A system of practical medicine. By American authors. Vol. 4

by Unknown

The superior and posterior surfaces of the petrous bone are in direct contact with the brain membranes. The posterior wail contains the passage into the mastoid cells by way of the antrum, through which middle-ear inflammations spread and involve the mastoid cell cavities, and may result in some cases in thrombosis of the transverse sinus.

The inner wall presents two weak points—the one the round foramen, covered with membrane; the other, the oval foramen, covered with the stirrup and the annular ligament. Inflammation can cause destruction of these coverings and give free access of pus through their foramina into the labyrinth, and thence through the internal auditory canal into the brain cavity. It is not difficult, therefore, with so many ways of communication between the middle ear and brain cavity to have easy spread of inflammation between these two regions.

(a) PURULENT MENINGITIS may arise from continuance of the inflammation along the veins which penetrate the roof of the tympanic cavity in their passage from the middle ear to anastomose with the blood-vessels of the meninges, or may in rare instances be caused by pus entering the brain cavity by way of the internal ear, or it can result from caries of the petrous portion of the temporal bone.

SYMPTOMS.—Fever will be present; distressing headache; vertigo, a most significant symptom, and often present even when the head is quiet and in a horizontal position, but greatly increased by the vertical position and motion; pain of a lancinating character, shooting over the entire affected side and even down the neck; the occiput and vertex are favorite points for pain to locate. Nausea and hiccough are present. Abdomen depressed; pupils reacting to light but feebly; slow pulse; and in some cases paralytic symptoms are prominent. Post-mortem appearance: meninges congested, and lymph and pus often found at various points. Dura mater over the diseased petrous bone will be found thick, congested, and pus may be found between it and the bone. Caries of the petrous bone also is found in some cases.

(b) ABSCESS OF THE BRAIN.—With the exception of wounds and injuries, chronic purulent middle-ear inflammation is the most frequent cause of brain abscess. Meyer, in a collection of 89 cases of brain abscess tabulates the causes as follows: Typhus, 1; intercranial tumor, 2; disease of nasal mucous membrane, 3; disease of the blood-vessels, 5; inflammation of neighboring parts of the brain, 5; unknown causes, 11; suppuration of distant organs, especially the lungs, 19; caries of the petrous bone, 20; injuries, 21. Lebert collected 80 cases of brain abscess, and found that one-fourth were caused by purulent middle-ear inflammation, caries of the petrous bone being frequently present; in one-seventh of the cases the brain abscess appeared before puberty, in the remaining cases mostly between the sixteenth and thirtieth years; also, that in some cases the abscess developed in the part of the brain lying over the bony roof of the middle ear; in other cases it was found in a distant part of the brain or the cerebellum, probably developing as a metastatic abscess. Toynbee considered the retention of purulent products in the middle ear or mastoid cells as the chief cause of brain complications from ear sources: he also endeavored to show that an inflammation of the external auditory canal will tend to implicate the cerebellum and lateral sinus—that inflammation of the middle-ear cavity would extend to the cerebrum, and that of the labyrinth to the medulla oblongata. But, practically, such a rule will not hold good, and Gull has modified Toynbee's law as follows: The cerebellum and lateral sinus may suffer from mastoid disease, while the cerebrum is threatened by caries of the roof of the tympanic cavity.

Brain abscess is generally located in the medullary substance, very rarely in the cortex. The middle portion of the brain hemisphere is the most frequent seat of abscess, and very often in that part adjacent to the diseased ear. The abscess may be located directly over the diseased bone, so that the dura mater forms its covering on one side and the brain tissue on the other, or it may be located in the brain parenchyma with perfectly healthy brain tissue between it and the diseased bone. Meyer traces the origin of a brain abscess from ear disease in this manner: A chronic catarrh of the middle-ear mucous membrane results in an hypertrophy of the mucosa on one side and a chronic inflammation of the neighboring bone on the other side. Caries of the petrous bone, so caused, produces inflammation and adhesion of the dura mater, and from here as a starting-point the inflammation spreads into the brain tissue. In rare cases the brain abscess has been found connected by a fistulous tract with the diseased bone.

SYMPTOMS.—Headache is generally present in varying degree, often of a lancinating character. Vertigo frequently present. Fever generally present, with or without chill. Convulsions frequent, with loss of consciousness and unsteadiness of gait, and often paralysis of different parts of the body. The pupils are often contracted, and not unfrequently this disease may closely resemble typhus fever. Lebert noticed in his cases that failure of the intellect was not the rule, but paralysis of sensibility occurred in two-thirds of them. It is also to be noted that cases occur where all these symptoms are absent. This disease can run an acute or chronic course. In the acute condition a fatal termination is caused by the great destruction of brain tissue involved in the suppurative process. In the chronic cases the abscess becomes encapsulated, but finally terminates by rupture of the abscess and escape of pus into the ventricles or over the surface of the brain. In Lebert's cases the fatal termination occurred in half of them during the first month, in one-third of the remainder toward the end of the second month, and in the remaining cases in a varying time between the third and eighth months.

(c) PHLEBITIS WITH THROMBOSIS.—This sequela of middle-ear suppuration is not infrequent. Von Dusch in 32 cases of phlebitis with thrombosis found that purulent middle-ear disease was the cause of 20 of them. It is frequently found in the venous sinuses in proximity to the petrous portion of the temporal bone, especially in the lateral and petrosal sinuses, and often caused by caries of the petrous bone.

Phlebitis with thrombosis of the lateral sinus is characterized by a swelling of the mastoid region which extends downward into the neck, due to an extension of the phlebitis from the lateral sinus along the veins leading from that sinus through the mastoid process to the exterior of the skull. Giddiness and unsteady gait are often present. If the inflammation involves also the superior longitudinal sinus, it will cause symptoms such as epileptic convulsions and violent hemorrhage from the nose. Wreden considers that the epileptic seizure is due to a capillary hemorrhage in the cortical substance of the posterior cerebral lobes, caused by obstruction of the veins passing over the brain substance. The nose-bleeding is due to the fact that a part of the blood circulating through the veins of the nasal passages, and then through the superior longitudinal sinus, is hindered by the sinus obstruction and accumulates in the veins of the nasal passages, and finally causes a rupture in some part.

Phlebitis with Thrombosis of the Cavernous Sinus.—Urbantschitsch gives the following summary of this complication:¹⁰ A thrombosis of the cavernous sinus can be caused by a thrombus in the internal jugular or facial veins or by a clot passing from the superior petrosal sinus into the cavernous sinus, or, finally, by inflammation and thrombosis in the venous circulation of the carotid canals.