22 Billroth relates an altogether exceptional case of a limited pseudo-hypertrophy with lipomatous degeneration, localized in the hamstring and adductor muscles of one thigh, in a girl seventeen years old. The only generalized lesion was an immense development of subcutaneous fat (Archiv für klin. Chir., Bd. xiii.).
Dyce Brown (Edin. Med. Journal, 1870) relates a case, also in an adult of twenty-six years, where hypertrophy of the thigh-muscles is said to have preceded by three weeks that of the calves.
These symptoms all point to failure of power in the gastrocnemii muscles, whose function it is to raise the heel from the ground in running, to steady the heel by their tension during the act of standing, and to raise the foot with considerable force during the act of going up stairs. In descending a staircase or any inclined plane great tension is required of these same muscles, and this act should therefore be even more difficult than that of ascension. But it does not seem to have been as carefully studied.
Attention is not often directed to the infirmity at this early stage, especially if the child be very young, since the apparently excellent development of the legs satisfies the parents that nothing serious can be the matter, and the falling is explained by childish awkwardness. Not infrequently, indeed, this is really due to a rachitis which has preceded the degenerative lesion, and at the early stage of the latter a diagnosis from the less severe disease is always required, and is sometimes difficult to make.
The following test may be applied in doubtful cases: The child (if old enough) is requested while standing to rise on the tips of his toes. This act necessitates a powerful effort on the part of the sural muscles, and of this, even at an early stage of degeneration, they are generally incapable.
Functional weakness may precede for several years all visible alteration of the muscles; the child may not learn to walk at all until two or even three years of age; then walks badly until five or six, when, for the first time, the calves begin to enlarge. More often the paresis precedes the hypertrophy by only a few months or weeks, or the symptoms occur simultaneously. A certain amount of hypertrophy will be overlooked; but when the calves enlarge sufficiently to render the child's stockings too tight, attention is forcibly called to the change. The enlargement is more marked at the upper part of the calf, so that the symmetry of the leg is deranged by it. Often, however, the impression of vigor conveyed by the appearance of the child's legs is with difficulty dispelled by the discovery of their functional weakness.
Eulenburg23 affirms that the consistency of the muscle is soft and doughy, recalling, when grasped in the hand, a lipomatous tumor. This description, however, does not apply to the early stage of the disease; for then the hypertrophied muscles feel extremely hard to the touch; there is even a stony hardness (Duchenne fils); somewhat later, the hypertrophy continuing, these muscles "seem to make hernial protrusions through the skin" (Duchenne). This appearance is most marked when the subcutaneous fat is atrophied; when, as happens especially in the adult cases,24 the diseased muscles are covered by a thick layer of subcutaneous fat, their protrusion is concealed. A rapid exchange of the hardness characterizing the first stage of the lesions for a lipomatous softening is of bad omen, as indicating a more rapid and irresistible march in the disease (Mobius).
23 Ziemssen's Handbuch, Bd. xii.
24 See case by Billroth, quoted p. 853, note.
At this early stage the electrical reactions of the enlarging muscles are all intact. Disturbances of sensibility, however, are not uncommon. Especially frequent are pains in the back and loins and stabbing pains in the lower limbs. These pains sometimes follow the track of the crural or sciatic nerves; at other times they appear in the joints; sometimes are limited to the affected muscles. The pains are diminished by repose and a recumbent position, but are greatly aggravated by movement. Paræsthesias, or a feeling of cold and formication, are also observed—never anæsthesia. Seidel25 has found the cutaneous sensibility to be intact, as also the sense of space and pressure. The temperature sensibility has not been tested. The temperature of the affected part is, according to Eulenburg, often lowered several degrees. This statement probably refers to the advanced degree of degeneration. At an earlier stage Ord26 found the temperature of the calves to be increased.