MUSCLES, DISEASES OF.
Progressive Muscular Dystrophies, This is a general name applied by Erb to several clinical types of progressive muscular degeneration with or without preliminary hypertrophy, involving vari ous groups of muscles, and due to primary morbid changes in the muscles them selves. The disease is markedly hered itary in type. Erb subdivides the pro gressive muscular dystrophies into two classes:— 1. The progressive muscular dystrophy of infancy. This includes the hypertro phic form, formerly known as pseudo hypertrophic 'muscular paralysis, which really represents two types: (a) one in which the hypertrophy is fictitious, the mnseles having undergone lipoinatosis, and (b) one in which the hypertrophy is real, the muscle-fibres having become en larged.
The atrophic form, consisting, in turn, of two types: (a) the infantile type of progressive muscular atrophy of Dejerine Landouzy, in which there is muscular atrophy of the face, shoulder, and arm (infantile form of Duchenne), and (b) a form in which the face is not involved.
2. The progressive muscular atrophy of youth and adult life, Erb's juvenile atro phy, which usually begins in the scapulo humeral muscles.
Symptoms.—The earliest manifesta tions of the disease denote impairment of muscular power. The child's move ments become awkward, and resort must be had to various stratagems to accom plish What previously was done without difficulty. In climbing stairs, for in stance, the patient finds it necessary to grasp the banister, while he pulls himself up with his hands. To rise from the ground he is obliged to first get on his hands and knees, partly raise the body bv straightening the lees, then gradu ally reach the upright position by using his lower limbs as supports for his hands,—"climbing his legs," as it were, —Gowers's pathognomonic sign. While standing, his legs are apart, the body is bent backward, and the abdomen pro jects. His gait is waddling and he fre quently falls.
After a period, varying greatly in dif ferent cases, enlargement of some of the muscles becomes noticeable. The mus cles of the calves are usually the first to be affected. The extensors of the thighs, the muscles of the nates (glutei), of the arms and of the back (the deltoid, triceps, infraspinatus, and latissimus dorsi) are usually the next to become involved, singly or in various groupings, each af fected muscle standing out prominently. The patient's limbs and body may thus become very irregular in outline, one calf appearing much larger than the other, the muscles of one arm appearing un usually developed for the size of the fore arm, etc. This becomes especially no ticeable when, as usually happens, atro phy of adjoining muscles simultaneously occurs.
There is no electrical degenerative re action, but the latter may be diminished in proportion to the muscular weakness present. The hypertrophied muscles are often, however, unusually strong.
The Dejerine-Landouzy type begins, usually, in the face, and gives the latter a typical appearance due to thickening of the lips, described as the "tapir m ou th." "Loose shoulders" is a symptom upon which Erb lays considerable stress. When an attempt is made to raise thc child by placing the hands under his arms, the shoulders are alone raised until the level of the ears is reached; the child's head and neck sink between them, as it were, and the body seems to slip down between I,. 1 t usually stand : ..1 from the spinal col . T. .1), ( he point of t. I.. I t .1 ft 11- ile ti 57. '5Iany of e kick, the arms, and 1.,1". 11 \ t re mut 't enlarged and hard t. neh. Hie allected muscle,: re ,. ftt Hy to the utradie current.
NN .-111 exti•td portion NVI1S examined, r.t rt IN re i01111(1 te be tWiee rtS .r,e dinint ter SIS normally: the in •• tissue tuts not increased, and t re Nt as no trace of fat-cells. The c' tt ere transverswly striped in most one or two, however, showed prest,nt. Mental torpor is sometimes, and epileptoid spasms occasionally, observed. Increasing loss of physical power usually attends these cases. and death supervenes after a period of general marasmus. Some cases never reach the advanced stages of the disease; they merely com plain of localized or general weakness, and die of intercurrent diseases; others rapidly show its active manifestations and die early: the forme frusta of French Etiology.—The muscular dystrophies can generally be traced to heredity, the lcngitudinal markings. Fulda (Deut.
hiv f. klin. Med., 13. 54, 6).
Lc( r in the history of the disease -ract .ire of some of the muscles gives rise dcfr rmitics: contracture of the r....z. lis, for instance, so raises the heel a= ti prevent its apposition to the floor. clia-foo', spinal curvature, etc., may *Iviz be I rought about. Again, weakness cf the muscles may cause lordosis, or 1-,tPral deviation of spinal column, the raticnt being unable to stand or even to pright. No sensory symptoms are disease being usually transmitted through the mother, though she may not stiffer from the disease herself. Thus, all the children of a woman by different hus bands have suffered from the malady. It may occur successively in two or more generations or merely show a family tend ency by attacking only some of its mem bers through several generations. A large number, twenty to thirty, have been traced in but five generations. The dis ease visually appears early in life, very seldom after the twenty-fifth year. Males are more frequently affected than fe males.
Diagnosis. — In sufficiently advanced cases the diagnosis is not difficult, espe cially when hypertrophy of one or more muscles is present. When this distinctive feature is absent. confusion with other forms of progressive atrophy is possible.