Tips for diagnosing metabolic myopathies page 2 of 4 the. Metabolic myopathies muscular dystrophy association. 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. The free achilles reflex in hypothyroidism and hyperthyroidism. Metabolic myopathies definition of metabolic myopathies. Energy supplements to improve exercise tolerance in metabolic. 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. Not all people with a metabolic myopathy experience the same symptoms. Clinically, a variety of neuromuscular presentations are seen at different ages of life. Myopathy the main symptoms of mitochondrial myopathy are muscle fatigue, weakness, and exercise intolerance. 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. Myopathy is a disease of the muscle in which the muscle fibers do not function properly. The second has onset in adulthood and is called late.
While many people are unaware that this condition even exists, it is common among those who abuse alcohol. Mitochondrial myopathy with lactic acidosis genetic and. Metabolic myopathies american college of rheumatology. This meaning implies that the primary defect is within the muscle, as opposed to the nerves neuropathies or neurogenic disorders or elsewhere e. A diagnostic algorithm for metabolic myopathies ncbi. Metabolic myopathy an overview sciencedirect topics.
Metabolic myopathy definition of metabolic myopathy by. Metabolic myopathies are rare genetic diseases that cause muscle problems. Here you can read posts from all over the web from people who wrote about metabolic myopathy and rhabdomyolysis, and check the relations between metabolic myopathy and rhabdomyolysis. You may require intravenous fluids to avoid kidney failure. Apart from the manual muscle testing for muscle strength, the examination of. 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 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. 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. The genedx metabolic myopathy panel includes genes causing glycogen storage disorders, fatty acid oxidation disorders and other wellestablished metabolic myopathies.
Pdf the investigation and management of metabolic myopathies. 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. Treatments include changes in physical activity and diet, aerobic and anaerobic resistance exercise training, and the use of various vitamins and supplements. Education of the patient regarding intervention is critical for understanding the problems associated with metabolic diseases of musculature. Muscle disorders arise from abnormalities that affect the muscles structure or metabolism, and have a variety of causes. In some cases, the pathology extends to involve cardiac muscle fibers, resulting in a hypertrophic or dilated cardiomyopathy. This article cites 14 articles, 2 of which you can access for free at. Pdf metabolic myopathies mm are rare inherited primary muscle disorders. When benign entities are ruled out and metabolic myopathy is suspected, the first diagnostic step is to perform an electromyogram. Free fatty acids are first converted to acylcoenzyme a coa compounds by the action of fatty acylcoa synthetases. Test metabolic myopathies, rhabdomyolysis and exercise. This topic will briefly describe fatty acid oxidation disorders faods, which are inborn errors of metabolism resulting in failure of.
Detailed descriptions of the different disorders are presented separately. A normal emg, however, does not rule out a metabolic muscle disease. 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. However, recurrent rhabdomyolysis is often genetic in nature. Accordingly, the three main categories of metabolic myopathies are glycogen. Metabolic myopathies article about metabolic myopathies. Other metabolic myopathies with massive lipid storage and weakness are. Please direct any questions regarding coding to the payer being billed. 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. The genetic causes for rhabdomyolysis include metabolic myopathy, disorders of intramuscular calcium release, mitochondrial disorders and muscular dystrophies. Metabolic myopathies are a group of genetic muscular diseases resulting from defective metabolism affecting primarily muscles. Commonly used icd10 code s when ordering the metabolic myopathy and rhabdomyolysis panel.
Statinassociated myopathy cardiology jama jama network. 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. Metabolic myopathies article about metabolic myopathies by. 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. Metabolic myopathies stony brook school of medicine. P royal free and royal national orthopaedic hospitals, and institute of neurology, london. Tips for diagnosing metabolic myopathies page 2 of 4. With appropriate activity changes, regular aerobic exercise, diet and use of supplements, the symptoms often can be controlled. Pdf metabolic myopathies comprise a clinically and etiologically diverse group of disorders caused by. It usually presents with episodic cramps, weakness or myoglobinuria after exertion or prolonged exercise. This chapter book comes from a respected multidisciplinary group of myologists who are affiliated with oxford university. 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 main sources of adenosine triphosphate atp in cells are glycogen, glucose, and free fatty acids.
During administration of propofol 3 mgkghour, a 40yearold man developed a fever of 41 c, resistant to diclofenac and physical cooling. See overview of inherited disorders of glucose and glycogen metabolism and metabolic myopathies caused by disorders of lipid and purine metabolism and. Mitochondrial myopathy fact sheet national institute of. The severity of any of these symptoms varies greatly from one person to the next, even in the same family. Patients with metabolic myopathies have underlying deficiencies of energy production in muscle due to a wide variety of defects. 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. 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. Test information sheet 207 perry parkway, gaithersburg, md 20877 p. Patients may present with indolent myopathic features, exercise intolerance or recurrent rhabdomyolysis. 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 differential diagnosis of metabolic myopathy includes a long list of inherited disorders affecting the provision of energy for skeletal muscle metabolism. These metabolic diseases cause problems with the energy levels associated with activity.
Energy supplements to improve exercise tolerance in. Metabolic myopathies are a heterogeneous group of disorders characterized by mostly inherited defects of enzymatic pathways involved in muscle cell metabolism. 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. These include defects in lipid, glycogen, glucose, adenine nucleotide, and mitochondrial metabolism. Metabolic myopathies presenting with exercise intolerance, cramps, and myoglobinuria cramps and myalgia may occur after brief exercise or after prolonged physical activity. A diagnostic algorithm for metabolic myopathies springerlink. 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. Metabolic myopathies are genetic diseases, usually inherited, that affect the bodys muscles. Myopathy refers to a clinical disorder of the skeletal muscles. Metabolic neuropathies and myopathies sciencedirect.
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. Metabolic myopathies are genetic skele tal muscle disorders that impact en zymes and proteins involved in intermediary metabolism of glucose and free fatty. Cpt coding is the sole responsibility of the billing party. Common symptoms include muscle weakness, cramps, stiffness, and tetany. Cardiopulmonary exercise testing provides valuable insights into the integrated functioning of the cardiovascular, ventilatory, and skeletal muscle systems.
A metabolic myopathy has been described in a patient who received propofol 60 a. Diagnostic delays are common and clinicians need a high index of suspicion to recognise and differentiate metabolic myopathies from other conditions that present in. Genetic testing for metabolic myopathy and rhabdomyolysis. Abnormalities of muscle cell structure and metabolism lead to various patterns of weakness and dysfunction.
Metabolic myopathy symptoms vary among individuals. The next step would be to perform an ischemic exercise test. 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. 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. Some people with a metabolic myopathy muscle disease develop weakness. The cpt codes provided are based on ama guidelines and are for informational purposes only. This condition can cause severe kidney damage, and should be dealt with as an emergency see below. The goal of treatment is to control symptoms and minimize progression of muscle weakness. Prenatal diagnosis for known familial mutation s in atrisk pregnancies. 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.
The presentation of metabolic myopathy is variable. The prevalence and annual incidence of nam are not known but the disorder is very rare. A clinical approach to muscle diseases university of chicago. Metabolic myopathies treatments vary according to the patients particular myopathy.
His urine darkened and his urinary output fell and eventually ceased completely. 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. 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. 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. Mitochondrial dysfunction has been implicated as a central mechanism in the metabolic myopathy accompanying critical limb ischemia cli. Metabolic myopathies are a diverse group of rare genetic disorders and their associated muscle symptoms may be subtle. 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. Annals of the american thoracic society ats journals. 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. Metabolic myopathies mm are rare inherited primary muscle disorders that are mainly due to abnormalities of muscle energy metabolism resulting in skeletal muscle dysfunction. Listing a study does not mean it has been evaluated by the u. Metabolic refers to chemical reactions that provide energy, nutrients and substances necessary for health and growth.
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. However, some patients of metabolic myopathies present with fixed or slowly progressive wecikness. 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. The investigation and management of metabolic myopathies. Metabolic myopathies have varying levels of symptoms, being most severe when developed during infancy. 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. Confirmation of a clinical diagnosis can help direct treatment and medical management. What diet and exercise is best with metabolic myopathy. Glycogen is the main source of energy during brief exercise, while free fatty acids are the most important source of fuel during prolonged exercise. 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 by classification can be primary or secondary 5, 6. Because these diseases are rare, many people with metabolic disorders of muscle have to spend some time figuring out what is causing their muscle weakness, myoglobinuria or other symptoms. 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.