Dados do Trabalho

Título

Pseudometabolic symptoms in congenital and dystrophic myopathies

Resumo

Introduction: Metabolic myopathies comprise a diverse group of muscle disorders that result in impaired energy production due to defects in glycogen, lipid, or mitochondrial metabolism. Most of the patients have exercise intolerance, pain, muscle cramp, myoglobinuria, variation in CK levels, with or without progressive muscle weakness. Structural myopathies can also present with symptoms triggered by exercise, and thus mimic the metabolic myopathies, being referred to as the pseudometabolic myopathies. To date, there is only few articles about pseudometabolic symptoms in structural myopathies, and the actual frequency and genetic correlations is not yet well established in large cohorts.
Objective: identify and genetically characterize patients with pseudometabolic symptoms and to identify the frequency of this symptoms amongst patients with RYR1-myopathies
Methods: Observational study conducted from 2020 to April 2022 at HCFMUSP. Among 1310 patients evaluated, 30 (2,3%) had symptoms resembling metabolic myopathies. Inclusion criteria was the presence of at least one of the following four typical metabolic symptoms, being the most important complaint: (1) exercise intolerance, (2) muscle pain, (3) muscle cramps, (4) myoglobinuria, with or without muscle weakness. Exclusion criteria: patients whose most important complaint/symptom was weakness, patients with inconclusive genetic test or genetic test confirming a metabolic myopathy.
Results: From 30 selected patients, twelve (40%) had genetic confirmation of structural myopathy. Four patients had RYR1-myopathy (33,3%), three patients had Dystrophinopathy (25%), two siblings had Gamma-sarcoglycanopathy (16,6%), and the other three patients had FKRP, ANO5 and COL6-related myopathy, respectively. All patients had exercise intolerance and muscle pain, five (41,7%) patients had muscle cramps and four (33,3%) had myoglobinuria
Conclusion: Our cohort highlight the need to consider structural myopathies in the differential diagnosis of patients who present with complaints suggestive of a metabolic myopathy, particularly when metabolic studies have been unrevealing. It also highlight the need to consider not only genes of muscular dystrophy, but genes of structural myopathy, specially RYR1-related myopathy.

Palavras Chave

pseudometabolic, myopathy, muscle pain