Sympathetic innervation, 182 Symphyseal, 1109 Symptomatic seizure, 881 Synchronous cardioversion, 58 Syncope, 882 autonomic, 518 cardiac, 518 –520 causes, 519 t clinical evaluation, 521 –523 ambulatory ECG (Holter) monitoring, 523 cardiovascular testing, 523 diagnostic approach, 521 f echocardiography, 523 electrocardiogram (ECG), 522 –523 , 523 t exercise stress testing, 523 head-upright tilt table test (HUTT), 523 neuroimaging, 523 sequence of events, 521 –522 conditions that mimic syncope, 520 –521 definition, 518 drug induced, 521 epileptic seizure and, 520 orthostatic hypotension and, 520 psychogenic causes of, 520 treatment, 523 –524 conditions that require hospitalization, 524 t Syndrome of Inappropriate Antidiuretic Hormone secretion, 670 –671 Synthetic Drug Abuse Prevention Act of 2012, 1074 , 1079 Syphilis, 312 , 468 Systemic antimicrobial therapy, 1342 Systemic corticosteroids, inner ear injury, 1115 Systemic infectious emergencies, 804 Systemic inflammatory response syndrome (SIRS), 75 , 196 , 500 Systemic juvenile idiopathic arthritis, 997 , 1012 –1013 Systemic lupus erythematosus (SLE), 120 , 190 , 235 , 302 , 402 , 406 , 449 , 990 –999 clinical assessment, 994 –995