Figure 4: Suggested diagnostic approach to muscle weakness in the Rheumatology setting. *Present in physical examination. If relevant family history is present, consider first an inherited disease. Metabolic myopathies include: glycogenosis, mitochondrial, and lipid storage myopathies.^‡Systemic connective tissues diseases.^‡Depending on the context, relevant different diagnosis may include muscular dystrophies, motor neuron disease, infectious myopathies, and toxic myopathies