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McArdle's Disease (mcardle's + disease)
Selected AbstractsGlycogenosis type V or McArdle's diseaseDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 9 2003Neil Gordon MD FRCP HonFRCPCH First page of article [source] Phosphoglycerate kinase deficiency in two brothers with McArdle-like clinical symptomsEUROPEAN JOURNAL OF NEUROLOGY, Issue 1 2000J. Aasly Phosphoglycerate kinase (PGK) catalyses the transfer of the acylphosphate group of 1,3-diphosphoglycerate to ADP with formation of 3-phosphoglycerate and ATP in the terminal stage of the glycolytic pathway. Two young brothers are presented who both experienced muscle pain, cramps and stiffness shortly after beginning heavy exercise. After these episodes they noticed that the urine was dark brown, indicating rhabdomyolysis and myoglobinuria. The neurological examinations were without remarks. There was no lactate increase in the ischaemic forearm exercise test. Both had very low PGK levels in muscle, erythrocytes, leukocytes and fibroblasts. This is the first family with more than one affected case of PGK deficiency and exercise-induced stiffness, myalgia and rhabdomyolysis. The clinical manifestations may resemble myophosphorylase deficiency (McArdle's disease: glycogenosis Type V) and muscle phosphofructokinase deficiency (Tarui's disease: glycogenosis Type VII). PGK deficiency is inherited as an X-linked trait and may show other features such as mental retardation and/or haemolytic anaemia. [source] Impaired oxygen extraction in metabolic myopathies: Detection and quantification by near-infrared spectroscopyMUSCLE AND NERVE, Issue 4 2007Bruno Grassi MD Abstract Patients with mitochondrial myopathies (MM) or myophosphorylase deficiency (McArdle's disease, McA) show impaired capacity for O2 extraction, low maximal aerobic power, and reduced exercise tolerance. Non-invasive tools are needed to quantify the metabolic impairment. Six patients with MM, 6 with McA, 25 with symptoms of metabolic myopathy but negative biopsy (patient-controls, P-CTRL) and 20 controls (CTRL) underwent an incremental cycloergometric test. Pulmonary O2 uptake (V,O2) and vastus lateralis oxygenation indices (by near-infrared spectroscopy, NIRS) were determined. Concentration changes of deoxygenated hemoglobin and myoglobin (,[deoxy(Hb + Mb)]) were considered an index of O2 extraction. ,[deoxy(Hb + Mb)] peak (percent limb ischemia) was lower in MM (25.3 ± 12.0%) and McA (18.7 ± 7.3) than in P-CTRL (62.4 ± 3.9) and CTRL (71.3 ± 3.9) subjects. V,O2 peak and ,[deoxy(Hb + Mb)] peak were linearly related (r2 = 0.83). In these patients, NIRS is a tool to detect and quantify non-invasively the metabolic impairment, which may be useful in the follow-up of patients and in the assessment of therapies and interventions. Muscle Nerve, 2006 [source] Exercise tolerance and daily life in McArdle's diseaseMUSCLE AND NERVE, Issue 5 2005Karen Ollivier MSc Abstract McArdle's disease is a common disorder of muscle metabolism and is due to myophosphorylase deficiency. The major complaint of patients with this disease is effort intolerance. Although the clinical features of affected patients are well known, their daily lifestyle is not well documented. The main objective of this work was to assess their mean daily energy expenditure (DEE) and compare it with control subjects. Thirty patients and 87 control subjects completed a questionnaire. A 3-day self-record of daily physical activities was used to estimate the mean DEE for patients and control subjects. A separate section of the questionnaire was used to assess patients' clinical features and daily lifestyle. The DEE of patients (44.1 ± 6.9 kcal/kg) was not significantly different from control subjects (44.5 ± 5.6 kcal/kg). Half of the patients with McArdle's disease performed a daily physical leisure activity as sport, sometimes at a high level (17%). Despite large individual variation, physical abilities and patients' symptoms were negatively correlated. Physical leisure activity significantly decreased the sensation of muscle pain (P < 0.03). These findings show that patients with McArdle's disease do not have a strictly sedentary lifestyle. Moreover, physical exercise appears to have positive effects on the main clinical features, such as effort intolerance. Thus, regular, moderate physical activity may be beneficial in McArdle's disease. Muscle Nerve, 2005 [source] Breakdown of adenine nucleotide pool in fatiguing skeletal muscle in McArdle's disease: A noninvasive 31P-MRS and EMG studyMUSCLE AND NERVE, Issue 6 2003Jochen Zange PhD Abstract Energy metabolism and electrical muscle activity were studied in the calf muscles of 19 patients with proven McArdle's disease and in 25 healthy subjects. Phosphorus magnetic resonance spectroscopy and surface electromyography (S-EMG) were performed during two isometric muscle contractions of 3 min at 30% maximum voluntary contraction, one performed during normal perfusion and the other during applied ischemia. After about 1 min of ischemic muscle contraction in diseased muscle a significant acceleration in phosphocreatine breakdown was observed, along with a significant decrease in adenosine triphosphate. During both contractions the absence of glycolysis was shown by a significant alkalinization. Furthermore, in patients we observed a greater increase in the S-EMG amplitude than in control subjects. We conclude that early on during moderate exercise, a small number of muscle fibers reach metabolic depletion, indicated by a reduction in the adenine nucleotide pool. An increasing number of motor units, which are still in a high-energy state, are continuously recruited to compensate for muscle fatigue. This functional compartmentation may contribute to the pathophysiology of exercise intolerance in McArdle's disease. Muscle Nerve 27: 728,736, 2003 [source] A diagnostic cycle test for McArdle's diseaseANNALS OF NEUROLOGY, Issue 4 2003John Vissing MD We investigated whether the second wind phenomenon (ie, a decrease in heart rate and perceived exertion during exercise) is pathognomonic for McArdle's disease. Twenty-four patients with McArdle's disease, 17 healthy subjects, and 25 patients with other inborn errors of muscle metabolism cycled a constant workload for 15 minutes. In McArdle's disease patients, heart rate consistently decreased by 35 ± 3 beats per minute from the 7th to the 15th minute of exercise, whereas heart rate increased progressively with exercise in all 42 control subjects. The findings indicate that cycling at a moderate, constant workload provides a specific, sensitive, and simple diagnostic test for McArdle's disease. Ann Neurol 2003;54:539-542 [source] | ||||||||||