HTLV-1 associated polymyositis in Jamaica

The clinical, laboratory and epidemiological characteristics of 38 adult Jamaican patients with polymyositis were evaluated. Twenty-four patients (63%) were human T-lymphotropic virus 1 (HTLV-1) seropositive and 14 patients (37%) were HTLV-1 seronegative. Polymyositis runs a more protracted course in seropositive patients who had more frequent hospital admissions and a significantly longer duration of symptoms prior to presentation. Joint swelling, chest pain and dyspnoea were more frequent complaints among the seronegative patients. There was no significant difference between the two serological groups in muscle enzyme levels, antinuclear antibody positivity or frequency of Jo-1 antibodies. HTLV-1 infection may define a subgroup of polymyositis patients with a more insidious presentation and poorer response to corticosteroid therapy.     

A case of polymyositis associated with Kawasaki disease

We report a 3-year-old boy with proximal painful muscle weakness associated with Kawasaki disease. The muscle biopsy revealed inflammatory cell infiltration with vasculopathy. This unique coexistence of polymyositis and Kawasaki disease is quite uncommon and suggests a newly recognized complication during Kawasaki disease.     

Giant cell polymyositis associated with myasthenia gravis and thymoma

We report a case of a 40-year-old woman who developed generalized muscle weakness over a period of 2 months. Physical examination revealed palpable masses in her arms and hands. Serum creatine kinase levels were elevated. Electromyography showed myopathic changes and 3 Hz repetitive nerve stimulation revealed a decremental pattern on repetitive nerve stimulation. Muscle MRI demonstrated increased signal intensity in the biceps brachii on T1-weighted images. Chest CT scan showed a mediastinal mass suggestive of thymoma. Muscle biopsy revealed giant cell polymyositis. The patient was treated with cholinesterase inhibitors and corticosteroids with improvement of strength, and subsequently underwent thymectomy followed by radiotherapy.     

Mycophenolate mofetil in the therapy of polymyositis associated with a polyautoimmune syndrome

Mycophenolate mofetil 1.5 g daily (30 mg/kg body weight) was given to a patient with ankylosing spondylitis, ulcerative colitis, and severe refractory polymyositis after conventional treatment regimes had failed. No severe side effects occurred. Considerable improvement of clinical symptoms and electromyographic findings were seen within 6 months after the initiation of mycophenolate mofetil, allowing for tapering and discontinuation of methylprednisolone. Mycophenolate mofetil may be considered as an useful alternative in the treatment of polymyositis when standard therapeutic regimens fail.     

Giant cell polymyositis and myocarditis associated with myasthenia gravis and thymoma

We describe an unusual case of myasthenia gravis. Our patient had been diagnosed as having myasthenia gravis with thymoma at the age of 64 years, and died of acute respiratory failure at the age of 80 years. Post mortem examination revealed CD8‐positive lymphocytic infiltration with numerous giant cells in the skeletal muscles and myocardium. Immunohistochemical and ultrastructural studies revealed that there were two types of giant cells: histiocytic and myocytic in origin. Furthermore, both types of giant cells were immunopositive for proteins implicated in the late endosome and lysosome‐protease systems, suggesting that endocytosis may be the key mechanism in the formation of giant cells. The present case, together with a few similar cases reported previously, may represent a particular subset of polymyositis, that is, giant cell polymyositis and myocarditis associated with myasthenia gravis and thymoma.     

A case of polymyositis with ophthalmoplegia☆ Laboratory examinations

OBJECTIVE： Polymyositis （PM） mainly involves proximal limb and trunk muscles. Ocular muscles are not affected, except in rare cases with both PM and myasthenia gravis （MG）. Thus, the results of laboratory examinations in such a patient deserve to be reported. METHODS： To analyze the clinical, imaging and pathology datas on a 65-year-old woman patient with PM with complex symptoms, who presented mainly ophthalmoplegia. The patient consented to all examinations and the hospital Ethics Committee approved the study. The laboratory examinations included creatine kinase （CK）, ENA, tumor marker, function of thyroid, cranial MRI, and electromyogram （EMG）. Biopsy of the left quadriceps femoris was performed, frozen specimens were stained with hematoxylin and eosin, ATPase, NADH tetrazolium reductase, periodic acid Schiff, oil red O, modified Gomory trichrome and MHC-I, to investigate the pathology of muscle fibers RESULTS： Laboratory results showed： CK, 108.32μ kat/L; antinuclear antibody： （＋）; ENA, （-）; tumor marker, （-）; normal thyroid function, MRI showed no abnormal signals in brain and extraocular muscles. Electromyography of the bilateral deltoid, biceps brachii, musculus quadriceps fexoris, anterior tibialis showed fibrillation potentials, positive potentials and short-duration, small-amplitude polyphasic potentials on voluntary movements with a full interference pattern on mild exertion. Repetitive stimulation did not result in any increment or decrement in these potentials. A muscle biopsy of the left quadriceps femoris showed many small round muscle fibers without peripheral bundle distribution and apparent myofiber degeneration, necrosis and phagocytosis. There were several focal lymphocyte infiltrations. MHC-I immunohistochemical staining was positive in most fibers revealing inflammatory infiltration of normal fibers with MHC-I expression. CONCLUSION： This patient showed increased CK, typical triad of myopathy in EMG, and apparent degeneration and necrosis in biopsy     

Acute polymyositis with subcutaneous oedema

Three patients are described, presenting with a short history of excruciating muscle pain, weakness and extensive subcutaneous oedema, and who were found to have an acute inflammatory myopathy. Histological examination of the muscles showed considerable muscle necrosis with a relatively sparse inflammatory response and little evidence of regeneration. The place of this disorder in the spectrum of polymyositis is discussed.     

Generalized myositis mimicking polymyositis associated with chronic active Epstein-Barr virus infection

Background Chronic generalized myositis has not so far been reported as a complication of chronic active Epstein–Barr virus infection (CAEBV). We encountered three patients with chronic generalized myositis mimicking polymyositis associated with CAEBV. Methods To clarify the pathological character of this myositis, we investigated the distribution, clonality, and the immunophenotype of EBV–infected cells and lymphocytes infiltrating in muscles. Results Clinically, two patients showed symmetrical proximal weakness and muscle atrophy as the initial and main symptom. Although the condition resembled polymyositis, they had also lingual and/or orbital myositis. The other patient showed generalized myositis at the late phase of CAEBV. In all of them, immunotherapy was ineffective and prognosis was poor. Intramuscular infiltrating lymphocytes in our patients were mainly CD45RO+, CD3+, CD4–, CD8–, TCR F1–, TCR TCS1–, CD56–, CD79a–, CD21–, HLA-DR+, ZEBRA –, LMP1–, and EBER+ T cells. Oligoclonal expansion of EBV–infected T cells was shown in the muscles. However, there were no malignant lymphocytes. Conclusions This new form of myositis must be distinguished from polymyositis and the other conventional forms of myositis. Careful investigation of hidden CAEBV is recommended when patients present with steroid non–responsive chronic progressive generalized myositis, in particular, with lingual or orbital involvement.     

多发性肌炎合并心脏损害的临床特点

目的　探讨多发性肌炎合并心脏损害的临床特点、诊断、治疗与预后。方法　回顾性分析41例多发性肌炎合并心脏损害患者的临床资料。结果　合并心脏损害者占同期全部多发性肌炎患者的38 3%,其中无症状者25例(60. 1% );平均年龄较无心脏损害者高(P<0 .05);出现发热、合并间质性肺病的比率高(P<0. 05);心电图异常主要表现为窦性心动过速(31.7% )、窦性心律不齐(26. 8% )。超声心动图异常者中以心包积液居多。血清抗核抗体(ANA)阳性率及C 反应蛋白含量明显增高(均P<0 .05)。对心脏损害采用病因及对症治疗,治愈14例,症状改善23例,恶化2例,死亡2例。结论　心脏损害是多发性肌炎最常见的并发症,大多数患者无自觉症状,心电图是诊断心脏损害的主要方法。严重的心脏损害是导致患者死亡的重要因素,及时发现心脏损害并采取有效治疗对于改善患者的预后有重要意义。     

多发性肌炎和皮肌炎201例临床病理研究

201例多发性肌炎和皮肌炎,根据Bohan分型标准分成五组类型,其临床上以肢体肌无力、皮肤损害、疼痛、血肌酶升高、肌电图改变、肌活检肌纤维坏死及炎性细胞浸润为特征,但不同类型有所侧重,揭示其发病机制不同。治疗体会仍以激素为首选,必要时加用免疫抑制剂,开始治疗时间不应晚于1.5年,防治肺部感染是改善预后的重要措施之一。     

CD8 and CD4 T cell-mediated polymyositis complicating the HTLV-1 associated myelopathy. Quantitative evaluation of corticosteroid treatment

Introduction – Inflammatory myopathy is a treatable cause of worsening in the spectrum of neurological conditions that may develop during the course of HTLV-1 infection. Material and methods — To investigate the cause of subacute worsening in the strength of a 46-y-old black male with HTLV-1 associated myelopathy we performed electrodiagnostic examination and a muscle biopsy which was studied with histochemistry, immunocytochemistry and electron microscopy. Serial measurements of isometric muscle strength were performed during the course of corticosteroid treatment. Results — The muscle biopsy showed evidence of denervation atrophy and prominent inflammatory changes with autoaggressive features. Lymphocyte typing showed a predominance of CD8+ T cells. The patient had sustained, marked improvement in strength, especially of the upper extremities, with oral, high single-dose, alternate-day prednisone therapy. Conclusion — A muscle biopsy should be considered in all patients with HTLV-1 associated weakness, especially when electromyography indicates possible coexisting primary muscle involvement and/or serum creatine kinase levels are elevated. HTLV-1-associated polymyositis can be successfully treated with corticosteroids.     

Frequency of relapses in patients with polymyositis and dermatomyositis

The frequency of clinical and biochemical relapses was determined in a group of 50 patients with polymyositis (PM), dermatomyositis (DM), or overlap syndromes who were followed for periods of up to 13 years. Relapses occurred in 30 of the 50 patients (60%) during the period of follow-up. The annual relapse rate was not significantly different in the three groups of patients. Subclinical relapses occurred in each group but were less frequent in the DM than in the PM and overlap groups. Relapses could occur at any time but were more frequent during periods of stable maintenance therapy. There was no correlation between relapses and initial disease severity, delay to diagnosis and commencement of treatment, or any class I or II histocompatibility locus antigen. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21: 1668–1672, 1998     

Clinicopathologic characteristics of polymyositis patients with numerous tissue eosinophils

Introduction – We evaluated associated clinicopathologic features of polymyositis (PM) patients with numerous tissue eosinophils. Materials and methods — 680 muscle biopsies were examined in our institution and eight were identified with greater than 0.3 eosinophils per square millimeter in the inflammatory infiltrate without concomitant peripheral eosinophilia. Results — All eight patients had typical PM, but neither dermatomyositis nor inclusion body myositis was identified. Clinically, a large number of PM patients with eosinophils manifested an acute- or subacute-onset of symptoms, myoglobinuria, a marked elevation of serum creatine kinase, a good response to steroid therapy, and a relatively benign course compared with 26 PM patients without eosinophils. Muscle biopsies demonstrated necrotic fibers more frequently in PM patients with eosinophils than in PM patients without eosinophils. Hypertrophic fibers, fiber splitting, basophilic fibers, and lobulated fibers were less frequently observed in PM patients with eosinophils. Conclusion — These results suggest that the majority of PM patients with eosinophils may be steroid-responsive and suffer an acute or subacute onset of PM.     

Immunohistochemical characteristics of polymyositis in patients with HTLV-1–associated myelopathy and HTLV-I carriers

The immunohistochemical characteristics of polymyositis in patients with HTLV-I-associated myelopathy (HAM) and HTLV-I carriers were studied. Infiltrating cells were predominantly T cells and were not different from in the control group. All specimens contained positively staining muscle fibers for MHC class I antigens, but class II antigens were also expressed in some muscle fibers in 1 patient with HTLV-I-negative polymyositis, 3 patients with HTLV-I-positive polymyositis, and all 5 HAM patients with polymyositis. Expression of the neural cell adhesion molecule was lowest in the HAM patients. These findings may suggest a different immune environment in polymyositis with HAM. © 1993 John Wiley & Soncs, Inc.     

Quantitative electromyography in polymyositis and dermatomyositis

Twelve patients with polymyositis or dermatomyositis were examined repeatedly during the course of the illness by muscle strength tests, serum enzyme determinations, frequency analysis of the electromyographic signal, and estimations of the spontaneous activity. All methods can be used to follow the course of the disease. Increasing muscle strength was correlated to decreasing serum enzyme values, decreasing spontaneous activity, and decreasing proportion of high-frequency components in the EMG signal, except during the initial period of treatment, when a temporary increase in high-frequency components was recorded.     

AAEM case report #22: polymyositis

Polymyositis usually presents with progressive proximal muscle weakness, increased serum levels of muscle enzymes, inflammatory changes on muscle biopsy, and characteristic electromyographic (EMG) abnormalities. Motor unit action potential (MUAP) changes of configuration, duration, and amplitude are the most frequently observed EMG abnormality. Fibrillation potentials are commonly seen and tend to reflect active disease, diminishing after successful medical management or disease regression. Other muscle diseases can present with similar electromyographic abnormalities, thereby necessitating muscle biopsy for definitive diagnosis.     

Detection of immune complexes in polymyositis

There is good evidence to suggest a role for immunological factors in the pathogenesis of polymyositis although the exact mechanism and type of immunological disorder is unknown. The specific cellular and humoral hypersensitivity to muscle antigens described is most likely to represent an epiphenomenon.
Thirty-three patients with polymyositis, with or without skin involvement, were investigated for the presence of circulating immune complexes: positive results were obtained in 70% of the group.     

Acute fulminant myoglobinuric polymyositis with picornavirus-like crystals.

Myoglobinuria was found in an 11 month old girl suffering from fever, dyspnoea, and muscle hypotonia. Muscle biopsy showed focal degenerative necrosis of the muscle fibres. Electronmicroscopically, picornavirus-like crystals were demonstrated in the muscle fibres. These and other findings strongly suggest that she suffered from acute myositis with myoglobinuria probably caused by Coxsackie B6 virus infection. The causal relationship of viral infection (Coxsackie, influenza, or myxo-viruses) and acute or chronic polymyositis with or without myoglobinuria is discussed.     

Magnetic resonance imaging of the muscles in patients with polymyositis and dermatomyositis

Magnetic resonance imaging (MRI) of the muscles was performed in patients with polymyositis and dermatomyositis. Lesions with high intensity on T2-weighted image, but normal intensity on T1-weighted image, were observed in 7 of 8 patients in the active stage of the disease. Following clinical improvement with corticosteroid therapy in 4 patients, the high intensity lesions reverted to normal. The high intensity lesions seen on T2-weighted image in the active stage may represent edema and inflammation of the muscle. MRI of the muscle may serve as a diagnostic tool and be useful for follow-up of the patients with polymyositis or dermatomyositis.     

Antioxidant status of serum bilirubin and uric acid in patients with polymyositis and dermatomyositis

Objective: Oxidative stress and variations in antioxidant status are implicated in the pathogenesis of inflammatory and autoimmune diseases. Polymyositis and dermatomyositis (PM/DM) are autoimmune diseases with inflammatory cells infiltrating into skeletal muscles, and the antioxidant status is still controversial. The aim of our study was to investigate the correlation between PM/DM and the antioxidant status of serum bilirubin (Tbil, Dbil and Ibil) and uric acid (UA). Materials and Methods: We measured serum concentrations of bilirubin (Tbil, Dbil and Ibil) and uric acid in 384 individuals, including 110 PM/DM patients and 274 healthy controls. Results: We found that PM/DM patients had significantly lower serum concentrations of bilirubin (Tbil and Ibil) and uric acid than healthy controls, whether male or female. Also, after separately adjusting the covariances of age and gender, Tbil, Dbil, Ibil and UA were all relevant factors for PM/DM. Moreover, there were no significant differences in serum antioxidant molecule levels between PM and DM subgroups. Conclusion: Our study demonstrated the low serum levels of bilirubin and uric acid in patients with PM/DM. This suggested low antioxidant status in PM/DM patients with excessive oxidative stress.