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Query: UMLS:C0027121 (myositis)
 4,538 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report an experimental model of autoimmune inflammatory myopathy. Splenic cells from two inbred murine strains (BALB/c and SJL/J) are activated (immunized) in vitro by co-culture with their respective syngeneic skeletal muscle myotubes. Subsequent injection of the activated splenocytes with or without B. pertussis into the respective syngeneic hosts results in inflammatory myopathy in the SJL/J mice but never in the BALB/c mice. The muscle inflammation is very similar in appearance to human autoimmune inflammatory myopathies. The myositis is not effector cell-skeletal muscle specific because splenocytes activated by co-culture with smooth muscle will also elicit skeletal muscle lesions. Both strains of skeletal muscle appear to express class II (Ia) antigens and the splenocytes from both strains appear to be equally activated. Thus we postulate that the difference in the expression of myositis between the two strains is in the effector phase of the disease. Since SJL/J mice have vasoactive amine sensitive vascular systems and BALB/c do not, it is likely that activated splenocytes emigrate from muscle microvessels in the SJL/J strain whereas they cannot do so in the BALB/c strain. The most significant contribution of this model may be in its potential for addressing a sine qua non of cellular autoimmune disease, i.e. lymphocyte migration from the vascular compartment into the target tissue. Finally, the data support a cellular more than a humoral pathogenesis in this model.
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PMID:Experimental autoimmune inflammatory myopathy. 362 32

Lymphoid masses can be centered predominantly within an extraocular muscle (EOM), as exemplified by computed tomography (CT) scanning and biopsy confirmation in the seven cases reported in this study. In these patients, an insidious and painless onset of exophthalmos was overshadowed by ptosis or a motility disturbance (particularly limited upgaze) in the absence of chemosis and lid erythema. The lesions were located in the superior rectus-levator complex (6 cases) and in the medial rectus muscle (1 case). One patient, with an exclusive infiltration of the levator, had a complete ptosis, whereas four others had a partial ptosis. Important clinical clues included palpable masses (4 cases) and preserved downward gaze (all cases), the latter suggesting the absence of fibrotic restriction, as is often seen in Graves' myopathy and the idiopathic myositis of pseudotumor. The biopsy specimens showed spill-over of the hypercellular and stroma-free lymphoid tissue into the orbital fat (all cases) and into the lacrimal gland (3 cases). Full extraocular motility on upgaze was restored after local orbital radiotherapy, although a residual ptosis persisted in five cases. Five patients had well-differentiated lesions and nonocular disease did not develop, whereas a widespread disease developed in one of two patients with a cytologically malignant lymphoma; the patient eventually died.
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PMID:Orbital lymphoid tumors located predominantly within extraocular muscles. 362 18

A single injection of TPA (12-0-tetradecanoyl-phorbol-13-acetate) into the superior rectus muscle of New Zealand white rabbits produced inflammation and edema, followed by fibrosis and muscle restriction. Strain gauge measurements showed a 60% increase in muscle restriction at 24 hours and an increase greater than 400% at 12 weeks. Clinical and histologic characteristics paralleled those of human idiopathic orbital myositis and thyroid orbital myopathy. The combination of initial muscular inflammation and enlargement, subsequent fibrosis and restricted extraocular motility, and histologic evidence of these changes creates a useful model of orbital myositis.
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PMID:Phorbol ester-induced orbital myositis. 363 47

Three Collies with a skin disorder, 6 progeny from a breeding of 2 of the Collies (incross litter), and the 4 progeny from the breeding of an affected Collie male and a normal Labrador Retriever female (outcross litter) were examined. By 7 to 11 weeks of age, all 6 dogs in the incross litter developed a qualitatively similar, but variably severe, dermatitis of the ears, face, lips, tip of the tail, and over bony prominences of limbs. Later, myopathic signs characterized by bilaterally symmetrical skeletal muscle atrophy of the head, neck, trunk, and extremities; facial palsy; decreased jaw tone; stiff gait; and hyperreflexia were observed in the dogs more severely affected by the dermatitis. Of the 4 dogs in the outcross litter, 3 had similar, but milder, clinical manifestations of the dermatitis and myopathy. Cutaneous lesions consisted of intraepidermal and subepidermal vesicles or pustules with intradermal infiltration by leukocytes. Muscle lesions included myositis; myofiber degeneration, regeneration, and atrophy; and fibrosis. A generalized myopathy in the severely affected dogs was indicated by abnormal readings on needle electromyograms and normal motor nerve conduction velocities. Spontaneous needle electromyogram abnormalities were fibrillation potentials, positive sharp waves, and bizarre high-frequency discharges. Retrospective and prospective genetic analyses disclosed a definite familial tendency and indicated the condition has an autosomal dominant component.
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PMID:Familial canine dermatomyositis: clinical, electrodiagnostic, and genetic studies. 405 Dec 92

A patient is described in whom a neuromyopathy developed during a long chloroquine treatment for systemic lupus erythematosus (SLE). The presence of a granular deposition within the muscle fibers was observed and led to discontinuation of the drug and to a gradual recovery of muscle strength. The difficult differential diagnosis with polymyositis, steroid-induced myopathy and SLE myositis is discussed.
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PMID:Chloroquine-induced neuromyopathy. Report of a case. 407 94

Of 105 cases seen over 12 years with mean 4 years followup, there were 69 with polymyositis (PM) and 36 with dermatomyositis (DM). and in 43 this complicated another connective tissue disease (CTD). Primary PM had onset a decade later than others and most severe myopathy occurred in DM. Earliest symptoms were polyarthritis and Raynaud's phenomenon with frequent sicca syndrome (51%). The less than universal prevalence of elevated muscle enzymes (68%), myopathic electromyography (86%). and abnormal muscle biopsy (78%) emphasizes the need for complete evaluation in all cases. Improvement occurred in 69% overall, including all 23 given no therapy or low dose corticosteroids and 59% of the remainder who received high dose corticosteroids with added cytotoxics in one-quarter. Outcome was worse in older patients and in those where weakness exceeded 4 months before diagnosis. Eight of 19 deaths were due to myositis or its therapy which also caused considerable morbidity. Malignancy in 16 cases was temporally related to myositis in half of these cases.
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PMID:Dermatopolymyositis and other connective tissue diseases: a review of 105 cases. 409 21

An investigation was made into the occurrence of muscular atrophy and muscular pathology in a series of 170 patients with myasthenia gravis. The results can be summarized as follows: (1) Of the 148 patients with generalized myasthenia gravis, 14 showed local muscular atrophies. Of 10 biopsies from atrophic muscles, eight showed neurogenic changes, with or without lymphocytic infiltrations. One biopsy showed lymphocytic infiltrations only, and one showed type II-fibre atrophy (Table 1). No relationship was demonstrable between the presence of clilnical muscular atrophy and age, sex, duration of the disease, severity of the disease, presence of a thymoma, or drug resistant ophthalmoplegia. (2) In this group of patients 61 biopsies were examined from 46 individuals; 40 of these biopsies were taken from the quadriceps muscle. A thymoma was present in 17 patients. Examination disclosed neurogenic changes in 17 biopsies, lymphocytic infiltrates in 21, and myositis in one biopsy (Table 2). A distinct correlation was established between the presence of a thymoma and lymphocytic infiltrates, but none was demonstrable between thymoma and neurogenic changes (Table 3). (3) An enzyme-histochemical study was carried out in 35 cases, including 12 with neurogenic changes. A normal differentiation of type I- and type II-fibres was observed in eight instances, type grouping of type II-fibres in three, and type II-fibre atrophy in two cases. (4) In 21 patients and 19 controls, the smallest mean diameter was determined in the quadriceps muscle. Both type I- and type II-fibres proved to have a smaller mean diameter in the female patients than in the controls. In the male patients this could not be proven. (5) Of the eight patients who had died without disorders of ventilation, 90 muscle specimens were examined postmortem. Four of these patients had a thymoma. Lymphocytic infiltrations, found in 32 biopsy specimens, were mostly observed in the presence of a thymoma. Neurogenic changes were apparently unrelated to the presence of a thymoma (Tables 5 and 6). The post mortem examination included the spinal cord in five, and peripheral nerves in three cases. No abnormalities were found. (6) The muscular atrophy found in patients with myasthenia is not a myopathy but an affection of the lower motor neurone. Neurogenic changes were regularly found in the muscles of patients with myasthenia, even without muscular atrophy. The finding of these changes is no reason to reject the diagnosis. It is postulated that denervation occurs at the neuromuscular junction as a result of permanent absence of acetylcholine.
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PMID:Neurogenic muscle involvement in myasthenia gravis. A clinical and histopathological study. 470 58

Three patients presented with gradual onset of proximal muscle weakness. Electromyography and muscle biopsy were abnormal in each patient and typical of myositis. All three had an IgG kappa monoclonal paraprotein in the serum. Examination of muscle biopsy specimens by direct immunofluorescence revealed linear deposits of IgG kappa along the sarcolemmal basement membrane of individual fibres. Stains for lambda light chains, other immunoglobulins, and complement components were negative. Plasmapheresis and immunosuppressive drugs produced clinical improvement in all three patients. Muscle biopsies were taken from two of the patients after plasma exchange and drug therapy and showed no immune deposits. These observations suggest a possible cause-and-effect relation between the serum paraprotein and the inflammatory myopathy in these patients.
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PMID:Polymyositis associated with monoclonal gammopathy. 615 Feb 37

Patients with active rheumatoid disease may develop encephalopathy, myelopathy, peripheral neuropathy, and myopathy through a variety of tissue mechanisms. Brain involvement is usually characterized by the formation of rheumatoid nodules or by the development of vasculitis or its complications, and there is evidence to suggest that the trapping of immune complexes within the choroid plexus may be important in pathogenesis. Structural damage to the spinal cord and lower brain stem, on the other hand, most commonly results from narrowing of the bony canal, leading either to direct compression of neural tissue or to compromise of its vascular supply. The appearance of peripheral neuropathy generally signifies the presence either of inflammatory epineurial arterial disease or entrapment by neighboring anatomical structures. Skeletal muscle dysfunction may be due to vasculitis, myositis, or denervation atrophy. Both systemic and local anatomical factors, therefore, are of importance in determining the manner in which different parts of the nervous system may be affected in rheumatoid disease.
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PMID:The neuropathology of rheumatoid disease. 625 49

A 13-year-old girl with chronic graft versus host disease (GVHD) developed severe proximal weakness. Muscle biopsy showed necrotic fibers with anti-IgG deposits and interstitial inflammation. Steroid treatment helped, but her weakness recurred. Repeat biopsy showed persistent inflammation and possible steroid myotoxicity. Numerical ratio of capillaries to myofibers and capillary numerical density were higher than childhood dermatomyositis (CD), and capillaries had no tubuloreticular inclusions. Absence of quantitative histologic, ultrastructural, or immunocytochemical abnormalities of capillaries differentiated our patient from CD. We conclude that myositis of chronic GVHD can present as a severe myopathy that responds to steroids and differs from CD.
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PMID:Myositis of chronic graft versus host disease. 635 Sep 24


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