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Myositis caused by Borrelia burgdorferi: report of four cases.

Myositis was proven histopathologically in 4 patients (age range 36-66 years) who suffered from early or late stages of Borrelia burgdorferi infection. Muscle weakness was present in 3 patients, 1 complaining of additional myalgias. One man came to medical attention because of skin discoloration and swelling of one leg. Deep biopsy from skin, fascia and muscle revealed acrodermatitis chronica atrophicans, panniculitis, fasciitis, and myositis, respectively. Creatine kinase was slightly elevated in 3 cases and normal in one. Infiltrates were found in the perimysium and within the muscle bundles, mainly around small vessels. The infiltrates consisted of many B cells and T4 lymphocytes with fewer cytotoxic T cells, suggesting that Borrelia myositis might be due to a local immune response to unknown Borrelia antigens. Cultivation of Borrelia from muscle was not successful. Antibiotic therapy cured the myositis.

Adult↗

Myositis in Lyme borreliosis: an immunohistochemical study of seven patients.

Myositis is a rare complication of Lyme disease. In order to get information about the pathogenesis of this disorder, muscle specimens of 7 patients suffering from myositis as a manifestation of Lyme borreliosis were examined by immunohistology. Lyme spirochetes could be found in muscle biopsies of 6 patients. Infiltrates consisted mainly of macrophages and T helper/inducer cells. The T4/T8 ratio was 1.7 in the endomysium and 2.1 in the perimysium. Increased expression of MHC-I molecules by several muscle fibers was observed in 2 subjects only. No MHC-II molecules were expressed by muscle fibers. Lymphocytes expressing the interleukin-2 receptor were detected in 2 patients. Leu-15+ and Leu-11+ cells were found only to a slight extent in 2 patients. In conclusion the immunohistochemical findings in myositis due to Lyme borreliosis are different from other manifestations of this disease, and also from other forms of myositis.

Adult↗

Focal myositis of the perioral musculature.

Focal myositis, a benign inflammatory pseudotumor, is a relatively newly defined clinicopathologic entity which arises as a rapidly enlarging swelling within an isolated skeletal muscle. It occurs most often in the lower extremity, and we are reporting what we believe to be the first cases of perioral involvement. There is no apparent age or sex preference. Focal myositis must be differentiated from neoplasm, nodular pseudosarcomatous fascilitis, proliferative myositis, myositis ossificans, polymyositis, and, in the oral region, salivary gland lesions and hypertrophic branchial myopathy. No lesions have recurred.

Adult↗

Predominant right leg dysfunction without asymmetric muscle inflammation in CD1 Swiss mice with coxsackievirus B1-induced myositis.

To establish the existence of predominant right leg involvement in Coxsackievirus B1-induced myositis (CB1 myositis) 189 neonatal CD1 Swiss mice were inoculated with 300 pfu CB1, and regularly observed for posture, mobility, and gait. After 2 and 4 weeks, quantitative comparison of motor dysfunction of right and left leg yielded an asymmetry score; on light microscopy mononuclear cell infiltration and muscle fiber necrosis were quantified in bilateral hamstring muscles, using a five-grade scale (0-4). Motor asymmetries were seen during acute viral myositis as soon as hind leg dysfunction appeared, and animals with a predominant dysfunction of one leg preserved that preference throughout the observation period. At 2 weeks, mice with predominant right leg dysfunction (n = 34) significantly outnumbered those with predominant left leg dysfunction (n = 11) (p = 0.01). At 2 and 4 weeks, infiltration and necrosis in hamstrings from legs with predominant dysfunction were not higher than in those from contralateral legs, and infiltration in right-sided hamstrings was not higher than in left-sided ones, nor was infiltration at 4 weeks. At 4 weeks right-sided muscles were more necrotic (mean +/- SD, 1.8 +/- 1.5) than left-sided muscles (1.1 +/- 1.2; p = 0.03). In the absence of predominant inflammatory disease of the right leg, we interpret the hind leg asymmetry as a preferential use of the left leg, due to left-leggedness, and suggest that in CD1 Swiss mice left-leggedness is associated with increased susceptibility to CB1 myositis.

Animals↗

A clinical, serological, and histopathological study of myositis patients with and without anti-RNP antibodies.

Twenty-nine patients with myositis, including 10 with polymyositis (PM), 6 with dermatomyositis (DM), and 13 with myositis associated with a connective tissue disease (CTD), were followed up for a mean observation time of 49 months. The 13 patients with CTD-associated myositis were further separated by the presence or absence of anti-RNP antibodies. The functional disability at diagnosis was pronounced without differences between the groups. The patients with anti-RNP antibodies did not differ from the other patients regarding initial muscle weakness, erythrocyte sedimentation rate, or creatinine phosphokinase values, but the histopathological muscle changes were generally milder. Rapid improvement of muscle strength on moderate doses of corticosteroids was seen in most patients. At the end of study, corticosteroid treatment had been withdrawn from 17 patients because of remission, including 6 of the 7 patients with anti-RNP antibodies. The presence of electromyographic changes compatible with myositis, pronounced muscle weakness before treatment, and a low erythrocyte sedimentation rate seemed to indicate a less favorable outcome unrelated to diagnostic subgroupings. However, the combination was rarely found among the anti-RNP-positive patients.

Adolescent↗

Infection and musculoskeletal conditions: Infectious myositis.

Infectious myositis, an infection of the skeletal muscle(s), is uncommon. This clinical entity may be caused by viral, bacterial, fungal, and parasitic pathogens. Viral etiologies typically cause diffuse myalgias and/or myositis, whereas bacteria and fungi usually lead to a local myositis which may be associated with sites compromised by trauma or surgery and are more common among immunocompromised patients. Localized collections within the muscles are referred to as pyomyositis. Other pyogenic causes of myositis include gas gangrene, group A streptococcal myonecrosis, and other types of non-clostridial myonecrosis. Early recognition and treatment of these conditions are necessary as they may rapidly become life-threatening.

Gas Gangrene↗

Immunopathogenic pathways in canine inflammatory myopathies resemble human myositis.

Progress in the treatment of inflammatory myopathies is impeded by the lack of suitable animal models. Inflammatory myopathies occur spontaneously in the dog, are a heterogeneous group of disorders, and are more common than in humans. Clinical signs of weakness and muscle atrophy are reliably present, and there are histological and immunohistological similarities to forms of human myositis. In this study, microarray technology followed by quantitative real-time PCR and immunohistochemistry on muscle biopsy sections was used to investigate gene expression in cases of canine inflammatory myopathies. Several genes involved with innate and adaptive immunity were highly upregulated including those that participate in macrophage and dendritic cell activation and migration, and antigen processing and presentation. Other genes including those that participate in B cell growth, development, migration and activation, immunoglobulin genes, genes in pro-inflammatory and anti-inflammatory pathways, and genes involved with tissue remodeling were upregulated. In previous reports utilizing microarray technology in human myositis, there was activation of similar pathways involved in the immune response. This study strengthens the argument that forms of canine myositis may be important animal models of human myositis and suggests useful biomarkers for therapeutic response using the dog in pre-clinical trials.

Animals↗

Myositis associated with a Baerveldt glaucoma implant.

PURPOSE: To describe a case of myositis in the presence of a Baerveldt glaucoma implant. METHOD: Case report. RESULTS: A 41-year-old black woman developed myositis after placement of a Baerveldt glaucoma implant. Echography demonstrated migration of the seton plate against the medial rectus muscle insertion. Myositis resolved after removal of the Baerveldt glaucoma implant. CONCLUSION: The Baerveldt glaucoma implant may have precipitated myositis in this patient.

Adult↗

Recent advances in the morphology of myositis.

Myositis in man may be divided into infectious and non-infectious forms. The myopathologist more often deals with the latter forms which comprise dermatomyositis/polymyositis, inclusion body myositis, mixed connective tissue disease/collagenoses, and granulomatous myopathies. Modern morphological techniques as enzyme-histochemistry, electron microscopy, immunohistology, and morphometry are of different value in various forms of myositis, but are often indispensable techniques in up-to-date diagnostic work up of a myositis.

Dermatomyositis↗

Quantitative assessment of myositis in thigh muscles using magnetic resonance imaging.

Magnetic resonance (MR) imaging has been suggested as a technique for diagnosing and monitoring myositis, an inflammatory muscle disease. To date, the assessment of disease from MR images has been by subjective visual analysis. We describe here an objective, semi-automatic, computer-based method for quantifying the degree of disease from MR images, without the need for a radiologist or physician trained in the visual assessment of the MR images. The method is based on analysis of the histogram of intensity values produced from the MR images. The analysis yielded measures of the intensity and extent of disease. These two measures were combined to produce a calculated myositis index (CMI) which described the degree of disease evident from the MR images. This index was compared with a clinical assessment of the patient's condition, based on currently accepted, invasive and non-invasive, non-imaging criteria. Receiver operating characteristic (ROC) curve analysis showed that calculated myositis index agreed at least as well with clinical assessment as did visual analysis (receiver operating characteristic area = 0.93 and 0.94, p = not significant (NS), respectively, for separating remission from disease). Even using only two central MR slices for each patient, the receiver operating characteristic area for calculated myositis index was 0.92, implying that very short acquisition times are possible. We conclude that quantitative histogram analysis of MR images can be successfully performed with minimal operator input and using few MR slices. Agreement with more invasive clinical assessment is good and the method has the advantages of repeatability, objectivity, and decreased scan and analysis time.

Adult↗

Rimmed vacuoles and the added value of SMI-31 staining in diagnosing sporadic inclusion body myositis.

Problems in diagnosing sporadic inclusion body myositis may arise if all clinical features fit a diagnosis of polymyositis, but the muscle biopsy shows some rimmed vacuoles. Recently, immunohistochemistry with an antibody directed against phosphorylated neurofilament (SMI-31) has been advocated as a diagnostic test for sporadic inclusion body myositis. The aims of the present study were to define a quantitative criterion to differentiate sporadic inclusion body myositis from polymyositis based on the detection of rimmed vacuoles in the haematoxylin-eosin staining and to evaluate the additional diagnostic value of the SMI-31 staining. Based on clinical criteria and creatine kinase levels in patients with endomysial infiltrates, 18 patients complied with the diagnosis of sporadic inclusion body myositis, and 17 with the diagnosis of polymyositis. A blinded observer counted the abnormal fibres in haematoxylin-eosin-stained sections and in SMI-31-stained sections. The optimal cut-off in the haematoxylin-eosin test was 0.3% vacuolated fibres. Adding the SMI-31 staining significantly increased the positive predictive value from 87 to 100%, but increased the negative predictive value only to small extent. We conclude that (1) patients with clinical and laboratory features of polymyositis, including response to treatment, may show rimmed vacuoles in their muscle biopsy and that (2) adding the SMI-31 stain can be helpful in differentiating patients who respond to treatment from patients who do not.

Adult↗

Inclusion body myositis: morphological clues to correct diagnosis.

The aim of this study was to investigate variability of morphological changes found in patients with sporadic inclusion body myositis, to assess the diagnostic value of muscle biopsy. The study included all 43 definite inclusion body myositis patients (86 biopsies) diagnosed at Sahlgrenska University Hospital, Gothenburg, Sweden, between 1984 and 2000. Invasion of mononuclear inflammatory cells in non-necrotic muscle fibres was found in 72 of 86 specimens, while all investigated biopsies showed up-regulation of major histocompatibility complex class I. Cytochrome c oxidase-negative muscle fibres were demonstrated in 84 of 86 biopsies. Rimmed vacuoles were present in all specimens from the vastus lateralis and tibialis muscles, and in 43 of 51 biopsies from the deltoid muscle. In cases with clinical suspicion of inclusion body myositis, where the muscle biopsy does not show inflammatory cell infiltration and rimmed vacuoles, inclusion body myositis should still be considered if there are cytochrome c oxidase-negative fibres and up-regulation of major histocompatibility complex class I. In such cases repeat muscle biopsy may be helpful.

Adult↗

Myopathological findings in interstitial myositis in type II polyendocrine autoimmune syndrome (Schmidt's syndrome).

We report on a patient with an interstitial myositis in type II polyendocrine autoimmune disease (Schmidt's syndrome) showing an immunohistochemical demonstrated perifascicular expression of Leu 19 indicating perifascicular denervation, which could not be detected with classical histological methods. In neurogenic muscular atrophy, idiopathic polymyositis and normal muscle we could not find such an exclusive perifascicular expression of the Leu 19 antigen. We conclude that perifascicular denervation is a characteristic feature in IM and thus might have diagnostic value. Furthermore the interstitial myositis is characterized by a complement-mediated angiopathy (vascular deposition of the membranolytic attack complex C5b-9). This pattern is comparable to well-known changes in dermatomyositis. Interstitial myositis and dermatomyositis are evidently pathogenetically similar according to myopathological criteria, but show phenotypic differences. Additional in interstitial myositis and idiopathic polymyositis inflammatory infiltrates surrounding Leu 19 expressing myocytes are regarded as the cause of disseminated intrafascicular muscle fibre denervation.

Adult↗

Recurrent acute myositis after allogeneic bone marrow transplantation for myelodysplasia.

A 54-year-old woman developed polymyositis 6 months after allogeneic bone marrow transplantation (BMT) for acute myelogenous leukemia transformed from myelodysplasia. At the onset of myositis, the patient had oral dryness, and the histology of oral mucosa was compatible with chronic graft-versus-host disease (GVHD). Muscle biopsy revealed focal muscle necrosis with massive lymphocytic infiltration. She was diagnosed with polymyositis, and the dose of cyclosporine was increased. Three months later, a complete resolution of myositis had been obtained, and the cyclosporine was tapered off. However, 51 months after the first episode of myositis, she again noted severe myalgia and was diagnosed with a recurrence of polymyositis based on high serum creatinine kinase (CK) and the findings of magnetic resonance imaging (MRI). At that time, chronic GVHD in other organs was not present. She achieved a second remission of polymyositis with cyclosporine, and has remained in remission for 4 years. The pathogenesis of myositis can be attributed to the immunologic imbalance characteristic of the post-allogeneic BMT setting.

Bone Marrow Transplantation↗

Infective pyomyositis and myositis in children in the era of community-acquired, methicillin-resistant Staphylococcus aureus infection.

BACKGROUND: Cases of pyomyositis and myositis have been increasing in frequency at Texas Children's Hospital (Houston) since 2000. The increase appears to correlate with the emergence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA). METHODS: The medical records of patients with pyomyositis and myositis hospitalized at Texas Children's Hospital during the period from January 2000 through December 2005 were reviewed. Available S. aureus isolates were obtained for susceptibility testing, to determine the presence of pvl (lukS-PV and lukF-PV), and for pulsed-field gel electrophoresis analysis. RESULTS: Forty-five previously healthy children with bacterial pyomyositis or myositis were analyzed. The causes were S. aureus (in 57.8% of children) and Streptococcus pyogenes (in 2.2%); 40.0% of children had negative culture results. The number of cases increased between 2000 and 2005, primarily as a result of an increase in the prevalence of community-acquired MRSA. The mean patient age was 5.5 years (range, 0.06-15 years). The thigh (40.0% of children) and pelvis (28.9%) were the most commonly affected sites. The mean abscess diameter was 3.5 cm. Eighteen children required at least 1 muscle drainage procedure. Of the 24 available S. aureus isolates (15 community-acquired MRSA isolates and 9 community-acquired, methicillin-susceptible S. aureus [MSSA] isolates), 16 were found to be USA300 by pulsed-field gel electrophoresis, and 17 carried pvl. Patients with community-acquired MRSA, USA300, and/or pvl-positive strains required more drainage procedures than did those with community-acquired MSSA, non-USA300, and/or pvl-negative strains (81% vs. 40% [P=.05], 82% vs. 29% [P=.02], and 81% vs. 38% [P=.07], respectively). CONCLUSIONS: Community-acquired MRSA is an increasing cause of pyomyositis and myositis in children. Community-acquired MRSA, USA300, pvl-positive S. aureus isolates caused more severe disease than did community-acquired MSSA, non-USA300, and pvl-negative isolates, respectively.

Adolescent↗

Myositis induced by naked DNA immunization with the gene for histidyl-tRNA synthetase.

Polymyositis is regarded as an autoimmune inflammatory muscle disease. A major subgroup of patients have autoantibodies to cellular histidyl-transfer RNA synthetase (HRS). We have analyzed the role of the autoantigen HRS in the induction of murine myositis in a comparative study of inoculation of BALB/c mice with recombinant HRS protein versus naked DNA coding for HRS. Adult BALB/c mice produced antibodies to human HRS following inoculation with HRS protein and adjuvant, but myositis was not observed. Alternatively, expression plasmid DNA constructs encoding full-length and truncated human HRS were inoculated intramuscularly in gene transfer studies. DNA-inoculated mice produced relatively low anti-HRS antibody titers. However, in contrast to recombinant HRS protein-inoculated mice, HRS gene transfer induced pathology with evidence of cellular infiltration of perivascular and endomysial regions of the inoculated muscle. Multiple inoculations of a plasmid construct encoding a hybrid molecule consisting of HRS and the transferrin receptor cytoplasmic tail induced the highest levels of antibodies and persisting cellular infiltration. Unlike HRS, expression of influenza virus hemagglutinin (HA) following inoculation of an HA plasmid did not induce myositis. Transfer of naked DNA constructs expressing HRS is likely to provide valuable information on the autoimmune response to this protein and its role in the development of myositis.

Animals↗

Veillonella myositis in an immunocompromised patient.

Infectious myositis is rather uncommon. When caused by anaerobic organisms, myositis is usually polymicrobial. Trauma, ischemia, or a contiguous focus of infection is often an antecedent of myositis. We report a case of monomicrobial veillonella myositis in an immunocompromised patient. The infection responded to debridement and therapy with metronidazole.

Anti-Bacterial Agents↗

Treatment of traumatic myositis ossificans with acetic acid iontophoresis.

The purpose of this case report is to document the treatment of a patient who had traumatic myositis ossificans with acetic acid iontophoresis. A 16-year-old boy developed quadriceps femoris muscle myositis ossificans as a result of a springboard diving accident. A 2% acetic acid solution was administered via iontophoresis into the myositis ossificans, followed by 8 minutes of pulsed ultrasound at 1.5 W/cm2. The treatment was performed three times per week for 3 weeks. At the conclusion of the treatments, radiographic findings indicated a 98.9% decrease in the size of the ossified mass. The patient regained full range of motion and was able to return to pain-free activity. This case report demonstrates the potential for a therapeutic program of acetic acid iontophoresis and ultrasound in eliminating myositis ossificans.

Acetates↗