Neonatal Seizure

DEFINITION:

Paroxysmal alteration in neurologic function (ie, behavioral, motor, or autonomic function)

CAUSES OF SEIZURES:

PERINATAL ASPHYXIA

Most common

Occur within the 1st 24 h of life

Premature: generalized tonic type

Full term: multifocal clonic type

Both: accompanying subtle seizures

INTRACRANIAL HEMORRHAGE

Subarachnoid hemorrhage

occur on the 2nd postnatal day

appears quiet well during the interictal period.

Periventricular or intraventricular hemorrhage

subtle seizures, decerebrate posturing, or generalized tonic sizures

Subdural hemorrhage

focal seizures and focal cerebral sign

METABOLIC DISTURBANCE

Hypoglycemia

frequently in IUGR and infant of diabetic

mother (IDMs)

Hypocalcemia

LBW infants, IDMs, asphyxiated infants.

Hyponatremia

improper fluid management

result of SIADH

Hypernatremia

dehydration

excessive use of sodium bicarbonate

incorrect dilution of concentrated formula

Other

Pyridoxine dependency: resistant to

anticonvulsant, born with meconium

staining, asphyxiated infants.

Amino acid disorders: hyperammonemia

and acidosis are commonly present.

INFECTIONS

Bacterial infection: group B streptococcus, E. coli, L. monocytogenes.

Nonbacterial infection: toxoplasmosis, herpes simplex, cytomegalovirus, rubella, coxsackie B viruses.

DRUG WITHDRAWAL

Passive addiction from the mother

Analgesic: heroin, methadone

Sedative-hypnotics: secobarbital, alcohol

TOXINS

CLINICAL PRESENTATION:

SUBTLE SEIZURES

More common in premature

Eyelid blinking or fluttering

Sucking, smacking, or drolling

‘Swimming’, ‘rowing’, or ‘pedalling’ movements

Apneic spels

CLONIC SEIZURES

Common in full term

Two types:

Focal seizures: well localized, rhythmic, slow, jerking movement on one side of the body.

Multifocal siezures: several body parts seize in a sequential (eg, left arm jerking followed by right leg jerking)

TONIC SEIZURES

Occur primarily in premature infants

Two types:

Focal seizures: sustained posturing of a limb, asymmetric posturing of the trunk or neck, or both

Generalized seizures: tonic extension of both upper and lower extremities (decerebrate posturing), tonic flexion of the upper extremities with extension of lower extremities (decorticate posturing)

MYOCLONIC SEIZURES

Both in full-term and premature

Characterized by single or multiple syncronous jerks.

Three types:

Focal seizures: involve the flexor muscles of an upper extremity.

Multifocal seizures: asyncrhonous of several

parts of the body.

Generalized seizures: bilateral jerks of flexion of the upper and sometimes the lower extremities.

DIAGNOSIS:

HISTORY

Family history

Maternal drug history

Delivery

PHYSICAL EXAMINATION

General: gestational age, blood pressure, presence of skin lession, presence of hepatosplenomegaly.

Neurologic evaluation

Notation of the seizure pattern

LABORATORY STUDIES

Serum chemistries

Spinal fluid examination

Metabolic disorders

RADIOLOGIC STUDIES

USG of the head

CT Scanning of the head

OTHER STUDIES

EEG

MANAGEMENT:

HYPOGLYCEMIA

10% dextrose in water, 2-4 mL/kg/IV followed by 6-8 mg/kg/min by continious IV infusion.

HYPOCALCEMIA

Slow IV infusion of Ca Gluconate

ANTICONVULSANT THERAPY

Phenobarbital as a drug of choice

Phenytoin (Dilantin)

Pyridoxine

Diazepam (Valium): not been used extensively

Lorazepam (Ativan): quite effective and save

IV midazolam and oral carbamazepin

Paraldehyde: give rectally

DURATION OF ANTICONVULSANT THERAPY

Has not been established

Some clinicians: prolonged periode

Others: stopping after seizure have been absent for 2 weeks.

PROGNOSIS:

Modern NICU Mortality rate ↓ from 40 to 20%.

Neurologic sequele are still in 25-35% of cases

Hypocalcemic convulsions : excellent prognosis

Varies with the cause.

Symptomatic hypoglycemia: 50% risk of death

Asphyxiated infants: 50% change of poor outcome.

17% of patient have recurrent seizures later in life.

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