Respiratory failure is a common complication of acute neuromuscular disease and high cervical cord lesions and should be monitored by measuring forced vital capacity and respiratory rate. Urgent imaging is mandatory if there is any clinical suspicion of spinal cord disease. Treatment of Guillain-Barré syndrome with plasma exchange or intravenous immunoglobulin (IVIg) speeds up the rate of recovery. Treatment of patients in a myasthenic crisis with plasma exchange or IVIg often results in significant short-term improvement. A drug side effect or metabolic disturbance should be considered in a patient presenting acutely with proximal weakness, myalgia and high creatine kinase.