Retrospective study of a large population of patients with asymptomatic or minimally symptomatic raised serum creatine kinase levels

A retrospective evaluation of asymptomatic subjects with persistent elevation of serum creatine kinase (CK) levels (hyperCKemia) was made in order to verify the presence of subclinical myopathy or idiopathic hyperCKemia and to define the most appropriate diagnostic pathway. Persistently increased serum CK levels are occasionally encountered in healthy individuals. In 1980 Rowland coined for them the term idiopathic hyperCKemia. Despite the increase of scientific knowledge, several healthy subjects with hyperCKemia still represent a problem for the clinician. We made a retrospective evaluation of 114 asymptomatic or minimally symptomatic individuals with incidentally detected persistent hyperCKemia. They underwent neurological examination and laboratory/instrumental evaluation. Skeletal muscle biopsy was performed and thoroughly investigated. Biochemical and genetic investigations were added in selected cases. Logistic regression analysis was applied. We diagnosed a neuromuscular disorder in 21 patients (18.4 %), and found, by muscle biopsy and/or EMG, pathological but not conclusive findings in 57 subjects (50 %). The statistic correlation between elevated serum CK levels and the probability of making a diagnosis changed according to the age of the patient. Conclusions Muscle biopsy is the basic tool for screening asymptomatic subjects with hyperCkemia. It allowed us to make a diagnosis of disease in 18.4 % of patients, and to detect skeletal muscle abnormalities in 38.6 % of the subjects. Interestingly, 31.6 % of individuals had completely normal muscle findings. These best fit the “diagnosis” of idiopathic hyperCKemia. Received: 13 March 2001, Received in revised form: 3 July 2001, Accepted: 5 July 2001     

Open muscle biopsy in suspected myopathy: diagnostic yield and clinical utility

Background:  The purpose of the study was to investigate the diagnostic yield and clinical utility of open muscle biopsy and to identify pre-biopsy factors that might predict useful clinical results for suspected myopathy.
Methods:  Two-hundred fifty-eight muscle biopsies, performed for investigation of suspected myopathy, were evaluated.
Results:  A specific clinical diagnosis following muscle biopsy was made in 43% of cases. As a result of the biopsy, clinical diagnosis was changed in 47% and treatment was changed in 33% of cases. Results either led to a specific clinical diagnosis or changed the diagnosis/treatment in 74% of patients. Positive family history of myopathy and findings of myopathic irritability on electromyography had a negative predictive value for diagnosis change.
Conclusions:  Open muscle biopsy is useful in myopathy evaluation in the modern genetic era.     

Muscle-fiber conduction velocity and electromyography as diagnostic tools in patients with suspected inflammatory myopathy: a prospective study

Combinations of different techniques can increase the diagnostic yield from neurophysiological examination of muscle. In 25 patients with suspected inflammatory myopathy, we prospectively performed needle electromyography (EMG) and measured muscle-fiber conduction velocity (MFCV) in a single muscle, using a technique with direct muscle-fiber stimulation and recording. Results of MFCV were compared with final diagnosis, EMG, and needle muscle biopsy. Diagnostic accuracy of combined MFCV and EMG studies was 72%, compared to 60% for EMG alone. This improvement was due to a gain in specificity. The MFCV did not prove useful in discriminating inflammatory myopathy from other myopathies. Furthermore, we found a correlation of 92% between variability of MFCV and myopathic changes in muscle biopsy. We conclude that the utility of electrodiagnostic examination can be increased if EMG examination is combined with MFCV studies.     

Myopathy secondary to intravascular large B-cell lymphoma

We report a case of a 78-year-old woman presenting with progressive proximal muscle weakness mainly to lower limbs and myopathic EMG associated with intravascular large B-cell lymphoma.Muscle biopsy showed myopathic changes, intravascular large B-cell lymphoma but no inflammation or fibre necrosis; the patient’s serum cross-reacted with an unidentified nuclear antigen of approximately 45 kDa present in muscle and lymphoma cells.Our case illustrates a myopathy associated with intravascular large B-cell lymphoma probably mediated by antibodies cross-reacting with a nuclear protein expressed by neoplastic cells and normal muscle. The nature of this nuclear antigen remains unidentified.     

Clinical,morphological and immunological evaluation of six patients with dysferlin deficiency

Limb girdle muscular dystrophy (LGMD) type 2B and distal Miyoshi myopathy (MM) are caused by mutations in a recently discovered mammalian gene coding for a skeletal muscle protein called dysferlin. The protein is normally expressed at the skeletal muscle level and absent or reduced in affected patients. We selected a clinically heterogeneous population of Italian myopathic patients with clinical evidence of myopathy and/or hyperCKemia, EMG myopathic pattern, and no alterations of the dystrophin-sarcoglycan complex. Calpain, merosin, emerin and caveolin were also tested and found normal in all patients. Dysferlin immunohistochemical and Western blot analyses allowed us to identify six patients with dysferlin deficiency: one with distal myopathy, four with limb girdle myopathy and one with hyperCKemia. No apoptosis was found in any of the six muscle specimens, although expression of the pro-apoptotic Fas antigen was mildly increased in two cases. Inflammatory reactions were present in two of the six cases, but we found no evidence of immune-mediated processes.     

Isolated gluteal and paravertebral muscle weakness due to anti‐3‐hydroxy‐3‐methylglutaryl‐coenzyme a reductase antibody–associated necrotizing autoimmune myopathy

Introduction: A 56‐year‐old man with a distant history of statin use presented with progressive isolated very proximal lower limb and truncal weakness. Electromyogram (EMG) showed isolated gluteal and lumbar paraspinal muscle involvement. Methods: Gluteus medius muscle biopsy was performed under general anesthesia. Results: The biopsy showed a pauci‐inflammatory necrotizing myopathy. Serum antibodies to 3‐hydroxy‐3‐methylglutaryl‐coenzyme A reductase (HMGCR) were positive. He has since partially responded to corticosteroids and methotrexate. Conclusions: Anti‐HMGCR–associated necrotizing autoimmune myopathy (NAM) can present in a restricted form after cessation of a statin. Biopsy of a symptomatic but uncommonly studied muscle is worthwhile. Muscle Nerve 54 : 150–152, 2016     

A primigravida with very‐long‐chain acyl‐CoA dehydrogenase deficiency

Introduction: Valosin‐containing protein (VCP) is a ubiquitously expressed, multifunctional AAA‐ATPase protein. Its dominant mutations cause hereditary inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia (IBMPFD) or amyotrophic lateral sclerosis. The pattern of muscle weakness in IBMPFD patients is variable and includes limb‐girdle, scapuloperoneal, distal, or axial distributions. Case Report: We report a 63‐year‐old man with progressive scapuloperoneal weakness, head drop, and hyperCKemia since age 40 years. Electromyography showed myopathic changes and rare myotonic discharges. Muscle biopsy revealed numerous lobulated fibers, few fibers with glycogen accumulation, and rare fibers with polyglucosan bodies. Rimmed vacuoles and congophilic inclusions, often seen in IBMPFD, were absent. VCP sequencing identified a novel heterozygous c. 1160G>A mutation resulting in p.Asn387Ser substitution. Conclusions: Our patient broadens the pathological spectrum of VCP‐myopathy and emphasizes the importance of VCP analysis in patients with scapuloperoneal muscular dystrophy despite the absence of Paget disease, dementia, rimmed vacuoles, or intracellular amyloid deposition. Muscle Nerve 50:295–299, 2014     

Cytoplasmic body myopathy masquerading as motor neuron disease

Cytoplasmic body myopathy (CBM) is characterized by proteinaceous inclusion bodies in muscle tissue. A 43-year-old woman presented with rapidly progressive weakness and dysphagia. Electromyography (EMG) elsewhere demonstrated lower-limb chronic partial denervation. Muscle biopsy showed fiber size variation without diagnostic features. A diagnosis of possible motor neuron disease was made and the patient was commenced on riluzole. Subsequently, the patient's condition stabilized, prompting reassessment. Repeat EMG demonstrated no features of denervation and was more suggestive of a myopathic process. Review of the original muscle biopsy showed cytoplasmic bodies. The case highlights a further diagnostic possibility in the assessment of patients with "possible" motor neuron disease. The clinical features of CBM are briefly reviewed.     

Welander''s distal myopathy: clinical, neurophysiological and muscle biopsy observations in young and middle aged adults with early symptoms.

Nine young or middle aged patients with early symptoms of Welander's distal myopathy were subjected to a detailed neurological examination including quantitative sensory testing, determination of motor and sensory nerve conduction velocity (NCV), sensory nerve action potentials, electromyography (EMG) and muscle biopsy from the tibialis anterior muscle (TA). Slight weakness of the extensors of the fingers and hands was found in all nine patients, and of the dorsiflexors of the feet in seven. All patients had a distal sensory disturbance most prominent for temperature which agrees with earlier observations. EMG changes in TA and extensor digitorum communis (EDC) muscles were of myopathic type. Slight abnormalities compatible with either myopathy or early neuropathy were found in one muscle biopsy. These findings indicate that a neurogenic lesion affecting at least the peripheral sensory system is present at an early stage of Welander's distal myopathy and that the neurogenic lesion might precede the myopathic changes.     

Muscle “islands”: An MRI signature distinguishing neurogenic from myopathic causes of early onset distal weakness

Muscle MRI has an increasing role in diagnosis of inherited neuromuscular diseases, but no features are known which reliably differentiate myopathic and neurogenic conditions. Using patients presenting with early onset distal weakness, we aimed to identify an MRI signature to distinguish myopathic and neurogenic conditions. We identified lower limb MRI scans from patients with either genetically (n = 24) or clinically (n = 13) confirmed diagnoses of childhood onset distal myopathy or distal spinal muscular atrophy. An initial exploratory phase reviewed 11 scans from genetically confirmed patients identifying a single potential discriminatory marker concerning the pattern of fat replacement within muscle, coined “islands”. This pattern comprised small areas of muscle tissue with normal signal intensity completely surrounded by areas with similar intensity to subcutaneous fat. In the subsequent validation phase, islands correctly classified scans from all 12 remaining genetically confirmed patients, and 12/13 clinically classified patients. In the genetically confirmed patients MRI classification of neurogenic/myopathic aetiology had 100% accuracy (24/24) compared with 65% accuracy (15/23) for EMG, and 79% accuracy (15/19) for muscle biopsy. Future studies are needed in other clinical contexts, however the presence of islands appears to highly suggestive of a neurogenic aetiology in patients presenting with early onset distal motor weakness.     

DNAJB6 myopathy: A vacuolar myopathy with childhood onset

Introduction: DNAJB6 mutations cause an autosomal dominant myopathy that can manifest as limb‐girdle muscular dystrophy (LGMD1D/1E) or distal‐predominant myopathy. In the majority of patients this myopathy manifests in adulthood and shows vacuolar changes on muscle biopsy. Methods: Clinical, electrophysiological, pathological, and molecular findings are reported. Results: We report a 56‐year‐old woman, who, like 3 other family members, became symptomatic in childhood with slowly progressive limb‐girdle muscle weakness, normal serum creatine kinase (CK) values, and myopathic electromyographic findings. Muscle biopsy showed vacuolar changes and congophilic inclusions, and molecular analysis revealed a pathogenic mutation in the DNAJB6 gene. Differences and similarities with previously described cases are assessed. Conclusions: Childhood‐onset of DNAJB6 myopathy is more frequent than previously believed; congophilic inclusions may be present in the muscle of these patients. Muscle Nerve 49:607–610, 2014     

Chronic renal failure presenting as proximal muscle weakness in a child

A 13-year old boy presented with a three-year history of slowly progressive proximal muscle weakness, particularly involving the lower extremities. Chronic renal failure was uncovered in the course of his evaluation. Urologic investigation showed small and poorly functioning kidneys with a BUN of 118 mg/dL and a creatinine of 10.7 mg/dL. There were no anomalies of the proximal or distal collecting systems or history suggestive of recurrent urinary tract infection. The neurologic examination revealed proximal muscle weakness primarily of the lower extremities and especially of the proximal musculature of the pelvic girdle. Nerve conduction studies were normal. The electromyogram (EMG) showed high-voltage polyphasic potentials consistent with neurogenic muscle disease. A biopsy of the right quadriceps muscle demonstrated type II muscle fiber atrophy with histochemical staining. The patient's clinical findings, EMG studies, and muscle biopsy were not specific for either neurogenic or myopathic disease. Following a period of home peritoneal dialysis and renal transplantation, there was significant clinical improvement of the muscle weakness.     

Clinical correlates of granulomas in muscle

We evaluated the clinical and myopathological features of all patients with granulomas in muscle biopsy specimens identified over a 5-year period (1992–1996) at the Washington University Medical Center. Ten patients were found to have granulomas in their muscle biopsy specimens. Of these, eight patients had myopathic changes. Seven had dysphagia as a major functional difficulty during the course of their disease. None had elevated levels of serum creatine kinase (CK). Four of the patients with myopathy had systemic sarcoidosis and relatively severe proximal weakness with functional disability. Treatment with corticosteroids was followed by marked improvement in strength and functional disability. The four other patients with myopathy had no systemic signs of sarcoidosis. Weakness was especially prominent distally in three of these patients. The two patients in this group treated with corticosteroids did not improve. The final two patients, who had granulomas in muscle but no myopathic changes, had clinical syndromes of mononeuritis multiplex and eosinophilic fasciitis (Shulman syndrome). We conclude that granulomatous myopathy, in the presence or absence of systemic sarcoidosis, is commonly associated with dysphagia (87%) and a normal serum CK. Clinical features in patients with sarcoidosis included severe proximal weakness with functional disability that often responded to corticosteroid treatment. Granulomatous myopathy without systemic sarcoidosis was associated with milder, but more predominantly distal weakness. Received: 10 August 1997 Received in revised form: 13 January 1998 Accepted: 27 January 1998     

Acquired rod-body myopathy associated with human immunodeficiency virus infection

A 35 year old homosexual man showed clinical features of myopathy, with progressive muscular weakness of proximal muscles. EMG demonstrated a myopathic pattern; serum CPK was mildly elevated and CSF examination revealed antibodies to HIV and a blood-brain barrier damage. An open biopsy of the quadriceps femoris muscle showed myopathic changes with inflammatory features including a marked variation in fiber size, necrotic fibers and phagocytosis, a profusion of internal nuclei. Fiber type analysis with myosin ATPase reaction revealed that myopathic changes involved both fiber types. Changes in the oxidative enzyme activities were also observed in the degenerating muscle fibers. Electron microscopy showed patterns of myofibrillar degeneration and characteristic rod bodies in 30% of fibers. The close resemblance of the present morphological results with those recently observed in some HIV antibody positive men seems to indicate the existence of a specific structural myopathy associated with AIDS.

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Sommario Gli AA riportano il caso di un soggetto di 35 anni omosessuale con una debolezza muscolare progressiva prossimale ai 4 arti ad impronta miopatica. L’EMG era di tipo miogeno; il CPK era lievemente aumentato; l’esame del liquor evidenziava un danno di barriera e positività degli anticorpi HIV. La biopsia muscolare evidenziava un quadro miopatico, con aspetti infiammatori, che comprendeva: marcata variabilità del diametro delle fibre, fibre necrotiche e fagocitosi, nuclei interni ed infiltrati linfo-istiocitari. Lo studio istochimico e istoenzimatico evidenziava compromissione di entrambi i tipi di fibre con modificazione delle attività ossidative nelle fibre in degenerazione. La microscopia elettronica mostrava un quadro di degenerazione miofibrillare con la presenza di caratteristici “rod bodies” nel 30% delle fibre. La stretta bra indicare l’esistenza di una specifica miopatia strutturale associata con l’AIDS.

     

头颅下垂综合征和轴性肌病

头颅下垂综合征指患者站立时颈脊部伸肌群无力抬头,因而头颅下垂,背部弯曲。平卧时可缓解。该综合征由原发性和继发性的病因造成。原发性的轴性肌病,病因不明,十分罕见。这种肌病发生于40￣60岁,主要累及颈脊旁肌群,出现头颅下垂。脊旁肌肌电图和组织活检证实为一种慢性肌病。本病是一种应引人注意的临床肌病症状群之一。     

Congenital myopathy due to phosphorylase deficiency

A 4-year-old boy had delayed psychomotor development, proximal weakness, increased serum CK, and myopathic EMG. Muscle biopsy was normal, but histochemical stain for phosphorylase showed no reaction. The enzyme defect was confirmed biochemically and in studies of anaerobic glycolysis in vitro. Glycogen concentration was twice normal. Atypical presentations of myophosphorylase deficiency have included progressive weakness of late onset and fatal infantile myopathy. This patient represents another example of clinical heterogeneity.     

Sodium and chloride channelopathies with myositis: Coincidence or connection?

Introduction: A proximal myopathy develops in some patients with muscle channelopathies, but the causative molecular mechanisms are unknown. Methods: We reviewed retrospectively all clinical and muscle biopsy findings of 3 patients with channelopathy and additional myositis. Direct DNA sequencing was performed. Results: Pathogenic mutations were identified in each case. Biopsies demonstrated inflammatory infiltrates. Conclusions: Clinicians should consider muscle biopsy in channelopathy patients with severe myalgia and/or subacute weakness and accompanying elevated creatine kinase. Chance association of myositis and channelopathy is statistically unlikely. An alternative hypothesis suggests that inflammatory insults could contribute to myopathy in some patients. Muscle Nerve, 2011     

Colchicine-induced myopathy with myotonia in a patient with chronic renal failure

Although colchicine induced myopathy has been described in patients with chronic renal failure, colchicine induced myopathy with myotonia has been reported very rarely. A 49-year-old man with chronic renal failure was hospitalised for investigation of fatigue, malaise and severe pain in all extremities. He was on colchicine therapy for 5 months. Neurological examination showed mildly decreased sensation in a distal symmetric pattern in lower extremities, moderate proximal limb weakness, hyporeflexia and severe myalgia on palpation. No clinical evidence of myotonia was present. Laboratory studies showed elevated creatine phosphokinase (CK), lactic dehydrogenase (LDH), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels. Electromyographic (EMG) findings were compatible with myopathy and abundant, widespread myotonic discharges were determined. Muscle biopsy was consistent with vacuolar myopathy. After withdrawal of colchicine, CK, LDH, AST and ALT levels were normalised and the symptoms were disappeared gradually. In conclusion, the detection of myopathic motor unit potentials with myotonic discharges on EMG in patients on colchicine therapy is an important finding and it is possible to suggest that this clue may lead to the invasive procedure of muscle biopsy unnecessary.     

Debrancher deficiency neuromuscular disorder with pseudohypertrophy in two brothers

Summary 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.     

Targeted gene panel screening is an effective tool to identify undiagnosed late onset Pompe disease

Mutations in the GAA gene may cause a late onset Pompe disease presenting with proximal weakness without the characteristic muscle pathology, and therefore a test for GAA activity is the first tier analysis in all undiagnosed patients with hyperCKemia and/or limb-girdle muscular weakness. By using MotorPlex, a targeted gene panel for next generation sequencing, we analyzed GAA and other muscle disease-genes in a large cohort of undiagnosed patients with suspected inherited skeletal muscle disorders (n = 504). In this cohort, 275 patients presented with limb-girdle phenotype and/or an isolated hyperCKemia. Mutational analysis identified GAA mutations in ten patients. Further seven affected relatives were identified by segregation studies. All the patients carried the common GAA mutation c.-32-13T >G and a second, previously reported mutation. In the subcohort of 275 patients with proximal muscle weakness and/or hyperCKemia, we identified late-onset Pompe disease in 10 patients. The clinical overlap between Pompe disease and LGMDs or other skeletal muscle disorders suggests that GAA and the genes causing a metabolic myopathy should be analyzed in all the gene panels used for testing neuromuscular patients. However, enzymatic tests are essential for the interpretation and validation of genetic results.