Seizures / Febriles Seizures

Dr. Kalpana MallaMD Pediatrics

Manipal Teaching Hospital

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Topics

• Seizure***• Causes / Classification • Neonatal seizures• Febrile seizures***• Epilepsy & Specific epileptic syndromes***• Status epilepticus• Drug therapy in epilepsy

Seizures in children

• Common neurological disorder in children

• Do not constitute diagnosis-Is symptom of underlying CNS disorder

Definition- Seizure :

• Paroxysmal alteration in behavior due to any transient brain pathology-cerebral dysrhythmias, Transient ischemic or anoxic attacks (faints) - excessive and abnormal discharge from cortical neurons

**May be manifested as Transient, involuntary alteration or loss of consciousness, abnormal motor activity, behavioral abnormalities, sensory disturbance or autonomic dysfunction

• 10% of children have seizure• Most seizures are provoked by somatic

disorders originating outside brain – like – high fever, toxins, hypoxia, arrhythmias, psychogenic etc.

• Less than 1/3rd of seizures are caused by epilepsy

Terminology

• Fit :- Clinical manifestation of cerebral dysrhythmia - Maybe convulsive-GTC - Maybe nonconvulsive – absence or complex partial

Terminology

• Convulsion:-• Tonic clonic motor component of seizure

• When child shows sudden episode of decerebrate posturing which is followed by clonic jerking-

**all convulsions are not epilepsy

Terminology

• Epilepsy : Two 0r more unprovoked seizure occurring at an interval greater than 24 hrs apart

– recurrent fits due to repeated primary cerebral dysrhythmias

• What are nonepileptic conditions that may mimic seizures?

Seizure Mimicers

1. Breath-holding spells

2. Cough Syncope3. Tics4. Acute dystonia5. Pseudoseizures 6. Benign myoclonus7. Night terrors

1. Benign paroxysmal vertigo2. Benign paroxysmal

torticollis of infancy3. Hereditary chin trembling4. Narcolepsy

5. Day dreaming6. Hysteria 7. Migraine

Mimicking seizures

Jitteriness– Absence of abnormal gaze movements– Provoked by passive flexion or extension– Movement to and fro shorter duration – Normal EEG– No increase in blood pressure or heart rate

• No postictal phase after these episodes

Mechanisms

• Exact cause unknown• Basis-Failure of mechanism that aborts S1. Excessive persistent excitation - by

excitatory neurotransmitters -- glutamate, aspartate, acetylcholine also N-methyl-d-aspartate (NMDA)

2. Ineffective recruitment of inhibition -dominant inhibitory neurotransmitter gamma aminobutyric acid (GABA)

Mechanisms

3.Significant neuronal burst discharge-usually by voltage dependent calcium currents

4.Arise from areas of neuronal death-these regions promote development of hyperexcitable synapses that promote seizure

Causes of seizures

1. Febrile convulsions**2. Epilepsy**3. Infections- Meningitis**, encephalitis*, brain

abscess**,Cerebral malaria4. ICSOL**5. Cerebral ischemia, trauma

Causes

6. Metabolic – Hypocalcemia, Hypoglycemia,

Hypomagnesemia, Dyselectrolytemia, Inborn errors of metabolism

7. Toxic – Uremia, Hepatic encephalopathy, Reye’s

syndrome, Lead ,phenothiazine Strychnine poisoning, Shigelosis, Tetanus

Causes

8.Renovascular- Acute nephritis, Hypertensive encephalo[athy,

Hemolytic –Uremic syndrome9.Arterio-venous malformation10. Hysterical conversion reaction

Febrile Seizures

Febrile Convulsion

**Most common seizure disorder with excellent prognosis

• Definition:- Seizure occurring with temp ≥38oC in absence

of detectable CNS infections but there may be association of acute extra cranial infections and high environmental temperatures

Febrile Convulsion

• Incidence – 3-5%• Autosomal dominant pattern of inheritance• Chromosome 19p & 8q.• Thus , family history imp.

PATHOGENESIS

• Due to temporary impairment of the balance between the convulsant and anticonvulsant system of brain

• Threshold level of anticonvulsant system in these genetically predisposed children is lower

PATHOGENESIS

• Studies in children suggests – that the cytokine network is activated and may have a role in the pathogenesis of febrile seizures

• Other suggestion - endogenous pyrogens, such as interleukin 1, increasing neuronal excitability & causing seizures

Causes - Febrile Convulsion

1.ARI-URTI(Otitis media )2.LRTI 3.Viral fever- Roseola and Influenza A , other

fever with rash 4.UTI 5. Gastroenteritis

Typical F. Convulsion

1. Age- 6months – 5 yrs peak 14 - 18 months2. With rapid rise of temp ≥38oC ,within 24 hrs of

onset of fever3.Should not last more than 10 min4. Generalized not focal

Typical F. Convulsion

5. Positive family history ( 50%) - AD in some families

6. One seizure attack at each episode7. No residual weakness of limb or disability

except a brief period of drowsiness8.EEG between and after seizure is normal9.Extracranial infection may be + but no CNS

infection

Criteria for Diagnosis

• Above features plus • M>F• Infections: 90% of the cases are due to viral

infections, Common infections are URTI, Otitis Media, Pneumonia, UTI and Roseola

• Recurrence: 30- 50% under 1 year. Frequency decreases after 5 yrs of age.

Classification

• SIMPLE- Age group-6months – 5 yrs peak 14 - 18 months

- GTCS- <10 MIN- Single in 24 hrs1 fit per febrile episode- Brief / no post ictal phenomenon- EEG - N

Classification• ATYPICAL/ COMPLEX - > 15 MIN - >1 Episode per fever - Occurs more than once in 24 hrs - Focal - + family history - Pre existing CNS disorder - Delayed devl or regression- - Followed by Todd paralysis, but no significant other - reason or CNS infection can not be found - EEG may remain abnormal for 2wks or more• Continuous prophylaxis therapy may be given

Risk factor for 1st episode

• + family history• After immunization – DPT , MMR.• INFECTIONS esp Herpes virus • Fe def

Risk Factors for Recurrent Febrile

• Younger than 18 months• Duration of fever (i.e., shorter duration of fever

before seizure - higher risk of recurrence)• Complex febrile seizure at onset• Family history of epilepsy• Family history of febrile seizures• Height of fever (i.e., the lower the peak fever,

the higher the rate of recurrence)

Risk factors for devp of epilepsy

1.+ family history2. 1st F .seizure before age 9 month3. Atypical F. seizure4. Delayed milestones5. Abnormal neurological findingsRisk of epilepsy increases to 9% from 1% if

above factors are ++

AAP Practice Parameter• Lab testing - identifying source of fever - part of routine evaluation

• Do blood glucose in all patients• Blood Studies: No indication for routine testing of electrolytes, calcium, magnesium, CBC

• Neuroimaging: No need to perform in routine evaluation of first febrile seizure

Investigations - AAP Practice Parameter

• EEG: not needed for first simple febrile seizure but done in complex febrile seizure

• LP: should be “strongly considered” in < 12 mos and “considered” between 12-18 mos.

• If older than 18 mo, rely on meningeal S&S• Also consider LP if prior antibiotic treatment

Hospital care

1.Position –semi prone –ABC2. Control fever-antipyretics, tepid sponge3.Control convulsion-Diazepam IV/PR 4. Infection should be looked for and treated - LP? - CBC?• Parents reassurance

Treatment

• Home management• Reduction of body temp- - PCM/Ibuprofen -Tepid water sponging

Treatment

5.prophylaxis- - Intermittent with oral diazepam -0.3mg

/kg/ dose TID clobazam, midazolam –effective - Long term prophylaxis- sodium valproate

SEIZURE PROPHYLAXIS

• Intermittent• Diazepam• Clobazam• Midazolam

• Continuous• Valproate• No role of

phenytoin/CBZ/Phenobarbitone

• Criteria for Prophylactic anticonvulsant therapy:

1. <18mo with previous abnormal development or abnormal neurological signs

2. Atypical febrile seizure 3. Recurrent febrile seizure 4. High level of parental anxiety

• Continuous daily prophylaxis given with Sodium Valproate 30- 60mg/kg/day in two divided doses to be continued for at least 2 fit free years or until child is 6 yr old, whichever comes earlier.

Patient Education

• Counsel on the benign nature of febrile seizures• Reassured that simple febrile seizures do not lead to

neurological problems or developmental delay • If their child has another seizure - • To call for assistance if the seizure lasts longer than 10

minutes or if the postictal period lasts longer than 30 minutes

Prognosis

• 50% with single F. convulsion have no recurrence even if untreated

• 30-50% have recurrence• 40% in 1st episode have > one or more further

convulsions,10% will have multiple attacks• 1% with no risk factors and 9% with risk

factors develop epilepsy by age 7 yrs

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