Inclusion‐body myositis presenting with facial diplegia

Introduction: The hallmark clinical presentation of inclusion‐body myositis (IBM) is slowly progressive weakness that characteristically affects the quadriceps and finger and wrist finger flexor muscles. Facial weakness can also occur, but it is typically mild and not a prominent finding. Methods: We describe the clinical features, laboratory investigations, and muscle biopsy findings in a 58‐year old man who presented with a 6‐year history of marked progressive symmetrical facial weakness. Examination also showed shoulder abduction and hip extensor weakness. Results: The patient's serum creatine kinase level was 655 U/L, and electromyography showed fibrillation potentials and myopathic motor unit potentials. A biopsy specimen of the left biceps muscle was pathognomonic for IBM. Conclusions: This patient did not have a typical presentation for IBM but rather fulfilled the pathological criteria for IBM. To our knowledge, facial diplegia has not been reported previously as a presenting manifestation of IBM. Muscle Nerve 49 : 287–289, 2014     

Further observations on forearm flexor weakness in inclusion body myositis

In order to further characterize and provide a possible mechanism for the asymmetrical involvement of forearm muscles in inclusion body myositis (IBM), we measured isometric hand and pinch grip strength, and forearm muscle girth on 15 IBM patients. Forearm muscle strength and girth were significantly greater on the dominant versus nondominant side: mean grip strength, 173.9 vs. 98.8 N; mean pinch strength, 47.6 vs. 29.7 N; and mean forearm girth, 22.5 vs. 19.9 cm. This observation may suggest a role for exercise in delaying the disease progression in IBM. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21:659–661, 1998.     

Glucocorticoid-sensitive hereditary inclusion body myositis

We report a hereditary muscle disorder with features of inclusion body myositis (IBM) in two adult sisters with slowly progressive asymmetrical muscle weakness. The findings of light microscopic and ultrastructural investigations of muscle biopsy specimens were consistent with a diagnosis of IBM. Both patients improved and stabilized on immunosuppressive treatment with corticosteroids and azathioprine. This differentiates our patients from other sporadic and familial cases of IBM. Clinical and histological features are described and compared with those of other previously reported families with IBM.     

Inflammatory and non-inflammatory inclusion body myositis

Summary In ten patients with inclusion body myositis (IBM) five muscular biopsies showed profuse inflammatory exudates and three showed a few scattered inflammatory cells with partial invasion in some muscle fibers. No inflammatory cells were seen in two cases. In all patients, histopathological, histomorphometric and immunocytochemical studies were performed. Immunocytochemistry for the class I and class II major histocompatibility complex gene product (MHC) was performed in all cases and in ten control muscles including: normal muscles [3], dermatomyositis [3], polymyositis [3], scleroderma [1]. In the five cases of IBM with inflammatory exudates, subsets of lymphocytes were analyzed with a panel of monoclonal antibodies against B cells, T4 cells, T8 cells, K and natural killer cells and macrophages. Some muscle fibers expressed class I MHC antigens in the inflammatory cases of IBM. These fibers were near the inflammatory exudates and occasionally showed a partial invasion. No expression of class I MHC was found in normal muscles and in non-inflammatory cases of IBM. The antigen which triggers the mononuclear cells in the inflammatory forms of IBM is probably not the filamentous inclusions in rimmed vacuoles. In other inflammatory myopathies, expression of class I MHC was present on all fibers in polymyositis, only in the perifascicular area in dermatomyositis and in scleroderma. It could be suggested that the term inclusion body muscle disease be applied to cases with rimmed vacuoles and IBM-like filaments without inflammatory cells.     

A novel case of inclusion body myositis and myasthenia gravis

The co-existence of myasthenia gravis and other inflammatory myopathies has been reported in the literature before, but no clinical cases involving inclusion body myositis have been reported. We report a case of a 67-year-old patient who presented with dysphagia, exhibiting the typical electrophysiological features of postsynaptic neuromuscular junction defect with positive muscle acetylcholine receptor antibodies, consistent with the diagnosis of myasthenia gravis. Nevertheless, response to acetylcholinesterase inhibitors and immunomodulatory treatment was unexpectedly poor. As the disease progressed, the patient developed asymmetric muscle weakness, initially affecting mainly the quadriceps and the finger flexors. Muscle MRI imaging supported the presence of an inflammatory myopathy and muscle biopsy confirmed the diagnosis of inclusion body myositis. Thus, our patient represents the first reported overlap case of myasthenia gravis and inclusion body myositis.     

Sporadic distal myopathy

Summary The sporadic distal myopathies are uncommon primary muscle diseases, the pathogenesis of which is still unclear. The inclusion body myositides are inflammatory myopathies, the distal form of which presents some features resembling those of sporadic distal myopathy. A case is reported of a patient showing features of both the first and the second forms.     

Physical function and muscle strength in sporadic inclusion body myositis

Introduction: In this study, self‐reported physical function, functional capacity, and isolated muscle function were investigated in sporadic inclusion body myositis (sIBM) patients. Methods: The 36‐item Short Form (SF‐36) Health Survey and 2‐min walk test (2MWT), timed up & go test (TUG), and 30‐s chair stand performance were evaluated. In addition, patients were tested for knee extensor muscle strength (isokinetic dynamometer) and leg extension power (Nottingham power rig). Results: TUG performance was the strongest predictor of self‐reported physical function (r ² = 0.56, P < 0.05). Knee extension strength and between‐limb strength asymmetry were the strongest multi‐regression indicators of TUG performance (r ² = 0.51, P < 0.05). Strength asymmetry showed the strongest single‐factor (negative) association with 2MWT performance (r ² = 0.49, P < 0.05). Discussion: TUG assessment appears to sensitively predict self‐perceived physical function in sIBM patients. Notably, between‐limb asymmetry in lower limb muscle strength had a substantial negative impact on motor tasks involving gait function. Muscle Nerve 56 : E50–E58, 2017     

Dermatomyositis with inclusion body myositis pathology

The pathogenic role of inflammation in inclusion body myositis (IBM) remains uncertain. A 63‐year‐old man developed a severe, rapidly progressive myopathy with clinical features typical of dermatomyositis (DM), but muscle pathology was typical of IBM. Treatment with prednisone and methotrexate resulted in complete remission of symptoms. Together with two similar cases reported previously, this case suggests that the inflammatory process of DM may trigger the pathologic changes of IBM. Muscle Nerve, 2009     

Mitochondrial DNA variants in inclusion body myositis

Mitochondrial DNA variants have been shown to be associated with many diseases. Mutations at mitochondrial DNA nucleotide positions 3192, 3196, 3397 and 4336 have been described in association with late-onset Alzheimer's disease. The pathological similarities between inclusion body myositis and Alzheimer's disease prompted an analysis of the relationship between the reported mutations and sporadic inclusion body myositis. The 4336G variant was not significantly increased in patients with inclusion body myositis or Alzheimer's disease when compared to controls. None of the patients with inclusion body myositis carried mutations at nucleotide positions 3192, 3196 and 3397. A transition at nucleotide position 4580 was detected in some patients with inclusion body myositis and Alzheimer's disease but was not significantly higher in frequency when compared to controls. Phylogenetic analysis showed that the 4336G and 4580A variants clustered together in their respective group. A group of patients with inclusion body myositis also clustered together on a separate branch of the phylogenetic tree. Closer investigation of this group revealed a common polymorphism at nucleotide position 16311. The frequency of the 16311C variant was higher in inclusion body myositis than in Alzheimer's disease and controls, although when only caucasian patients were considered the increased frequency was not statistically significant. Further studies will be required to determine whether this variant plays a role in the pathogenesis of inclusion body myositis.     

Differential and quantitative neuroimaging characteristics of inclusion body myositis

In clinical settings, it is often difficult to distinguish inclusion body myositis (IBM) from other neuromuscular diseases. In order to clarify clinically useful characteristics for making the differential diagnosis of IBM, we performed clinical, epidemiological, and neuroimaging analyses in patients with various types of neuromuscular disorders. We enrolled 333 patients with myopathy and 12 patients with amyotrophic lateral sclerosis (ALS) who had been hospitalized in our department from January 1, 1979, to December 31, 2018. Among them, 18 patients with IBM, 16 patients with polymyositis (PM), and 12 patients with ALS who showed equivalent severity of muscle weakness in their lower limbs underwent the quantitative neuroimaging analysis using lower limb CT and clinical assessment. Patients with IBM exhibited significantly greater muscular degeneration in the rectus femoris, vastus, sartorius, adductor, anterior calf, and medial gastrocnemius muscles than those with PM or ALS. The ratio of the remaining muscle area of the quadriceps relative to that of the hamstrings and the duration from onset to CT imaging were negatively correlated in patients with IBM, indicating that the anterior thigh muscles were preferentially affected over the posterior muscles. Characteristic muscular degeneration in the lower limbs on CT imaging may aid for making the diagnosis of IBM.     

A review on the treatment of sporadic inclusion body myositis with Bimagrumab and Alemtuzumab

Background: Sporadic inclusion body myositis is the most common inflammatory myopathy over the age of 50. The aetiopathogenesis of the disease remains unclear and to the day there is no effective treatment.

Objectives: The aim of the present review is to present the latest data on the new insights and developments in the treatment of sporadic inclusion body myositis, focusing on Bimagrumab and Alemtuzumab.

Methods: For the purpose of the review we searched multiple internet databases in order to find the most recent studies and clinical trials on the safety, tolerability and efficacy of Bimagrumab and Alemtuzumab in sporadic inclusion body myositis.

Results: We found four trials on Bimagrumab, with one of them being an extension phase III study, and one small series trial on Alemtuzumab. The first clincopathological trial on Bimagrumab showed promising evidence, which were partially confirmed by the double-blinded controlled multicentre trial, however the primary endpoint of improving 6-m walking distance or improving the muscle strength has not been reached. The evidence from the Alemtuzumab trial was also promising, but the risk of bias of the study was relatively high, because it was open labelled, the number of patient was low and the yearly disease progression was much higher than in other recent studies.

Conclusions: Although both Bimagrumab and Alemtuzumab were well tolerated and showed promising results, the Bimagrumab trial did not reach the primary endpoint, and the Alemtuzumab trial has a relatively high risk of bias and the results need to be interpreted with caution.     

Trunk muscle activation pattern in parkinsonian camptocormia as revealed with surface electromyography

IntroductionCamptocormia is frequently seen in Parkinson's disease (PD) and multiple system atrophy. It is characterized by a pathological forward bending of the trunk during standing, often combined with a lateral trunk deviation. The etiology of camptocormia in PD is still unknown. Muscle MRI studies show abnormalities mainly of the erector spinae confirmed by muscle biopsies. Quantitative electromyographic examination of trunk muscle activity is missing.MethodsVentral (rectus and obliquus externus abdominis) and dorsal (iliocostalis lumborum, longissimus, multifidus) trunk muscles and the rectus femoris were recorded bilaterally with surface electromyography in standing PD patients with camptocormia (n = 10) and matched healthy controls (n = 10) who mimicked the patients' posture. EMG amplitudes were compared quantitatively. In controls, the relation between varying degrees of trunk flexion and EMG was established systematically.ResultsIncreasing forward trunk flexion was associated with increasing back muscle activity in controls, while abdominal muscle activity was negligible. During anterolateral trunk flexion, back muscle activity increased particularly on the contralateral side. The patients showed a similar pattern. However, normalized EMG activity of their trunk extensors was significantly higher than in controls, often reaching half-maximal amplitudes. Their rectus femoris and oblique abdominal muscles were overactive, but to a lesser extent.ConclusionsPD patients with camptocormia must use the functional reserve of their lumbar trunk muscles to counteract gravity. We interpret this as a weakness of the paravertebral muscles. Compared to the other examined muscles the paravertebral muscles are most affected. The increased EMG activity of the rectus femoris warrants further research.     

Mitochondrial DNA depletion in sporadic inclusion body myositis

Sporadic inclusion body myositis (sIBM) is a late onset disorder of unkown aetiology. Mitochondrial changes such as cytochrome oxidase deficient fibres are a well recognised feature and mitochondrial DNA (mtDNA) deletions have also been reported, but not consistently. Since mtDNA deletions are not present in all cases, we investigated whether other types of mtDNA abnormality were responsible for the mitochondrial changes. We studied 9 patients with sIBM. To control for fibre loss or replacement with inflammatory cells, we compared sIBM patients with necrotising myopathy (n?=?4) as well as with healthy controls. Qualitative anlysis for mtDNA deletions and quantitative measurement of mtDNA copy number showed that muscle from patients with sIBM contained on average 67% less mtDNA than healthy controls (P?=?0.001). The level of mtDNA was also significantly depleted in sIBM when compared to necrotising myopathy. No significant difference in copy number was seen in patients with necrotising myopathy compared to controls. Deletions of mtDNA were present in 4 patients with sIBM, but not all. Our findings suggest that mtDNA depletion is a more consistent finding in sIBM, and one that may be implicated in the pathogenesis of the disease.     

Inclusion body myositis with abundant ring fibers

Summary A 37-year-old male presenting with a 7-year history of leg weakness was found to have moderate weakness confined to the quadriceps and myopathic changes on electromyography. Serum creatine phosphokinase was 2130 units/liter. Biopsy of the quadriceps muscle revealed an inflammatory myopathy with cytoplasmic and nuclear filamentous inclusions characteristic of inclusion body myositis. An unusual finding was the large proportion of ring fibers along with severe atrophy and fibrosis. The pathogenesis of the ring fibers in this setting is discussed.     

Demographic and clinical features of inclusion body myositis in north America

Introduction: Few studies of the demographics, natural history, and clinical management of inclusion body myositis (IBM) have been performed in a large patient population. To more accurately define these characteristics, we developed and distributed a questionnaire to patients with IBM. Methods: A cross‐sectional, self‐reporting survey was conducted. Results: The mean age of the 916 participants was 70.4 years, the male‐to‐female ratio was 2:1, and the majority reported difficulty with ambulation and activities of daily living. The earliest symptoms included impaired use and weakness of arms and legs. The mean time from first symptoms to diagnosis was 4.7 years. Half reported that IBM was their initial diagnosis. A composite functional index negatively associated with age and disease duration, and positively associated with participation in exercise. Conclusions: These data are valuable for informing patients how IBM manifestations are expected to impair daily living and indicate that self‐reporting could be used to establish outcome measures in clinical trials. Muscle Nerve 52: 527–533, 2015     

High-dose immunoglobulin therapy in sporadic inclusion body myositis: a double-blind, placebo-controlled study

Sporadic inclusion body myositis (s-IBM) is an acquired inflammatory muscle disease of unknown cause. In general, s-IBM presents with slowly progressive, asymmetric weakness, and atrophy of skeletal muscle. There is a mild transitory or nil responsiveness to standard immunosuppressive treatment. A controlled cross-over study of 22 s-IBM patients over 3 months showed a partial improvement in those treated with high-dose intravenous immunoglobulin therapy (IVIG) versus placebo. The present study included 22 patients aged 32-75 years and with a mean duration of disease of 5.2+/-3.6 years. They were randomized by a double-blind, placebo-controlled, cross-over design to monthly infusions of 2 g/kg bodyweight IVIG or to placebo for 6 months each, followed by the alternative treatment. After 6 and 12 months the response to treatment was evaluated, using a modified Medical Research Council scale, Neuromuscular Symptom Score (NSS), the patient's own assessment of improvement, arm outstretched time, and electromyography. No serious side effects were seen, in particular no viral infection and no major cardiac or neurological complications. Overall there was no progression of the disease in 90% of patients, unlike that which might have been expected in untreated patients. A mild and significant improvement (11%) in clinical symptoms was found using NSS, but not with other test procedures. There was a trend to mild improvement in treated patients when using other tests. Individual responses to treatment was heterogeneous. The validity of this study may be reduced by mismatch of groups with regard to age at onset and variability in disease expression. The findings of this study largely confirm those of a previous IVIG trial. Treatment with IVIG may be mildly effective in s-IBM by preventing disease progression or inducing mild improvement. Long-term studies are needed to evaluate further the benefit of IVIG therapy in s-IBM.     

Sporadic inclusion body myositis: HLA-DRB1 allele interactions influence disease risk and clinical phenotype

Susceptibility to sIBM is strongly associated with the HLA-DRB1*03 allele and the 8.1 MHC ancestral haplotype (HLA-A1, B8, DRB1*03) but little is known about the effects of allelic interactions at the DRB1 locus or disease-modifying effects of HLA alleles. HLA-A, B and DRB1 genotyping was performed in 80 Australian sIBM cases and the frequencies of different alleles and allele combinations were compared with those in a group of 190 healthy controls. Genotype–phenotype correlations were also investigated. Amongst carriers of the HLA-DRB1*03 allele, DRB1*03/*01 heterozygotes were over-represented in the sIBM group (p < 0.003) while. DRB1*03/*04 heterozygotes were under-represented (p < 0.008). The mean age-at-onset (AAO) was 6.5 years earlier in DRB1*03/*01 heterozygotes who also had more severe quadriceps muscle weakness than the rest of the cohort. The findings indicate that interactions between the HLA-DRB1*03 allele and other alleles at the DRB1 locus can influence disease susceptibility and the clinical phenotype in sIBM.