Clinical factors associated with invasive testing and imaging in patients with complex febrile seizures

Complex febrile seizures (CFSs) are a common diagnosis in the pediatric emergency department (PED). Although multiple studies have shown a low likelihood of intracranial infections and abnormal neuroimaging findings among those who present with CFS, the absence of a consensus recommendation and the diversity of CFS presentations (ie, multiple seizures, prolonged seizure, focal seizure) often drive physicians to do a more extensive workup than needed. Few studies examine the factors that influence providers to pursue invasive testing and emergent neuroimaging.

The objective of this study was to determine the clinical factors associated with a more extensive workup in a cohort of patients who present to the PED with CFSs.

Patient visits to a tertiary care PED with an International Classification of Diseases, Ninth Revision, diagnosis of CFS were reviewed from April 2009 to November 2011. Patients included were 6 months to 6 years of age. Complex febrile seizures were defined as febrile seizures lasting 15 minutes or longer, more than 1 seizure in 24 hours, and/or a focal seizure. Charts were reviewed for demographics, clinical parameters (duration of fever, history of febrile seizure, focality of seizure, antibiotic use before PED, and immunization status), PED management (antiepileptic drugs given in the PED or by Emergency Medical Services, empiric antibiotics given in the PED, laboratory testing, lumbar puncture, or computed tomography [CT] scan), and results (cultures, laboratories, or imaging). A logistic regression model was created to determine which clinical parameters were associated with diagnostic testing.

One hundred ninety patients were diagnosed with CFS and met study criteria. Clinical management in the PED included a lumbar puncture in 37%, blood cultures in 88%, urine cultures in 47%, and a head CT scan in 28%. There were no positive cerebral spinal fluid or blood cultures in this cohort. Of the 90 patients, 4 (4.4%) with urine cultures had a urinary tract infection. Of the 53 patients who had head CT imaging, there were no significant findings that guided therapy. The only factor associated with having a lumbar puncture performed was whether empiric antibiotics were used (odds ratio [OR], 2.96; 95% confidence interval [CI], 1.28-6.8). History of a febrile seizure was associated with lower odds of a lumbar puncture (OR, 0.29; 95% CI, 0.12-0.69). In addition, higher age category was also associated with lower odds of a lumbar puncture (OR, 0.53; 95% CI, 0.31-0.91). Those who received an antiepileptic drug had a higher odds of getting a head CT (OR, 3.5; 95% CI, 1.5-8.6). Furthermore, patients presenting with a focal seizure also had higher odds of getting a head CT (OR, 4.89; 95% CI, 1.41-16.9).

Despite the low utility of associated findings, there are important clinical parameters that are associated with obtaining a lumbar puncture or a head CT as part of the diagnostic workup. National practice parameters to guide evaluation for CFSs in the acute setting are warranted to reduce the amount of invasive testing and imaging.