Etiology.—Although cerebral traumatism and the infectious fevers have been regarded by some as being responsible for this condition, the specific cause is unknown. Some cases are congenital, though a very large majority of cases develop during the first three or four years of life.
Pathology.—In the majority of cases, the nature of the primary lesion is unknown. In an analysis of ninety autopsies made from the literature on this subject, Osler found the following:
(a) In sixteen cases there was embolism, thrombosis, or hemorrhage. In seven of these a Sylvian artery was occluded; in nine there was hemorrhage. It is interesting to know that in ten of these cases the disease set in in children over six years of age.
(b) Atrophy and sclerosis, which are the common conditions in the majority of cases. The wasting is either of groups of convolutions, an entire lobe, or one hemisphere. The meninges may look normal, though more commonly they are tightly adherent and the brain-substance tears. The convolutions are shrunken, firm, and hard. In some instances there is a remarkable unilateral atrophy, in which the brain-tissue is a mere shell over the greatly dilated ventricle. Thus, in one of my cases, the atrophied hemisphere weighed 169 grammes and the normal 553 grammes.
(c) Porencephalus was present in twenty-four of the ninety autopsies. This term was applied by Heschi to a loss of substance in the form of cavities or cysts at the surface of the brain communicating with the arachnoid space, and in some cases passing deeply into the hemisphere, reaching even to the ventricle. Of 103 cases of porencephalus analyzed by Audry, hemiplegia was present in 68. (Pepper's "Practice.")
Symptoms.—The onset is not infrequently attended by general malaise and slight fever, the temperature rarely exceeding 102°. This is followed in twenty-four or forty-eight hours by convulsions, generally on the side which is afterwards paralyzed. The convulsions may occur at slight intervals, the patient losing consciousness.
Many times the disease comes on suddenly without a single premonitory symptom, the patient suddenly becoming unconscious. and on the return to consciousness it. is found that the child is paralyzed, the right side being the most frequently involved and the arm more seriously than the leg. Atrophy of the muscles, especially of the arm, is quite marked.
Epilepsy is a frequent result, especially when the hemiplegia is from birth.
Generally there is arrested or retarded mental development, and idiots or imbeciles are not uncommon among this class of unfortunates.
The knee-jerk and ankle clonus may be present.
Post-hemiplegic movements consist of tremors, choreiform movements, and athetosis.
Diagnosis.—This is readily made from the characteristic symptoms that accompany hemiplegia.
Prognosis.—As regards life, the prognosis is good, though mental impairment and some degree of paralysis remain. Aphasia is rarely ever permanent.
Treatment.—Aside from the treatment for the convulsions, and these should be controlled as soon as possible, the treatment will be symptomatic, and means and methods used for improving the general health.
A nutritious and easily digested diet, plenty of fresh air and sunshine, massage and faradization, and patient and systematic education, will be important factors in the treatment.