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Spinal Muscular Atrophy

disease, muscles, nerves, degeneration, legs and affected

SPINAL MUSCULAR ATROPHY (a) Forms in Adults not Occurring in F'antilies The fact that this disease only exceptionally attacks (larger) chil dren seems to make a detailed description of it superfluous in this work. It has never been definitely proved that. these muscular atrophies are endogenons in character. The symptoms of the disease are quite typical: First, atrophy of the muscles of the hand (thenar and antithettar [hypo thenar]). Extension of the atrophy to the muscles of the shoulder, neck and throat and, finally, atrophy of a lesser degree in the legs. All the affected muscles are flaccid and atonic, and function is soon completely abolished. The tendon reflexes are diminished or absent; electrical irritability greatly impaired. The paralysis is often preceded by fibrillar twitching. Sometimes the niuseles of the shoulder-girdle are primarily attacked. The course is slow and may extend over years. Death results, if not through some intercurrent disease, from involv ment of the bulbar nerve centres and paralysis of the diaphragm. Post mortem a pronounced atrophy and degeneration of the motor cells of the spinal cord, the root fibres and peripheral nerves, and severe atrophy and degeneration of the muscle substance are found. So called aniyo trophic lateral sclerosis represents a special form of spinal muscular atrophy. It is only exceptionally a disease of childhood, although there is some reason to assume a congenital predisposition. In the distribu tion of the palsies, their extent, and in the presence of fibrillary twitch ing it presents much similarity to spinal muscular atrophy; but, while tbere is atrophy of the arm muscles, there is -weakness of the legs accom panied by spasticity and great exaggeration of the reflexes, which are also preserved for some time in the arms. The course is more rapid than that of the simple spinal form and the occurrence of terminal bulbar phenomena quite frequent. Pathologically the two forms are distin guished by. the fact that the pyramidal tracts are also degenerated in

amyotrophic lateral sclerosis, which is therefore a disease of the entire cortico-muscular nervous apparatus.

(b) Early Infantile Spinal Progressire Husenlar Atrophy This was first described by Werdnig, and later a well-defined clinical picture was outlined by Hoffmann in a series of monographs. The symptomatology of this disease is a valuable addition to our knowl edge. It is a disease of the first years of life and exhibits a marked tendency- to occur in members of the same family. Almost all the cases that have been described, about 30 in number, occurred in several children of the same family. The disease could be traced through two or three generations. The symptomatology is as follows: A previously healthy: child in the second half of its first year develops weakness of the legs, the back, then of the muscles of the neck and shoulder and finally of the hands and toes, so that in a short time it becomes com pletely paralyzed. The affected muscles exhibit marked atrophy, rarely a pseudobypertrophy. Fihrillary twitching is not constant; the reflexes soon disappear and there is marked disturbance of the electric irritability of both nerves and muscles. The cranial nerves and the sphincters escape; speech and the sensorium are not affected. There is no pain. Death ensues in from one to four years from involvement of the muscles of respiration, pneumonia, or intestinal catarrh. Atypical cases, both as regards the period of onset and the duration, have been described (Beevor, Bruns and Torild). The pathologic basis of the disease is a uniform atrophy of most of the cells of the anterior horns in the entire spinal cord, degeneration of the root-fibres and of the motor nerves, and pronounced muscular atrophy. Prognosis and treat ment are hopeless.