be exposed and the cranium opened with a trephine before working downward and exposing the mastoid region. In not a few instances both operations are combined and the area of bone to be cut away is relatively large. Thus complete tympanic eventration, with removal of much of the mastoid, may be combined with trephining and opening of a brain abscess, or opening of the sinus, in which latter there may be found such a condition as to make it advisable to ligate the common jugular low in the neck, and irrigate from the sinus to the location of the ligature, where the vein is laid open, or even to pass a small swab upon the end of a flexible probe. Nothing can more predispose to typical pyemia than a breaking-down clot within a sinus or vein involved in thrombophlebitis.
Temporosphenoidal abscess will often be indicated by the escape of pus through the dura, above the roof of the tympanum. Although such an abscess might be evacuated by enlarging the tympanic approach to it, it would ordinarily be much better to open the skull above the ear, and thus make free access and provision for drainage. In any part of such an operation when the dura has once been exposed its appearance should be carefully noted. The coarse of the pial vessels can usually be traced through it. Therefore when it is sufficiently opaque to prevent any appreciation of conditions beneath, or sufficiently distended, it may be opened.
When cerebellar abscess is suspected the trephine should be applied about midway between the tip of the mastoid and the external occipital protuberance (inion), i. e., one inch beneath Reed’s base-line and one and a half inches back of the mastoid. The instrument should here be used with care, as the occipital bone is of irregular and variable thinness. In a brain abscess which can be freely opened gauze packing will be found serviceable, even though its use necessitates the employment of secondary sutures or perhaps leaving the wound open in order to permit of its removal.
Localizing symptoms are only occasional in connection with cerebral abscess, because the majority of these lesions are located without the motor area. Pupillary alterations are indefinite. As an abscess enlarges the size of the pupil may increase. Infective thrombosis rarely affects the pupils, save that when located in the cavernous sinus it may produce ptosis. In temporosphenoidal abscess pain is usually localized in or near the ear upon the same side. As the motor area becomes involved there is a gradual development of localizing phenomena, referred to the opposite side. Facial paralysis is common in advanced destructive lesions in the mastoid and tympanum. When produced by cortical lesion it is rarely so pronounced as when by direct paralysis of the nerve. In frontal abscess there are few localizing phenomena. Abscess in the parietal region is most commonly of traumatic origin, and is to be suspected in accordance with external surface markings. Occipital abscess is exceedingly rare, and cerebellar abscess furnishes few localizing symptoms. Its most prominent clinical features are retraction of the head and neck; slow, feeble pulse and respiration; subnormal temperature; violent yawning; rigidity of the masseters; slow speech; optic neuritis; vertigo and vomiting. If accompanied by thrombosis there is pain upon pressure in the upper part of the neck. In all of these cases when abscess is near the surface there is more or less leptomeningitis, which becomes diffuse at once when the abscess bursts. If meningitis be present we have high temperature without marked remissions, rapid pulse, and general irritability, rapidity of pulse indicating predominance of leptomeningitis over encephalitis, since the more marked the latter the slower the pulse. As distinguished from sinus thrombosis we have in the latter high temperature with marked remission, rapid and weak pulse, frequent chills, profuse sweats, and often symptoms of pulmonary infarct or diarrhea, with cervical and submastoid tenderness and involvement along the jugular vein upon the affected side. If all three conditions be associated the symptoms of thrombosis usually prevail, although there may be retraction of the head due to basilar meningitis. As between tumor and abscess we have in the former absence of explanation of infection, slow progress of symptoms, more definite localizing phenomena, progressive involvement of nerves, pronounced optic neuritis, absence of chill, and alternating periods of mitigation of symptoms. Temperature and pulse afford little help, save that subnormal temperature points rather to abscess.
Prognosis.
—From every direction come statements that the tendency of cerebral abscess is invariably toward fatality. No matter what the cause, unless relief be promptly afforded, death is the sure result. Of the acute cases those not promptly operated usually die within a few weeks. The more chronic or prolonged cases rarely come under surgical treatment; most of those which do are the result of disease in or about the middle ear. Were it possible to early diagnosticate formation of these abscesses prognosis would be much more favorable. When seen before necessarily fatal complications have arisen, in instances where the position can be reasonably well determined, surgical attack is likely to give good results. After proper evacuation even complete mental and bodily recovery is possible. Anchoring of the brain by adhesions may leave a train of disquieting symptoms, which, however, are not so bad as fatality. Abscesses may remain for a long time encysted, and yet be a fruitful source of danger. Multiple abscesses may complicate both the diagnosis and the treatment and produce a condition beyond help.