Myopathic EMG Changes Research Articles

Electrodiagnostic findings in COVID-19 patients: A single center experience

ObjectiveNeurological manifestations in patients with coronavirus disease 2019 (COVID-19) have been reported from early features of anosmia and dysgeusia to widespread involvement of the central nervous system, peripheral nervous system, as well as the neuromuscular junction and muscle. Our study objective is to evaluate the electromyography and nerve conduction study (EMG/NCS) findings among COVID-19 patients and look for possible correlations. MethodsThis is a hospital-based retrospective observational study. All COVID-19 patients between the period of 1st January 2020 to 31st December 2020 undergoing an EMG/NCS were included. ResultsEighteen patients (12 male and 6 female) were included. Mean age was 55 ± 12 years. 11 patients required intubation for a mean period of 18.6 days (range: 3–37 days). Electrodiagnostic findings were consistent with a myopathy in a majority of these patients (82%). Five of them also had a concurrent axonal neuropathy. In the remaining patients who did not require intubation (n = 7), three patients had myopathic EMG changes and one had Guillain Barre syndrome. ConclusionAt this time, there are no neuromuscular-specific recommendations for patients who contract COVID-19. Only time and additional data will unveil the varying nature and potential neurological sequelae of COVID-19. SignificanceMyopathic EMG changes are commonly seen in critically ill COVID-19 patients, especially with a prolonged hospital stay.

EP21 Tumour necrosis factor inhibitor for the treatment of refractory extra-pulmonary disease including sarcoid arthritis and myositis

EP21 Tumour necrosis factor inhibitor for the treatment of refractory extra-pulmonary disease including sarcoid arthritis and myositis

Focal and other unusual presentations of facioscapulohumeral muscular dystrophy

Facioscapulohumeral dystrophy (FSHD) presents classically with facial and shoulder-girdle weakness. We report focal atypical presentations of FSHD. Our aim was to identify focal/unusual phenotypes in genetically confirmed FSHD cases. We undertook a retrospective review of an academic center database of the period from 1996 to 2011. Of 139 FSHD cases, 7 had atypical genetically confirmed disease. Clinical data were abstracted. Seven cases (4 men) had a mean age of 37 years at onset (range 18-63 years) and mean 43 years at diagnosis (range 20-74 years). Presenting symptoms were monomelic lower limb (n = 3) or upper limb (n = 2) atrophy, or axial weakness (n = 2). Five patients had focal weakness on examination. CK was normal to borderline high. Two patients had a relative with FSHD. Coexistent unusual features included dyspnea (n = 1), S1 radicular pain with calf atrophy (n = 2), and peripheral neuropathy (n = 1). Almost all patients had myopathic EMG changes. DNA analysis showed a D4Z4 EcoRI fragment size ranging from 20 to 37 kilobases. FSHD may present with focal weakness, dyspnea and myopathic EMG changes. These findings should raise the possibility of FSHD.

Expanding the Spectrum of ANO5-Muscular Dystrophy: Skeletal Muscle Amyloidosis, Cardiac Arrhythmia and Novel Mutations (PD6.001)

Objective: To investigate the clinical and pathological spectrum of ANO5-muscular dystrophy. Background Anoctamin-5 (ANO5) is a putative calcium-activated chloride channel and is highly expressed in skeletal and cardiac muscles and in bone. Dominant mutations in ANO5 cause gnathodiaphyseal dysplasia, while recessive mutations result in limb-girdle muscular dystrophy or distal myopathy. Design/Methods: Clinical examination, EMG, EKG, echocardiography, muscle histochemical studies, and mutational analysis in 4 unrelated patients. Results:Patient (Pt) 1: A 53-year-old woman with exercise-induced myalgia since childhood, rhabdomyolysis, adult-onset progressive limb-girdle weakness and asymmetric calf atrophy and weakness. Pt2: A 42-year-old man with progressive asymmetric distal and proximal weakness and paroxysmal atrial fibrillation since late 309s. Pt3: A 32-year-old woman with delayed motor milestones, myalgia, progressive limb-girdle weakness since mid 209s, and supraventricular tachyarrhythmia requiring ablation. Pt 4: A 68-year-old man with long standing history of asymptomatic hyper-CKemia followed by weakness of the calf muscles, subsequently extending to the limb-girdle muscles. All patients had elevated CK and myopathic EMG changes. Muscle biopsy revealed nonspecific myopathic changes in Pt1, Pt2, and Pt4; signs of reinnervation in Pt3; and amyloid deposits within the interstitium and blood vessel walls in Pt1 and Pt2. Echocardiogram revealed septal wall global hypokinesis in Pt3 and normal findings in the other patients. All 4 patients harbored two heterozygous ANO5 mutations; Pt2, Pt3 and Pt4 carry novel ANO5 mutations. Conclusions: The presence of cardiac arrhythmia in 2/4 patients suggest that cardiac involvement can occur in ANO5-muscular dystrophy and underlines the need for close cardiac monitoring. The presence of skeletal muscle amyloidosis in 2/4 patients increases the pathological similarity between ANO5-muscular dystrophy and dysferlinopathy and provides a clue to the diagnosis in the absence of dysferlin deficiency and/or dysferlin mutations. Supported by: The Neurology Department at Mayo Clinic, Rochester MN. Disclosure: Dr. Liewluck has nothing to disclose. Dr. Dimberg has nothing to disclose. Dr. Winder has received personal compensation for activities with PreventionGenetics. Dr. Milone has nothing to disclose.

Multisystem Disorder in Late-Onset Chronic Progressive External Ophthalmoplegia

Chronic progressive external ophthalmoplegia (CPEO) is a mitochondrial syndrome on a disease spectrum with Kearns-Sayre syndrome (KSS). Clinical presentation is variable and our experience suggested that phenotypic differences exist in CPEO with onset after age 20. This descriptive study is a retrospective chart review of 40 patients with late-onset CPEO. Clinical features, laboratory and neurophysiology results were reviewed. Multisystem dysfunction was very common in this series. Gastrointestinal dysfunction was more common than expected (60%) as was migraine headache (40%). Clinical characteristics on the KSS disease spectrum were uncommon in this series with only 2.5% having pigmentary retinopathy, 5% with cardiac conduction abnormality, and 22.5% having endocrinopathy (most often thyroid dysfunction rather than diabetes). Neurophysiology abnormalities included length-dependent axonal polyneuropathy in 44% (sometimes subclinical) and myopathic EMG changes in 26%. Exposure to sources of acquired mitochondrial toxicity including cigarette use and hepatitis C infection were more common than expected in this series. Phenotype was different in this late-onset series compared with previous reports in CPEO patients. In this series of late-onset patients, multi-organ dysfunction was more common than previously reported in CPEO, and some classical mitochondrial manifestations, such as pigmentary retinopathy were rare. We suggest that acquired mitochondrial toxicity may have a role in the pathogenesis of adult-onset CPEO.

A unique case of limb‐girdle muscular dystrophy type 2A carrying novel compound heterozygous mutations in the human CAPN3 gene

A unique sib pair afflicted by limb girdle muscular dystrophy type 2A (LGMD2A) is described showing a slowly progressive autosomal recessive type of muscular dystrophy with onset in the third and fourth decades. The patients had early asymmetric muscle involvement characterized by prominent biceps brachii atrophy with sparing of the knee extensors. Additional findings included elevation of serum creatine kinase level, myopathic EMG changes and dystrophic type of pathology on muscle biopsy. Asymmetrical wasting of muscles in the extremities exhibited uniform and highly selective CT imaging patterns. RNA and DNA analyses confirmed novel compound heterozygous mutations (R147X/L212F) in the human CAPN3 gene.

Infantile polymyositis with normal serum creatine kinase level

A 30-month-old boy who has been suffering progressive proximal muscle weakness and severe atrophy in shoulder and hip muscles from 11 months of age had prominent perivascular inflammatory cellular infiltration in his muscle biopsy and myopathic EMG changes. But his serum creatine kinase (CK) levels were repeatedly found to be within normal ranges. Oral prednisolone therapy (2 mg/kg/d) brought a complete recovery of muscle power and normalization of EMG and muscle biopsy findings. This report provides an additional support that the cases of infantile polymyositis with normal serum CK levels may respond well to steroid therapy.

Protein energy malnutrition and the nervous system

Protein-energy malnutrition (PEM), a natural ramification of poverty, continues to be a perennial source of concern to a large segment of the world population. The developing nervous system of a child is specially vulnerable to deprivations in nurture. Peripheral nerve and muscle derangements are clinically evident by weakness, hypotonia and hyporeflexia in accordance with severity and duration of PEM. Motor and sensory nerve conduction studies exhibit significant abnormalities and often furnish useful and ominous correlation with grades of PEM. The human sural nerve histology in cases of severe PEM is characterized by persistence of small myelinated fibres, striking failure of internodal elongation and significant segmental demyelination. Young rhesus monkeys are ideal experimental PEM models and they show myopathic EMG changes amenable to rehabilitation. Muscle pathology comprises obliteration of cross-striations, streaming of Z bands, increased interfibrillary spaces, mitochondriomegaly and small-for-age fibres. Radioisotope assays reveal anomalous incorporation into various nerve and muscle constituents. Central nervous system, specially the neurophysiological functions are affected in a lasting manner. Learning deficits, behavioural problems and manual indexterity are most obtrusive features.

Neuromuscular causes of prolonged ventilator dependency.

We prospectively evaluated 21 patients with prolonged ventilator dependency, to determine the frequency of unsuspected neuromuscular disease as a cause of this condition, and to determine the types of such diseases. Assessment was performed with routine and specialized electrophysiologic procedures. None of the patients had known prior neuromuscular disease, and none had ongoing medical problems that could account for their continued ventilator dependency. Sixty-two percent were found to have a neuromuscular disease severe enough to account for the ventilator dependency. Most of the remaining cases had a contributory neuromuscular disease. In addition to critical illness polyneuropathy, several other significant categories were identified. Myopathic EMG changes were found in 50% of the subgroup assessed by quantitative EMG. We conclude that neuromuscular disease is the most important factor in prolonged ventilator dependency, and that diseases other than critical illness polyneuropathy represent an important cause of this syndrome.

Debrancher deficiency neuromuscular disorder with pseudohypertrophy in two brothers

A neuromuscular disorder is reported in two brothers, aged 28 and 38 years, with glycogenosis type III. Both patients had proximal weakness, pseudohypertrophy of sternocleidomastoid, trapezius and quadriceps muscles, mild distal wasting and myopathic EMG changes. Pseudohypertrophy was more evident in the younger brother, whereas weakness was prominent in the older one. In the former, muscle biopsy revealed vacuolar myopathy and virtual absence of amylo-1,6-glucosidase enzyme. Few familial cases of debrancher deficiency neuromuscular disorder have been reported. Distal wasting has been considered a quite characteristic manifestation of the disease. It is also suggested that this particular kind of pseudohypertrophy may represent a distinctive feature of glycogenosis type III.

Skeletal muscle involvement in tropical endomyocardial fibrosis

Evidence for neuromuscular dysfunction was sought in 20 consecutive, angiographically proven cases of tropical endomyocardial fibrosis (Group I). Statistical comparison was made with equal number of age, sex, and weight-matched normal healthy volunteers (Group II), as well as similarly matched cases of consecutive heart failure (Group III). A myopathic pattern in the EMG was found in 85% of Group I and 65% of Group III patients. However, the severity and global extent of the EMG changes was much more marked in Group I than in Group III. The summed motor unit potential duration was reduced by 20.1% in Group I and by 9.5% in Group III. Corresponding figures for summed motor unit potential amplitude were 27.9% and 15.4%. The summed frequency of polyphasic potentials was significant in Group I and not in Group III. Involvement of 3 or 4 muscles in the same patient was found in 80% of Group I, and 10% of Group III. The upper limb muscles were affected in 80% of Group I and 50% of Group III. The motor nerve conduction velocity and distal latency time were normal in all the patients. It is suggested therefore that the myopathic EMG changes in Group I patients may be related to the disease process itself, rather than a reflection of long standing CHF alone. Light-microscopic study of the quadriceps muscles in 8 patients of Group I did not reveal any abnormality.