Acute non-traumatic weakness may be life threatening if it involves the respiratory muscles or is associated with autonomic dysfunction. Most patients presenting with acute muscle weakness have a worsening neurological disorder that requires a rapid, systematic evaluation, and detailed neurological exam to localize the disorder. Urgent laboratory tests and neuroimaging are needed in many patients to make the diagnosis. Because acute weakness is a common presenting sign of neurological emergencies, it was chosen as an Emergency Neurological Life Support protocol. Causes of acute non-traumatic weakness are discussed by both presenting clinical signs and anatomical location. For each diagnosis, key features of the history, examination, investigations, and treatment are outlined in the included tables.
Keywords: Acute weakness; Neuromuscular weakness; Respiratory failure.