Full text is available as a scanned copy of the original print version. The diet, levels of physical activity and dietary supplements recommended for. Secondary types occur with abnormal production of parathyroid, thyroid, and cortisol production and vitamin d defi ciency. Muscle phosphoglycerate mutase deficiency pgamd is a metabolic myopathy characterised by exerciseinduced cramp, myoglobinuria, and presence of tubular aggregates in the muscle biopsy.
However, whether mitochondrial dysfunction is directly related to lower extremity ischemia and the structural and molecular mechanisms underpinning mitochondrial dysfunction in cli patients is not understood. Cells free fulltext mitochondrial structure and function. Metabolic myopathies are a diverse group of rare genetic disorders and their associated muscle symptoms may be subtle. It is characterised by progressive exercise intolerance manifesting in childhood, onset of sideroblastic anaemia around adolescence, lactic acidaemia, and mitochondrial myopathy. My emg showed mild chronic myopathy, and the docs are trying to figure out the cause. However, pain is usually not common in most muscle diseases and is more likely to be due to orthopedic or rheumatological disorders kincaid, 1997. The evaluation of patients mr rabbit by nicolas gajardo pdf suspected of having a myopathy motu midi timepiece pdf begins with a. The first five chapters describe the clinical approach to the patients who are suspected of having a metabolic myopathy, and summarize the role and the range of findings that may be seen with electromyography, muscle biopsy and magnetic resonance spectroscopy, and the normal response of skeletal muscle during exercise. They are suspecting metabolic myopathy, associated with metabolic bone disease sounds scary, right.
Glycogen is the main source of energy during brief exercise, while free fatty acids are the most important source of fuel during prolonged exercise. This topic will briefly describe fatty acid oxidation disorders faods, which are inborn errors of metabolism resulting in failure of. Primary metabolic myopathies are associated with genetic defects in glycogen and lipid metabolism. While the symptoms of a metabolic myopathy are usually first experienced in childhood or early adulthood, they may also develop later in adult life.
Some male patients can develop multiple metabolic risk factors when the waist circumference is only marginally increased, e. Metabolic myopathies american college of rheumatology. Although some experts have considered myoadenylate deaminase deficiency to be part of the group of metabolic myopathies,2,3 it is not directly involved in intermediary metabolism, and its role in causing a metabolic defect in muscle is seriously questioned. This article provides an overview of the most common metabolic myopathies. Patients may present with indolent myopathic features, exercise intolerance or recurrent rhabdomyolysis. These disorders may include defects in glucose metabolism, lipid metabolism, or defects in oxidative phosphorylation. Patients with metabolic myopathies may also develop fixed proximal muscle weakness, generally mild in severity, and be misdiagnosed as having polymyositis. The diagnosis of metabolic myopathies begins with a detailed history and physical examination. I had a full body triple phase bone scan and thats where they saw metabolic bone disease skull and costrochondral area. Turnbull muscle contraction is dependent on the highenergy molecule adenosine triphosphate atp, and deficiency of atp synthesis leads to premature muscle fatigue and weakness.
Differentiating idiopathic inflammatory myopathies from metabolic. The cpt codes provided are based on ama guidelines and are for informational purposes only. Mcardle disease gsd iv myophosphorylase deficiency exertional myalgia, rhabdomyolysis. Pdf the investigation and management of metabolic myopathies. The first has onset in infancy, does not progress past adolescence, and is not incapacitating. A different kind of metabolic myopathy caused by acid maltase deficiency is called pompe disease. In order to study metabolic changes, serum and urine samples from nine horses with atypical myopathy and 12 control samples from clinically healthy horses were collected and then analysed using a highperformance liquid chromatography coupled with tandem mass spectrometry. The main symptom of most of the metabolic myopathies is difficulty performing some types of exercise, a situation known as exercise intolerance, in which the person becomes tired very easily. Disorders of muscle can be simplified into the following categories. People with this condition have muscle weakness myopathy due to the accumulation of fats in muscle tissue.
Such patients may have a strong genetic contribution to insulin resistance. You may require intravenous fluids to avoid kidney failure. Please direct any questions regarding coding to the payer being billed. Metabolic myopathies are rare genetic diseases that cause muscle problems. Myopathies in systemic disease results from several different disease processes including endocrine, inflammatory, paraneoplastic, infectious, drug and toxininduced, critical illness myopathy, metabolic, and myopathies with other systemic disorders. Mitochondrial dysfunction has been implicated as a central mechanism in the metabolic myopathy accompanying critical limb ischemia cli. May 19, 2015 energy supplements to improve exercise tolerance in metabolic myopathies the safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Neutral lipid storage disease with myopathy is a condition in which fats lipids are stored abnormally in organs and tissues throughout the body. Energy supplements to improve exercise tolerance in metabolic.
Metabolic myopathies include disorders of glycogen and glycolysis metabolism, known as glycogen storage diseases gsd, lipid metabolism, and mitochondrial respiratory chain. Avoiding rhabdomyolysis and myoglobinuria when overexertion triggers acute muscle breakdown rhabdomyolysis, muscle proteins are released into the blood and ultimately appear as rustcolored urine myoglobinuria. Metabolic myopathy refers to a group of disorders that limit production of adenosine triphosphate atp 105. Confirmation of a clinical diagnosis can help direct treatment and medical management. The metabolic myopathies are a heterogeneous group of diseases characterized by impaired skeletal muscle energy production. A number of other metabolic myelopathies, also frequently associated with other neurological dysfunction, have been characterized and should be considered in the diagnosis of patients with subacute or chronic myelopathies. Oct 19, 2016 metabolic myopathies presenting with exercise intolerance, cramps, and myoglobinuria cramps and myalgia may occur after brief exercise or after prolonged physical activity. Mitochondrial myopathy and sideroblastic anemia genetic. A careful history and clinical examination will direct investigation towards an accurate molecular diagnosis. Muscle pain myalgia in muscle diseases myopathies hereditary disease defects in or defi ciencies of muscle proteins muscle weakness and muscle wasting e. Pdf metabolic myopathies mm are rare inherited primary muscle disorders that are mainly due to abnormalities of muscle energy. The next step would be to perform an ischemic exercise test.
Get a printable copy pdf file of the complete article 1. A normal emg, however, does not rule out a metabolic muscle disease. Metabolic myopathies are a heterogeneous group of disorders characterized by mostly inherited defects of enzymatic pathways involved in muscle cell metabolism. Clinical manifestations and diagnosis of rhabdomyolysis. Facts about metabolic diseases of muscle muscular dystrophy. They are generally genetic defects that interfere with muscles ability to create energy. Administration of nicotinamide mononucleotide nmn reduces metabolic impairment in male mouse offspring from obese mothers previous article in journal recent progress of stem cell therapy in cancer treatment. Not all people with a metabolic myopathy experience the same symptoms. Most servere form is pompes disease which is gsd ii.
However, for some, these are the symptoms coming from metabolic myopathy. There are 10 metabolic diseases of muscle myopathies in mdas program. Jun 01, 2019 the following other wikis use this file. Metabolic myopathies are a diverse group of inherited biochemical diseases involving limitation of the use of fuels by skeletal muscle to generate energy. Living with metabolic myopathies everyone has run out of energy, become tired when doing physical activities, or experienced muscle pains and cramps after exercising. Metabolic myopathies renaissance school of medicine at stony. Metabolic myopathies in spanish espanol download printfriendly pdf. The goal of treatment is to control symptoms and minimize progression of muscle weakness. Mitochondrial structure and function in the metabolic. Detailed descriptions of the different disorders are presented separately. Cpt coding is the sole responsibility of the billing party.
Full text full text is available as a scanned copy of the original print version. Education of the patient regarding intervention is critical for understanding the problems associated with metabolic diseases of musculature. Some of these disorders share a common pathogenetic mechanism and similar pathological findings with the myelopathy of vitamin b12 deficiency and. However, recurrent rhabdomyolysis is often genetic in nature. Genetic testing for metabolic myopathy and rhabdomyolysis. Metabolic myopathies are rare, so diagnosis can be delayed. Pdf the recognition of a series of metabolic enzymatic dysfunction in metabolic myopathies has allowed new therapeutic advances. Myopathy, any skeletal muscle disorder that directly affects the muscle fibres and does not arise secondarily from disorders of the nervous system. Metabolic myopathy definition of metabolic myopathy by. Treatment of metabolic myopathy in dogs extensive studies have been undertaken to further understand and treat metabolic myopathies. Patients with metabolic myopathies have underlying deficiencies of energy production in muscle due to a wide variety of defects. The age of onset for most metabolic myopathies is childhood or teenage years.
Rosenson icahn school of medicine at mount sinai, ny, ny, and dr peter p. Diagnostic delays are common and clinicians need a high index of suspicion to recognise and differentiate metabolic myopathies from other conditions that present in a. It is rare for a muscle disease to be responsible for vague 14 table 11 classification of myopathies hereditary. Metabolic myopathies are myopathies that result from defects in biochemical metabolism that primarily affect muscle. When benign entities are ruled out and metabolic myopathy is suspected, the first diagnostic step is to perform an electromyogram. Different forms of metabolic myopathies are distinguished by which enzyme is deficient or missing. Myopathies are marked by muscular degeneration and weakness and may have a genetic or nongenetic basis. Mitochondrial myopathy with lactic acidosis genetic and. Metabolic myopathies treatments vary according to the patients particular myopathy. After the full panel met, subpanels developed individual papers on the. Patients with a metabolic myopathy often report episodes of exercise intolerance, fatigue, muscle pain and weakness, but are often free of. Links to pubmed are also available for selected references. Metabolic myopathies should be considered in the differential diagnosis of patients with exercise induced muscle symptoms, static or progressive myopathy. Myopathies pdf myopathies are classified as either inherited or acquired.
All may result in fatigue and functional limitations such as impaired exercise capacity. The degree of exercise intolerance in the metabolic myopathies varies greatly between disorders and even from one individual to the next within a disorder. Myopathies pdf myopathies pdf myopathies pdf download. Those that begin in childhood or adulthood tend to be less severe, and changes in diet and lifestyle can help most people with the milder forms adjust. Neutral lipid storage disease with myopathy genetics. Mitochondrial myopathy lactic acidosisdeafness is a type of metabolic myopathy described only in two sisters to date, presenting during childhood, and characterized clinically by growth failure, severe muscle weakness, and moderate sensorineural deafness and biochemically by metabolic acidosis, elevated serum pyruvate concentration. Common symptoms include muscle weakness, cramps, stiffness, and tetany. Muscular pain myalgia in muscle diseases change pain. The investigation and management of metabolic myopathies. The physical you might also like myopathies metabolic myopathies 2015 acrarhp annual meeting. Myopathic causes of exercise intolerance with rhabdomyolysis. Metabolic myopathies associated with energy defects involve primarily defects in fao, glycogenolysis, glycolysis, oxidative phosphorylation, and mitochondrial disorders. Accordingly, the three main categories of metabolic myopathies are glycogen storage diseases, fatty acid oxidation defects, and mitochondrial disorders due to. See overview of inherited disorders of glucose and glycogen metabolism and metabolic myopathies caused by disorders of lipid and purine metabolism and.
Diagnostic delays are common and clinicians need a high index of suspicion to recognise and differentiate metabolic myopathies from other conditions that present in. The genedx metabolic myopathy panel includes genes causing glycogen storage disorders, fatty acid oxidation disorders and other wellestablished metabolic myopathies. Tips for diagnosing metabolic myopathies page 3 of 4. Treatment is focused on changes in physical activities, aerobic. Metabolic myopathy in dogs symptoms, causes, diagnosis. The genetic causes for rhabdomyolysis include metabolic myopathy, disorders of intramuscular calcium release, mitochondrial disorders and muscular dystrophies. Listing a study does not mean it has been evaluated by the u.
Metabolic myopathies muscular dystrophy association. At the cellular level, metabolic myopathies lack some kind of enzyme that prevent the chemical reactions necessary to create adenosine triphosphate atp. A diagnostic algorithm for metabolic myopathies ncbi. These include defects in lipid, glycogen, glucose, adenine nucleotide, and mitochondrial metabolism. Myopathy is a disease of the muscle in which the muscle fibers do not function properly. The metabolic myopathies result from inborn errors of metabolism affecting intracellular energy production due to defects in glycogen, lipid, adenine nucleotides, and mitochondrial metabolism. Despite the fact that metabolic myopathies are inherited, treatments can help many people with these diseases live normal lives. Those who do not develop a form of a metabolic myopathy until they are in their young adult or adult life tend to have more treatable symptoms that can be helped with a change in diet and exercise. Metabolic myopathies mm are rare inherited primary muscle disorders that are mainly due to abnormalities of muscle energy metabolism resulting in skeletal muscle dysfunction. However, metabolic myopathies may predispose to statininduced myopathy or may be unmasked as a result of increased creatine kinase testing in patients on statins. Other diagnostic tests that can be used to confirm or rule out specific metabolic myopathies include blood tests, urine tests, electromyography emg, muscle biopsy, exercise testing, and genetic testing. This includes a proper neurological examination with. Recommendations for energy, diet, and exercise are difficult because diagnosis is sometimes missed. This condition can cause severe kidney damage, and should be dealt with as an emergency see below.
Metabolic myopathies are genetic disorders that impair intermediary metabolism in skeletal muscle. Frontiers stepwise approach to myopathy in systemic disease. Muscular dystrophies and acquired myopathies are inflammatory and non inflammatory. Prenatal diagnosis for known familial mutation s in atrisk pregnancies. When to suspect a met bolic myopathy when approaching a patient with a suspected metabolic myopathy, the. Treatments include changes in physical activity and diet, aerobic and anaerobic resistance exercise training, and the use of various vitamins and supplements. For instance, mcardle disease is due to a lack of enzyme that assists in carbohydrate metabolism. Mitochondrial myopathy and sideroblastic anemia belongs to the heterogeneous family of metabolic myopathies. These metabolic diseases cause problems with the energy levels associated with activity. Table 1 includes a nonexhaustive list of more frequently encountered disorders. Apart from the manual muscle testing for muscle strength, the examination of. Metabolic myopathies should be considered in the differential diagnosis of exercise intolerance, and a detailed clinical approach will help determine which of the three main disorders glycogenoses, lipidrelated disorders, or mitochondrial diseases is the underlying cause. The metabolic myopathies are a group of muscle disor ders resulting from failed energy production related to defects in glycogen, lipid, or mitochondrial. To date, most of these conditions offer supportive care only, in the form of rest, nutrition and supplementation for instance, icarnitine is an amino acid prescribed to aid in protein building.
This meaning implies that the primary defect is within the muscle, as opposed to the nerves neuropathies or neurogenic disorders or elsewhere e. Metabolic myopathies are a group of genetic muscular diseases resulting from defective metabolism affecting primarily muscles. A patient that presents with muscle weakness can have any of these. Muscle diseases can constitute a large variety of both acquired and hereditary disorders.
Myopathy and biochemical defect disorders of glycogen glucose metabolism metabolic myopathy and rhabdo evaluation metabolic myopathy carnitine in disorders of fatty acid metabolism ischemic forearm exercise test related topics. A clinical approach to muscle diseases university of chicago. Metabolic myopathies have varying levels of symptoms, being most severe when developed during infancy. Abstract a retrospective clinical and biochemical study of 6 patients with metabolic bone disease has shown that 6 out of 91 patients with primary hyperparathyroidism and at least 20 out of 45 patients with osteomalacia developed remediable proximal muscle weakness. From our experience, we present our insights into some of these disorders and address other conditions that can present in a pseudo metabolic fashion. These diseases can be categorized as disorders of lipid metabolism, glycogen and glucose metabolism, or mitochondrial myopathies that impair both lipid and glucose metabolism.
Other features of this condition may include a fatty liver, a weakened and enlarged heart. Inherited metabolic myopathy and hemolysis due to a mutation in aldolase a. Myopathies in systemic disease results from several different disease processes including endocrine, inflammatory, paraneoplastic, infectious, drug and toxininduced, critical illness myopathy, metabolic, collagen related, and myopathies with other systemic disorders. Mar 12, 2018 an overview of the clinical manifestations resulting from a metabolic myopathy and the approach to the patient suspected of having a metabolic myopathy is discussed separately. Metabolic muscle diseases that have their onset in infancy tend to be the most severe, and some forms are fatal.
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