Myositis

MYOSITIS (myositis), more correctly miitis, is an inflammation of the skeletal muscles. In clinical and pathological-anatomical terms, several forms of myositis are distinguished, each with a highly diverse etiology inherent to that form (see below). Purulent myositis (myositis purulenta) arises from the penetration of pyogenic microorganisms into the muscle mass, either from the outside during trauma through damaged skin, or by the spread of purulent inflammation from adjacent parts (in cases of phlegmons, bedsores, purulent periostitis, and osteomyelitis), or finally by a metastatic route from distant inflammatory foci (in glanders, typhoid fever, erysipelas, gonorrhea, and general purulent infection). A muscle bruise or overexertion during work serves as a predisposing factor. The pathological-anatomical picture is expressed by abundant round-cell infiltration with necrosis and disintegration of muscle fibers. In some cases, this process is diffuse (phlegmonous myositis), while in others it is limited to a specific area of the muscle (muscle abscess). Clinically, purulent myositis is expressed by the onset of local pain, tenderness of the affected muscle, its density, reflex contracture with immobility of the corresponding body part, and finally, general febrile phenomena. After a few days, a softer area forms in the dense mass of the muscle, in which fluctuation is then obtained. A more severe course is taken by diffuse phlegmonous myositis, which often leads to death. If recovery occurs, it is always with significant destruction of the muscle. Since the regenerative capacity of the muscle tissue itself in purulent myositis is usually insufficient, healing occurs with the formation of an extensive connective tissue scar and the development of significant muscle shortening. Treatment is the same as for acute inflammation of soft tissues in general. Acute non-purulent myositis (myositis acuta non purulenta) often develops as a complication of other pathological processes in the muscles themselves (trauma, degeneration, tumors, parasites—e.g., in trichinosis), as well as during the spread of an inflammatory process from adjacent parts (tonsils, lymph nodes, joints, etc.). Being a local affliction, it is sometimes diagnosed as myalgia (see). Much less frequently, acute non-purulent myositis occurs as a general disease spreading to several muscles, sometimes to the muscles of the entire body. Several subtypes of such a disease can be noted. Acute muscular rheumatism (myositis rheumatica) represents a toxic-infectious disease, with cooling being a predisposing cause. It develops either as an independent disease or as a complication of other infections (influenza, acute articular rheumatism, etc.). In the pathological-anatomical respect, besides the usual proliferative and exudative phenomena in the intermuscular connective tissue and alterative changes in muscle fibers, the focal changes ("lymphoid follicles") described by Grauhan together with Rössle are interesting; these are encountered in this disease between muscle fibers both in skeletal muscles and in the myocardium. Some authors consider them analogous to the "Aschoff bodies" (Aschoff) found in acute articular rheumatism. Clinically, rheumatic myositis is characterized by the onset of acute pain in the muscles of one or another part of the body and sharp tenderness upon palpation, and sometimes some swelling and tension of the muscle can be noticed. Due to the pain, a significant limitation of mobility of the corresponding body part is noted. Almost always, a more or less pronounced febrile state can be noted. Usually, the disease affects specific groups of muscles or individual muscles, e.g., the sternocleidomastoid muscle (torticollis rheumatica), muscles of the shoulder girdle, and the lumbar region (lumbago rheumatica). Acute myositis of individual muscles, most often the biceps muscle (m. bicipitis), which is periodically recurring and sometimes precedes the development of articular rheumatism, was described by Laquer under the name of intermittent monomyositis (tonomyositis interstitialis intermittens). The course is usually short, a few days, and exacerbations of the disease and the transition of the process from one group of muscles to another can be observed. The outcome is either recovery or transition to a chronic form. Treatment: salicylate preparations, local analgesics (camphor spirit, chloroform with Hyoscyamus oil, etc.), local and general light therapy and heat procedures, and diaphoretic treatment (light, steam, hot water baths). During the period of pain relief, local massage and ionization with a sodium salicylate solution are used. In prolonged cases, treatment with sulfur and mud baths is used. Acute polymyositis (polymyositis acuta), described by Wagner as early as 1863, is still a little-studied disease due to its rarity. At present, acute polymyositis is recognized by almost everyone as an infectious disease with an unidentified pathogen. The disease usually affects most or all muscles of the body without exception, and simultaneously, not sequentially as is usually the case with muscular rheumatism. Immediately or after a short prodromal period with general febrile phenomena, pain in the muscles, tenderness upon pressure and movement, limitation of limb mobility as a result, swelling and hardening of the affected muscles, and finally, edema of the surrounding connective tissue and skin arise. When the myocardium is involved in the process, dilation of the heart chambers, tachycardia, and arrhythmia occur. Sometimes endocarditis and nephritis are observed. The spleen is usually enlarged. Sometimes intestinal bleeding and other phenomena of hemorrhagic diathesis are noted. The disease usually lasts from 8 days to 3-6 months (although cases of two years' duration have been described) and often ends in death from paralysis of the respiratory muscles, pneumonia, or complications from the heart. In cases of recovery, muscle atrophy, retraction, contractures, and persistent limitation of mobility often remain. Besides this pure form of polymyositis, cases are observed where this clinical picture is complicated by acute phenomena of the skin; such cases are called dermatomyositis (Unverricht). In other cases, along with muscle damage, symptoms of polyneuritis are observed: true paralysis and sensory disturbances of the peripheral type, tenderness of nerve trunks, and reaction of degeneration. This is the so-called neuromyositis (Senator). Recently, a special form of polymyositis with particularly sharp involvement of blood vessels (a peculiar endarteritis with narrowing of the vessel lumen and gelatinous degeneration of the intima) has been identified—the so-called angiomyositis (H. v. Meyenburg). Finally, a case of polymyositis with the excretion of muscle pigment in the urine was described by Günther, which he named myositis myoglobinurica. Treatment in all forms of polymyositis is symptomatic: analgesics, salicylate preparations, cardiac drugs, strychnine. In the chronic stage: warm baths, light therapy, massage, gymnastics, sulfur and mud resorts. Chronic myositis (myositis chronica) is observed either as a secondary inflammatory process with the formation of scar fibrous tissue in the muscle after trauma, purulent or specific inflammation, trichinosis, local ischemia, etc., or as a primary fibroplastic inflammation of individual muscles and muscle groups. Such fibrous myositis (myositis fibrosa, s. fibroplastica) is characterized by the formation of moderate round-cell infiltration in the muscle connective tissue layers, which soon gives rise to the proliferation of interstitial connective tissue with the formation of dense, tendon-like cords. Muscle fibers in this process partly perish during phenomena of degeneration and partly undergo primary atrophy. The development of the disease is slow (over many months or years) and is characterized by the onset of more or less sharp pain in the muscles, the appearance of nodules or indurations in the muscle mass, usually at the sites of muscle attachment to the bone (Müller's nodules), and the formation of muscle contractures in the end. The muscles of the neck, back, and lower extremities are mostly affected. Durante considers this disease the initial stage of acute muscular rheumatism; König and Lorenz see at its core a special constitutional anomaly with a tendency to the development of connective tissue; Thomson and Gordon believe that fibrous myositis is a partial manifestation of a general disease of connective tissue, the so-called fibrositis, by which they mean an inflammatory reaction of the fibrous, supporting connective tissue of the organism to external poisons of bacterial or non-organized origin. A predisposing factor is tension, overwork, and cooling of the muscles. Therefore, the parts of the body most often exposed to these influences become ill. Therapy consists, on the one hand, in destroying the focus of toxins and removing already circulating poisons from the blood (elimination of septic foci in the oral cavity, in the upper respiratory tract, in the genitourinary organs, treatment of prolonged bronchitis, catarrhs of the digestive organs, etc.), and on the other hand, in combating the formation of scar tissue and subsequent contractures.

For this latter purpose, heat is applied in the form of general water baths, phototherapy, steam showers, massage, gymnastics, and iodine ionization; sulfur, saline-alkaline, and mud resorts are also indicated. A peculiar form of chronic inflammation of the muscles is represented by the so-called progressive ossifying Myositis (myositis ossificans progressiva multiplex). Besides the local formation of bone plates within the thickness of one muscle or another (in the adductors of the thigh in cavalrymen, in the deltoid muscle in infantrymen) due to repeated occupational injuries, a progressive, continuous development of bone formations is observed in many muscles of the body, predominantly in the muscles of the back, neck, and abdomen. The cause and essence of this disease are unknown. Some authors, beginning with Mays and Virchow, consider it a developmental anomaly with a congenital perversion of the ossification processes in the organism; others see at its foundation a traumatic or rheumatic Myositis with a special predisposition to subsequent bone formation; thirdly, some consider ossifying Myositis as a primary or secondary myopathy developing following a lesion of the nervous system. Recently, a theory of the endocrine origin of this disease has been put forward (disorder of calcium metabolism due to disease of the parathyroid glands). This disease develops almost always in childhood or adolescence and proceeds slowly, in spurts. Suddenly, usually with general febrile phenomena, soreness and swelling of one muscle or another or a muscle group arise. After a few days, the painful phenomena subside, but the muscle becomes dense due to the development of fibrous tissue. Then, in this thickening of the muscle, a process of ossification begins to develop, which spreads gradually along the length of the muscle to the attachment to the bone. Eventually, a bizarre bone crossbar is formed, which connects by means of bridges with similar bone formations in neighboring muscles. After a period of rest, sometimes of several¹ years, a new attack of the disease arises with the formation of new bone deposits in the muscles. Over many years, the process affects a whole series of muscles, and in the case of spreading to the muscles of the neck, chest, or abdomen, it begins to cause disorders of the internal organs. An inability to chew, swallow, or breathe develops, and patients die from phenomena of general exhaustion. The prognosis regarding recovery is hopeless, and all therapeutic measures applied until now have not had success. Syphilitic Myositis (myositis syphilitica) is observed either in the form of diffuse inflammation of the intermuscular connective tissue or in the form of the formation of gummas within the thickness of the muscles. The diffuse form of syphilitic myositis is encountered in the earlier stages of syphilis, and its starting point is the vessels, through the infiltrated walls of which numerous wandering cells penetrate; the multiplying cells of the perimysium form a small-cell infiltrate. Due to the further organization of this latter and the simultaneously occurring death of muscle fibers, fibrous tissue is formed in the form of islands and cords, abundantly penetrating individual sections of the muscle. Clinically, this form of syphilis of the muscles proceeds as chronic myositis and is recognized only on the basis of accompanying manifestations of syphilis and serological reactions. The gummatous form of syphilitic Myositis manifests itself by the formation of limited dense nodules, sometimes of significant size. These nodules are usually painless and give cause for confusion with neoplasms of the muscles. Subsequently, they either resolve or disintegrate and open up with the formation of a gummatous ulcer, which then gradually scars over. The resulting destruction of the muscle can be so great that eventually a retraction of the muscle belly is formed. Most often, gummas are encountered in the sternocleidomastoid muscle and in the tongue. Treatment is the usual anti-syphilitic one. Tuberculous Myositis (myositis tuberculosa) is usually observed upon the spread to the muscles of a process from affected tuberculous bones, joints, and lymphatic glands. In extremely rare cases, it develops by way of infection through the blood. In these latter cases, the disease may remain unrecognized for a long time, because the granulomas forming during this process develop slowly and are slightly painful. The essence of the affliction reduces to chronic inflammation of the interstitial connective tissue with the formation of tubercles and to secondary degeneration of the muscle fibers. Upon the disintegration of caseously degenerated tubercles, a cold abscess forms in the muscle with characteristic contents, allowing one to determine the nature of the disease upon puncture. Treatment: local—surgical, and general—as in tuberculosis of the lungs and bones.

S. Chugunov. Occupational Myositis. In addition to the infectious group of diseases described above, there is another, no less common group of myositis, which includes a whole series of occupational diseases of the neuromuscular apparatus, mainly of the extremities. A detailed study of the working and living conditions of workers and the diseases associated with them revealed the presence of a number of diseases of the muscular system developing on the basis of occupational overexertion, and introduced some differentiation and clarity into the concept of so-called muscular rheumatism, to which a whole series of forms of muscular diseases of unclear etiology were usually attributed earlier. A very frequent cause of muscle disease is their overexertion in the course of occupational work. Constant overexertion of muscles, causing a change in blood circulation and nutrition within them, leads to local disturbances of biochemical processes, entailing a change in muscle tissue, and thereby in its function. Diseases of the muscles of the extremities are observed in persons of clerical labor (typists, stenographers, scribes), and in musicians (violinists, pianists, etc.). Diseases of the hands in persons of these professional groups have been known for a long time (since 1883), but they usually went under the diagnosis of functional coordinative neuroses, writer's cramp, neuralgias, or in extreme cases, plexitis, and only comparatively much later was attention drawn to and pointed out that in persons of the above-mentioned professions, diseases occur predominantly or exclusively in the muscles of the upper extremities. But besides this sufficiently studied occupational group, diseases of the neuromuscular apparatus of the extremities, and in particular myositis, are encountered among representatives of professions of heavy physical labor, especially among those where the factor of overexertion of individual muscle groups is clearly expressed. In persons working with a pneumatic chisel (chippers, riveters), in whom the muscles of the hands are in a state of constant vibration and very strong tension, severe muscular diseases of the corresponding muscle groups that take a particularly large part in the work develop. For example, in rollers at metal rolling mills, especially those working on manual machines, on cold rolling, and passing several thousand kilograms of metal per day, the muscles of the left arm and shoulder girdle suffer most severely. The muscles of the hands suffer to a significant degree in furriers in the fur industry, who have to scrape animal skins on a sharp large knife, then in pantograph operators in the lace and curtain industries, who punch out a lace pattern with their left hand, with the hand being in a tense state on the weight the whole time; in persons forced to do fast, tense work with their fingers, such as, for example, binders of elements for electric batteries, packers in tea-packing plants, sewing machine operators, as well as pressers; in a bus driver, who is forced to 'depress' the clutch with his left foot weighing up to 30-40 kg each time he starts the machine, and with his right hand shift gears and hold the steering wheel, the muscles of the left leg and right arm suffer mainly. In the muscles of such patients, there are no typical acute myositic, i.e., inflammatory phenomena with infiltrates, but foci of induration are found in them, starting from very small ones, the size of a lentil (Cornelius points) and ending with indurations of the entire muscle. Sometimes the muscles are pasty, sometimes fibrotically changed. English authors (Thomson and Gordon) proposed the term 'fibrositis' for these phenomena. Microscopically, it is usually difficult to find any changes in the muscles, as a result of which there is a whole series of theories attempting to explain the nature of this muscular process. The most probable can be considered the theory of Schade, who speaks of the thickening of muscle colloids, occurring both during strong cooling, disturbance of blood circulation and metabolism, and during overexertion (see Myalgia). Occupational myositis develops most often gradually and bears a chronic character; acute cases are encountered more rarely, when the disease was preceded by some exceptional overexertion (overtime, urgent, nervous work). Acute infections usually aggravate and exacerbate the disease; complications and combinations of occupational diseases in connection with influenza infection are especially frequent. Clinically, two main forms are distinguished: 1) with a predominance of the pain syndrome (see Myalgia) and 2) with a predominance of exhaustion of the neuromuscular apparatus. Complaints mainly boil down to pains in the extremities, weakness in them, and the inability to perform one's work with the same productivity. Objectively, there is soreness, induration, or pastiness mainly of those muscle groups that are in static tension during work; those same muscles that work dynamically suffer less (for the picture of objective changes in muscles, see Myalgia). For example, in typists, the muscles fixing the arm in a forced position suffer mainly, namely the trapezius muscle, the long supinators, and the first interosseous muscles on the hand; in rollers—the muscles of the shoulder girdle on the left (trapezius muscle), etc. In cases with a predominance of neuromuscular exhaustion, pain phenomena recede into the background (at times the muscles are even completely painless to the touch), and the foreground is occupied by a decrease in strength, flabbiness of the muscles, and fibrous changes in them, with sometimes even a visually noticeable hypertrophy of the muscle itself (pseudohypertrophy). Both the second and the first forms of the disease are accompanied by a decrease in strength in the extremities and a change in reflexes (increase or slight decrease). There are no gross changes in sensitivity and electrical excitability. Nerve trunks can also be involved in the suffering, but the latter macroscopically usually suffer less than the muscle itself and are only slightly painful to the touch. Where only the muscles suffer, one can speak of myositis; in cases where nerve trunks are involved—of neuromiositis. However, the concept of neuromuscular overexertion must also include disturbances in the central cerebral apparatuses. In cases where, in addition to static tension, there is a factor of significant dynamic tension, the distal ends of the muscles most often suffer, i.e., in the area of their attachment to bones and joints (tendomyositis). On the basis of occupational overexertion, tendovaginitis is also encountered (ironers, seamstresses). In terms of prognosis, clearly expressed and far-advanced cases of muscle disease are unfavorable, since the changes in the muscles are usually of such a deep and persistent nature that one cannot speak of their complete cure. Acute forms of the diseases pass significantly better. Treatment, depending on the above-mentioned causes of the disease, must proceed in two directions. Since the main etiological moment is overexertion, the diseased organ must be provided with complete rest. Without special treatment (see below), this rest must be understood as the cessation of work for many months, a year. In view of the fact that the disease develops mainly in persons with the presence of other general diseases, then, of course, that underlying disease against the background of which the muscle disease develops must be treated. Prophylactically, all persons of special clerical labor and workers of heavy physical labor must be subjected to periodic medical examination and, in sharply expressed cases that do not show improvement, be transferred to work that does not require great muscle tension, so that the patients do not reach an even higher degree of disability. As the most effective method of treating occupational myositis, as well as myalgia, it is necessary to point out massage according to Cornelius; warm baths, diathermy, mountain sun, etc., must be considered only as auxiliary treatment. Thermal treatment at a resort can also be useful. L. Korst.