Antibody Therapies in Autoimmune Inflammatory Myopathies: Promising Treatment Options

Inflammatory myopathies, including polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM), necrotizing myopathy (NM), antisynthetase syndrome (ASS) and overlap myositis (OM), in short myositis, are rare diseases. All forms of myositis have progressive muscle weakness in common, with each subtype characterized by different autoantibody profiles, histological findings and extramuscular manifestations. Due to better understanding of the pathogenesis of the muscle inflammation in myositis, new molecular pathways for targeted therapy have been discovered. Current therapies aim at different components of the innate or the adaptive immune response. Additionally, non-inflammatory mechanisms in myositis have come into focus as possible treatment targets. The use of therapeutical antibodies in myositis has been examined in various clinical studies, several of them randomized controlled ones: Depletion of B-cells by rituximab has been established as treatment of refractory myositis. IVIG, an antibody therapy in the wider sense, has now been licensed for DM following a recent positive clinical trial. Negative study results were reported in randomized trials with infliximab, sifalimumab and bimagrumab. Studies on basiliximab and eculizumab are currently underway, and are expected to yield results in a couple of years. Despite some promising results of clinical studies with antibody therapy in myositis, further research is crucial to optimize the treatment for this debilitating disease and to find treatment alternatives for treatment-refractory patients.

Patient-reported dermatomyositis and polymyositis flare symptoms are associated with disability, productivity loss, and health care resource use

BACKGROUND: Flare activity or worsening symptoms are not well defined for myositis. OBJECTIVES: To (a) characterize dermatomyositis (DM) and polymyositis (PM) flares from the patient perspective and (b) report the corresponding disability and rate of unplanned medical encounters. METHODS: Online survey data were collected from volunteer patients from The Myositis Association and Johns Hopkins Myositis Center. Flare frequency; Health Assessment Questionnaire Disability Index (HAQ-DI), HAQ-Pain Index, Work Productivity and Activity Impairment (WPAI) scales; emergency department/urgent care (ED/UC) visits; and hospital admissions during the past year were examined. RESULTS: 564 individuals with selfreported diagnoses of DM/PM were surveyed between December 2017 and May 2018. Recall of symptom flares was reported by 524 respondents (78.1% were female, mean age of 55 years). Among the respondents, 378 (72.1%) reported ≥ 1 flare in the past year. The pattern of flare frequency was similar for DM and PM respondents. The most common symptoms were muscle weakness (83%), extreme fatigue (78%), and muscle pain/discomfort (64%). Increasing flare frequency was associated with significantly (P < 0.01) greater mean HAQ-DI and HAQ-Pain scores, myositis-related ED/UC visits, hospital admissions, WPAI work productivity loss (among those employed), and WPAI nonwork activity impairment. CONCLUSIONS: DM/PM-related flares are common with exacerbations of muscle weakness and fatigue being the most common flare symptoms. Flare frequency was associated with greater disability, pain, work productivity loss, nonwork activity impairment, and increased ED/UC utilization. Higher frequency of patient-reported flares may serve as a marker of worsening physical functioning and intensifying health care needs and, therefore, suggests their importance in the clinical assessment of patients with DM/PM. DISCLOSURES: This study was supported by Mallinckrodt Pharmaceuticals (Bedminster, NJ) via grants to Vedanta Research and The Myositis Association. Christopher-Stine has received compensation from previous Mallinckrodt Advisory Board meetings, unrelated to this subject matter. Wan is an employee of Mallinckrodt Pharmaceuticals and is a stockholder of the company. Reed and Bostic received grant support from Mallinckrodt Pharmaceuticals for data collection and analysis. McGowan is an employee of The Myositis Foundation, which received grant funding to support study data collection. Kelly has no conflicts to disclose. This study was presented, in part or full, at the 2019 Annual American College of Rheumatology and Association of Rheumatology Professional Meeting (November 8-13, 2018; Atlanta, GA) and at the Third Global Conference on Myositis (March 27, 2019; Berlin, Germany).

Mortality in Patients with Polymyositis and Dermatomyositis in an Israeli Population

BACKGROUND

The reported mortality rates of patients with polymyositis and dermatomyositis are highly variable worldwide. The excess mortality of patients with polymyositis/dermatomyositis has not been evaluated in an Israeli population.

OBJECTIVES

To investigate the overall mortality in a large and well-established cohort of patients with polymyositis/dermatomyositis as compared to the mortality expected in the matched general population in a tertiary medical center.

METHODS

In this retrospective cohort study, the mortality of 166 patients with polymyositis/dermatomyositis was compared to age- and sex-matched control subjects in the general population. All-cause standardized mortality ratios (SMRs) were estimated.

RESULTS

Overall, 47 (28.3%) deaths were observed among patients with polymyositis/dermatomyositis during a mean follow-up period of 5.8 ± 4.8 years, which was 7 times higher than in the control group (SMR 7.4, 95% confidence interval [95%CI] 5.5-9.8). The SMRs were comparable in patents with polymyositis (7.7, 95%CI 4.8-12.3) and dermatomyositis (7.2, 95%CI 5.0-10.3). The 1-, 5-, 10-, and 15-year overall survival rates were 90.0%, 82.8%, 51.5%, and 26.1%, respectively, in patients with polymyositis, and 80.3%, 59.6%, 40.0%, and 17.1%, respectively, in patients with dermatomyositis.

CONCLUSIONS

The overall mortality among Israeli patients with polymyositis/dermatomyositis is 7.4 times greater than for the general population. Although long-term mortality was comparable between patients with dermatomyositis and polymyositis, patients in the former group died at a notably earlier stage.

Hospitalization mortality and associated risk factors in patients with polymyositis and dermatomyositis: A retrospective case-control study

BACKGROUND

Polymyositis and dermatomyositis (PM/DM) are systemic autoimmune diseases with multiple organ involvements that manifest as muscular and cutaneous disorders, interstitial lung disease (ILD) and malignancies. However, information concerning the outcomes and associated factors for PM/DM patients who are hospitalized is limited.

METHODS

We retrospectively reviewed the medical charts of PM/DM patients admitted to a Chinese tertiary referral hospital (Peking Union Medical College Hospital, PUMCH) from 2008 to 2014. The deceased group included 63 patients who had "deceased discharge" status or were confirmed to have died within two weeks of hospital discharge. The demographic data, clinical manifestations, and direct causes of death were analyzed retrospectively. Medical records for 126 age- and sex-matched PM/DM patients were selected as controls from 982 inpatients successively admitted to the same center during the same period. In addition to the comparison of clinical manifestations between the two groups, binary logistic regression was conducted to explore the risk factors related to PM/DM mortality.

RESULTS

Over the past 6 years at PUMCH, the in-hospital mortality rate of PM/DM patients was 4.58%. The male gender and the elder patients had a high risk of death (P = 0.031 and P = 0.001 respectively). The three most frequent causes of death for PM/DM patients were pulmonary infection (35%), ILD exacerbation (21%) or both conditions (25%). Pulmonary infection (P<0.001, OR = 5.63, 95% CI, 2.37-13.36), pneumomediastinum (P = 0.041, OR = 11.02, 95%CI, 1.10-110.54), Gottron's papules (P = 0.010, OR = 3.24, 95%CI, 1.32-7.97), and elevated erythrocyte sedimentation rate (ESR) (P = 0.005, OR = 9.9, 95%CI 2.0-49.0) were independent risk factors for in-hospital mortality of PM/DM patients.

CONCLUSION

PM/DM patients continue to display high in-hospital mortality. Pulmonary infection is the strongest predictor of poor prognosis in PM/DM patients, followed by pneumomediastinum, Gottron's papules, and elevated ESR.

Treatment of Fulminant Giant Cell Myocarditis Associated with Polymyositis Using a Left Ventricular Assist Device and Subsequent Corticosteroid and Immunosuppressive Therapy Leading to Remission

A 58-year-old man with a recent history of generalized myalgia and muscle weakness was transferred to our hospital because of acute progressive dyspnea. The patient underwent left ventricular (LV) assist device (LVAD) implantation due to cardiogenic shock with a LV ejection fraction (LVEF) of 6%. The histological findings obtained from LV apex showed the infiltration of multinucleated giant cells and severe myocardial contusion. Combining this histological finding with our experienced neurologists comments, resulted in a final diagnosis of fulminant giant cell myocarditis associated with polymyositis. A day after LVAD implantation, the patient received corticosteroid and immunosuppressive therapy, and the LVEF recovered to 68%.

[Paraneoplastic myasthenia gravis and polymyositis secondary to a thymoma in a young woman]

We present the case of a 33-year-old woman who within weeks developed severe swallowing difficulties and weakness in her limbs to an extent requiring hospitalization. Workup confirmed clinically suspected diagnoses of polymyositis and autoimmune myasthenia. A suspicion of malignant thymoma based on chest computed tomography was histologically verified. Patient treatment and response are presented. The case emphasizes the importance of recognizing that thymomas, in rare instances, may present with a combination of neuromuscular disorders in the same patient.

Dermatomyositis and polymyositis: from immunopathology to immunotherapy (immunobiologics)

Idiopathic inflammatory myopathies (IIM), which include dermatomyositis (DM) and polymyositis (PM), are chronic systemic diseases associated with high morbidity and functional disability. Current treatment is based on the use of glucocorticoids and immunosuppressive drugs, but a considerable number of patients is refractory to traditional therapy. That has led to the attempted use of biologics based on the physiopathogenesis of IIM. From the immunopathological viewpoint, PM and DM differ: the former is more related to cellular immunity, while the latter, to humoral immunity. In both, however, elevated concentrations of proinflammatory interleukins (TNF, IL-1, IL-6) and increased expression of molecules related to costimulation of T lymphocytes have been described; thus, the use of biologics in those conditions seems reasonable. Considering the biologics available, open-label studies are scarce, comprising mainly case reports and series. TNF blockers have yielded conflicting results, with no evidence of good response to treatment. The anti-CD20 therapy has the most promising results. Data on T lymphocyte costimulation blockade and anti-IL-6 therapy are extremely scarce, preventing any consideration. Thus, the use of biologics in IIM still remains an unconquered frontier. Biologics may have an important role in the management of IIM refractory to conventional therapy, but further prospective studies based on objective parameters of response to treatment are needed. So far, anti-CD20 therapy seems to be the most promising treatment for refractory IIM.

[Idiopathic inflammatory myopathies: main clinical and immunological variants, difficulties of differential diagnostics and therapy]

Idiopathic inflammatory myopathies are rare autoimmune diseases with inflammatory lesions in skeletal muscles. They include polymyositis, dermatomyositis, juvenile myositis and inclusion body myositis. These are clinically and immunologically heterogeneous conditions differently responding to therapy. The authors consider the main manifestations of polymyositis/dermatomyositis and principal differences between them. Therapy is based on the prescription of glucocorticoids in combination with immunesuppressors. Better understanding immunological, genetic, and molecular mechanisms opens up new prospects for the management of idiopathic inflammatory myopathies.

Immunosuppressant and immunomodulatory treatment for dermatomyositis and polymyositis

BACKGROUND

Idiopathic inflammatory myopathies are chronic diseases with significant mortality and morbidity. Whilst immunosuppressive and immunomodulatory therapies are frequently used, the optimal therapeutic regimen remains unclear. This is an update of a review first published in 2005.

OBJECTIVES

To assess the effects of immunosuppressants and immunomodulatory treatments for dermatomyositis and polymyositis.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (August 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 3 2011), MEDLINE (January 1966 to August 2011), EMBASE (January 1980 to August 2011) and clinicaltrials.gov (August 2011). We checked the bibliographies of identified trials and wrote to disease experts.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) or quasi-RCTs involving participants with probable or definite dermatomyositis and polymyositis as defined by the criteria of Bohan and Peter, or definite, probable or mild/early by the criteria of Dalakas. In participants without a classical rash of dermatomyositis, inclusion body myositis should have been excluded by muscle biopsy. We considered any immunosuppressant or immunomodulatory treatment. The two primary outcomes were the change in a function or disability scale measured as the proportion of participants improving one grade, two grades etc, predefined based on the scales used in the studies after at least six months, and a 15% or greater improvement in muscle strength compared with baseline after at least six months. Other outcomes were: the International Myositis Assessment and Clinical Studies Group (IMACS) definition of improvement, number of relapses and time to relapse, remission and time-to-remission, cumulative corticosteroid dose and serious adverse effects.

DATA COLLECTION AND ANALYSIS

Two authors independently selected papers, extracted data and assessed risk of bias in included studies. They collected adverse event data from the included studies.

MAIN RESULTS

The review authors identified fourteen 14 relevant RCTs. They excluded four trials.The 10 included studies, four of which have been added in this update, included a total of 258 participants. Six studies compared an immunosuppressant or immunomodulator with placebo control, and four studies compared two immunosuppressant regimes with each other. Most of the studies were small (the largest had 62 participants) and many of the reports contained insufficient information to assess risk of bias.Amongst the six studies comparing immunosuppressant with placebo, one study, investigating intravenous immunoglobulin (IVIg), showed statistically significant improvement in scores of muscle strength in the IVIg group over three months. Another study investigating etanercept showed some evidence of a steroid sparing effect, a secondary outcome in this review, but no improvement in other assessed outcomes. The other four randomised placebo-controlled trials assessed either plasma exchange and leukapheresis, eculizumab, infliximab or azathioprine against placebo and all produced negative results.Three of the four studies comparing two immunosuppressant regimes (azathioprine with methotrexate, ciclosporin with methotrexate, and intramuscular methotrexate with oral methotrexate plus azathioprine) showed no statistically significant difference in efficacy between the treatment regimes. The fourth study comparing pulsed oral dexamethasone with daily oral prednisolone and found that the dexamethasone regime had a shorter median time to relapse but fewer side effects.Immunosuppressants were associated with significant side effects.

AUTHORS' CONCLUSIONS

This systematic review highlights the lack of high quality RCTs that assess the efficacy and toxicity of immunosuppressants in inflammatory myositis.

[Organ-protective effect of continuous renal replacement therapy in a patient with severe polymyositis and dermatomyositis]

A patient with skin rash, skin denudation, anuria, general dropsy and dyspnea for unknown etiology underwent continuous renal replacement therapy (CRRT) for 3 consecutive days. The biochemical indexes were monitored during the therapy and biopsy was performed on the right thigh. Pathological examination of the biopsy sample established the diagnosis of polymyositis(PM) and dermatomyositis(DM). After the start of CRRT, the patient's heart, liver, kidney and lung injuries showed obvious improvement, and the urine volume (UV) increased and serum creatinine (Cr), urea, total bilirubin (TBIL), alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK), creatine kinase isoenzyme (CK-MB) and lactate dehydrogenase (LDH) levels all decreased promptly. The patient showed progressive improvement of the physiological condition even after CRRT, and was discharged 10 days later. This case suggests the efficacy of CRRT in the management of severe PM/DM and its value as a good option for treatment of severe autoimmune disease, especially systemic inflammatory response syndrome.

[Polymyositis/dermatomyositis--clinical picture and treatment]

The clinical presentation ofmyositis ranges from a painless muscle weakness to significant myalgia with muscle weakness and constitutional symptoms. Along with muscle and skin affection and constitutional symptoms, the disease can affect lungs, joints, heart and gastrointestinal system. It is important to note that the clinical presentation ofmyositis syndrome may overlap with symptoms of other connective tissue disease in overlap syndromes (SLE, SSCL, RA, SSjö). Common manifestations of the disease are weakness and muscle fatigue, which is the result of skeletal muscles inflammation (usually the proximal group of muscles, bilaterally and symmetrical). Severe forms of the disease with affection of the throat and respiratory muscles can vitally endan- ger patients. Among constitutional (general) symptoms, fever, malaise and weight loss are usually expressed. Skin affection in dermatomyositis can be localized or generalized like vesiculobullous erythroderma. Pathognomonic cutaneous manifestations of dermatomyositis are Gottron's papules and heliotrope erythema. Lungs are most commonly affected organs (with exception of muscles and skin) in polymyositis and dermatomyositis. The affection of lung can sometimes result in fatal outcome (interstitial lung disease, secondary pulmonary hypertension). Cardiac affection is usually subclinical, but can also be expressed as heart failure, acute coronary syndrome or conduction disturbances. Infrequent manifestations of the disease are gastroesophageal reflux, malabsorption, gastrointestinal mucosal ulceration, soft tissue calcification, Raynaud's syndrome, arthralgia/arthritis and some other less common clinical manifestations of the disease. Treatment of polymyositis/dermatomyositis includes immunosuppressive/immunomodulatory therapy and supportive, symptomatic treatment. The basis for myositis treatment are glucocorticoids, which are applied orally in a daily dosage regimen of 0.75 to 1 mg/kg/day, and in severe forms of the disease in the i.v. pulse doses of 1 g/day. Immunosuppressants/immunomodulators are added in the therapy along with glucocorticoids for better control of the disease and to reduce the required dose of glucocorticoids (side effects of longterm high doses glucocorticoide use). The most commonly used immunosuppressive drug is methotrexate at a dose of up to 25 mg/week. Hydroxychloroquine has a good effect on the cutaneous manifestations of the disease. Among other immunosuppressants which are used in the treatment of myositis are azathioprine, cyclosporine (in patients with pulmonary affection), mycophenolate mofetil and tacrolimus. Intravenous immunoglobulins applied parenterally in a dose of 2 g/kg divided into multiple doses showed an excellent clinical effect in patients with affection of the esophagus and throat muscles, in patients with pulmonary affection and in patients with resistant disease. The experience with the biologics is limited to a small number of patients. Physiotherapy is a necessary form of treatment for the recovery of muscle strength in the remission phase of the disease. A prompt treatment of infections and heart failure is sometimes life-saving in patients with myositis. Symptomatic treatment of pain with analgesics and NSAIDs reduces pain, speeds up recovery and improves the quality of life in patients with myositis.

[Dermatomyositis and polymyositis: 21 cases in Senegal]

Dermatopolymyositis (DPM) is a term describing a group of disorders comprising multiple distinct entities depending on interactions between genetic and environmental factor. There is a paucity of studies on DPM in black Africa. The purpose of this report is to describe epidemiological, clinical, laboratory and therapeutic aspects of dermatomyositis (DM) and polymyositis (PM) observed at the Principal Hospital in Dakar, Senegal. A retrospective review as conducted of patients hospitalized for DM and PM in Medical Departments of Principal Hospital. Diagnosis of DRM was based on the criteria of Bohan and Peter's in all cases. A series of 21 black African patients was compiled including 15 with DM and 6 with PM. Mean age was 52 years and the M/F sex ratio was 0.6. The mean delay for diagnosis was 6 weeks (range, 3 to 12 weeks). Initial signs were dermatological in 12 patients, pulmonary in one and muscular in the remaining cases. The most common dermatological sign was erythema characterized by a zebra-like aspect on the extended limbs. Erythema was frequently pruriginous with a flagellate aspect on the back. Muscular signs were observed in 18 patients and included pharyngeal manifestations in 10 patients. Amyopathic DM was not observed. Cardiac abnormalities included tachycardia (4 cases), AVB (1), ischemic lesion (1), relaxation disturbances (4), pericardial effusion (3), myocarditis (2) and pulmonary hypertension (1). The most common pulmonary manifestation was interstitial lung disease observed in 6 patients. Gastrointestinal signs were noted in 9 patients including endoscopic evidence of superficial erosion in 4 cases. Electromyography (EMG) tracings revealed myogenic disease in 14 cases including 2 associated with reduced peripheral nervous conduction speed. Severe lymphopenia was observed in 3 patients but HIV serology was negative in all cases. Paraneoplasic DM was observed in 3 cases. Death occurred in 5 cases due to the cancer-related, pulmonary and infectious complications. Based on the findings of this study, the three main features of DM and PM in Senegal are flagellated and often pruriginous erythema, cardiac and interstitial lung disease, and peripheral neural involvement.

WITHDRAWN: Immunosuppressant and immunomodulatory treatment for dermatomyositis and polymyositis

BACKGROUND

Idiopathic inflammatory myopathies are chronic skeletal diseases with significant mortality and morbidity despite treatment by corticosteroids. Immunosuppressive agents and immunomodulatory therapy are used to improve disease control and reduce the long-term side effects of corticosteroids. While these treatments are used commonly in routine clinical practice, the optimal therapeutic regimen remains unclear.

OBJECTIVES

To systematically review the evidence for the effectiveness of immunosuppressants and immunomodulatory treatments for dermatomyositis and polymyositis.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group trials register (searched February 2002 and updated in November 2003) and MEDLINE (January 1966 to December 2002). We checked bibliographies of identified trials and wrote to disease experts.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials including patients with probable or definite dermatomyositis and polymyositis as defined by the criteria of Bohan and Peter or definite, probable or mild/early by the criteria of Dalakas. Patients with inclusion body myositis should have been excluded by muscle biopsies. Any immunosuppressant or immunomodulatory treatment including corticosteroids, azathioprine, methotrexate, ciclosporin, chlorambucil, cyclophosphamide, intravenous immunoglobulin, interferon and plasma exchange was considered. Primary outcome was assessment of muscle strength after at least six months. Other outcomes were: change in disability, number of relapses and time to relapse, number of patients in remission and time-to-remission, cumulative corticosteroid dose and serious adverse effects.

DATA COLLECTION AND ANALYSIS

Two authors (EC and JH) independently selected trials for inclusion in the review. Four authors independently assessed each study. Methodological criteria and the results of each study were recorded on data extraction forms.

MAIN RESULTS

Seven potentially relevant randomised controlled trials were identified. One trial was excluded. Three studies compared immunosuppressant with placebo control, one trial compared one immunosuppressant (methotrexate) with another (azathioprine), another trial compared ciclosporin A with methotrexate and the final trial compared intramuscular methotrexate with oral methotrexate plus azathioprine. The study comparing intravenous immunoglobulin with placebo concluded that the former was superior. Two randomised placebo-controlled trials assessing plasma exchange, leukapheresis and azathioprine produced negative results. The fourth study compared azathioprine with methotrexate and found azathioprine and methotrexate equally effective but methotrexate had a better side effect profile. The fifth study comparing ciclosporin A with methotrexate and the sixth study comparing intramuscular methotrexate with oral methotrexate plus azathioprine found no statistically significant differences between the treatment groups. Immunosuppressants are associated with significant side effects.

AUTHORS' CONCLUSIONS

This systematic review highlights the lack of high quality randomised controlled trials that assess the efficacy and toxicity of immunosuppressants in inflammatory myositis.

Update on idiopathic inflammatory myopathies

The inflammatory myopathies are a group of acquired diseases, characterized by an inflammatory infiltrate of the skeletal muscle. On the basis of clinical, immuno-pathological and demographic features, three major diseases can be identified: dermatomyositis (DM); polymyositis (PM); and inclusion body myositis (IBM). New diagnostic criteria have recently been introduced, which are crucial for discriminating between the three different subsets of inflammatory myopathies and for excluding other disorders. DM is a complement-mediated microangiopathy affecting skin and muscle. PM and IBM are T cell-mediated disorders, where CD8-positive cytotoxic T cells invade muscle fibres expressing MHC class I antigens, thus leading to fibre necrosis. In IBM, vacuolar formation with amyloid deposits are also present. This article summarizes the main clinical, laboratory, electrophysiological, immunological and histologic features as well as the therapeutic options of the inflammatory myopathies.

Idiopathic inflammatory myopathies

Since the description of the first case of dermatomyositis over a century ago, our understanding of myositis has evolved. Bohan and Peter in 1975 established diagnostic criteria for polymyositis and dermatomyositis. Subsequent investigations by Arahata and Engel delineated differences in the lymphocyte subsets on muscle histopathology distinguishing polymyositis and dermatomyositis. Following that, myositis-specific antibodies have been reported in association with various myositis subtypes and with interstitial lung disease. Polymyositis and dermatomyositis are in general responsive to immunosuppressive therapy. Inclusion body myositis (IBM) became recognized as a distinct entity nearly half a century ago. IBM is clinically and pathologically distinct from the other inflammatory myopathies. The weakness in IBM is characteristic, involving both the proximal and distal muscle groups, such as finger flexion, knee extension and ankle dorsiflexion. Vacuolated fibers, amyloid deposition, and filaments on electron microscopy are pathologic hallmarks of IBM. IBM is refractory to corticosteroids and intravenous gamma globulins. This clinical observation and the pathologic features support the hypothesis that IBM is a muscle-degenerative disease. Most recently, a fourth inflammatory myopathy subtype called necrotizing myopathy was described. Necrotizing myopathy may be related to malignancy, other autoimmune diseases, toxic exposure or can be idiopathic. The key histopathologic findings of this entity are necrotic fibers undergoing phagocytosis. Though patients ultimately respond to immunosuppressive therapy, they tend to be more refractory and therefore often require a more aggressive treatment approach.

[Recent advance in polymyositis and dermatomyositis research]

Past paradigm that the muscle tissue injury is driven by CD4 T cells and associated humoral immunity in dermatomyositis (DM), and by cytotoxic T cells in polymyositis (PM) is now under challenge. Although pathogenic autoantigens are to be identified, skeletal muscle C-protein was an excellent immunogen to provoke experimental myositis mimicking human PM. Serum antibodies against aminoacyl tRNA synthases appear in PM/DM patients, but more often in interstitial pneumonitis patients. Inflammatory cytokines are obviously involved in the pathogenesis. Animal studies showed that autoimmune myositis occurs without tumor necrosis factor alpha. Indeed, its blockade has yielded inconsistent outcome. Most crucial ones will be therapeutic targets in the future.

Idiopathic inflammatory myopathies: current and future therapeutic options

Idiopathic inflammatory myopathies (notably polymyositis and dermatomyositis) are relatively uncommon diseases with a heterogeneous clinical presentation. Only a few randomized, double-blind, placebo-controlled trials have been performed, measures to assess outcome and response to treatment have to be validated. Initial treatment options of first choice are corticosteroids, although rarely tested in randomized, controlled trials. Unfortunately, not all patients respond to them and many develop undesirable side effects. Thus, second line agents or immunosuppressants given in combination with corticosteroids are used. For dermatomyositis/polymyositis, combination with azathioprine is most common. In case this combination is not sufficient or applicable, intravenous immunoglobulins are justified. Alternative or stronger immunosuppressants, such as cyclosporine A, cyclophosphamide, methotrexate, or mycophenolate are also used. There are no defined guidelines or best treatment protocols agreed on internationally; therefore, the medical approach must be individualized based on the severity of clinical presentation, disease duration, presence of extramuscular features, and prior therapy and contraindications to particular agents. Approximately 25% of patients are nonresponders and continue to experience clinical relapses. Those are candidates for alternative treatment options and experimental therapies. New immunoselective therapies directed toward cytokine modulation, immune cell migration, or modification of certain immune subsets (B- and T-cells) are a promising avenue of research and clinical application. Possible future therapeutic options are presented and discussed.

[Current therapy for polymyositis and dermatomyositis]

Polymyositis (PM), dermatomyositis (DM) and sporadic inclusion body myositis (s-IBM) are severe inflammatory muscle disorders of unknown cause, which may present life-threatening complications. Prognosis and response to medications may be predicted not only from the clinical and pathologic diagnostic group into which a patient belongs, but also from the patient's myositis-specific antibody status, extraskeletal muscle involvement, and the interval between onset of muscle weakness, and the start of the treatment. Corticosteroids remain the mainstay of treatment in PM and DM. In patients refractory or intolerant to corticosteroids, another therapy, often an immunosuppressive agent, or intravenous immunoglobulin (IVIg), is added. IVIg seems the treatment of choice in severe myositis with dysphagia. New molecules, anti-TNF and monoclonal antibodies anti-CD20 justifies randomised trial and long term follow up.

Successful therapy with intravenous immunoglobulin in the management of polymyositis

Polymyositis is an inflammation of muscle tissue of unknown etiology. It is characterized by symmetric, mainly proximal muscle weakness, muscle fiber damage proved on biopsy, increased enzymes and myoglobin, and has corresponding electromyography findings. Other systems such as joints, lungs, heart, and gastrointestinal system are involved. Lung involvement is rather common. The most frequent symptom represents shortness of breath caused by muscle weakness. We report a case of a 66 year old woman with primary idiopathic polymyositis. The clinical state of the patient was complicated by progressive muscle weakness, dysphagia, and respiratory failure. Due to the ineffectiveness of the treatment with corticsteroids and cyclophosphamide, treatment with high doses of immunoglobulins was started. A total of 100 g of i.v. immunoglobulin therapy was administered beginning on the 13th day after hospital admission. The state of the patient progressively improved and after 7 weeks of treatment in a significantly improved state the patient was transferred to a Rehabilitation Unit. We therefore conclude that IVIg therapy may be an effective therapeutic approach for the treatment of acute complications of polymyositis, especially in cases in whom other therapeutic strategies are ineffective or harmful (Ref. 10). Full Text (Free, PDF) www.bmj.sk.

Disease-specific quality indicators, outcome measures and guidelines in polymyositis and dermatomyositis

Polymyositis and dermatomyositis are chronic inflammatory muscle disorders with frequent involvement of other organs hence outcome measures should include these different aspects of disease. Muscle strength and muscle endurance are the most specific clinical features that should be assessed during treatment and longitudinal follow-up. Extramuscular involvement should also be assessed. An international, interdisciplinary network, the International Myositis Assessment Clinical Study Group (IMACS) has proposed a core set of outcome measures to assess three dimensions of myositis disease; disease activity (MYOACT), disease damage (MYODAM) and health related quality of life (SF-36) to be used in clinical trials. These include scoring of extramuscular involvement (skin, lungs, articular, cardiac, gastro-intestinal tract) in both the disease activity and damage scores. In the disease activity score, muscle strength is measured by the manual muscle test (MMT)- 8, this could easily be used in clinical practice. Other myositis specific outcome measures are the Functional Index of myositis (FI) -- 2 to measure muscle endurance and a questionnaire, the Myo-sitis Activities Profile (MAP) to measure patient perspective. A close collaboration between physicians, physical and occupational therapists and specialized nurses is of great value in care and disease assessment of patients with polymyositis and dermatomyositis.

Correlation of muscle biopsy, clinical course, and outcome in PM and sporadic IBM

OBJECTIVE

To correlate muscle biopsy findings with prebiopsy and postbiopsy clinical course and response to therapy in polymyositis (PM) and sporadic inclusion body myositis (IBM).

BACKGROUND

Existence of pure PM has recently been questioned; subsequently, the definition and criteria for diagnosing PM were debated.

METHODS

Patient records, follow-up information, and muscle biopsies were analyzed in 107 patients whose biopsies were initially read as PM and IBM.

RESULTS

The patients fell into three groups by combined biopsy and clinical criteria: PM, 27 patients; IBM, 64 patients; PM/IBM, 16 patients with biopsy diagnosis of PM but clinical features of IBM. For the three groups, the respective mean periods from disease onset to end of follow-up were 5.9, 8.5, and 9.6 years. Another autoimmune disease was present in 4 of 27 PM, 8 of 64 IBM, and 1 of 16 PM/IBM cases. An autoimmune serologic marker occurred in one-third of each group. Nineteen PM patients had no associated autoimmune disease or marker. Nonnecrotic fiber invasion by mononuclear cells appeared in all IBM, 17 of 27 PM, and 13 of 16 PM/IBM patients. The density of both invaded fibers and cytochrome-c oxidase-negative fibers was higher in IBM and PM/IBM than in PM. Immunotherapy improved 22 of 27 PM patients but had only transient beneficial effects in 2 of 32 IBM and 1 of 14 PM/IBM patients.

CONCLUSIONS

1) Sixteen of 43 patients (37%) with biopsy features of polymyositis (PM) had clinical features of inclusion body myositis (IBM). 2) Absence of canonical biopsy features of IBM from clinically affected muscles of IBM patients challenges biopsy criteria for IBM, or the IBM markers appear late in some patients, or their distribution in muscle is patchy and restricted compared with that of the inflammatory exudate. 3) The muscle biopsy is a reliable instrument in the diagnosis of PM and IBM in close to 85% of the patients. Errors of diagnosis in the remaining 15% can be avoided or reduced by combined evaluation of the clinical and pathologic findings.

Attenuation of Experimental Autoimmune Myositis by Blocking ICOS-ICOS Ligand Interaction

Polymyositis (PM) is an acquired, systemic, connective tissue disease characterized by the proximal muscle weakness and infiltration of mononuclear cells into the affected muscles. To understand its etiology and immunopathogenesis, appropriate animal model is required. It has been demonstrated that immunization with native human skeletal C protein induces severe and reproducible experimental autoimmune myositis (EAM) in Lewis rats, and that the muscle inflammatory lesions in the EAM mimic those of human PM. In the present study, we prepared recombinant skeletal C protein fragment and succeeded in inducing as severe EAM as that by native C protein. We found ICOS expression on muscle fiber-infiltrating T cells in the EAM rats, but not in normal rats. Treatment with anti-ICOS mAb reduced incidence and severity of myositis; decreased the number of muscle-infiltrating CD11b/c+, TCR+, and CD8a+ cells; and inhibited the expression of IL-1alpha and CCL2 in the hamstring muscles of the EAM rats. However, the treatment neither inhibited serum anti-C protein IgG level, C protein-induced proliferation of lymph node (LN) cells, or LN T cells, nor production of IFN-gamma by C protein-stimulated LN cells in EAM rats. These data indicate that analysis of C protein-induced EAM provides not only insights into pathogenesis of PM, but also useful information regarding development of effective immunotherapy against the disease. ICOS-ICOS ligand interaction would be a novel therapeutic target for PM.

Grand round cases: Australian Association of Neurologists Annual Scientific Meeting, Canberra 2006

The Annual Scientific Meeting of the Australian Association of Neurologists includes a Grand Rounds Session in which unusual cases are presented. The Chairmen of the 2006 session, Drs Richard Stark and Heather Waddy, lead the audience through a discussion of the history, physical signs, diagnostic investigations and finally the diagnosis at intervals throughout the case presentation. In introducing the cases Dr. Stark emphasized that the cases were selected because they were unusual and the final diagnosis may not be evident at the outset. The approach to the clinical problems and the process of thinking through the differential diagnoses and the method of investigation were as important to the discussion of these cases as the final diagnosis itself. These cases are reported here including an edited summary of the discussion with the same emphasis on the method of clinical analysis and the diagnostic process.

Potential therapeutic targets for idiopathic inflammatory myopathies

The inflammatory myopathies essentially comprise three diseases with different immunopathologic features. Dermatomyositis (DM) is a complement-mediated microangiopathy. The immune response in polymyositis (PM) and sporadic inclusion body myositis (IBM) is a CD8+ T-cell-mediated cellular reaction against an unknown muscle fiber antigen. The multiple immune factors that guide inflammatory cell diapedesis and trafficking have been elucidated over the past two decades. Many of these molecules can now be targeted by monoclonal antibodies and other pharmacologic approaches. Randomized controlled trials are being started on a number of new agents to find out whether more specific immune interventions than the currently used glucocorticosteroids can treat DM and PM patients with fewer side effects, and may represent a first treatment modality for IBM, an entity unresponsive to all currently available pharmacological treatments.

A new murine model to define the critical pathologic and therapeutic mediators of polymyositis

OBJECTIVE

To establish a new murine model of polymyositis (PM) for the understanding of its pathologic mechanisms and the development of new treatment strategies.

METHODS

C protein-induced myositis (CIM) was induced by a single immunization of recombinant human skeletal C protein in C57BL/6 mice, as well as in CD4-depleted, CD8-depleted, and mutant mice as controls. Some mice were treated with high-dose intravenous immunoglobulin (IVIG) after disease induction. Muscle tissues were examined histologically.

RESULTS

In mice with CIM, inflammation was confined to the skeletal muscles. Histologic examination revealed a common pathologic feature of CIM and PM, involving abundant infiltration of CD8 and perforin-expressing cells in the endomysial site of the injured muscle. Suppression of myositis was achieved by depletion of both CD4 and CD8 T cells. Despite the development of serum anti-C protein antibodies in wild-type mice, severe myositis was induced in mice deficient in B cells. Induction of myositis was suppressed in interleukin-1alpha/beta (IL-1alpha/beta)-null mutant mice, but not in tumor necrosis factor alpha (TNFalpha)-null mutant mice. Use of IVIG, a treatment with proven efficacy in PM, suppressed CIM in the subgroup of treated mice.

CONCLUSION

CIM mimics PM pathologically and clinically. Infiltration of CD8 T cells is the most likely mechanism of muscle injury, and IL-1, but not B cells or TNFalpha, is crucial in the development of CIM. IVIG has therapeutic effects in CIM, suggesting that the effects of IVIG are not mediated by suppression of antibody-mediated tissue injury. This murine model provides a useful tool for understanding the pathologic mechanisms of PM and for developing new treatment strategies.

A case of polymyositis complicated with myasthenic crisis

We report a 62-year-old woman who suffered from polymyositis (PM) complicated with myasthenic crisis. Electromyography and muscle biopsy indicated a diagnosis of PM; however, respiratory failure due to respiratory muscle weakness was seen in spite of a normal serum creatine kinase (CK) level. The positive anti-acetylcholine receptor antibody led us to the diagnosis of myasthenic crisis. PM with respiratory muscle weakness is rare. We suggest that the possibility of other neurological disorder complications should be considered when PM patients have respiratory muscle weakness out of proportion to the serum CK level.

Paraneoplastic Polymyositis Associated With Squamous Cell Carcinoma of the Lung

An association between polymyositis and lung cancer has been debated. Published data usually lack either lung cancer histologic differentiation or biopsy-based delineation between polymyositis and dermatomyositis. We reported a case of a 56-year-old man with squamous cell carcinoma of the lung confined to a single hilar lymph node presenting with biopsy-proven polymyositis of 3 months in duration. Polymyositis should be considered as a potential presentation of paraneoplastic syndrome, especially in patients who are at risk for lung cancer.

Complications musculaires de l’infection par le virus de l’immunodéficience humaine (VIH) à l’ère des trithérapies

Introduction of highly active antiretroviral therapy (HAART) has dramatically modified the natural history of HIV disease, but lengthening the survival of HIV-infected individuals has been associated with an increasing prevalence of iatrogenic conditions. Muscular complications of HIV infection are classified as follows: (1) HIV-associated myopathies and related conditions including polymyositis, inclusion-body myositis, nemaline myopathy, diffuse infiltrative lymphocytosis syndrome (DILS), HIV-wasting syndrome, vasculitis, myasthenic syndromes, and chronic fatigue; (2) iatrogenic conditions including mitochondrial myopathies, HIV-associated lipodystrophy syndrome, and immune restoration syndrome; (3) opportunistic infections and tumor infiltrations of skeletal muscle; and (4) rhabdomyolysis. These features are described in the present review.

Entzündliche Muskelkrankheiten

Dermatomyositis, polymyositis, inclusion body myositis and myositis overlap syndromes are systemic immune disorders of unknown origin with muscle weakness and elevated values of creatinkinase in the serum. Muscle biopsy is pivotal for a proper clinical diagnosis. Extramuscular findings at the skin, the joints or internal organs (lung, heart) are characteristic for the different clinical presentations of dermato- or polymyositis and are usually absent in inclusion body myositis. With the exception of inclusion body myositis myositis-associated autoantibodies are frequently present and associated with distinct clinical manifestations (e. g. antisynthetase syndrome). The rate of malignancy is elevated for several years after onset of myositis. Especially in polymyositis an appropriate differential diagnosis of infectious, endocrine, metabolic or neuromuscular causes of muscle disease is necessary. Glucocorticosteroids are the first choice of treatment in dermato- or polymyositis. Methotraxate, azathioprine, cyclophosphamamide, i.v. immunoglobulins and other drugs are used in diseases courses with continuous high dose requirement of corticosteroids.

IVIg in myasthenia gravis, Lambert Eaton myasthenic syndrome and inflammatory myopathies: current status

Intravenous immunoglobulin (IVIg) is an effective tool for the treatment of diseases with immune pathogenesis. This article reviews the current knowledge of the benefits of treating with IVIg patients with myasthenia gravis (MG), Lambert Eaton myasthenic syndrome (LEMS), dermatomyositis (DM), polymyositis (PM) and inclusion body myositis (IBM). Myasthenia gravis: Treatment of MG with IVIg was reported to be beneficial in a number of case series and two randomised controlled trials, in which efficacy was measured by clinical improvement using myasthenic muscle score and decrease in anti-acetylcholine receptor antibodies (AchRAb). According to the results, IVIg could be recommended for crisis and severe exacerbation. In many other clinical conditions, such as response to treatment of mild or moderate exacerbation, changes in steroid dosage and before thymectomy, IVIg has also been reported to be helpful, but no controlled trials to confirm its efficacy have been performed. Lambert-Eaton myasthenic syndrome: A placebo-controlled crossover study reported a significant clinical improvement in the amplitude of the resting CMAP following IVIg treatment. Further experience from case reports also indicates that IVIg is useful in patients with LEMS, both as a short- and long-term treatment, especially when immunosuppressive drugs are not fully effective. Inflammatory myopathies/dermatomyositis: In a double-blind placebo-controlled crossover trial in patients with DM resistant to other treatments, IVIg was shown to produce a significant increase of muscle strength as well as a marked improvement in immunopathological parameters in repeated muscle biopsies (before and after IVIg). Thus, IVIg is an important therapy in patients with DM resistant to other conventional therapies. Polymyositis: No randomised trials have been undertaken. One study showed clinical improvement and a reduction in the need of prednisone in patients with chronic refractory PM. Inclusion body myositis: Three controlled trials showed some muscle strength improvement, although the changes did not reach statistical significance. However improvement in swallowing was repeatedly observed, suggesting that some patients with severe dysphagia may derive a modest benefit from IVIg therapy.

CONCLUSION

Controlled trials indicate that in MG, LEMS, and DM, IVIg at a total dose of 2 g/kg is a highly useful therapy. Uncontrolled trials and case reports indicate benefit in many different clinical situations, but further clinical investigation is required.

Immunosuppressant and immunomodulatory treatment for dermatomyositis and polymyositis

BACKGROUND

Idiopathic inflammatory myopathies are chronic skeletal diseases with significant mortality and morbidity despite treatment by corticosteroids. Immunosuppressive agents and immunomodulatory therapy are used to improve disease control and reduce the long-term side effects of corticosteroids. While these treatments are used commonly in routine clinical practice, the optimal therapeutic regimen remains unclear.

OBJECTIVES

To systematically review the evidence for the effectiveness of immunosuppressants and immunomodulatory treatments for dermatomyositis and polymyositis.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group trials register (searched February 2002 and updated in November 2003) and MEDLINE (January 1966 to December 2002). We checked bibliographies of identified trials and wrote to disease experts.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials including patients with probable or definite dermatomyositis and polymyositis as defined by the criteria of Bohan and Peter or definite, probable or mild/early by the criteria of Dalakas. Patients with inclusion body myositis should have been excluded by muscle biopsies. Any immunosuppressant or immunomodulatory treatment including corticosteroids, azathioprine, methotrexate, ciclosporin, chlorambucil, cyclophosphamide, intravenous immunoglobulin, interferon and plasma exchange was considered. Primary outcome was assessment of muscle strength after at least six months. Other outcomes were: change in disability, number of relapses and time to relapse, number of patients in remission and time-to-remission, cumulative corticosteroid dose and serious adverse effects.

DATA COLLECTION AND ANALYSIS

Two authors (EC and JH) independently selected trials for inclusion in the review. Four authors independently assessed each study. Methodological criteria and the results of each study were recorded on data extraction forms.

MAIN RESULTS

Seven potentially relevant randomised controlled trials were identified. One trial was excluded. Three studies compared immunosuppressant with placebo control, one trial compared one immunosuppressant (methotrexate) with another (azathioprine), another trial compared ciclosporin A with methotrexate and the final trial compared intramuscular methotrexate with oral methotrexate plus azathioprine. The study comparing intravenous immunoglobulin with placebo concluded that the former was superior. Two randomised placebo-controlled trials assessing plasma exchange, leukapheresis and azathioprine produced negative results. The fourth study compared azathioprine with methotrexate and found azathioprine and methotrexate equally effective but methotrexate had a better side effect profile. The fifth study comparing ciclosporin A with methotrexate and the sixth study comparing intramuscular methotrexate with oral methotrexate plus azathioprine found no statistically significant differences between the treatment groups. Immunosuppressants are associated with significant side effects.

AUTHORS' CONCLUSIONS

This systematic review highlights the lack of high quality randomised controlled trials that assess the efficacy and toxicity of immunosuppressants in inflammatory myositis.

Inflammatory disorders of muscle: progress in polymyositis, dermatomyositis and inclusion body myositis

PURPOSE OF REVIEW

To provide an update on the major advances in inflammatory myopathies.

RECENT FINDINGS

Polymyositis is an uncommon disorder that can be misdiagnosed when the old, and never validated, criteria of Bohan and Peter are used. New diagnostic criteria were recently introduced, in which the MHC/CD8 complex is considered a specific immunopathological marker because it distinguishes the antigen-driven inflammatory cells that characterize polymyositis and sporadic inclusion-body myositis from the non-specific, secondary inflammation seen in other disorders, such as dystrophies. In sporadic inclusion-body myositis the inflammatory cells invade non-vacuolated fibers, whereas the vacuolated fibers are not invaded by T cells, implying two independent processes, a primary immune process with antigen-driven T cells identical to polymyositis, and a degenerative process in which beta-amyloid and amyloid-related proteins participate in vacuolar degeneration. In polymyositis and sporadic inclusion-body myositis, antigen-specific and clonally expanded autoinvasive T cells persist for years, even in different muscles, as reconfirmed by proof-of-principle techniques involving CDR3 spectratyping combined with laser microdissected single-cell polymerase chain reaction of the T-cell receptor genes. The formation of immunological synapse between autoinvasive T cells and muscle fibers was recently strengthened by the upregulation of co-stimulatory molecules ICOS/ICOS-L and PD-L1. A new, distinct myopathy characterized by T-cell-triggered macrophage hyperactivation has now been recognized in patients with dermatomyositis-like disease.

SUMMARY

Despite recent progress, the antigen(s) responsible for T-cell activation in polymyositis and sporadic inclusion-body myositis and the cause of vacuolar degeneration in sporadic inclusion-body myositis remain unclear. Newer, more aggressive immunotherapies may be encouraging, but control trials are needed to prove efficacy.

An unusual presentation of tropical pyomyositis

Tropical pyomyositis is a primary pyogenic infection of skeletal muscle, often caused by Staphylococcus aureus. The most common presentation of tropical pyomyositis is that of multiple acute abscesses with fever. Hepatitis is a rare manifestation of this disease. We report a case of tropical pyomyositis who presented with hepatic encephalopathy leading to initial diagnostic dilemma.

Neuromuscular rehabilitation and electrodiagnosis. 3. Diseases of muscles and neuromuscular junction

This self-directed learning module highlights formation of a differential diagnosis as well as electrodiagnostic evaluation for those patients who present with the common complaint of weakness. It is part of the chapter on neuromuscular rehabilitation and electrodiagnosis in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. This article specifically focuses on the common symptoms and typical clinical findings that allow the clinician to narrow the differential diagnosis. This is followed by the diagnostic evaluation, with emphasis on the technical aspects and interpretation of electrodiagnostic studies.

OVERALL ARTICLE OBJECTIVE

To summarize the clinical presentation and electrodiagnostic findings in persons with disorders of muscle or disorders of the neuromuscular junction.

[The treatment of inflammatory muscle diseases]

THE TREATMENT OF DM AND PM: Among primary inflammatory muscle diseases, there are three principle subsets depending on immuno-histochemical and clinical aspects: dermatomyositis (DM), polymyositis (PM) and inclusion body myositis (IBM). Despite their physiopathogenic differences, the treatment of PM and DM is very similar. It relies on principally on oral corticosteroid therapy, occasionally initiated via the intravenous route and which is active in 50 to 70% of cases. In patient with primary or secondary resistance, intolerance or dependence regarding corticosteroids, a second treatment line with immunosuppressive agents or intravenous immunoglobulin should be added.

IN THE FUTURE

Methrotrexate or azathioprine are still the most commonly used immunosuppressors today. However, the imminent launch of new molecules such as anti-TNF agents and new immunosuppressors suggest that interesting therapeutic alternatives may soon be available. INCONSISTENT EFFICACY IN IBM: However, the treatment of IBM remains controversial. Physiotherapy is crucial. The moderate and inconsistent efficacy with corticosteroids and various immunomodulators suggests a predominately degenerative physiopathogenic mechanism, and/or reflects the far too late onset of treatment at the muscular involvement stage of the disease.

Polymyositis masquerading as motor neuron disease

BACKGROUND

Several conditions have been reported to mimic motor neuron disease (MND), and misdiagnosis remains a common clinical problem.

OBJECTIVE

To report a case of bulbar-onset polymyositis where the initial clinical presentation was suggestive of MND.

CASE DESCRIPTION

A 73-year-old woman was admitted for investigation of acute-onset dysphagia without dysarthria. Examination revealed nasal dysphonia and severe oropharyngeal weakness. Subtle upper-limb weakness, brisk tendon reflexes, and fasciculations in the right deltoid muscle were also demonstrated. A clinical diagnosis of MND was entertained. The serum creatine kinase value was within the reference range. Findings from electromyographic studies, however, were suggestive of a myopathic rather than a neurodegenerative process, and a muscle biopsy specimen was diagnostic of polymyositis. The dysphagia rapidly resolved upon treatment with corticosteroids and azathioprine.

CONCLUSIONS

Bulbar-onset polymyositis may mimic MND, particularly in the absence of inflammatory markers or elevated muscle enzyme levels. Caution should be exercised in the clinical diagnosis of bulbar dysfunction, and further investigations such as electromyography and muscle biopsy are indicated to confirm the diagnosis.

[Idiopathic myositis]

The idiopathic myositis, dermatomyositis, polymyositis and inclusion body myositis are recognized by their clinical and laboratory presentation, and by morphological changes in the muscle biopsy. A rapid diagnostic process is important, in order to start early treatment, which will be more effective and to direct further investigations and management. In the presence of dermatomyositis a precise investigation of neoplasia is important because they are often associated, which is not the case with inclusion body myositis. Symptoms in dermatomyositis and polymyositis respond sometimes quite well to immunomodulatory therapy but not in inclusion myositis. Controlled muscle training may sometimes slow progression in inclusion myositis.