R56 - Convulsions, not elsewhere classified

LEE CHUN YENG

Introduction

Febrile – Pertaining to or characterized by fever

Seizure – A single episode of epilepsy, often named for the types it represents

Fits – Seizure Convulsion – an involuntary

contraction or series of contractions of the voluntary muscles; seizure

Epilepsy – Any of a group of syndromes characterized by paroxysmal transient disturbances of brain function that may be manifested as episodic impairment or loss of consciousness , abnormal motor phenomena, psychic or sensory disturbances, or perturbation of the autonomic nervous system ; symptoms are due to the disturbance of the electrical activity of the brain.

Definition

Febrile seizure Convulsion occurring in association with

fever in children in between 3 months and 6 years of age, in whom there is no evidence of intracranial pathology or metabolic derangement

age dependent and are rare before 9 mo and after 5 yr of age.

Peak age of onset is ≈14–18 mo of age

3–4% of young children genetic predisposition Slight male predominance Mode of inheritance is unclear

Pathophysiology

occur in young children at a time in their development when the seizure threshold is low

Animal studies suggest a possible role of endogenous pyrogens, such as interleukin 1, that, by increasing neuronal excitability, may link fever and seizure activity.

but the precise clinical and pathological significance of these observations is not yet clear.

Suggested contributing factors Circulating toxins, immune reaction

products, and viral or bacterial invasion of the central nervous system

relative lack of myelination in the immature brain and increased oxygen consumption during the febrile episode. Immaturity of thermoregulatory mechanisms and a limited capacity to increase cellular energy metabolism at elevated temperatures

Types

Simple febrile convulsion

1)< 15 minutes2)Generalized seizure3)Does not recur

during febrile episode

Complex febrile convulsion

1)> 15 minutes2)Focal features3)> 1 seizure during

the febrile episode4)Residual

neurological deficit post-ictally such as Todd’s paralysis

Risk factors Family history of febrile seizures High temperature Parental report of developmental delay Perinatal illness (Especially affecting the

CNS)Presence of 2 of these risk factors increases

the probability of a first febrile seizure to about 30%.

Maternal alcohol intake and smoking during pregnancy has a 2-fold increased risk.

Risk factors of recurrent febrile seizures

Young age at time of first febrile seizure Relatively low fever at time of first seizure Family history of a febrile seizure in a first

degree relative Brief duration between fever onset and

initial seizure Patients with all 4 risk factors have

greater than 70% chance of recurrence. Patients with no risk factors have less than a 20% chance of recurrence.

Risk factors for subsequent epilepsy(1) complex febrile seizures, (2) a family history of epilepsy,(3) an initial febrile seizure before 12 mo of

age(4) neurologic impairment prior to the febrile

seizure The incidence of epilepsy is >9% when

several risk factors are present, compared with an incidence of 1% in children who have febrile convulsions and no risk factors.

Clinical manifestationSimple febrile seizure core temperature increases rapidly

to ≥39°C initially generalized and tonic-clonic

in nature lasts a few seconds and rarely up to

15 min followed by a brief postictal period of

drowsiness

Complex febrile seizure duration is >15 min repeated convulsions occur within 24

hr when focal seizure activity or focal

findings are present during the postictal period

Significance Viral illnesses are the predominant cause

of febrile seizures Viral infections of the URT, roseola, and

acute otitis media Complex febrile seizures may indicate a

more serious disease process, such as meningitis, abscess, or encephalitis.

viral meningoencephalitis, especially that caused by herpes simplex

Shigella gastroenteritis

Differential DiagnosisMeningitis, Signs of meningitis (eg, bulging fontanelle,

stiff neck, stupor, and irritability) may all be absent, especially in a child younger than age 18 months.

In older children, meningeal signs (eg, headache, nuchal rigidity, positive Kernig and Brudzinski signs) should be sought, and their presence or absence recorded.

Seizures occur in up to 30% of children with bacterial meningitis.

Encephalitis, Encephalitis may present like

meningitis with photophobia, headache or a stiff neck but without meningeal sign

Physical findings for encephalitis are fever, headache, and decreased neurological function (altered mental status, focal neurological function, and seizure activities).

CSF analysis shows pleocytosis (mononuclear cells) and high levels of protein (3-5% of samples have normal CSF).

Cerebral malaria Live in or returning from malaria

endemic areas Fever can be very high from the first

day. >40°C, usually continuous or irregular. Classic periodicity may be established after some days.

Febrile convulsions: Seizures are common and may occur at the onset of the disease, even before high fever has set in. Differentiating postictal impairment of consciousness from cerebral malaria is often difficult

Investigations

Need for blood counts, blood sugar, lumbar puncture, urinalysis, chest X-ray, blood culture etc will depend on clinical assessment

Serum calcium and electrolytes are rarely necessary

EEG not indicated even if multiple occurrences or complex febrile convulsion

Lumbar puncture Must be done if (unless contraindicated)

Any signs of intracranial infection Prior antibiotic therapy Persistent lethargy and not fully interactive 6

hours after the seizure Strongly recommended if,

Age < 12 months old First complex febrile convulsion In district hospital without paediatrician Parents have trouble bring child in again if

deterioration at home

Management

Main reason for admission to the hospital are: To exclude intracranial pathology,

especially infection Fear of recurrent fits To investigate and treat cause of fever

besides meningitis or encephalitis To allay parental anxiety

Advise parents on first aid during convulsion Do not panic, note time of onset Loosen child’s clothing Place the child in the left lateral position with

head lower than the body Wipe any vomitus or secretion from the mouth Do not insert any object into the mouth Do not give fluid or drugs orally Stay near the child until the convulsion is over

Control fever Take off clothing and tepid sponging Antipyretic (syrup or rectal PCM 15mg/kg 6 hourly),

indicated for patient’s comfort but does not reduce the recurrence rate of febrile convulsion

Rectal Diazepam Parents of child with high risk of recurrent febrile

convulsion should be supplied with rectal diazepam (0.5mg/kg)

They should be advised on how to administer it in case the convulsion last > 5 minutes

Prevention

Anticonvulsants are no longer recommended: Risks and potential side effects

outweighs the benefits Does not prevent future onset of

epilepsy Febrile convulsion have an excellent

outcome with no neurological deficit nor any effect on intelligence

Prognosis Febrile seizure are benign events with

excellent prognosis1)3-4% of population have febrile convulsions2)30% recurrence after 1st attack3)48% recurrence after 2nd attack4)2-7% develop afebrile seizure or epilepsy5)No evidence of permanent neurological

deficits following febrile convulsion or even febrile status epilepticus

6)No deaths were reported

ReferenceFrom the web http://emedicine.medscape.com/

article/801500-overview http://www.ilae-epilepsy.org/ctf/

febrile_convulsions.html http://emedicine.medscape.com/

article/802760-overview http://emedicine.medscape.com/

article/998942-overview

From books Nelson Textbook of Pediatrics, 18th

ed 2007 Pediatric Protocols for Malaysian

Hospitals 2nd Edition Febrile seizures by Tallie Z. Baram Current Pediatric Diagnosis &

Treatment 18th ed (CPDT)