Efficacy of a "standard" seizure workup in the emergency department

In many institutions it is the "standard of care" to obtain serum chemistries and anticonvulsant levels as part of the emergency department evaluation of seizure patients. To determine the efficacy of such a workup in the ED, 163 seizure patients presenting to an inner-city teaching hospital were studied in a standardized, prospective manner. After the clinical examination all patients had CBC, serum electrolyte, BUN, creatinine, glucose, calcium, magnesium, and if indicated, anticonvulsant drug level determinations performed. Any patient presenting with a first-time seizure (in patients greater than 6 years old), recent head trauma, focal neurologic deficit, or focal seizure activity had cranial computerized tomography (CCT). After obtaining historical and physical examination and before receiving laboratory results, as many as five likely etiologies were listed and assigned probability ratings. After review of the laboratory data (and CCT scan, if obtained), final etiologies again were listed and assigned percentages of likelihood. Significant abnormalities (ie, those that changed diagnosis, management, or disposition) were found in 104 patients; 96 had subtherapeutic anticonvulsant levels, five had abnormal CCT scans, two had hypoglycemia, and one had hyperglycemia as the cause of seizure. The clinical examination successfully predicted those abnormalities in all but two cases (one each of hyperglycemia and subdural hematoma). We contend tha routine serum chemistries in patients presenting to the ED are of extremely low yield, and that the clinical examination can predict accurately the need to obtain these studies. CCT scanning is useful in selected patients, and was found to be abnormal in five of 19 (25%) patients.(ABSTRACT TRUNCATED AT 250 WORDS)