MENINGITIS.
The generic term “meningitis” includes all inflammations of the arachnoid, pia mater and internal surface of the dura mater.
These forms of inflammation occur in diseases such as tuberculosis and in parasitic diseases of the brain. Under other circumstances, they are rare, and may be produced by very varying causes.
An epizootic cerebro-spinal meningitis of the bovine species has also been described, principally in Germany. It seems almost unknown in France, and French literature contains no well-authenticated case.
Furthermore, an epizootic cerebro-spinal meningitis of sheep, or rather of lambs, has been described in Germany, in Italy, and in France. These descriptions are all open to many objections. It seems that under the term “cerebro-spinal meningitis” have been grouped cases of enzootic tetanus, doubtful cases of poisoning, and particularly cases of cœnurosis in the first stage of development. We therefore discard these descriptions, which differ too much among themselves to be of any value.
Causation. Meningitis occurs in the ox and sheep as a complication of wounds in the cranial region, accompanied by fissuring of the bone, periostitis, abscess formation, etc.
It is also seen as a complication of fractures of the horns, and old-standing catarrh of the facial sinuses. In the sheep it follows parasitic catarrh due to the larvæ of œstridæ.
The meningitis appears, according to circumstances, in the forms of local meningitis, anterior frontal meningitis, basilar meningitis, etc. Finally, it may develop as a complication of different diseases, such as gangrenous coryza, purulent infection, subparotid abscess, suppurative phlebitis, suppuration of the eye or of the orbit, etc.
Symptoms. It is difficult to detect and interpret the first symptoms shown, because these chiefly consist in dulness, want of appetite and constipation, without any particular fever. At a later stage, excessive excitability is produced by noises, by changes of light, or by handling. Careful examination of the patients shows a change in their expression, rapidly followed by contraction and inequality of the pupils or deviation of the visual axis (strabismus, squinting). The pulse becomes irregular, as also the respiration. The appetite is entirely lost, and it is not uncommon to note a contraction of the muscles of the neck and jaws, as well as inability to move about and symptoms similar to those of dropsy of the cerebral ventricles.
The chronic form is rare.
Lesions. The lesions comprise local or general hyperæmia and exudative inflammation of the pia mater and arachnoid, together with the formation of false membranes or of pus in the subdural space. The meninges are partially adherent, and the superficial layers of the brain are also inflamed by contiguity of tissue.
Diagnosis. The diagnosis must be based on the disturbance of vision, movement, and appetite, and on the course of the symptoms, as well as on the external signs in the case of such diseases as are prone to become complicated with meningitis.
Prognosis. Sooner or later the case is likely to end fatally, and there is no practical use in treating the patient.
Treatment. If in exceptional cases slaughter is objected to, setons and blisters may be applied to the poll or the parotid region, or the parts may be enveloped in ice bags or compresses of iced water frequently renewed.