16 neonatal seizures

7/27/2019 16 Neonatal Seizures

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NEONATAL SEIZURES

Seizures are the most frequent manifestaon of neonatal neurological diseases.It is important to recognize seizures, determine their aeology and treat thembecause:

1. the seizures may be related to signicant diseases that require specic treatment

2. the seizures may interfere with supporve measures e.g. feeding and assisted

respiraon for associated disorders

3. the seizures per se may lead to brain injury.

Table 1. Classicaon of neonatal seizures

Clinical seizure

Subtle

Clonic

Focal

Mulfocal

Tonic

Focal

Generalized

Myoclonic

Focal,Mulfocal

Generalized

EEG seizures

common

common

common

common

uncommon

common

Manifestaon

ocular phenomena

- tonic horizontal deviaon of eyes common in term infants- sustained eye opening with xaon common in preterm infants

- blinkingoral-buccal-lingual movements

- chewing common in preterm infants- lip smacking, cry-grimace

limb movements

- pedaling, stepping, rotary arm movements

apnoeic spells common in term infants

well localized clonic jerking, infant usually not unconscious

mulfocal clonic movements; simultaneous or in sequenceor non-ordered ( non-Jacksonian) migraon

sustained posturing of a limb, asymmetrical posturing of trunkor neck

tonic extension of upper and lower limbs (mimic decerebrateposturing)

tonic exion of upper limbs and extension of lower limbs( mimicdecorcate posturing)

those with EEG correlates; autonomic phenomenae.g. increased blood pressure are prominent features.

well localized, single or mulple, migrang jerks usually of limbs

single or several bilateral synchronous jerks or exionmovement occurring more in upper than lower limbs.

Aeology

Hypoxic ischaemic encephalopathy- usually secondary to perinatal asphyxia.

- most common cause of neonatal seizures (preterm and term)

- seizures occur in the rst day of life (DOL)

- presents with subtle seizures; mulfocal clonic or focal clonic seizures

- if focal clonic seizures may indicate associated focal cerebral infarcon

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ATALOGY


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NEONATO

LOGY

Intracranial hemorrhage (ICH)

- principally germinal matrix-intraventricular (GM-IVH), oen with periventricularhaemorrhagic (PVH) infarcon in the premature infant

- in term infants ICH are principally (may occur with HIE) and subdural(associatedwith a trauma , presenng with focal seizures in the rst 2 DOL)

Intracranial Infecon

- common organisms are group B streptococci, E. coli., toxoplasmosis, herpes simplex,coxsackie B, rubella and cytomegalovirus

Malformaons of corcal development- neuronal migraon disorder resulng in cerebral corcal dysgenesis

e.g. lissencephaly, pachygyria and polymicrogyria

Metabolic disorder

- hypoglycemia common in SGA infants and infants of diabec mothers (IDM)

(see protocol on Neonatal Hypoglycemia

- hypocalcaemia has 2 major peaks of incidences: rst 2 to 3 DOL, in low birth weight infants, IDM and history of perinatal asphyxia. later-onset of hypocalcaemia associated with endocrinopathy (maternal

hypoparathyroidism, neonatal hypoparathyroidism) and heart disease (with orwithout Di George Syndrome), rarely with nutrional type (cows milk, highphosphorus synthec milk). Hypomagnesemia is a frequent accompaniment.

- inborn errors of metabolism: represent 3days

+

+

+

+

+

Premature

+++

++

++

++

+

+

Full term

+++

+

++

++

+

+

+

+

Time of onset Relave frequency

footnote: 1. postnatal age2. relave frequency of seizures among all eologies:

+++ most common, ++ less common, +least commonAbbreviaons. IEM, inborn errors of metabolism

Table 2. Major aeology in relaon to me of seizure onset and relave frequency

Eology

Hypoxic ischemic encephalopathy

Intracranial hemorrhage

Intracranial infecons

Developmental defects

Hypoglycaemia

Hypocalcaemia

Other metabolic disturbances & IEM

Epilepc Syndromes

Table 3. Inborn errors of metabolism presenng with neonatal seizures

Treatable

Pyridoxine-dependent epilepsy

Pyridoxal phosphate responsive epilepsyFolinic acid-responsive seizures

Bionidase deciency

Glucose transporter 1 deciency

Serine deciency syndromes

Creane deciency syndromes

Phenylketonuria

Non-treatable

Nonketoc hyperglycinemia

(poor outcome though seizure may be beercontrolled with dextromethorphan)

Sulphite oxidase deciency/Molybdenum cofactor deciency

Mitochondrial disorders

Peroxisomal disorder

Neuronal ceroid lipofuscinoses

Adenylosuccinate lyase deciency(purine disorder)


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Seizures versus Jieriness and Other Non-epilepc Movements

Some movements e.g. jieriness and other normal movement during sleep(Myoclonic jerks or generalized myoclonic jerks as infant wakes from sleep) or whenawake/ drowsy (roving somemes dysconjugate eye movements, sucking not accom-panied by ocular xaon or deviaon) in newborn may be mistaken for seizures.

Management

consensus is lacking on necessity for treatment of minimal or absent clinicalmanifestaons.

treatment with anconvulsant is to prevent potenal adverse eects onvenlatory funcon, circulaon and cerebral metabolism ( threat of brain injury)

controversy regarding idencaon of adequacy of treatment, eliminaon ofclinical seizures or electrophysiology seizures. Generally majority aempt to

eliminate all or nearly all clinical seizures.

Duraon of Anconvulsant Therapy - Guidelines

Duraon of therapy depends on the probability of recurrence of seizures if the drugsare disconnued and the risk of subsequent epilepsy. This can be determined byconsidering the neonatal neurological examinaon, cause of the seizure and the EEG.

Neonatal Period

if neonatal neurological examinaon becomes normal, disconnue therapy

if neonatal neurological examinaon is persistently abnormal,

- consider eology and obtain electroencephalogram(EEG)- in most cases connue phenobarbitone, disconnue phenytoin

- and reevaluate in a month

One Month aer Discharge

if neurological examinaon has become normal, disconnue phenobarbitone over2 weeks

if neurological examinaon is persistently abnormal, obtain EEG

if no seizure acvity or not overtly paroxysmal on EEG, disconnue

phenobarbitone over 2 weeks if seizure acvity is overtly paroxysmal connue phenobarbitone unl 3 months of

age and reassess in the same manner

Table 3. Dierenang seizures form non-epilpec events, e.g. jierinessClinical Features

Abnormality of gaze or eye movement

Movements exquisitely smulus sensive

Predominant movement

Movements cease with passive exion of aected limb

Autonomic changes ( tachycardia, BP, apnoea,salivaon, cutaneous vasomotor phenomena)

Jieriness

0

+

tremors

+

0

Seizure

+

0

clonic, jerking

0

+

footnote: 1. alternang movements are rhythmical and of equal rate and amplitude

2. clonic, jerking movements with a fast and slow component

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footnote. 1. Prognosis is based on those cases with the stated neurological disease when seizures area manifestaon. This will dier from overall prognosis of the disease.

Table 4. Prognosis according to aeology of neonatal seizures

Neurological Disorder

Hypoxic Ischemic Encephalopathy

Severe Intraventricular Haemorrhage with PVH infarcon

Hypocalcaemia

Early onset (depends on the prognosis of complicang illness, if

no neurological illness present prognosis approaches later onset )Later onset (nutrional type)

Hypoglycemia

Bacterial Meningis

Developmental defect

Normal Development (%)

50

10

50

100

50

50

0

infant withclinical seizures

Ensure venlaon

perfusion adequate (ABCs)

DEXTROSTIX

Invesgaons to consider

blood sugar, calcium, magnesium, electrolytes

sepc screen: FBC, Blood C&S, LP, TORCHES

metabolic screen: blood gas, ammoniaamino acids, organic acids

neuroimaging: US, CT Scan brain electroencephalography (EEG)

Figure 1. Approach to neonatal seizures

IV 10% Dextrose 2 ml/kg (200mg/kg)then IV glucose infusionat 8 mg/kg/min

Maintenance therapy

IV or Oral 3-4mg/kg/d in 2 divided dosesgiven 12-24 h aer loading

adverse eects:respiratory depression, hypotension

IV Phenobarbitone 20mg/kg

over 10 -15 minutes

A repeat loading dose of20mg/kg may be necessary

IV Phenytoin 20mg/kg loading dose

via infusion at 1mg/kg/min

- with cardiac rate, rhythm monitoring

- repeat a 2nd loading dose if ts recur

Maintenance therapy

IV 3-4mg/kg/d q12h

given 12-24 h aer loading

adverse eect: heart block

Benzodiazepine:

IV Diazepam 0.3 mg/kg/h infusion

or

IV Midazolam:1-4 mcg/kg/min infusion

consider

IV Calcium Gluconate, 10% soluon: 0.5 ml/kg slow bolusIV Magnesium sulfate, 50% soluon: 0.2 ml/kg

Oral Pyridoxine: 50-100mgPyrodoxal phosphate/Folinic acid *

Maintenance therapy

Midazolamadverse eects: hypotension,respiratory depression, urinary retenon

hypoglycaemia

no

hypoglycaemia

sll seizures

sll seizures

sll seizures

NEONATO

LOGY

* consult a neurologist ora metabolic clinician

16 neonatal seizures

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