- Benign familial neonatal seizures
- Benign neonatal seizures (non-familial)
- Early myoclonic encephalopathy
- Ohtahara syndrome
The neonatal period is the most vulnerable period of life for developing seizures. Neonatal epileptic seizures often constitute a neurological emergency demanding urgent diagnosis and management. Neonatal seizures are paroxysmal, repetitive, and stereotyped events. They are usually clinically subtle. There is no recognizable post-ictal state. Generalized tonic-clonic seizures probably do not occur.
There are 5 main types of neonatal seizures:
- Subtle seizures (50%)
- Tonic seizures (5%)
- Clonic seizures (25%)
- Myoclonic seizures (20%)
- Non-paroxysmal repetitive behaviors
The prevalence of neonatal seizures is approximately 1.5%. The overall incidence is 3 per 1,000 live births (57 to 132 per 1,000 live births in pre-term infants). Eighty percent occur in the first 1 to 2 days to the first week of life. The etiology of neonatal seizures is extensive and diverse. Severe causes predominate. Hypoxic-ischemic encephalopathy is the most common cause (80% of all seizures in the first 2 days of life). Previously common acute metabolic disturbances such as electrolyte and glucose abnormalities are now unusual causes.
Prognosis is cause dependent because the main factor that determines outcome is the underlying cause and not the seizures themselves. Despite high mortality (approximately 15%) and morbidity (approximately 30%), one half of neonates with seizures achieve a normal or near-normal state. One third of the survivors develop epilepsy. Neonatal seizures often impose significant difficulties in their differentiation from normal or abnormal behaviors of neonates. As a rule, any suspicious repetitive and stereotyped events should be considered as possible seizures requiring video-electroencephalogram (video-EEG) confirmation.
Neonatal syndromes: Despite the high prevalence of neonatal seizures, epileptic syndromes in neonates are rare and infrequent. These are:
- Benign familial neonatal seizures
- Benign neonatal seizures (non-familial)
- Early myoclonic encephalopathy
- Ohtahara syndrome
The epileptic syndromes and their significance
A major advance in recent epileptology is the recognition of epileptic syndromes that allows an accurate diagnosis and management of seizure disorders.[1-3]
Medical diagnosis is the identification of a disease by investigation of its symptoms and history, which provides a solid basis for the treatment and prognosis of the individual patient. An accurate diagnosis is the golden rule in medicine, and epilepsies should not be an exception to this. Like in any other disease, the recognition of non-fortuitous clustering of symptoms and signs in epilepsies requires the study of detailed clinical and laboratory data.[1-3] However, often in current practice, the diagnosis is limited to either epilepsy or seizures, which is unsatisfactory because this cannot provide guidance on important items such as severity of the disease, prognosis, short- and long-term therapeutic decisions, and genetics (research and counselling), which are all factors that crucially affect personal, family, and social life; education; and career choices of patients. Defining the type of epilepsy should now be considered mandatory as it offers the best guide to both management and prognosis. Most epileptic syndromes and diseases are well defined and easy to diagnose. The benefits of syndromic diagnosis over seizure/symptom diagnosis or an inclusive diagnosis such as epilepsy far outweigh any morbidity from incorrect categorization that may arise in difficult cases.[4]
Important clinical features of a syndrome include the type of seizures, their localization, frequency, sequence of events, circadian distribution, precipitating factors, age at onset, mode of inheritance, physical or mental symptoms and signs, prognosis, and response to treatment.
Epilepsies or epilepsy?
The clinical and practical significance of the syndromic diagnosis of epilepsies is well illustrated by 3 common epileptic disorders. Benign childhood focal epilepsies, juvenile myoclonic epilepsy (JME), and hippocampal epilepsy have nothing in common other than the fact that they may all be complicated by generalized tonic-clonic seizures (GTCS), which are primarily GTCS in JME and secondarily GTCS in benign childhood focal epilepsies and hippocampal epilepsy.
Furthermore, the short-and long-term treatment strategies are entirely different for each disorder: benign childhood focal epilepsies may or may not require medication for a few years, appropriate anti-epileptic drug (AED) treatment is lifelong in JME while neurosurgery may be life-saving for patients with hippocampal epilepsy. What may be a life-saving drug such as carbamazepine for hippocampal epilepsy may be ill-advised for JME.
It should not be difficult to distinguish an intelligent child with benign focal seizures or childhood absence epilepsy from a child with Kozhevnikov-Rasmussen, Lennox-Gastaut, Down, or Sturge-Weber syndrome or a child with severe post-traumatic cerebral damage, brain anoxia, or catastrophic progressive myoclonic epilepsy. Describing all these children as simply having epilepsy just because they have seizures offers no more benefit than a diagnosis of febrile illness irrespective of cause, which may be a mild viral illness, a life-threatening acute bacterial meningitis, or a malignancy. Inappropriate generalizations with regard to terminology, diagnosis, and treatment are the single most important factor of mismanagement in epilepsies.[4]
C. P. Panayiotopoulos, MD, PhD, FRCP
Reviewed and revised June 2008 by Steven C. Schachter, MD
Back to topPrevalence
Only 50 families have been described.
Incidence
14.4/100,000 births.
Age at onset
First week of life, mainly on the second or third day.
Sex
Males = females.
Neurological and mental state
Normal.
Etiology
Channelopathy of an autosomal dominant pattern of inheritance and 85% degree of penetrance. It is caused by mutations in the voltage-gated potassium channel subunit gene KCNQ2 on chromosome 20q13.3 and KCNQ3 on chromosome 8q24. Mutations in either KCNQ2 or KCNQ3 can produce the same phenotype.
Clinical manifestations
Seizures mainly occur in full-term normal neonates after a normal pregnancy and delivery and without precipitating factors. Seizures are brief, usually 1 to 2 min, and may be as frequent as 20 to 30 per day. Most seizures start with tonic motor activity and posturing with apnea followed by vocalizations, ocular symptoms, other autonomic features, motor automatisms, chewing, and focal or generalized clonic movements. The clonic components of the later phase are usually asymmetrical and unilateral. The post-ictal state is brief. Inter-ictally the neonates are normal. Pure clonic or focal seizures are considered rare.
Diagnostic procedures
All relevant tests applied for neonatal seizures are normal.
Inter-ictal EEG
May be normal, discontinuous, or have focal or multifocal abnormalities or ‘théta pointu alternant’ pattern. It is of limited value, although it may exclude symptomatic neonatal seizures.
Ictal EEG
Onset with synchronous and bilateral flattening lasting from 5 to 19 sec and coinciding with apnea and tonic motor activity. This is followed by bilateral and often asymmetrical discharges of spikes and sharp waves for 1 to 2 min, which coincide with vocalizations, chewing, and focal or generalized clonic activity.
Prognosis
Usually good. Seizures remit between 1 and 6 months from onset. 10% to 14% may later develop other types of febrile (5%) or heterogeneous non-febrile seizures (mostly idiopathic generalized seizures). The risk of epilepsy depends on whether other affected relatives developed a seizure disorder later in life. Normal development occurs.
Differential diagnosis
A family history of similar convulsions eliminates the possibility of other diseases. Other causes of neonatal seizures should be excluded.
Benign familial neonatal seizures are entirely different from benign neonatal seizures (non-familial).
Management options
Anti-epileptic medication does not influence prognosis. Prolonged seizures may be terminated with benzodiazepines.
See also: http://professionals.epilepsy.com/page/syndromes_benignseizures.html
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
7% of neonatal seizures, but this has declined significantly in recent years.
Age at onset
First week of life, mainly (90%) in between the fourth and sixth days, for which the synonym ‘fifth day fits’ was coined.
Sex
Males (62%) slightly more than females.
Neurological and mental state
Normal.
Etiology
Unknown but probably environmental.
Clinical manifestations
There is a one-off event of a repetitive lengthy seizure that constitutes clonic status epilepticus, which occurs in otherwise normal full-term neonates. This consists of successive unilateral clonic convulsions affecting the face and the limbs. Convulsions may change sides and may also be less often bilateral. Apnea is a common concomitant in one third of these clonic seizures. Each seizure lasts from 1 to 3 min, repeating at frequent intervals and cumulating to discontinuous or continuous clonic status epilepticus. The whole seizure-status event lasts from 2 hours to 3 days, with a median of ~20 hours. It does not recur again. Tonic seizures are incompatible with this syndrome.
Diagnostic procedures
All relevant tests applied for neonatal seizures are normal.
Inter-ictal EEG
‘Theta pointu alternant’ pattern occurs in 1/2 of cases. In the others, the EEG may show focal or multifocal, non-specific abnormalities or a discontinuous pattern or it may be normal in ~10%.
Ictal EEG
Rhythmic spikes or slow waves, mainly in the Rolandic regions. The ictal paroxysms may be unilateral, generalized, or first localized and then generalized. Duration is 1 to 3 min and this may be followed by subclinical discharges for many hours.
Prognosis
Usually excellent, with normal development and no recurrence of seizures. Minor psychomotor deficits and occasional febrile or non-febrile seizures (0.5%) have been reported.
Differential diagnosis
The diagnosis can be made only after other causes of neonatal seizures have been excluded. Neonatal seizures with favorable outcomes include late hypocalcemia, subarachnoid hemorrhage, and certain meningitides.
They are entirely different from benign familial neonatal seizures.
Management options*
Prophylactic anti-epileptic drug (AED) treatment is generally not needed. Benzodiazepines or phenytoin can be used to terminate the prolonged seizure.
*Expert opinion, please check FDA-approved indications and prescribing information
See also: http://professionals.epilepsy.com/page/syndromes_benignconvulsions.html
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
Unknown. ~100 cases have been reported but this may be an underestimate. Neonates with such a severe disease and early death may escape clinico-EEG diagnosis.
Age at onset
First hours and days of life.
Sex
Males = females.
Neurological and mental state
Abnormal.
Etiology
Multifactorial disease. Inborn errors of metabolism are the most common causes (non-ketotic hyperglycinemia, propionic aciduria, methylmalonic acidemia, D-glyceric acidemia, sulphite and xanthine oxidase deficiency, Menkes disease, Zellweger syndrome, and molybdenum co-factor deficiency). Metabolic causes explain the high incidence of siblings with this disorder. Lesional brain abnormalities are rare.
Clinical manifestations
A triad of intractable seizures. Erratic myoclonus appears first followed by simple focal seizures and later by tonic epileptic (infantile) spasms.
Erratic myoclonias shift typically from one part of the body to another in a random and asynchronous fashion. They are often restricted in a finger, a toe, the eyebrows, eyelids, or lips, occurring in the same muscle group and often migrating elsewhere. Myoclonias are brief, single or repetitive, very frequent, and nearly continuous.
Massive, usually bisynchronous, axial myoclonic jerks may start from the onset of the disease or occur later, often interspersed with erratic myoclonias.
Other type of seizures
Simple focal seizures (eye deviation or autonomic symptoms such as flushing of the face or apnea), focal clonic seizures of any part of the body, asymmetrical tonic posturing.
Tonic seizures occur frequently; epileptic spasms are rare and generally appear later.
Diagnostic procedures
Metabolic screening is mandatory and analysis consists of mainly serum levels of amino acids, particularly glycine and glycerol metabolites, organic acids, and amino acids in the cerebrospinal fluid (CSF). Brain imaging is usually normal at the onset of the disease but atrophy often develops.
Inter-ictal EEG
‘Repetitive suppression-burst pattern’ without physiological rhythms. This evolves to atypical hypsarrhythmia or multifocal spikes and sharp waves 3 to 4 months from onset of the disease.
Ictal EEG
Erratic myoclonias usually do not have an ictal EEG expression and may follow the bursts.
Prognosis
Poor. More than half of the patients die within weeks or months from onset, and the others develop permanent, severe mental and neurological deficits.
Differential diagnosis
The main differential diagnosis is from Ohtahara syndrome.
Management options
Seizures are refractory to treatments.
See also: http://professionals.epilepsy.com/page/syndromes_encephalopathy.html
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
Unknown. ~100 cases have been reported but this may be an underestimate. Neonates with such a severe disease and early death may escape clinico-EEG diagnosis.
Age at onset
Mainly around the first 10 days of life, sometimes intra-uterine or up to 3 months of age. Epileptic spasms occur in 1.5 to 5 per 1000 newborns post-partum.
Sex
Males slightly predominate.
Neurological and mental state
Abnormal.
Etiology
The most common cause is malformations of cerebral development such as hemimegalencephaly, porencephaly, Aicardi syndrome, olivary-dentate dysplasia, agenesis of mamillary bodies, linear sebaceous nevus syndrome, cerebral dysgenesis, and focal cortical dysplasia. Rarely, other lesional brain or metabolic disorders may also be responsible.
Clinical manifestations
Mainly tonic spasms that usually consist of a forward tonic flexion lasting from 1 to 10 sec that is singular or in long clusters, 10 to 300 times every 24 hours. They may be generalized and symmetrical or lateralized. They occur in both the wake and sleep stages. Less often, 1/3 of the neonates may have erratic focal motor clonic seizures or hemiconvulsions. Alternating hemiconvulsions or generalized tonic clonic seizures (GTCS) are exceptional. Myoclonic seizures are rare. Erratic myoclonias are not featured.
Diagnostic procedures
As for neonatal seizures, in order to detect an etiological cause and possible treatment, brain imaging is used. Brain imaging usually shows severe abnormalities and malformations of cortical development. Metabolic screening is mandatory if brain imaging is normal.
Inter-ictal EEG
Pseudorhythmic repetitive suppression-burst pattern without physiological rhythms. There is an age-related evolution to hypsarrhythmia of West syndrome and then to slow spike-wave patterns of Lennox-Gastaut syndrome.
Ictal EEG
The suppression-burst pattern is associated with tonic spasms of variable duration concomitant with the burst phase. Tonic spasms may also occur with the following EEG features:
- Diffuse desynchronization with disappearance of suppression-burst activity when tonic spasms cluster in intervals of 5 to 10 sec.
- A pattern in which the suppression-burst pattern becomes more frequent, more diffuse, and of higher amplitude compared to the inter-ictal pattern.
Prognosis
Devastating syndrome associated with high mortality and morbidity. Half of the patients die within weeks or months from onset, and the others soon develop permanent, severe mental and neurological deficits.
Differential diagnosis
The main differential diagnosis of Ohtahara syndrome is from early myoclonic encephalopathy.
Management options
There is no effective drug treatment. Neurosurgery in focal cerebral dysplasia is sometimes beneficial.
This page was adapted from:
The educational kit on epilepsies
The epileptic syndromes
By C. P. Panayiotopoulos
Originally published by MEDICINAE
21 Cave Street, Oxford OX4 1BA
First published 2006 and reprinted in 2007
Reviewed and revised June 2008 by Steven C. Schachter, MD
 |
|
© 2009 Epilepsy.com. All rights reserved.
Site Map |
Privacy Statement |
Terms of Use |
Problems? Email webmaster@epilepsy.com
|