Enfermedad de McArdle en cuatro pacientes pediátricos. Algoritmo diagnóstico ante una intolerancia al ejercicio / McArdle’s disease in four pediatric patients. Diagnostic algorithm for exercise intolerance

Introducción: La enfermedad de McArdle está causada por una mutación en el gen PYGM y déficit de miofosforilasa muscular, resultando alterada la liberación de glucosa-1-P a partir del glucógeno. Suele manifestarse en la infancia con cansancio precoz y excesivo, mialgias, calambres y contracturas o rabdomiólisis, aunque no suele diagnosticarse hasta la etapa adulta. La creatincinasa se incrementa durante el ejercicio. Se presentan cuatro pacientes pediátricos, se resume la fisiopatología y se propone un algoritmo diagnóstico. Pacientes y métodos: Pacientes con edades entre 6 y 14 años. Se describe la anamnesis, la exploración física, la bioquímica, el electromiograma, el test de isquemia y el estudio genético, con biopsia muscular a un solo paciente. Se elabora un algoritmo a partir del test de isquemia. Resultados: En los tres varones, las mialgias aparecieron tras finalizar cada sesión deportiva, con un fenómeno second wind en un caso. Se apreció un test de isquemia sin elevación del lactato y marcada elevación del amonio en todos, una biopsia muscular con depósitos de glucógeno y ausencia de miofosforilasa, y gen PYGM con mutaciones homocigotas en todos. El tratamiento dietético les atenuó la sintomatología durante los ejercicios aeróbicos. Conclusiones: El test de isquemia resultó muy útil para demostrar una disfunción en la glucólisis anaeróbica. Se destaca que el suplemento oral de glucosa es muy útil para la enfermedad de McArdle, pero está contraindicado en los seis defectos de la glucólisis anaeróbica. El algoritmo también permite orientar el defecto de 20 miopatías metabólicas o estructurales, que se resumen.(AU)

INTRODUCTION: McArdle’s disease is caused by a mutation in the PYGM gene, causing a muscle myophosphorylase deficiency, altering the release of glucose-1-P from glycogen. It usually manifests itself in childhood with early and excessive tiredness, myalgias, cramps and contractures or rhabdomyolysis, although it is not usually diagnosed until adulthood. Creatine kinase increases sharply during exercise. Four pediatric patients are presented, the pathophysiology is summarized, and a diagnostic algorithm is proposed. PATIENTS AND METHODS: Ages between 6 and 14 years, the anamnesis, physical examination, biochemistry, elec­tro­myogram, ischemia test and genetic study are described. Muscle biopsy in a single patient. The algorithm was developed from the ischemia test. RESULTS: In the three men, myalgias appeared after finishing each sports session. Phenomenon ‘second wind’ in one case. Ischemia test without lactate elevation and marked ammonia elevation in all. Only one muscle biopsy with glycogen deposits and absence of myophosphorylase. PYGM gene with homozygous mutations in all. Dietary treatment attenuated their symptoms during aerobic exercises. CONCLUSIONS:The ischemia test was very useful to demonstrate a dysfunction in anaerobic glycolysis. It is worth noting that oral glucose supplementation is very useful in McArdle disease, but is contraindicated in all six defects of anaerobic glycolysis. The algorithm also allows targeting the defect of 20 metabolic or structural myopathies, which are summarized.(AU)

Rhabdomyolysis in a patient with McArdle's disease. / Rabdomiólisis en un paciente con enfermedad de McArdle.

INTRODUCTION: McArdle's disease or glycogenosis type V is a rare disease due to deficiency of muscle myophosphorylase leading to inability to degrade glycogen at this level. Patients have fatigue, pain, and cramps on a regular basis. In addition, after intense exercise or stressful situation, they are exposed to cellular lysis. This can occur in the form of rhabdomyolysis and myoglobinuria, a potentially serious clinical syndrome if not treated quickly. CASE EVALUATION: We present the care plan of a 38-year-old man with McArdle's disease and secondary rhabdomyolysis on physical exercise, which required attention in the Emergency Department for 24 hours, as well as his subsequent admission to the ward. A nursing evaluation was performed following the care model of Virginia Henderson. DIAGNOSIS: Priority was given to nurse diagnoses: (00016) deterioration of urinary elimination, (00092) activity intolerance, (00093) fatigue and (00132) acute pain; and potential complication: risk of acute renal failure. PLANNING: The Care Plan is developed following the NANDA-NIC-NOC methodology, with special attention to alterations in the elimination and musculoskeletal system. The diuresis is monitored. Fluid replenishment is performed, and analgesic medication is given. DISCUSSION: There is little literature on the nursing care of patients with McArdle's disease, which has limited the comparison of our results with those of other authors. However, given the good response of the subject through fluid replacement, optimal pain control and rest, they made a rapid recovery.

Unilateral pattern of macular dystrophy and associated systemic pathology. / Distrofia macular en patrón unilateral y enfermedad sistémica asociada.

Retinal pattern dystrophies are a heterogeneous group of generally bilateral and symmetrical maculopathies that, curiously, can be associated with different systemic diseases. This article describes a patient with unilateral pattern dystrophies, as well as associated McArdle disease and idiopathic pulmonary fibrosis.

McArdle's disease: Diagnostic approach after clinical symptoms of vigorous exercise intolerance in a snowboarder in Alpes / Enfermedad de McArdle: enfoque diagnóstico después de los síntomas clínicos de intolerancia al ejercicio vigoroso en un snowboarder en los Alpes

ABSTRACT McArdle's disease (glycogen storage disease type V) is an energy-dependent disorder of skeletal muscle caused by a deficiency of myophosphorylase, an important enzyme of carbohydrate metabolism that converts glycogen to glucose-1-phosphate. A 46 year-old man was sent to the rheumatology outpatient department with a 3-year history of severe exercise-induced cramps and myalgias. The episodes began when he worked in France and used to practice ski and snowboard in the Alps Mountain, with exercise intolerance, muscle cramps, and myoglobinuria. The laboratory results showed elevated serum creatine kinase levels (~15,000 U/L), and the biopsy of the deltoid muscle revealed glycogen subsarcolemmal vacuoles and absence of myophosphorylase enzymatic activity. This clinical case emphasises the importance of taking into account this metabolic disorder when faced with a patient with exercise intolerance and cramps, especially after vigorous/anaerobic exercise and elevated levels of CK activity. It is fundamental to explain the aetiology of the patient symptoms in order to improve quality of life and avoid unnecessary complications.

R E S U M E N La enfermedad de McArdle (enfermedad de almacenamiento de glucógeno tipo V) es un trastorno del músculo esquelético dependiente de la energía causado por una deficiencia de miofosforilasa, una importante enzima del metabolismo de los hidratos de carbono que convierte el glucógeno en glucosa-1-fosfato. Un hombre de 46 años de edad fue enviado al departamento de reumatología para pacientes ambulatorios con un historial de 3 años de calambres y mialgias severos inducidos por el ejercicio. Los episodios comenzaron cuando trabajó en Francia y solía practicar esquí y snowboard en el macizo de los Alpes, con intolerancia al ejercicio, calambres musculares y mioglobinuria. Las pruebas de laboratorio mostraron niveles elevados de creatina quinasa sérica (~ 15.000 U/l) y la biopsia del músculo deltoides reveló vacuolas subsarcolémicas de glucógeno y ausencia de actividad enzimática de la miofosforilasa. Nuestro caso clínico enfatiza la importancia de pensar en este trastorno metabólico cuando tenemos un paciente con intolerancia al ejercicio y calambres, especialmente después de un ejercicio vigoroso/anaeróbico y niveles elevados de actividad CK. Es fundamental explicar la etiología de los síntomas del paciente para mejorar la calidad de vida y evitar complicaciones innecesarias.

Treatment of a high cardiovascular risk patient with McArdle's disease with PCSK9 inhibitors. / Tratamiento de un varón con enfermedad de McArdle y muy alto riesgo cardiovascular con inhibidores de PCSK9.

A 60-year-old male with familial combined hyperlipidemia, ischemic heart disease and type 2 diabetes. Since childhood, intolerance to intense exercise. The patient was diagnosed of McArdle's disease after an episode of rhabdomyolysis associated with statins as treatment after a myocardial infarction. Since then, he had been treated with diet, fibrates and ezetimibe with good tolerance, despite this, LDL cholesterol (cLDL) remained >180mg/dl. He started to be treated with alirocumab 150mg/sc every 14 days, with excellent clinical response and a decrease in cLDL to 15mg/dl. Our case shows that PCSK9 inhibitors are effective and safe in patients with muscle diseases who have statin contraindication, and they are a good therapeutic tool for these patients.

Falso diagnóstico de caminador en puntillas de pies; sospecha de enfermedad de McArdle / False diagnosis of idiopathic toe walker (ITW); suspicion of McArdle disease

El caminar en puntillas de los pies es una condición patológica en la cual las personas caminan en las puntas de los pies sin presentar ninguna condición ortopédica o neurológica. Se ha encontrado que los caminadores en puntillas de pies presentan diferentes características en los músculos gastrocnemios, el tendón de Aquiles y en el pie. La enfermedad de McArdle es una condición médica autosómica recesiva caracterizada por la baja tolerancia a la actividad física, la atrofia de los músculos de la cintura escapular y, en algunos casos, con episodios de mioglobinuria después de realizar ejercicio vigoroso. Este reporte explica el caso de una paciente diagnosticada como caminadora idiopática en puntillas de pies, pero con los signos clínicos de la enfermedad de McArdle. Este reporte busca comentar las características clínicas que diferencian a los caminadores idiopáticos en puntillas de pies y a los pacientes con la enfermedad de McArdle.

Idiopathic Toe Walking is a pathological condition in which the gait takes place on the tip toes. ITW is diagnosed on the absent of any orthopedic or neurological condition. The physiological characteristics of the gastrocnemios muscles, the Achilles tendon, and the foot of Idiopathic toe walkers are different to individuals that are not affected by toe walking. McArdle disease is a medical autosomal-recessive condition, characterised by low exercise tolerance, muscular atrophy at the shoulder girdle, and in some cases myoglobinuria episodes have been reported after vigorous physical activities. In this case study we present a patient diagnosed as Idiopathic toe walker, but with the clinical characteristics of McArdle diseases. The aim of this case study is to present the clinical characteristics that differentiate these two pathological conditions.

McArdle disease: 2 case reports. / Enfermedad de McArdle: presentación de 2 casos clínicos.

A high serum level of creatine kinase (CK) is a common reason for referring to medical specialities. Myopathies are one of the causes of elevated levels of CK. McArdle disease is the most common disorder of skeletal muscle carbohydrate metabolism. The cases are presented on 2 patients who were referred to our medical consultation to study the cause of their increased CK levels: a 72 year old asymptomatic man with high levels of CK detected by chance in a routine analysis, and a 30 year old woman with very few symptoms, apart from slight muscle pain and tiredness. Electromyography was normal in both patients. There was null activity of myophosphorylase in muscle biopsy of both cases, so a diagnosis of McArdle disease was made.

[McArdle disease or glycogen storage disease type v: Should it affect anaesthetic management?]. / Enfermedad de McArdle o glucogenosis tipo v: ¿influye en el manejo anestésico?

McArdle disease is a metabolic myopathy that can may lead to severe perioperative problems. A case is reported of a woman with a history of McArdle disease, who was scheduled for a mastectomy. An understanding of the physiology and pathology, and the application of appropriate preventive measures can avoid complications. A overview of the complications and the management are described.