Symptoms. — The disease may begin abruptly, subacutely, or very gradually. When the onset is abrupt a chill more or less severe may mark the introduction, followed by fever, the temperature rang ing from 101° to 104°, occasionally higher. In children the onset may be attended with convulsions; aside from the general malaise and fever, the con stitutional disturbance may be slight. The essential nervous symptoms are usu ally irritative at first, although motor and sensory paralysis may be present from the start. These nervous symptoms vary widely with the locality and extent of the myelitis process. This variation in the symptom-picture, according to the locality affected, imperatively necessi tates a certain degree of familiarity with the topographical anatomy and func tional localization of the cord. The dor sal region is most frequently affected in the focal disease. Among the irritative symptoms hyperalgesia and hypermsthe sia are common. The patient may com plain, sometimes emphatically, of pain in the back and legs. Quite often the sensation is that of a tired aching in the limbs, as from excessive fatigue. If up and walking about, the legs are lifted wearily and the patient refers to them as being weighted with lead. There is a subjective numbness, or various paraes thesiin may be mentioned. The bladder is disturbed in function. There is reten tion, or the urine may dribble involun tarily. The bowels are usually obsti nately constipated; less frequently there is incontinence of faces. Sexual power is lost or there may be persistent pri apism. A feeling as of a band or belt encircling the hips, the waist, or the chest may be present. This is the so-called ceinture, or girdle symptom, and is quite constant in myelitis. The level of the ceinture feeling is a guide to the level of the cord-lesion. If the disease is of the cervical cord, involving the origin of the brachial plexus, the arms will be af fected. Pupillary changes are also fre quently noted when the disease is of the cervical cord through implication of Budge's cilio-spinal centre. Should the myelitis extend upward the functions of the vagus are disturbed and dyspnwa, with circulatory and vasomotor symp toms, is added to the picture. Following the irritative come the paralytic symp toms. The hypermsthesia is succeeded by anaesthesia, which is characteristically erratic in distribution, due to the destruc tion of some fibres and the escape of others. Any or all other forms of com mon sensation may be impaired or com pletely lost. There may be dissociation of sensation, though this symptom is not common. The motor weakness is suc ceeded by actual paralysis, which follows an anatomical distribution, but is usu ally not absolute. This paralysis may be flaccid or spastic, or first one and later the other, with abolished or exaggerated reflexes according to the location of the lesion. Wide-spread motor and sensory paralysis may follow slowly a prolonged irritative stage or it may be extensive and complete within a few hours or days after the onset of the disease. Within a few weeks or months atrophy of the mus cle, sometimes slight, sometimes extreme, occurs. The electrical reactions may re main normal, although both quantitative and qualitative changes have been fre quently noted. Bed-sores are exceed ingly common in severe cases, and are sometimes an extremely vicious and dan gerous symptom. In the spastic cases decided contractures may develop, the knees being flexed upon the abdomen, the heels touching the buttocks. Clonic or tonic spasms occurring in exquisitely painful paroxysms add to the sufferings of the patient in many instances. In the chronic variety of the disease the irrita tive symptoms are far less prominent. The mind remains unaffected in all cases except where an insanity may be super added from pain and abject helplessness. It should be remembered, too, that the syphilis or tuberculosis or alcohol caus ing a myelitis may later attack the brain.
Diagnosis.—The acute disease may oc casionally closely resemble Landry's pa ralysis. In the latter affection the sen sory symptoms are slight, usually there are no bladder or rectal symptoms, no girdle sensation, and the course of the disease is, as a rule, much more rapid.
Spinal meningitis rarely exists alone, the cerebral meninges being usually simul taneously involved. In syphilitic or tu bercular spinal pachymeningitis or lepto meningitis, the pain is usually much more conspicuous and the irritative spasms more decided. Usually, however, in both pachymeningitis and leptomeningitis due to these causes the cord itself is soon involved, and the differentiation is un important. Occasionally the symptom picture in myelitis may suggest locomotor ataxia. The knee-jerks may be abolished or greatly diminished, the genital func tions are involved, the sensory symptoms may be similar, Romberg's symptom may be present, and there may be an ataxic gait. The Argyll-Robertson pupil will be found wanting, however, as well as other ocular and optic-nerve changes; the pains are different in character and degree, and there is true motor paralysis in myelitis not present in tabes dorsalis. The his tory as regards mode of onset and rate of progress is of value in differentiating spinal muscular atrophy and amyotrophie lateral sclerosis and primary lateral scle rosis from myelitis. Tumor of the cord is almost invariably complicated with myelitis of focal type, and the symptoms are necessarily identical in great measure. It is possible, however, to determine the existence of tumor at times by the more intense and sometimes agonizing pain, the slower rate of progress, the narrower limitation of symptoms, and the lessened degree of constitutional disturbance. The presence of tumor elsewhere, especially if malignant, is often of assistance. Spi nal hemorrhage, if at all extensive, is usually quickly fatal from shock.
Etiology.—The disease may occur at any age and in either sex, though it is most common in males between the ages of fifteen and forty years. Prolonged or severe exposure to cold and dampness is a frequent and potent etiological factor. Next in frequency and importance, per haps, is trauma, including excessive phys ical effort or exertion. A relatively large number of cases are due to syphilis, which may act either directly and immediately or indirectly and remotely as the cause. Tuberculous myelitis is rare, though spi nal meningitis due to tuberculosis with secondary complicating invasion of the cord is not uncommon. Occasionally myelitis occurs during or immediately following (propter hoc) the acute infec tious diseases. Arsenic, lead, and other metallic poisons may induce the disease. Gross alcoholic excess is often a most im portant contributing factor and may occa sionally prove the sole cause, although the brain and peripheral nerves are usually affected equally and simultaneously in such instances. In a very appreciable proportion of patients the etiology cannot be positively determined. This is espe-• cially true in subacute and chronic mye litis.
Pathology.—The morbid anatomy of myelitis varies with the cause of the dis ease somewhat and to a still greater de gree with the stage during which death occurs. In patients dying during the acute stages the appearance of the cord in the areas affected is that of an acute inflammatory process. The blood-vessels are engorged and increased in number. Minute punctiform or capillary haemor rhages are sometimes present. The cells are swollen and the nuclei distorted or displaced. These changes are followed by an increase of connective tissue, with destruction of the nerve-cells and nerve fibres. The cord may be discolored and swollen in appearance on gross inspec tion or it may appear shrunken. Later the vessel-walls become thickened; the nerve-tissue is more or less completely displaced by connective tissue; the cells disappear and are replaced by granular and amorphous material. The pia and even the dura may be involved. In some instances, especially those due to syph ilis, the entire cord for several inches may be so softened as to be diffluent. The nerves may participate secondarily in the degenerative process.