from CNS infections, 119 common causes of, 118 t from CSF shunts, 120 definition, 117 differential diagnosis, 117 , 119 primary central nervous system disorders, 119 –120 systemic abnormalities, 120 –121 etiology of acute-onset, 118 t evaluation and decision, 121 –126 , 122 f abnormal breathing patterns, 123 of airway, breathing, and circulatory, 123 –124 airway, breathing, and circulatory, treatment of, 123 –124 blood gas analysis, 125 CSF analysis, 125 errors in, 126 t fever, 125 focal neurologic deficits, 125 head trauma, history of, 124 history and physical examination, 121 –123 increased ICP, 124 –125 laboratory and radiologic studies, 123 limb movement and postural changes, 123 metabolic abnormalities, 125 –126 neurologic examination and scoring, 123 ocular signs, 123 renal and hepatic functions, 126 seizures, history of, 124 toxic ingestions, history of, 124 –125 vital sign abnormalities, 123 –124 hypertension in, 124 hypoxic, 120 life-threatening causes of, 118 t metabolic alterations and, 121 pathophysiology, 117 from seizure activity, 119 thermoregulation disorders and, 120 from toxic ingestions, 120 –121