Is routine serum biochemistry helpful in the management of a child with unprovoked seizure?

Date First Published:
July 27, 2005
Last Updated:
September 16, 2005
Report by:
Anas Olabi, Consultant Paediatrician (Furness General Hospital)
Search checked by:
Krasimir Atanasov, Furness General Hospital
Three-Part Question:
In [a child who is neurologically healthy with an episode of unprovoked seizure] is [routine serum biochemistry helpful] at [guiding the management]
Clinical Scenario:
A 7 year old child, previously healthy attends Emergency Department following first generalised tonic clonic seizure. There is no history of drug and alcohol ingestion or other provoking factors. Clinically the child is afebrile and you wonder whether serum biochemistry is nessecary for the diagnosis and management of this patient
Search Strategy:
Search strategy from 1980 to Feb. 2005 was
Cochrane database of systematic review using nonfebrile unprovoked seizure AND laboratory evaluation AND children, no relevant systematic review or controlled trials of relevance
Using PubMed interface —"serum biochemistry"(MESH) AND "unprovoked seizure" (MESH) limits All child 0-18 years, English, clinical trials.
Search Details:
Search strategy from 1980 to Feb. 2005 was
Cochrane database of systematic review using nonfebrile unprovoked seizure AND laboratory evaluation AND children, no relevant systematic review or controlled trials of relevance
Using PubMed interface —"serum biochemistry"(MESH) AND "unprovoked seizure" (MESH) limits All child 0-18 years, English, clinical trials.
Outcome:
There were 118 hits (6 relevant), see table.
Relevant Paper(s):
Study Title Patient Group Study type (level of evidence) Outcomes Key results Study Weaknesses
Emergency department laboratory evaluation of children with seizures: dogma or dilemma? Nypaver MM, Reynolds SL, Tanz RR, Davis AT. 1992, USA 308 children (65% non-febrile) Retrospective Serum biochemistry performed in 40%. No abnormal test thought to have caused seizure. Includes febrile and recurrent seizures
Absence of serum chemistry abnormalities in pediatric patients presenting with seizures. Kenney RD. Taylor JA. 1992, USA 241 children (155 non-febrile) Retrospective 64% had biochemistry. All normal. Includes febrile and recurrent seizures
Utility of laboratory testing for infants with seizures. Scarfone RJ, Pond K. 2000, USA 134 children Retrospective cohort Serum biochemistry performed in 50%. 13% abnormal low Na , low Ca. Higher results in patient Seizures in ED. <1 month Temp <36.5 Age group infants, incl. FS
The role of routine serum lab. tests in children presenting to the emergency dept with unprovoked seizures. Valencia I, Sklar E. 2003, USA 107 children Prospective observational Serum biochemistry performed in 54%. 14.8% abnormal. Abnormal <2 years. GI symptoms. First seizures. Change mental status. Not all had laboratory tests
Author Commentary:
Only two of the studies are prospective, however the total studies' number of patients is clinically significant.
Only one of the studies assessed fully utility of laboratory testing for infants with seizures.
Bottom Line:
We concluded that routine determination of serum biochemistry values in paediatric patients presenting with unprovoked seizure is unnecessary unless specific clinical data strongly suggest otherwise.
Laboratory testing is recommended for non febrile seizures in infants who 1) are actively seizing in the ED, 2) have a temperature below 36.5 degrees C, or 3) are less than 1 month of age.
References:
  1. Nypaver MM, Reynolds SL, Tanz RR, Davis AT.. Emergency department laboratory evaluation of children with seizures: dogma or dilemma?
  2. Kenney RD. Taylor JA.. Absence of serum chemistry abnormalities in pediatric patients presenting with seizures.
  3. Scarfone RJ, Pond K.. Utility of laboratory testing for infants with seizures.
  4. Valencia I, Sklar E.. The role of routine serum lab. tests in children presenting to the emergency dept with unprovoked seizures.