LPs in Afebrile Infants with First Time Seizures

posted by L. Staple
Recently, I have seen a lot of young infants with new-onset afebrile seizures.  On a shift last week, a few providers began discussing the need to do a full septic workup for all of these patients, hence my literature search on the topic.  I found an article by our very own neurologists at CNMC in the Journal of Pediatrics from 2008 (attached with citation below).  

While I recognize the evidence isn't stellar, it's the best I could find.  I figured it would prompt an interesting practice management discussion among our ED providers.

Lateef TM, Tsuchida TN, Chang T, Johnson J, Gaillard WD and Nelson KB.  Diagnostic value of lumbar puncture in afebrile infants with suspected new-onset seizures.  Journal of Pediatrics.  2008; 153: 140-142.

Here are the highlights:
- There are no established guidelines addressing the need to LP afebrile infants < 6 months with new-onset seizure; however, the American Academy of Neurology recommends LP for infants < 6 months
- Of the 141 patients 1-6 months old admitted for 1st time seizure from October 2000-February 2006, 76 (54%) had an LP
- Of the 76 patients that had an LP, 17 (22%) had abnormal results (increased WBCs or protein)
- NO infant with abnormal CSF results initially had culture or PCR positive results for bacterial meningitis or HSV encephalitis respectively
- Frequency of abnormal CSF results decreased as the infants age increased
- NO relationship between abnormal CSF results and diagnosis of seizure
- Convulsions, in addition to tumors, demyelinating disease, metabolic disorders and traumatic LPs, can cause mild CSF pleocytosis and hyperproteinemia
- Observation for 24 hours without an LP may be optimal

While I know this study has many limitations (i.e. small sample size, no correlation data), it made me think twice about having to do LPs on all of these patients.  What do you think?