TUBERCULAR MENINGITIS.
Little seen in cattle. Acute and chronic cases. Miliary tubercles in pia. Hydrocephalus. Progresses slowly. Irritability, hyperæsthesia, photophobia, congested conjunctiva, grinding teeth, spasms, squinting, dilated pupils, congested disc, drowsiness, stupor, coma, palsy.
Tubercle of the encephalon has been little noticed in the lower animals, partly because it is especially a disease of early life, while animals usually contract tubercle later in life, and partly because subjective symptoms are inappreciable, and the cranium is seldom opened in post mortem examinations. As the affection usually appears as a secondary deposit, the tubercles elsewhere go a long way toward identifying the nature of the disease in the brain. It has usually been found consecutive to pulmonary tuberculosis.
In a case reported by Fischœder as seen at the Bromberg abattoir, in a 350 lbs. calf, the animal had shown weakness, stupor and a tendency to fall toward the right. The brain lesions consisted of small foci of tubercle on the posterior pillars of the fornix (trigone) and adjacent parts. The left eye had on its inner aspect, near the junction of sclerotic and cornea, a firm mass with tubercular centres, extending inward as far as the retina. The bronchial mediastinal, prepectoral, brachial and precrural glands were tuberculous.
In a case in a cow reported by Lesage there were unsteady gait, impaired vision, and great timidity. Necropsy showed a suboccipital tubercle extending into the frontal sinus and cranium, and invading the brain near the parietal lobe for more than an inch. There were retro-pharyngeal and pleural tubercles as well.
In a case of Routledge’s, with extensive recent exudate, the condition advanced from apparent health to extensive paralysis in three days, while in a case which the author obtained in slaughtering a tuberculous herd no special nervous symptoms had been noticed during life. Much therefore depends on the rapidity as well as the seat of development.
The primary lesions in the brain are of the nature of miliary tubercles in the pia mater which becomes congested, rough, granular, and throws out a free serous secretion. Thus hydrocephalus is a usual concomitant of the affection.
The disease is characterized by its slow advance in keeping with gradual increase of the tubercle and is thus distinguishable from the more acute congestions and inflammations. The earlier stages are usually marked by nervous irritability, hyperæsthesia, intolerance of light, closed eyelids, congested conjunctiva, grinding of the teeth and even spasms partial or general. The second stage shows somnolence, deepening into stupor or coma, or there may be going in a circle or other irregular movement. Squinting usually convergent, dilated pupils and congestion of the optic disc frequently occur. The sleep, stupor, paralysis or coma may set in early and is usually largely due to the amount of exudation and the rapidity of its effusion.