Carcinomata and sarcomata, particularly the former, are comparatively rapid in their progress. They sometimes involve the bones of the skull, even to the extent of perforation.
The existence of an inherited tendency and of tuberculosis in other organs, with the special phenomena of general tuberculosis, assists in the diagnosis of tubercular tumors.
The frequent occurrence of gliomata in early life, and the comparatively frequent absence of severe irritative symptoms, with the well-preserved general nutrition of the patient, speak for these growths.
Cerebral abscess is, on the whole, more difficult to diagnosticate from intracranial tumor than any other affection. Abscess, however, more frequently than tumor, can be traced directly to a traumatism. It is often associated with disease of the internal ear. Obernier speaks of the headache of cerebral abscess as slight, but this does not correspond with usual experience. Headache, on the whole, may be oftener absent or less agonizing in abscess than in tumor, but it is frequently present, and sometimes of great severity. Its greater mildness in a few cases is to be explained by the fact that abscess does not produce so much pressure within the intracranial cavity, and does not so frequently cause irritation of the branches of the trigeminus in the dura. Undoubtedly, the symptoms of abscess often remain for a long time comparatively latent, with then a sudden outburst of violent symptoms. The course of brain tumor is more uniformly and steadily progressive, and febrile phenomena, the results of pyæmia, are of more frequent occurrence in abscess than in tumor.
In old cases of tumor it is sometimes necessary to differentiate between it and the results of various forms of apoplexy, such as hemorrhage, thrombosis, and embolism. Cerebral hemorrhage, embolism, or thrombosis leaves a condition of paralysis, sometimes with, but usually without, accompanying spasm or convulsion, which simulates closely the paralysis and other permanent conditions of cases of tumor occurring in the same cerebral locality. In these cases, in the first place, the history of the disease will throw considerable light upon the diagnosis. In both hemorrhage and embolism the history is usually one of a sudden attack without special premonitory symptoms. Hemorrhage gives usually a precedent history of diseased kidneys, hypertrophied heart, or atheromatous blood-vessels, and occurs generally in advanced life; embolism, a history of rheumatism and valvular disease of the heart, occurring at any period of life, early or late. In brain tumor the previous history is usually one of traumatism, of constitutional infection, or of a special predisposing diathesis. Blows and falls upon the head are common antecedents, or a history of syphilis, tuberculosis, scrofula, or cancer is present. Tumor, like embolism and unlike hemorrhage, may occur at any time of life. While slight or dull headache, with more or less vertigo, may be present in cases of hemorrhage and thrombosis, the severe and often agonizing headache, with vomiting and serious vertiginous attacks, which precedes the paralytic or other phenomena of tumor, is a much more conclusive symptom in the latter cases than in the former. Choked discs and optic neuritis are much more likely to occur in tumor than in the other affections.
Brain tumor must sometimes be diagnosticated from the head symptoms of some form of Bright's disease. A case not long since presented itself to one of us with a history of having suffered at frequent intervals for two years with headache of gradually increasing severity. Dimness of vision and slight temporary œdema of the feet, circumscribed and painful swellings along the lymphatics of the thighs and legs, with some mental irritability, were other marked symptoms. The patient had been attended by several physicians of prominence, one of whom had diagnosticated tumor of the brain. The violent, apparently agonizing headache, with the diminution of vision, and the absence of marked symptoms indicating other organic disease, made the diagnosis of a growth in some non-excitable region of the cerebrum most probable. Examination of the urine showed no albumen. Careful examination of the eye-ground with the ophthalmoscope, however, revealed the appearances of retinitis albuminurica. Under a treatment directed to the relief of chronic nephritis the patient's headache and other symptoms improved.
It must not be forgotten just here, however, that, on the one hand, ophthalmoscopic appearances very similar to those of albuminuric retinitis are sometimes present in rare cases of brain tumor, and also in other constitutional disorders, such as leukæmia; and, on the other hand, that, as stated by Norris,36 exceptional forms of albuminuric retinitis have been reported where the only change seen in the fundus oculi was pronounced choking of the disc.
36 Op. cit.
Intracranial tumors must be diagnosticated from meningitis in its various forms. In children tubercular meningitis sometimes closely simulates brain tumor. Tumors of the brain are comparatively rare in children, but, as has already been shown, gliomata and other tumors do sometimes occur in early life. The course of tubercular meningitis, whether in children or in adults, differs from that of brain tumor. It is more irregular in its method of advance, or if it shows the regularity which is sometimes present, and which has led authors to subdivide it into three more or less completely separable stages, the symptoms of these stages do not correspond with any closeness to those of the initial, middle, and terminal periods of brain tumor, as already given. Headache is usually present in both affections, although the absence of headache in some cases of gliomata in children must be here borne in mind. When headache is present in tubercular meningitis, it is less likely to be localized, and, on the whole, it is not so severe as the terrible torture of the neoplasm. Irregular but very decided febrile phenomena are more likely to be present in meningitis than in tumor. Like brain tumor, tubercular meningitis of the convexity may give psychical disturbances, palsies, local spasms, general convulsions, sensory disturbances, peculiar disorders of the special senses, etc.; but these symptoms in the former usually come on more irregularly and are accompanied less frequently with paroxysmal exacerbations of headache, vomiting, vertigo, etc. Tubercular meningitis of the base can be more readily distinguished from cases of tumor by the fact that one cranial nerve after another is likely to become involved in the diffusing inflammatory process. Tubercular meningitis is of shorter duration than the majority of cases of brain tumor, and in it delirium and mental confusion come on more frequently and earlier. A history and physical evidences of more or less generalized tuberculosis favor the diagnosis of tubercular meningitis. In both affections the ophthalmoscope may reveal choked disc or descending neuritis. It will be seen that the differentiation between the affections is not always very clear, although in some cases the decision may be quickly reached from a study of the points here suggested.
Some of the forms of chronic hydrocephalus are difficult to distinguish from tumors, especially gliomata. In hydrocephalus, when not the result of, or not accompanied by, tubercular meningitis, the disease advances more slowly and with less irritative symptoms than in cases of tumor. Headache, vertigo, vomiting, and the other symptoms of meningeal irritation are not so frequently present, although the ophthalmoscopic appearances are often the same.