Journal Club

Lumbar puncture in febrile

seizures-are they needed?

Saskia Wills

16/01/18

Article

“Do All Children Who Present With a Complex

Febrile Seizure Need a Lumbar Puncture?”

Annals of Emergency Medicine

July 2017

Febrile Seizures

2-4% of children <5yrs have one

Peak 12-18 months

Boys>girls

Defined as:

Temp >38

Age 6m-5yrs

No CNS infection/metabolic cause

No previous afebrile seizures

Simple Vs Complex

Simple Complex

Duration <15 mins (usually

<5mins)

>15 mins

Morphology GTC/tonic/atonic Focal

Frequency Once Multiple within 24hrs

Risk Factors

Fever- maximum height, not rate of rise

Viral infection (HHV-6 35%, adenovirus 14%, RSV 11%, HSV

9%, Flu A)

Vaccination:

DTP- absolute risk <4/100,000. Max risk on day 1

MMR-25-34/100,000. 8-14 days after imms.

Risk higher if MMR given at 16-24m rather than 12-15m

Genetics

Other (allergy, Fe deficiency, prenatal nicotine)

Prognosis

1/3 will have another one

Doubles risk of epilepsy (but only to 2.4%)

Risk higher with complex seizures

No evidence for worse cognitive outcomes

after simple febrile convulsion

Differentials

Rigor

Generalised epilepsy w febrile seizures

(GEFS+)- mostly Aut Dominant

CNS Infection

Clinical question

What is prevalence of CNS infection in

children presenting with febrile convulsion but

no other features of meningitis/encephalitis?

When is an LP needed?

Study Design

Multicentre retrospective cohort study

Children attending ED in Paris (7 hospitals, all

with dedicated paeds ED)

Data from electronic medical records

Well vaccinated population (95% HiB & 90%

pneumococcal coverage in general

population)

Inclusion criteria

6m-5yrs

Complex seizure within past 24 hrs

Fever >38 (not necessarily recorded in ED)

Exclusion criteria

Simple febrile fits

Previous afebrile seizure

Conditions increasing risk of seizures (eg

cerebral malformation, genetic syndrome,

trauma in past 24hrs…)

Conditions increasing risk of CNS infection

(sickle cell, immunosuppression…)

Methods

Search for children 6m-5yrs w keywords

“seizure”,“febrile seizure”,“tonic”, “clonic”,

”shaking”, “jerks”, “twitch”

Records manually reviewed for complex fits

Randomised into 2 groups, data analysed by

blinded assistants using questionnaire

Searched for 30 words associated w

meningism/abnormal neuro exam

Outcome measures

Children w HSV/bacterial meningitis

diagnosed within 7 days

CSF WCC >7/+ve PCR/+ve latex

agglutination

Also checked meningitis database (incase

child re-presented elsewhere)

Clopper-pearson test (binomial confidence

interval)

Findings

839 visits w complex febrile fit

209 had features of CNS infection (56% had

LP)

630 no features (23% LP)

55 HSV PCR

Findings

5 bacterial meningitis (4 x pneumococcus, 1 x

meningococcus)

All had prolonged seizure

All had abnormal neuro signs

4/5 <12m old

No confirmed HSV

3 enterovirus

Critical appraisal

Was it original?

Clearly defined population?

Appropriate study design?

Efforts made to reduce bias?

Large enough cohort?

Conclusion

For well-vaccinated children, seizure is a rare

presentation of CNS infection

Caution in prolonged seizures and children

<1yr

Doesn’t apply to children with underlying

disorder (immunodeficiency etc)