ABSTRACT
Disorders of muscle (myopathies) present with floppiness, delayed motor milestones, abnormal gait, clumsiness or progressive muscle weakness. The majority of myopathies are inherited, and all are uncommon. Dystrophies are characterized by degeneration of muscle fibres. Myotonia is the failure of muscle relaxation after contraction. Myotonia may occur as an abnormal response to muscle relaxant agents (e.g. scoline) during anaesthesia resulting in total opisthotonus. There is an increased risk of this reaction in children with muscle disease. Disorders of the neuromuscular junction include myasthenia gravis and botulism.
