These two forms may exist with each other, and with other intracranial lesions, such as thrombi of the sinuses and exudation under the arachnoid and around the veins.
Parrot compares this form of softening to that occurring in the other extreme of life, dependent on vascular lesions; but although he supposes the method of production to be unlike in the two cases, it is by no means so certain, either from his conclusions or his cases, that it is always so. In some of his cases the vessels are said not to be abnormal, but in others old thrombi are distinctly mentioned. As secondary consequences may be observed intracranial dropsy, with perhaps hydrocephalic cranium and degeneration of the pons, bulb, and medulla.
Two cases of red softening of the cerebellum have been reported.71 In one of them the pia was adherent, in the other thickened and covered with exudation. The microscopic details are not given nor the state of vessels mentioned. They are probably not strictly analogous to those described by Parrot.
71 Jahrbuch. f. Kinderheilkunde, 1877.
The occurrence of granular corpuscles in the brain of the new-born is described by Virchow, and it is thought by him to be pathological and of an irritative character (encephalitis congenita). It is somewhat doubtful if this process is characterized by any distinct symptoms.
The ETIOLOGY is impaired nutrition, deficient or improper feeding, and depressing diseases, frequently tubercle.
The SYMPTOMS and DIGNOSIS of this form of softening are even more obscure than those of venous thrombosis in the same class of cases. Vague cerebral symptoms arising in an infant poorly nourished and suffering from acute disease may be due to this condition, but a positive diagnosis is out of the question. In the two cases of softening of the cerebellum just mentioned, in one, aged five, there was dilatation of the pupil, difficulty of hearing, and vertigo; in the other, aged six, vertigo, inclination to vomit, and clonic spasm of the left facial muscles. Parrot says that in the greater number of patients the encephalopathic troubles observed during life cannot be referred to it (softening), and in no case can it be diagnosticated.
Under these circumstances it is obvious that remarks upon the PROGNOSIS and TREATMENT must be purely works of the imagination.
Atheroma of the Cerebral Arteries
has already been spoken of as one of the most important factors in thrombosis, and perhaps of considerable consequence in embolism and hemorrhage. Its symptoms, when one of these accidents has taken place, are hardly to be separately considered; and if atheroma have produced complete occlusion, even without the assistance of a clot, the symptoms could not be distinguished from those of an ordinary thrombosis, and would follow the same course.