To determine whether a baby has muscle weakness can be based on relevant clinical manifestations, physical examination, laboratory tests, etc. It is recommended that professional judgment be made after timely consultation. 1. Clinical manifestations: symptoms of pediatric muscle weakness may include head and face muscle weakness, such as drooping eyelids, difficulty or inability to tilt the head, low facial expression, difficulty in swallowing, choking on drinking water, etc.; limb muscle weakness, such as unsteady holding, inability to lift the wrist, difficulty in standing, slow walking, easy to fall, gait abnormality, etc.; trunk muscle weakness, such as lumbar spine anteriorly protruding, duck step when standing, etc. 2. Physical examination: i.e. vital signs examination, muscle-related examination, neurological examination, etc., to determine whether there is muscle weakness, muscle atrophy, etc., and to look for the possible causes of the disease. 3. Laboratory tests: such as serum muscle enzyme test, immune-related antibody test, blood gas analysis, electrolyte test, vitamin level test, toxicology screening, metabolic function test, gene test, cerebrospinal fluid test, etc., which can determine whether there is a related etiology leading to myasthenia gravis. If your baby is not feeling well, it is recommended to go to the hospital for early and regular treatment.