. YELITTS In the present conception of poliomyelitis it is doubtful whether we are justified in describing myelitis in childhood as a nosologic entity. The difference, if there be any, is solely one of degree, depending on whether the inflammation involves the vascular domain of the entire cross-section of the spinal cord or is chiefly confined to the distribution of the anterior central arteries and therefore affects only the gray sub stance. It will be readily understood from the above-described spiv tomatology of poliomyelitis that an inflammatory affection of the spinal cord may begin as a myelitis and terminate as a poliomyelitis. There appears to be a difference between the spinal cord of children and that of adults as regards the manner in which the structure reacts to inflam matory irritation, and the seat of predilection of the disease also appears to vary at different ages. In the child inflammation of the spinal cord manifests itself chiefly as a poliomyelitis, in an adult as a myelitis. In the child the disease is found chiefly in the enlargements of the cord (cervical or lumbar portion); in the adult, chiefly in the dorsal portion. It may therefore be stated as an axiom that poliomyelitis represents the inflammation of the spinal cord characteristic of childhood and myelitis that of adult age.
The most important causes of myelitis are infectious diseases and intoxications. Traumatism and exposure to cold have lost much of the importance with which they were formerly credited. Bacteria have often been found in myelitic spinal cords, and the disease has also been produced experimentally. Syphilitic myelitis is discussed in section The pathology of myelitis consists in acute inflammation of the entire cross-section of the spinal cord, more often involving considerable portions of the structure. Di cases which clinically suggest a transverse lesion, disseminated foci of inflammation are often found in the vicinity of the blood vessels. In old cases sclerotic changes, with proliferation of connective tissue, are seen.
The symptoms are determined by the seat of the inflammation. When this is in the thoracic portion of the cord—a frequent localization —there are paraplegia with exaggerated reflexes, anxsthesia of the legs, paralysis of the bladder and rectum, and bedsores. When the lesion is
situated in the cervical portion, flaccid paralysis of the arms, with sensory disturbances are present in addition to the above symptoms. When the lesion is situated still higher up, oculopupillary- symptoms and interference with respiration arc to be expected. Myelitis of the lumbar portion gives rise to flaccid paralysis of the legs, with loss of sensation and paralysis of the bladder and rectum. Depending on the variety of paralysis present the reflexes are either increased or dimin ished, and electric initability is normal or distributed. Twitching of the affected muscles ("spinal convulsions") particularly in respon.se to external stimuli is not infrequent in myelitis.. For the details of the symp toms which may occur in the various localizations the reader is referred to the tables in the sections on spina bifida and tumor of the spinal cord.
Myelitis begins with high fever and rapidly spreading spinal symp toms. The fever may persist for some time with renewed exacerbations (cystitis, bedsores) which may come on suddenly with chills. In rare cases the disease ends in complete recovery; or it may be arrested and permanent paraplegia result; or, finally, the child may die from one of the above-mentioned complications. For the pediatrist the most im portant cases are those in which a myelitic clinical picture actually develops the symptoms of a poliomyelitis.
The most important conditions in the differential diagnosis are tumor of the spinal cord and spondylitis.
Abscess of the spinal cord is extremely rare. It results from trauma tism or, like brain abscess, may be metastatic. The favorite scats are in the upper portion of the spinal cord with a predilection for the gray substance. The symptoms are chiefly those of acute inflammation of the spinal cord, with intermittent fever. Such symptoms can be ascribed to an abscess only when a cause for the suppuration can be demon strated (Schlesinger).