Myalgia

MYALGIA (myalgia), pain in the muscles of a shooting or aching character, sometimes dull, nagging; appears in attacks, most often during work, but also frequently at night; sometimes it has a constant character with gradual intensification and similarly slow fading, while in other cases it flares up suddenly under the influence of cooling, careless movement, overexertion, injury; it appears especially easily in rheumatics, gout sufferers, diabetics, and the obese. M. does not constitute an independent disease, but is merely one of the symptoms of disorder of muscle function. The rhythmic character of muscle work is apparently determined by the fact that the basis of contraction of the muscle fiber lies in the rhythmically occurring chemical processes of formation of lactic acid from muscle glycogen. The interaction of the formed lactic acid with the contractile elements of the fiber gives their shortening and thickening—contraction of the entire fiber (Meyerhof). -The transition of lactic acid from the fibrils into the plasma surrounding them, its interaction with the proteins of the plasma, its transformations with partial reversion to glycogen corresponds to the relaxation of the fiber, ending in the pre-contraction pause. The excessive accumulation of lactic acid in the muscle must disrupt the rhythmic alternation of its contractile phases. Accumulating in the fibrils, lactic acid apparently causes in them a prolonged state of contraction and possibly contributes to the change of colloids of the muscle in the direction of their hardening; accumulating in the plasma, it contributes to the lengthening of the relaxation phase of the fiber. By means of palpation in the diseased muscle, a characteristic "unevenness," "mottledness" of consistency is discovered: tense density of muscle bundles (Müller's hypertonus) amidst areas of flaccid muscle tissue, hardening to the consistency of firm gel (aspic). These "myogeloses," according to Schade and Lange, are the consequence of changes in the colloids of muscle plasma. In such a changed muscle, Cornelius noted cord-like thickenings the size of a millet seed to a bean, in acute cases reacting to pressure by a change in shape and yielding to smoothing with the finger. To this symptom Cornelius gave the name "nerve point" (irritation from compression of nerve endings). Cornelius's and Müller's symptoms are found on palpation in all muscles of the body without exception, Schade's symptom—predominantly in the muscles of the neck, shoulder girdle, back, and in the quadriceps muscle. The main causes of M. must be, first, a change in the chemistry of muscle tissue (see Myositis) with disruption of the rhythmic course of the contractile process—"dysrhythmia" of the muscle fiber; second, disease of the nervous system regulating all phases of the contractile process; third, a change in the general metabolism of the body. Then come secondary, accidental causes: injuries, cooling, intoxications from diseases of internal organs, exogenous intoxications (tobacco, alcohol, drugs), then infections, especially influenza, which gives particularly severe complications in muscle tissue. Secondary processes appear in the muscles, arising on the basis of changes in nutrition, blood circulation, and condition of the nerves. Thus, in the muscles of the pelvic girdle in M., elongated, the size of an almond, more rarely nodular-round swellings are found, resembling glands in shape, and fatty tissue in consistency. They are often combined with panniculites, cellulites (French authors), phenomena of chronic inflammatory changes and proliferation of cellular, predominantly fatty elements in the subcutaneous tissue, felt as small and large, round and oval swellings causing pain. There are cases when the intermuscular connective tissue, excessively developing, suppresses the muscle tissue, gives hardenings in it, fibrousness, nodules, calluses (fibrositis). Simultaneously, the hardening process often extends to the tendons, ligaments, fasciae, joint capsules. All this also causes pain, which is often combined with a burning sensation.-One should also mention the possibility of deposition of uric acid salts (tophi urici) in the muscle, causing pain. All these pains as it were merge into pure M., and it is very difficult to differentiate them from it, all the more so as they are indirectly connected with it by a common basic cause. Palpation, which includes an element of movement, helps to sort out these differences. The fingertips, moving, perceive the skin, subcutaneous tissue, muscles, and the deepest layers of tissues down to the periosteum, carefully revealing individual elements, determining their mutual relationship, shape, size, consistency. Thus the diagnosis is established.-The treatment of M. is basically reduced to measures restoring muscle function. In acute cases—rest, moist heat in the form of fomentations, wraps, water compresses, steam showers, general warm (up to 41°) baths followed by slight sweating; pain-relieving rubs; internally—pyramidon and narcotics. In subacute and chronic cases, the same treatment is combined with medical massage and simple, gradually complicating physical exercises.-Prevention consists in a hygienic-dietetic way of life and in maintaining in the muscles the processes of tone and rhythm by performing special physical exercises.