Technical Report Summary: The Neurodiagnostic Evaluation of the Child With a First Simple Febrile Seizure

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PEDIATRICS Vol. 97 No. 5 May 1996 773

Technical

Report

Summary:

The

Neurodiagnostic

Evaluation

of the

Child

With

a First

Simple

Febrile

Seizure*

Febrile seizures are a common problem in clinical practice, occurring in 2.7% of children in the British

Birth Cohort Study.’ The subcommittee’s efforts

were focused on the large subgroup of children

(88%)’ who have simple febrile seizures, because in

the view of most clinicians and on the basis of the

epidemiologic evidence, this is a relatively homoge-neous clinical grouping2 in terms of age, clinical pre-sentation, course, and outcome.’3

DEFINITION OF THE PROBLEM

Children younger than 5 years who have their first

seizure in association with a fever are commonly

divided into three groups. Children with simple

fe-brile seizures make up the largest group. The second

group includes children whose seizures are

second-any to central nervous system (CNS) infection (symp-tomatic febrile seizures). In the third group, children

whose seizures are neither simple nor secondary to

CNS infection are classified as having complex

fe-brile seizures.

The definition of a simple febnile seizure in this

practice parameter corresponds to that in usual

clinical practice and is also supported by the

anal-ysis of data from the Collaborative Peninatal

Project of the National Institute of Neurological

and Communicative Disorders and Stroke.4 In that

project, Nelson and Ellenberg4 analyzed the data of

1706 children 7 years of age who had had one or

more febrile seizures. The risk of epilepsy (afebnile

seizures) was significantly higher for children

whose neurological development was not normal

before the seizures, whose seizures occurred

be-fore 6 months of age, whose seizure lasted longer

than 15 minutes, or who had more than one febnile

seizure per day. Most recently Verity and Golding’

examined the records of 398 children who had had

at least one febrile seizure. Follow-up continued

until 10 years of age. They found a higher rate of

epilepsy after a complex febrile convulsion (lasting longer than 15 minutes, focal or multiple seizures)

than after a simple febrile convulsion. The

avail-able data indicated that these children had adverse

neurologic outcomes (such as early mortality or

mental retardation) at rates similar to those of their

*The technical report contains the complete bibliography of articles sub-jected to analysis and details of the analytic methods used. The technical report may be obtained through the Publications Department, American Academy of Pediatrics, 141 Northwest Point Blvd, P0 Box 927, Elk Grove Village, IL 60009-0927.

The recommendations in this statement do not indicate an exdusive course

of treatment or serve as a standard of medical care. Variations, taking into account individual circumstances, may be appropriate.

peers. Nevertheless, their rate for single or

re-peated afebrile seizures (epilepsy is defined as

having two or more afebrile seizures) exceeded

that of the general age-matched population.2’4 The

study concluded that children with simple febnile

seizures had a higher rate of afebnile seizures than

that seen in the base population but had a lower

rate than children who had complex febrile

sei-zures.

METHODS

Pertinent articles were obtained by a MEDLINE

search and an additional search from the Epilepsy

Foundation of America using their database and

were suggested by subcommittee members; 203

anti-des were identified.

The goal of this search was to identify population-based studies limited to patients with well-defined, simple febrile seizures and in which neurodiagnostic

tests were used. The subcommittee attempted to use

the method of WooIf to develop these guidelines.

Such a rigorous analysis requires well-designed,

population-based or case-comparison studies. The

studies must adhere to a consistent definition of the

study group, in this instance children with simple

febrile seizures. The diagnostic test of interest must be applied in a standard way to all eligible patients.

The patients then must be followed for a sufficient

period to discover important outcomes.

None of the previously cited population-based

studies was designed to investigate the utility of

neurodiagnostic testing.’4 In all three studies, tests were selectively requested based on the physicians’ clinical judgment.

Given the scarcity of population-based studies,

data from hospital and clinic series were also

ana-lyzed. These studies had the following methodolog-ical problems.

Patient Selection

Most studies recruited patients from clinics,

emer-gency departments, or hospital admissions. The

se-lection factors that influenced the constitution of these patient groups were difficult, if not impossible,

to characterize. Moreover, children from these

pa-tient groups usually have substantially higher rates

of adverse outcomes than do children in population-based studies.

Disease Definition

Many studies either failed to define their criteria for febrile seizures, used definitions different from that used in the practice parameter, or did not

rigor-ously follow any specific definition. Often, no

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774 PRACTICE PARAMETER

tempt was made to exclude (or at least identify)

children with preexisting neurologic disease.

Uniformity of Neurodiagnostic Testing

Many studies failed to apply the test(s) to all eli-gible patients, raising serious questions about patient selection. An excess of positive tests and adverse

outcomes could be expected, based on physicians

who exempt healthier children from testing.

Duration of Follow-up

Few studies had extended follow-up periods. The

number of children having afebrile seizures increases

with age.’ Although the optimal duration of

fol-low-up is uncertain, in the Rochester, Minnesota,

study, most of the children were found to have had

seizures by 9 years of age.3

SUBCOMMIflEE RECOMMENDATIONS AND

LEVELS OF EVIDENCE

Recommendations were made based on the

qua!-ity of scientific evidence. In the absence of

high-quality scientific evidence, subcommittee consensus

or a combination of evidence and consensus was

used as the basis for recommendations.

Clinical options are actions for which the panel

failed to find compelling evidence for or against. A

health care provider may or may not want to

imple-ment clinical options, depending on the child.

No recommendation was made when scientific

ev-idence was lacking, and there was no compelling

reason to make an expert judgment.

PANEL RECOMMENDATIONS

Lumbar Puncture

The goal of lumbar puncture is to identify children

with CNS infection. Lumbar puncture with spinal

fluid examination is not an effective neurodiagnostic technique for evaluating the febnile seizure per se.68

An important concern is the number of children

presenting with fevers and seizures who have

men-ingitis (eg, 4 [3.4%1 of 119 according to Heijbel et al,9 28 [5%] of 562 according to Jaffe et al,7 13 [5.4%] of 241 according to Joffe et al,’#{176}21 [2.4%] of 878

accord-ing to Rossi et al,” and 6 [1.8%] of 328 according to

Rutter and Smales8).

Reviewing the emergency department records for

241 children who had first seizures with fevers and

underwent lumbar puncture, Joffe et al’#{176}found that the following five items were important in

determin-ing those with and without meningitis: (1) visiting a

physician within 48 hours of the seizure, (2) seizure activity at the time of arrival in the emergency de-partment, (3) a focal seizure, (4) suspicious findings on physical examination (rash or petechiae, cyanosis, hypotension, or grunting respirations), and (5) ab-normal neurologic examination results.

Clearly the clinical evaluation of young febrile

children requires skills that vary between examiners. Because this practice parameter is for practitioners

with a wide range of training and experience, the

committee chose a conservative approach, with an

emphasis on the value of lumbar puncture in

diag-nosing meningitis.

Electroencephalography (EEG)

The primary purpose of EEC in the evaluation of

children with simple febrile seizures is to predict the risk of future afebrile seizures. The subcommittee searched for but could not find a definitive study.

Given the high rate of simple febrile seizures and the low rate of subsequent afebrile seizures,

obtain-ing routine EEC studies would require a large

num-ben of tests to identify a small number of children

destined to have these seizures. For example, in the British Birth Cohort Study, only 2.6% of children

who had had their first simple febrile seizures

sub-sequently had single afebrile seizures before their

10th birthdays. Only 1.6% of the children had two or

more afebrile seizures (ie, epilepsy).’

BLOOD CHEMISTRY ANALYSES

In a population-based study that included 107 chil-dren with simple febrile seizures, Heijbel et al9 ret-rospectively reviewed the routine blood chemistry

studies requested by the treating physicians. They

found no dinically important abnormalities in serum

calcium (n = 92), phosphorus (n = 85), or glucose (n

=

56)

levels. One child with a low glucose level was

reportedly asymptomatic at follow-up.

Other studies were hospital based. For 100 consec-utive admissions, Gerber and Berliner reported

nor-mal values of serum glucose (n = 82), calcium (n =

58),

electrolytes, and urea nitrogen. The five children

with elevated glucose levels were asymptomatic.

Thirteen children had minimally reduced calcium

levels (8.3 to 8.9 mg/dL) and were asymptomatic.

Jaffe et al7 reviewed 323 records of children with

simple febnile seizures. Three children had

abnor-malities (one each had hyponatremia, hypocalcemia,

and hypokalemia), and the authors thought that the

abnormalities could have been anticipated on clinical

grounds independent of the occurrence of the simple

febrile seizure. Rutter and Smales8 reviewed 328 chil-dren admitted to the hospital after their first febrile

convulsions and found that determinations for

se-rum sugar, calcium, urea, electrolytes, and blood

counts were “commonly performed but were

un-helpful.”

Four authors6 determined that in their patients

with simple febrile seizures, the routine blood them-istry analyses performed did not alter patient

treat-ment in an important way. The child’s clinical

con-dition and underlying ifiness determined the need

for routine blood chemistry analyses. Otherwise, the

treatment of a child after a simple febrile seizure was not improved.

Neuroimaging

To our knowledge, no study has been done in

which children with simple febnile seizures have

un-dergone imaging. We also searched (without

suc-cess) for a related imaging study involving otherwise healthy children after first seizures. Three studies

reviewing skull radiographs in children with febrile

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AMERICAN ACADEMY OF PEDIATRICS 775 seizures conduded that skull radiographs were not

of value.6’7”2

ROBERT J. BAUMANN, MD SANDRA L D’ANGELO, PHD University of Kentucky Lexington

REFERENCES

1. Verity CM, Golding J. Risk of epilepsy after febrile convulsions: a national cohort study. Br Med J.1991303:1373-1376

2. Nelson KB, F.llenberg JH. Prognosis in children with febrile seizures.

Pediatrics. 1978;61:720-727

3. Annegers W, Hauser WA, Elveback LR, Kurland LT. The risk of epi.

lepsy following febrile convulsions. Neurology. 197929:297-303

4. Nelson KB, Ellenberg JH. Predictors ofepilepsy in children who have experienced febrile seizures. N Engi JMed. 1976295:1029-1033

5. A step-by.step approach to developing practice parameters. Adapted

from: Woolf SH. Interim Manual for Clinical Practice Guideline Development; 1994

6. Gerber MA, Berliner BC. The child with a “simple” febrile seizure:

appropriate diagnostic evaluation. Am JDis Child. 1981;135:431-433 7. Jaffe M, Bar-Joseph G, Tirosh E. Fever and convulsions-indications for

laboratory investigations. Pediatrics. 198157:fl9-731

8. Rutter N, Smales ORC. Role of routine investigations in children pre-senting with their first febrile convulsions. Arch Dis Child. 197752:

188-191

9. HeijbelJ, Blom 5,Bergfors PG. Simple febrile convulsions: a prospective incidence study and an evaluation of investigations initially needed.

Neuropadiatrie. 1980;11:45-56

10. Joffe A, McCormich M, DeAngelis C. Which children with febrile

sei-zures need lumbar puncture. Am JDis Child. 1983;137:1153-1156

11. Rossi LN, Brunelli G, Duzioni N, Gossi G. Lumbar puncture and febrile convulsions. Helv Paediatr Acta. 1986;41:19-24

12. Nealis GT, McFadden SW, Asnes RA, Ouellette EM. Routine skull roentgenogram in the management of simple febrile seizures. IPediatr.

197790:595-596

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1996;97;773

Pediatrics

Robert J. Baumann and Sandra L. D'Angelo

First Simple Febrile Seizure