ACUTE INFANTILE SPINAL PARALYSIS.
infantile spinal paralysis, or acute anterior polio-myelitis, is.not, as was formerly supposed, a disease peculiar to childhood. It is now known to occur also in adults, although in them much more rarely than in younger persons. This lesion constitutes the ordinary form of paralytic affection to which children are liable. It nearly always begins in babyhood—dur ing the time of the first dentition—but often lasts long after the first teeth have been completed, and indeed may render the child a cripple for life.
The disease is never a fatal one in itself, but if death occur from other causes in a child so paralysed, no naked-eye changes in the spinal cord can be discovered. Consequently the nature of the lesion was long doubt ful, and has only recently been elucidated. Now, however, owing to the researches of MM. Charcot, Joffroy, Roger, Damaschino, and others, the loss of power has been shown to be due primarily to an inflammation af fecting the gray matter of the anterior cornua of the spinal cord, causing atrophy and disappearance of the large multipolar ganglion cells in that situation. The reader may be reminded that these large ganglion cells are believed to be centres of reflex action and transmitters of impulses received through the spinal tracts. They therefore influence the movements of muscle. Besides this, they are probably trophic centres and regulate the nutrition of tissues. Consequently the disappearance of these cells is fol lowed by impairment or even abolition of reflex and voluntary action in the parts with which they are in communication, and also by impaired nutrition in muscles, tendons, bones, and joints.
Causation.—As the disease is mainly limited to the period of the first dentition, cutting of the teeth has been supposed to be a cause of the mye litis ; but if this be the case it is probably so only indirectly. An infant feverish from teething is in a high state of nervous irritability. His diges tion is impaired, and his pyrexia renders him exceptionally sensitive to chill and other causes of inflammatory and catarrhal disorder. For this
reason pulmonary and intestinal derangements are common at this period of life. But these ailments cannot be said strictly to be caused by denti tion, except in the sense that the process of teething, by making the child feverish, heightens his susceptibility to ordinary injurious influences. So, also, in the case of this disease, an infant, when feverish, is more likely to be affected by causes which produce the myelitis than he would be at an other time when his temperature is normal, his digestion good, and his nervous system undisturbed. What these causes may be is doubtful. The inflammation is often attributed to chills, and there is no doubt that the season of the year has a distinct influence in inducing the attacks. Drs. Wharton Sinklet, of Philadelphia, and Barlow, of Manchester, have made in quiries into this matter. Out of one hundred and forty-nine cases collected by the former physician no less then seventy-seven occurred in the months of July and August. In Dr. Barlow's one hundred and eleven cases forty eight occurred during the same months. Now July and August, although the hottest months in the year, are also those in which alternations of tem perature are most rapid and unexpected, and in which, therefore, sudden chills are very likely to be incurred. If the child at the time of the change is depressed and exhausted by previous intense heat—as he is apt to be in a tropical climate—the sudden lowering of the temperature is the more likely to produce an injurious effect. The disease sometimes occurs after typhoid fever : Dr. Buzzard has known it to come on after measles ; and the paralytic attack appeared iu a patient of my own—a little girl of two and a half years old—during convalescence from an obstinate chronic diarrhoea. Both sexes appear to be subject to it in an equal degree ; and, apparently, robust health is no protection from its attacks, for it as often affects a con stitutionally healthy child as a cachectic and weakly one.