Etiology.—Chronic myelitis may follow the termination of an acute attack, or it may be due to trauma, hemorrhage, tumors, or caries of the vertebra.
The disease may come on insidiously, the result of syphilis or from the toxin of some of the infectious fevers. In rare cases, it may be due to cold from exposure.
Pathology.—While it may be confined to a single focus, the lesions are most often disseminated or diffuse. Sclerosis is the most pronounced lesion, even the membranes, in some cases, sharing in the sclerosis. The ascending and descending tracts may be involved in the same process. The blood-vessels are thickened; hence there is an absence of recent hemorrhage. The pia may be thickened and adherent. The nerve-cells in the gray matter become atrophied or they may entirely disappear.
Symptoms.—The symptoms are about the same as in the acute form, save the fact that they come on more insidiously, and are not so well defined, several months elapsing before sufficiently pronounced to consult a physician.
There may be perverted sensation, such as numbness, tingling, crawling, etc., though complete loss of sensation is rare.
The motor symptoms are gradual in their onset, and irregular in their development, especially where the lesion is disseminated or diffuse. The patient notices a weakness in a part, as the hand or arm, which is followed soon by impaired sensation; then a foot or leg develops weakness, to be followed by disturbed sensation, and finally paralysis.
Where there is transverse myelitis of the lumbar or sacral region, there is paresis of the lower extremities, with involvement of the sphincters. Atrophy of the muscles is more pronounced, when the lesion is of the cervical or dorsal region. The degree of trophic changes depends upon destruction of the cells in the anterior horn of the spinal cord.
Diagnosis.—The diagnosis is not always readily made, though when the symptoms enumerated are well defined, there should be little difficulty.
Prognosis.—The disease has progressed to such an extent that degenerative changes have generally taken place before the physician is consulted; hence the prognosis is necessarily grave, though recovery may possibly take place in rare cases. The disease, however, may extend over a period of years before it terminates fatally by exhaustion.
Treatment.—In the early stages, rest in bed, associated with sponge-baths and massage, is very beneficial. As the disease becomes more chronic, our attention will be directed to maintaining as good a condition of the general health as possible. With the elaboration of a good blood, degenerative changes are stayed, and all the symptoms modified. To accomplish this end, hygienic and dietetic methods will be important adjuncts to the treatment. Change of air and climate, having the patient much in the open air, is very desirable.
Digestion will be improved by the bitter tonics, and secretion from the skin, kidneys, and bowels should be encouraged. For the motor disturbances, physostigma in from one to three drop doses is recommended by Goss. Phosphide of zinc in one-tenth grain doses three or four times a day has also been used. Electricity will have its place, though too much dependence must not be placed upon remedies or methods.