PSEUDO - HYPERTROPHIC MUSCULAR PARALYSIS.
This disease belongs to childhood, and rarely begins after the tenth year, although cases have been reported in children of fourteen or fifteen years. It occurs more frequently in boys than girls, and often attacks several members of the same family.
The direct examination of the diseased muscles during life has been made by removing small portions by means of the harpoon. This examination has enabled us to see that the hypertrophy is only apparent and that the increase in volume of the muscular prominences is due solely to an increase in fatty tissue. Under the microscope it is seen that the muscular fibre has almost entirely disappeared. At the same time there is an accumulation of adipose cells to such an extent that little by little the fatty tissue replaces the muscular. The more or less vivid red color of normal muscular tissue has disap peared and given place to a pinkish-yellow hue.
Alongside of the pseudo-hypertrophied muscles it is often possible to find others which are decreased in size—simply atrophied. The tendons never take part in the pseudo-hypertrophic process. Exam ination of the nervous centres gives negative results, and, notwith standing the observations published by Babes, in which the intra muscular nerves seemed to present some alterations, it is generally admitted to-clay that the muscular lesions constitute the entire disease.
Symptoins.--There are two things which attract attention and ex cite a suspicion of pseudo-hypertrophic paralysis, viz., an increase in volume of certain groups of muscles and a weakness which seems to increase in proportion to the progress of the apparent hypertrophy. At the beginning of the disease it is the lower extremities which are attacked, and what first attracts attention usually is the prominence of the calf muscles. The muscles of the thigh and glnteal region be come involved in the same process, and the glutei, the sacro-lumbar muscles, the flexors and adductors of the thighs are seen to stand out prominently. In the same way the quaclratus lumborum, the del toid, the serrates magnus, the periscapular muscles and those of the arm are invaded. Frequently these muscular groups atrophy in
stead of becoming hypertrophied. But the most salient feature of the picture is the excessive volume of the lower extremities, and, in interesting contrast to this, a gradually increasing weakness involving these same regions. At the commencement of the affection this weak ness is not very pronounced. It is only remarked that the child stands less firmly on his legs and often falls. As the lesion pro gresses and the muscular tissue gives place to fat, walking becomes more and more difficult. In order not to fall the patient separates his legs, and in walking he bends backward awl inclines his body to one and the other side ; in a word, he waddles like a duck. This expresses very accurately the manner of progression of a child with pseudo-hypertrophic muscular paralysis. After sitting or lying the patient experiences the greatest difficulty in raising himself to an erect posture, and he is forced to execute a series of movements in order to supplement the insufficiency of his thigh and leg muscles. The first thing that he does is to place himself on his belly ; then with his hailds he rolls himself together and rises with difficulty, sup porting himself with his hands resting successively on different seg ments of the lower extremities. It has been said very aptly that the patient climbs up himself.
Palpation of the affected parts gives the peculiar sensation of soft ness inherent in fatty tissue, which is very different from that of nor mal muscular tissue.
Pseudo-hypertrophic muscular paralysis invades gradually more and more of the muscles. After having halted for some time in the lower extremities it attacks most of the other muscles of the body, this time often under the atrophic form. The atrophy may also fol low upon the false hypertrophy. The feet are sometimes deformed, being drawn into the equinus position. The face may likewise be come involved, as has been noted by Duchenne, Weir Mitchell, and others. The patient then presents the phenomenon of a gaping mouth, and his atrophied muscles prevent the complete closure of his eyelids.