(1) General Diagnosis.—The differential diagnosis has regard first to certain general phenomena which are broadly indicative of a spinal disorder as distinct from a cerebral or peripheral one. Thus, mental symptoms are absent, or if present are an accompaniment of tumors high up in the spinal axis, are the results of suffering, or appear very late in the disease because of progressive weakness. Briefly stated, the phenomena which point with comparative certainty to the existence of spinal tumors are symptoms of meningeal irritation gradually increasing, and symptoms of slow compression of the cord. These have been sketched at the beginning of Symptomatology. As to duration, the data in the cases studied were somewhat meagre. The usual duration is from six months to three years.
The differential diagnosis of spinal tumors will be considered in reference to the following affections: congestion, hemorrhage, meningitis (simple and specific), caries, traumatisms, sclerosis, aneurisms, neuritis, metallic and infectious disorders, and hysteria. Spinal tumors, it will be recalled, are from constitutional or special causes, as syphilis, cancer, and tuberculosis. The onset is gradual and irregular. The duration is comparatively long. The progress is by irregular advances toward a fatal termination. The symptoms are inclined to be at first unilateral or local; later, bilateral. Special symptoms, as paralysis, spasm, sensory and visceral disorders, occur irregularly as to time. Decubitus and trophic changes are common late in the history. Reactions of degeneration are often present. Gowers refers to the fact that two morbid processes often occur, one consecutive upon the other, as a secondary degeneration or a hemorrhage, after the establishment of the morbid growth, with characteristic increase of symptoms.
In spinal congestion a constitutional cause is not likely to be present. The onset is usually sudden and after exposure. The duration is shorter than in tumors, and is from a few days to four months. The disease is stationary for a while; then retrogression of symptoms toward recovery occurs. The symptoms are more uniformly bilateral, and motor and other symptoms develop about the same time. Decubitus is rare. Reactions of degeneration are rare (?). It is desirable that cases of so-called spinal congestion should be differentiated from the forms of peripheral neuritis above referred to, the most characteristic symptom of which appears to be tenderness of nerve-trunks.
In spinal hemorrhage there is no special history, or a history and signs of cardiac and vascular degeneration may be present. The onset is quite sudden and the progress of the case regular. The first symptoms persist, and secondary degenerations follow, and differ according to the extent and location of the lesion, but are most likely to be uniformly bilateral.
In meningitis the symptoms of localized compression are absent. The girdle symptom is absent. The affection is sometimes curable, and especially so if it has been of syphilitic origin. The reactions of degeneration are not marked.
In caries of the spinal vertebræ deformity is rarely absent, especially if the case has continued a few months. Rigidity of the muscles of the back is an important symptom, which, however, is occasionally found with tumor. Jarring of the spinal column by tapping upon the head or jumping from a chair or stool is more likely to elicit pain in caries than in tumors. Strumous symptoms and evidence of tubercles in the lungs or other organs are often present.
In traumatisms usually a history of the injury can be obtained. The symptoms are those of caries, myelitis, meningitis, or of combinations of these, according to the character of the case.
In sclerosis the symptoms are usually those of progressive systemic affections, with absence of compression symptoms. The duration is longer. The progress is gradual and more regular.
Aneurisms are only to be distinguished when extra-spinal, causing erosion and compression.
In neuritis there is the soreness of the nerve-trunk already referred to, while compression symptoms and visceral disorders are absent. The motor and sensory symptoms are confined to the area of distribution of the affected nerve. It is amenable to treatment. In advanced stages the reactions of degeneration are marked. In the form of general peripheral neuritis, the existence of which, as a distinct disease, is being at present claimed, the characteristic symptoms are as yet not sufficiently determined or the pathology demonstrated by post-mortem research to admit of much discussion.