Miopatías inflamatorias idiopáticas: una mirada actualizada al diagnóstico y el manejo / Idiopathic inflammatory myopathies: a review

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of acquired immune-mediated diseases, which typically involve the striated muscle with a variable involvement of the skin and other organs. Clinically, they are characterized by proximal muscle weakness, elevation of muscle enzymes, myopathic changes on electromyography and an abnormal muscle biopsy. The different IIM have been classified according to their distinctive histopathologic features in dermatomyositis (DM), polymyositis (PM), inclusion body myositis (IBM) and immune-mediated necrotizing myopathy (IMNM). Several myositis-specific antibodies are associated with the different phenotypes, as well as with different risk of neoplastic disease and systemic complications. The basis for the treatment of DM, PM, and IMNM is immunosuppression. For IBM there are only symptomatic treatments. Steroids, associated or not with other immunosuppressant drugs, are the first line of treatment. Biologic drugs will allow future individualized therapies. The 10-year survival of DM, PM and IMNM is 62 to 90%. The leading causes of death are neoplastic, lung and cardiac complications. IBM does not impair survival, although it affects the quality of life.

Miopatías inflamatorias con evolución recidivante / Relapses in inflammatory myopathies

La mayoría de los estudios de tratamiento de las miopatías inflamatorias son de corte y no permiten establecer su eficacia en largo plazo. En este trabajo, describimos el seguimiento de siete pacientes con miopatías inflamatorias, 5 polimiositis y 2 dermatomiositis. Determinamos su presentación, su seguimiento clínico mediante el examen físico, las enzimas musculares y la respuesta al tratamiento. Esta última la definimos como cursos de tratamiento, donde cada curso termina al aumentar los corticoides o al colocar una nueva medicación inmunosupresora debido al empeoramiento clínico o aumento sostenido de las enzimas musculares. El tratamiento instaurado puede remitir, controlar parcialmente, o fracasar en controlar la enfermedad en cuanto se normalicen, estabilicen, o no modifiquen respectivamente tanto la clínica como las enzimas musculares. Se analizaron 20 ciclos, en 14 se logró la remisión, en cinco se controló parcialmente y en uno fracasó el tratamiento. La remisión se logró en un tiempo promedio de 139 ± 98 días y el control en un promedio de 160 ± 100 días. Excepto en una ocasión, todos los ciclos de tratamiento, independientemente del que fuera, remitieron o controlaron los síntomas, pero en el tiempo todos los pacientes recidivaron en su enfermedad.

Most studies about treatment of inflammatory myopathies consist of cross-sectional analyses that do not assess long-term efficacy. In the present study we describe the follow-up of seven patients with inflammatory myopathies, 5 polymyositis and 2 dermatomyositis. We describe their clinical features, follow-up, muscle enzyme levels, and treatment responses. We define the latter as treatment cycles, every one of which end when steroid doses need to be increased or a new immunosuppressive drug has to be added because of clinical worsening or sustained increases in muscle enzyme levels. Treatment can cause remission, partially control, or fail in achieving myositis improvement when it normalizes, stabilizes, or does not affect muscle enzymes or clinical features, respectively. We analyzed 20 cycles, in which remission was achieved in 14 cases, partial control in 5 instances, and treatment failure in one case. Remission occurred after an average of 139 ± 98 days, whereas partial control took place in 160 ± 100 days. Except in one case, all treatment cycles controlled or remitted the symptoms. However, in all patients the illness recurred with time.

Altered mean platelet volume in patients with polymyositis and its association with disease severity

Polymyositis (PM) is an autoimmune disease characterized by chronic inflammation in skeletal muscle. Mean platelet volume (MPV), a marker in the assessment of systemic inflammation, is easily measured by automatic blood count equipment. However, to our knowledge, there are no data in the literature with respect to MPV levels in PM patients. Therefore, in this study we aimed to investigate MPV levels in patients with PM. This study included 92 newly diagnosed PM patients and 100 healthy individuals. MPV levels were found to be significantly lower compared with healthy controls (10.3±1.23 vs 11.5±0.74 fL, P<0.001). Interestingly, MPV was found to be positively correlated with manual muscle test (MMT) score and negatively correlated with erythrocyte sedimentation rate (ESR) in patients with PM (r=0.239, P=0.022; r=−0.268, P=0.010, respectively). In addition, MPV was significantly lower in active PM patients compared with inactive PM patients (9.9±1.39 vs 10.6±0.92 fL, P=0.010). MPV was independently associated with PM in multivariate regression analyses, when controlling for hemoglobin and ESR (OR=0.312, P=0.031, 95%CI=0.108 to 0.899). The ROC curve analysis for MPV in estimating PM patients resulted in an area under the curve of 0.800, with sensitivity of 75.0% and specificity of 67.4%. Our results suggest that MPV is inversely correlated with disease activity in patients with PM. MPV might be a useful tool for rapid assessment of disease severity in PM patients.

Polymyositis presenting with respiratory failure.

Polymyositis is a systemic autoimmune disorder characterised by inflammatory myopathy of the skeletal muscles predominantly affecting the proximal muscles and associated with extra-muscular manifestations like dysphagia and skin involvement. In this case report, we describe the occurrence of diaphragmatic weakness and respiratory failure due to polymyositis with relatively well preserved power in limb muscles.

A study of morphometric and histopathological features of muscle biopsies from patients of myopathy.

The aim of this study is to analyse the morphological pattern of different types of myopathies including morphometric data. The cases were diagnosed as myopathy on the basis of clinical details, EMG findings, serum CK values. Muscle biopsies were performed and hematoxylin & eosin stain and Masson's trichrome stain were done. Muscle fiber diameters were measured using an eye piece micrometer of 100 fibers in each biopsy, these values were plotted and histograms were constructed. From this, mean fiber diameter (MFD), standard Deviation (SD), atrophy factor (AF), hypertrophy factor (HF) and variability coefficient (VC) were calculated. Degree of inflammation was scored semiquantitatively and presence of degenerating fibers, regenerating fibers, perifascicular atrophy, perivascular lymphocytic infiltration and vasculitis were noted. Out of 25 patients, 9 patients of inflammatory myopathy were adults, of the 16 patients of dystrophy 9 patients were adults. Along with weakness of limbs, skin rash was seen in 2 patients of dermatomyositis. Degree of inflammation was more in the patients of inflammatory myopathy than in the patients of dystrophy. Necrotic and regenerating fibers were seen in both groups. Perifascicular atrophy was seen in 1 case of dermatomyositis. Atrophy factor was higher in cases of dystrophy and so was hypertrophy factor. Variability coefficient >250 was found on 90% of dystrophy cases and it was <250 in the cases of inflammatory myopathy. Morphometry provides valuable data, which helps in distinguishing dystrophy from cases of myopathy with inflammation.

Inflammatory myopathy on HTLV-I infection: case report

We describe a 41 years old woman who 17 years ago presented hypotonia and proximal muscular weakness in the upper and lower limbs. On neurological examination, the biceps, triceps and Achilles reflexes were absent; the brachioradialis reflexes were decreased and the patellar reflexes were normal. There was bilateral Babinski sign. The remainder of the neurological examination was unremarkable. In the investigation a myopathic pattern was found in the electromyography. The nerve-conduction study was normal; a ELISA method for HTLV-I antibodies was positive in the blood and in the cerebral spinal fluid. The muscle biopsy showed inflammatory myopathy, compatible with polymyositis. This paper focuses the polymyositis in the beginning of an HTLV-I infection case

Diagnosis of dermatomyositis and polymyositis: a study of 102 cases

Patients with dermatomyositis (DM) or polymyositis (PM) were studied retrospectively. The patients were divided into four groups: definite PM 24, probable PM 19, definite DM 34 and mild-early DM 25 cases. PM patients complained more often proximal muscle weakness [p <0.01]. DM patients complained more arthralgia [p <0.05], dysphagia [p <0.03] and weight loss [p <0.04]. Five patients had a malignant neoplasm and 9 had other connective-tissue disease. DM presented higher ESR than PM [p <0.002]. PM presented more significant increase in creatine kinase (CK) [p <0.02] and in alanine aminotransferase (ALT) [p <0.001] levels. Electromyography showed myopathic pattern in 76 percent. Muscle biopsy was the definitive test. Perifascicular atrophy was more frequent in definite DM than in mild-early DM group [p <0.03]. CONCLUSION: A small association with connective-tissue diseases and neoplasms was found. DM and PM are clinically different. DM presents systemic involvement affecting the skin, developing more severe arthralgia, dysphagia and weight loss and presenting higher values of ESR. PM presents a restricted and more significant involvement of muscles generating more weakness complaints and higher levels of serum muscle enzymes

Polimiosite associada a infecçao por HTLV-I: relato de caso / Polymyositis and HTLV-I infection: case report

Apresentamos o caso de mulher com 57 anos de idade apresentando polimiosite, associada a infecçao pelo HTLV-I, sem manifestaçoes clínicas de acomentimento do sistema nervoso central e periférico. Fazemos alguns comentários sobre os aspectos fisiopatológicos do envolvimento muscular nas infecçoes pelo HTLV-I

Primary biliary cirrhosis and myopathy: an uncommon association

Primary biliary cirrhosis (PBC) is a cholestatic liver disease, which is characterized by a chronic inflammatory destruction of intrahepatic bile ducts. It is a rare disorder whose precise etiology is still to be elucidated. Even though the liver is the principal target of PBC, other organ systems also might be affected. Muscular involvement has rarely been described in this disease, and in the majority of cases, muscular weakness has been interpreted as polymyositis. We report the case of a 48-year-old woman suffering from classic PBC, in association with a myopathy whose histological features are distinct from the cases reported before. We also performed a MEDLINE research for PBC and concomitant muscular diseases

Esclerodermia-polimiositis - enfermedad de Charcot-Marie-Tooth / Scleroderma-polymiositis - Charcot-Marie-Tooth syndrome

Presentamos una paciente de sexo femenino de 42 años afectada de enfermedad de Charcot-Marie-Tooth. Hace dos años a nuestra paciente se le añade un cuadro de esclerodermia sistémica con insuficiencia pulmonar severa y síntomas típicamente dermatológicos. Los anticuerpos anti Scl 70 y anticentrómero fueron positivos. La anatomía patológica mostró además miositis y las características típicas de la esclerodermia. El tratamiento con corticoides, lidocaína y vasodilatadores periféricos no fue efectivo y nuestra paciente falleció

Polimiositis primaria asociada a HTLV-I / Primary polymyositis associated to HTLV-I

We report a 68 years old male with a polymyositis associated to HTLV-I. Diagnosis was based on clinical picture, an increased creatin-phosphokinase levels, electromyography and muscle biopsy. The patient had positive HTVL-I antibodies, measured by particle agglutination test, indirect immunofluorescence and polymerase chain reaction in lymphocytes. Skin biopsy showed a mycosis fungoides. Schirmer test and minor salivary gland biopsy showed a dacryosialoadenitis. There was no central nervous system involvement. This patient is the only with positive HTLV-I antibodies, among 18 patients with polymiositis in whom these antibodies were measured

La biopsia muscular en las miopatías inflamatorias idiopáticas / Muscular biopsy in idiopathic inflammatory myopathies

En el presente trabajo se realiza una actualización sobre los hallazgos histopatológicos en la biopsia muscular de las miopatías inflamatorias idiopáticas, en función de los recientes conceptos de etiopatogenia de la dermatomiositis y polimiositis, tomando como punto de partida los casos diagnosticados en un período de 3 años y medio por nuestro equipo. Se destaca el valor de la biopsia muscular para confirmar la afectación muscular, excluir otras enfermedades neuromusculares y definir el diagnóstico de miopatía inflamatoria