Metabolic myopathies article about metabolic myopathies by. However, recurrent rhabdomyolysis is often genetic in nature. Genetic testing for metabolic myopathy and rhabdomyolysis. Tips for diagnosing metabolic myopathies page 2 of 4 the. Mitochondrial myopathylactic 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. Metabolic myopathies comprise a clinically and etiologically diverse group of disorders caused by defects in cellular energy metabolism, including the breakdown of carbohydrates and fatty acids to. Newborns and infants commonly present with hypotonia and multisystem involvement liver and brain, whereas onset later in life usually presents with exercise intolerance with or without. Pdf a diagnostic algorithm for metabolic myopathies. However, some patients of metabolic myopathies present with fixed or slowly progressive wecikness. Tips for diagnosing metabolic myopathies page 2 of 4. The metabolic myopathies are a heterogeneous group of disorders that share the common feature of inadequate production of cellular energy in the muscle.
Necrotizing autoimmune myopathy nam is a rare form of idiopathic inflammatory myopathy characterized clinically by acute or subacute proximal muscle weakness, and histopathologically by myocyte necrosis and regeneration without significant inflammation. Education of the patient regarding intervention is critical for understanding the problems associated with metabolic diseases of musculature. Cpt coding is the sole responsibility of the billing party. While many people are unaware that this condition even exists, it is common among those who abuse alcohol. Apr 02, 2003 statins 3hydroxy3methylglutaryl coenzyme a reductase inhibitors are associated with skeletal muscle complaints, including clinically important myositis and rhabdomyolysis, mild serum creatine kinase ck elevations, myalgia with and without elevated ck levels, muscle weakness, muscle cramps.
The free achilles reflex in hypothyroidism and hyperthyroidism. The severity of any of these symptoms varies greatly from one person to the next, even in the same family. Metabolic myopathy symptoms vary among individuals. Alcoholic myopathy is a serious, debilitating condition that can hinder a persons ability to fully participate in life, significantly impacting the ability to perform normal daily tasks and causing intense muscular pain. The second has onset in adulthood and is called late. 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. The metabolic myopathies are a heterogeneous group of disorders caused by defects in muscle energy metabolism that cause inadequate production or maintenance of atp levels. Annals of the american thoracic society ats journals. Serum activities of ckmm may be increased in a number of conditions, including after strenuous exercise, inflammatory myopathies, infectious myopathies, dystrophinopathies, rhabdomyolysis, medications, metabolic myopathies, malignant hyperthermia, endocrine. Metabolic myopathies presenting with exercise intolerance, cramps, and myoglobinuria cramps and myalgia may occur after brief exercise or after prolonged physical activity.
During administration of propofol 3 mgkghour, a 40yearold man developed a fever of 41 c, resistant to diclofenac and physical cooling. These include defects in lipid, glycogen, glucose, adenine nucleotide, and mitochondrial metabolism. But its important to get an accurate diagnosis of a specific metabolic myopathy so the affected person can modify diet and exercise, and monitor potentially. These metabolic diseases cause problems with the energy levels associated with activity. 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. However, the identification of the underlying genetic cause has traditionally relied upon the findings provided by detailed clinical history and examination of the patient, which has. In fact, some people with the condition my live symptom free because their cells have found a. The goal of treatment is to control symptoms and minimize progression of muscle weakness. 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. Other metabolic myopathies with massive lipid storage and weakness are. 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. Metabolic myopathies may present in different stages of life and can be difficult to diagnose. The genedx metabolic myopathy panel includes genes causing glycogen storage disorders, fatty acid oxidation disorders and other wellestablished metabolic myopathies. Metabolic myopathies by classification can be primary or secondary 5, 6.
Treatments include changes in physical activity and diet, aerobic and anaerobic resistance exercise training, and the use of various vitamins and supplements. 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. Mitochondrial myopathy fact sheet national institute of. This topic will briefly describe fatty acid oxidation disorders faods, which are inborn errors of metabolism resulting in failure of. The main sources of adenosine triphosphate atp in cells are glycogen, glucose, and free fatty acids. Clinically, a variety of neuromuscular presentations are seen at different ages of life. A clinical approach to muscle diseases university of chicago. 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. The prevalence and annual incidence of nam are not known but the disorder is very rare. This article cites 14 articles, 2 of which you can access for free at. The cpt codes provided are based on ama guidelines and are for informational purposes only. Treatment for metabolic myopathies varies by myopathy, but is focused on changes in physical activities, aerobic exercise training, changes in diet, and the use of various vitamins or supplements.
Detailed descriptions of the different disorders are presented separately. Abnormalities of muscle cell structure and metabolism lead to various patterns of weakness and dysfunction. This meaning implies that the primary defect is within the muscle, as opposed to the nerves neuropathies or neurogenic disorders or elsewhere e. The first has onset in infancy, does not progress past adolescence, and is not incapacitating. Mitochondrial dysfunction has been implicated as a central mechanism in the metabolic myopathy accompanying critical limb ischemia cli. The differential diagnosis of metabolic myopathy includes a long list of inherited disorders affecting the provision of energy for skeletal muscle metabolism. Metabolic myopathies are rare genetic diseases that cause muscle problems. Metabolic myopathies are genetic diseases, usually inherited, that affect the bodys muscles. The next step would be to perform an ischemic exercise test.
His urine darkened and his urinary output fell and eventually ceased completely. Test metabolic myopathies, rhabdomyolysis and exercise. You may require intravenous fluids to avoid kidney failure. Metabolic refers to chemical reactions that provide energy, nutrients and substances necessary for health and growth. This condition can cause severe kidney damage, and should be dealt with as an emergency see below. Metabolic neuropathies and myopathies sciencedirect.
Cells free fulltext mitochondrial structure and function. Free fatty acids are first converted to acylcoenzyme a coa compounds by the action of fatty acylcoa synthetases. Energy supplements to improve exercise tolerance in. Metabolic myopathy definition of metabolic myopathy by. Cardiopulmonary exercise testing provides valuable insights into the integrated functioning of the cardiovascular, ventilatory, and skeletal muscle systems. When benign entities are ruled out and metabolic myopathy is suspected, the first diagnostic step is to perform an electromyogram. Metabolic myopathies muscular dystrophy association. With appropriate activity changes, regular aerobic exercise, diet and use of supplements, the symptoms often can be controlled. Diagnostic delays are common and clinicians need a high index of suspicion to recognise and differentiate metabolic myopathies from other conditions that present in. Muscle disorders arise from abnormalities that affect the muscles structure or metabolism, and have a variety of causes. Metabolic myopathies mm are rare inherited primary muscle disorders that are mainly due to abnormalities of muscle energy metabolism resulting in skeletal muscle dysfunction. Not all people with a metabolic myopathy experience the same symptoms. Metabolic myopathies treatments vary according to the patients particular myopathy. Myopathy refers to a clinical disorder of the skeletal muscles.
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. Common symptoms include muscle weakness, cramps, stiffness, and tetany. Statinassociated myopathy cardiology jama jama network. Commonly used icd10 code s when ordering the metabolic myopathy and rhabdomyolysis panel. Statins 3hydroxy3methylglutaryl coenzyme a reductase inhibitors are associated with skeletal muscle complaints, including clinically important myositis and rhabdomyolysis, mild serum creatine kinase ck elevations, myalgia with and without elevated ck levels, muscle weakness, muscle cramps, and persistent myalgia and ck elevations after statin withdrawal. Apart from the manual muscle testing for muscle strength, the examination of.
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. Metabolic myopathies article about metabolic myopathies. Listing a study does not mean it has been evaluated by the u. P royal free and royal national orthopaedic hospitals, and institute of neurology, london. Metabolic myopathies american college of rheumatology. A diagnostic algorithm for metabolic myopathies ncbi. Metabolic myopathies are a diverse group of rare genetic disorders and their associated muscle symptoms may be subtle. Test information sheet 207 perry parkway, gaithersburg, md 20877 p. However, metabolic myopathies may predispose to statininduced myopathy or may be unmasked as a result of increased creatine kinase testing in patients on statins. The investigation and management of metabolic myopathies. Please direct any questions regarding coding to the payer being billed. Metabolic myopathy an overview sciencedirect topics. 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.
Metabolic myopathies definition of metabolic myopathies. A diagnostic algorithm for metabolic myopathies springerlink. Prenatal diagnosis for known familial mutation s in atrisk pregnancies. 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. The degree of exercise intolerance in the metabolic myopathies varies greatly between disorders and even from one individual to the next within a disorder. 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. May 01, 2014 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.
It usually presents with episodic cramps, weakness or myoglobinuria after exertion or prolonged exercise. Pdf the investigation and management of metabolic myopathies. Serum activities of ckmm may be increased in a number of conditions, including after strenuous exercise, inflammatory myopathies, infectious myopathies, dystrophinopathies, rhabdomyolysis, medications, metabolic myopathies, malignant hyperthermia, endocrine myopathies, and channelopathies. Glycogen is the main source of energy during brief exercise, while free fatty acids are the most important source of fuel during prolonged exercise. Metabolic myopathies are a heterogeneous group of disorders characterized by mostly inherited defects of enzymatic pathways involved in muscle cell metabolism. 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. Mitochondrial myopathy with lactic acidosis genetic and. See overview of inherited disorders of glucose and glycogen metabolism and metabolic myopathies caused by disorders of lipid and purine metabolism and. The effects may be confined specifically to skeletal muscle, or may also be observed in other tissues with significant energy requirements such as the heart, liver, kidney, brain and retina kahler.
This chapter book comes from a respected multidisciplinary group of myologists who are affiliated with oxford university. The presentation of metabolic myopathy is variable. A metabolic myopathy has been described in a patient who received propofol 60 a. Patients may present with indolent myopathic features, exercise intolerance or recurrent rhabdomyolysis. Metabolic myopathies comprise a clinically and etiologically diverse group of disorders caused by defects in cellular energy metabolism, including the breakdown of carbohydrates and fatty acids to generate adenosine triphosphate, predominantly through mitochondrial oxidative phosphorylation. Myopathy is a disease of the muscle in which the muscle fibers do not function properly. Pdf metabolic myopathies mm are rare inherited primary muscle disorders. A normal emg, however, does not rule out a metabolic muscle disease. Accordingly, the three main categories of metabolic myopathies are glycogen. Metabolic myopathies are a group of genetic muscular diseases resulting from defective metabolism affecting primarily muscles.
Energy supplements to improve exercise tolerance in metabolic. Mitochondrial metabolic myopathy is another type that results from a lack of a particular enzyme normally present in the mitochondria, the energyproducing parts of cells. Tarnopolsky speculates that a rheumatologist may be most likely to encounter a patient with a metabolic myopathy as a referral from a family practice doctor for muscle weakness or for a high creatinine kinase ck level occurring with or without actual rhabdomyolysis. 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. Confirmation of a clinical diagnosis can help direct treatment and medical management. The three main categories of metabolic myopathy are 1 disorders of glycogenolysis and glycolysis, 2 disorders of mitochondrial function, and 3 disorders of lipid metabolism. What diet and exercise is best with metabolic myopathy. Patients with metabolic myopathies have underlying deficiencies of energy production in muscle due to a wide variety of defects. Myopathy the main symptoms of mitochondrial myopathy are muscle fatigue, weakness, and exercise intolerance. The genetic causes for rhabdomyolysis include metabolic myopathy, disorders of intramuscular calcium release, mitochondrial disorders and muscular dystrophies. Metabolic myopathies are genetic skele tal muscle disorders that impact en zymes and proteins involved in intermediary metabolism of glucose and free fatty. In some cases, the pathology extends to involve cardiac muscle fibers, resulting in a hypertrophic or dilated cardiomyopathy. Pdf metabolic myopathies comprise a clinically and etiologically diverse group of disorders caused by.
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