- Benign familial and non-familial infantile seizures (Watanabe-Vigevano syndrome)
- Benign myoclonic epilepsy in infancy
- Febrile seizures
- Generalized epilepsies with febrile seizures plus (GEFS ; Autosomal dominant epilepsy with febrile seizures plus)
An idiopathic epilepsy syndrome is a syndrome that is only epilepsy, with no underlying structural brain lesion or other neurological signs or symptoms. Idiopathic epilepsy syndromes are presumed to be genetic and are usually age dependent.
Idiopathic comes from the Greek words idios (meaning self, own, and personal) and pathic (suffer, see also pathology and pathological). Idiopathic is not synonymous with benign. There are idiopathic epilepsies with bad prognoses or lifelong duration and, conversely, there are symptomatic epilepsies with a few seizures that may not even need treatment.
The infantile period is defined as between 4 weeks and 1.5 years. Idiopathic epileptic seizures, are situation-related, isolated, or age-related benign epileptic seizures that do not require a diagnosis of epilepsy. Idiopathic epileptic seizures starting in the infantile and early childhood age include:
- Benign familial and non-familial infantile seizures (Watanabe-Vigevano syndrome)
Idiopathic epileptic syndromes starting in the infantile and early childhood age are:
- Benign myoclonic epilepsy in infancy
- Febrile seizures
- Generalized epilepsy with febrile seizure plus (autosomal dominant epilepsy with febrile seizures plus)
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
~100 cases have been reported; this may increase with improved awareness of the condition.
Age at onset
3 to 20 months; peak at 5 to 6 months.
Sex
Males = females in the non-familial form but more females are reported in the familial cases.
Neurological and mental status
Normal.
Etiology
The familial form is most likely autosomal dominant disorder with genetic heterogeneity (chromosomes 19q, 16, or 2).
Clinical manifestations
Diurnal focal seizures of motion arrest, decreased responsiveness, staring, eye and head deviation, simple automatisms, and mild clonic movements. They may or may not progress to generalized convulsions. Alternating from one side to the other side is common. Duration is usually short, from 30 sec to 3 min. They occur in clusters of a maximum of 8 to 10 per day for 1 to 3 days and may recur after 1 to 3 months.
Diagnostic procedures
All relevant tests are normal.
Inter-ictal EEG
Normal.
Ictal EEG
Focal discharges.
Prognosis
Excellent, with normal development and complete seizure remission.
Differential diagnosis
Difficult in sporadic form that requires long follow-up.
Management options
In the active seizure period, empirical drug treatment is usually effective. This is usually withdrawn after 1 to 3 years.
Reviewed and revised June 2008 by Steven C. Schachter, MD
Prevalence
~1% to 2% of epilepsies that start before the age of 3 years.
Age at onset
6 months to 3 years but also earlier (4 months) or later (4 years).
Sex
Males (66%) predominate.
Neurological and mental state
Normal.
Etiology
Probably genetic. It is the earliest form of idiopathic generalized epilepsy (IGE).
Clinical manifestations
Myoclonic jerks, singular or clusters. Consciousness is intact but mild clouding may occur during cluster of jerks.
There are no other types of seizures other than simple febrile seizures in 10%.
Seizure-precipitating factors
Photosensitivity (20%), unexpected acoustic or tactile stimuli (10%).
Timing
Awakening or during the first hours of sleep.
Inter-ictal EEG
Normal.
Ictal EEG
Generalized polyspike or spike and slow-wave discharges.
Prognosis
Remission usually occurs within 1 year (6 months to 5 years) from onset. 10% to 20% develop infrequent generalized tonic-clonic seizures in their early teens. 10% to 20%, if untreated, may develop mild cognitive, behavioral, or motor deficits. EEG photosensitivity may persist after remission of seizures.
Differential diagnosis
(1) Non-epileptic conditions (hypnagogic jerks and benign non-epileptic myoclonus) and (2) Dravet syndrome and West syndrome.
Management options*
Excellent response to valproate, which should be withdrawn 3 to 5 years from onset. Patients with acoustic and somatosensory evoked myoclonus may not need treatment.
*Expert opinion, please check FDA-approved indications and prescribing information
See also: http://professionals.epilepsy.com/page/syndromes_benignmyoclonic.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
~3% of children.
Incidence
460/100,000 in the age group 0 to 4 years.
Age at onset
6 months to 5 years; peak at 18 to 22 months.
Sex
Males (60%) slightly predominate.
Neurological and mental state
Normal.
Etiology
Often familial.
Clinical manifestations
Main types of seizures: generalized tonic-clonic seizures (GTCS; 80%), tonic (13%), atonic (3%), unilateral, or with focal onset tonic-clonic convulsions (4%).
Simple febrile seizures (70%) are GTCS lasting <15 min and without recurrence within the next 24 hours (or within the same febrile illness).
Complex febrile seizures (30%) may last >15 min (8%), have 2 or more recurrences within 24 hours (16%), or show focal or unilateral features (6%).
Seizure-precipitating factors
Fever at least 38ºC.
EEG
Not needed.
Prognosis
6-fold excess (3%) of subsequent epilepsy compared with controls; 2% after simple and 5% to 10% after complex febrile seizures.
Differential diagnosis
Other epilepsies, symptomatic seizures of febrile illnesses.
Management options
Acute management involves control of the seizure and treatment of the fever and of the underlying illness. Termination of long-lasting convulsions is the same as for status epilepticus. Antipyretic treatment during febrile illnesses does not reduce the recurrence rate.
Prophylactic management is usually not needed for simple febrile seizures.
Parental education is mandatory.
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 but possibly high considering the increasing numbers of publications and the broad spectrum of GEFS+.
Age at onset
The age at onset, from the first months of life to childhood, varies considerably among patients, even individuals of the same family. Febrile seizures start earlier (median 1 year) than the typical febrile seizures; they are often multiple and continue beyond 6 years.
Sex
Males = females.
Neurological and mental state
Normal.
Etiology
Purely genetic disorder with profound heterogeneity. Inheritance is generally autosomal dominant with incomplete penetrance, but this may not be the only situation. Two loci are on chromosome 19q (GEFS+) and chromosome 2q (GEFS2). Mutations were found in voltage-gated sodium channel subunits and GABAA–receptor gamma 2 subunit. Seizure predisposition determined by the GEFS+ genes probably modified by other genes and environmental factors.
Clinical manifestations
Febrile seizures plus (FS+) comprise childhood onset of multiple febrile seizures that (unlike the typical febrile seizure) continue beyond the age of 6 years.
The syndrome of GEFS+ is characterized by the presence of febrile and heterogeneous non-febrile seizures. There is a variety of clinical phenotypes, including typical febrile seizures (49%), FS+ (24%), and other seizure types (13%) such as absences, myoclonic or atonic seizures, and focal seizures. Absences are infrequent and unlike those of childhood absence epilepsy (CAE). Dravet syndrome probably represents the very severe end of the spectrum within the GEFS+ phenotype. Myoclonic astatic seizures such as those of Doose syndrome (epilepsy with myoclonic astatic seizures) occur in 14%.
Inter-ictal EEG
Usually normal background with generalized discharges.
Ictal EEG
Depends on seizure type.
Prognosis
Seizures usually remit by mid-childhood (median 11 years). Development is usually normal.
Differential diagnosis
Febrile seizures. The evolution to severe clinical phenotypes such as epilepsy with myoclonic astatic seizures (EM-AS) or Dravet syndrome becomes apparent only with the emergence of new types of seizures compatible with these disorders.
Management options*
Repetitive febrile seizures or FS+ may need prophylactic treatment. Valproate, lamotrigine, levetiracetam, or topiramate may be used for non-febrile generalized seizures, if these are frequent.
*Expert opinion, please check FDA-approved indications and prescribing information
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
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