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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)