Practice parameter: evaluating a first nonfebrile seizure in children: report of the quality standards subcommittee of the American Academy of Neurology, The Child Neurology Society, and The American Epilepsy Society

[Management of patients after a first seizure]

Neuroimaging evaluation in patients after a first seizure could be easily determined on the basis of seizure history, neurological examination, blood sample analysis and electroencephalography. The main objectives of the initial work-up are to differentiate a true seizure event from seizure-like symptoms, to exclude a single seizure as a manifestation of non organic cause and finally to consider the seizure as a result of cerebral lesion or inaugurate epilepsy. When a new onset seizure is diagnosed, urgent neuroimaging is recommended only in patients with focal neurological deficit, persistent or worsening alteration in the level of consciousness and when clinical and biological data lead to a suspected vascular or infectious etiology. Brain CT scan is usually more available in emergency to identify the cause of seizure. It may have an important role for the therapeutic strategy and may defer MRI investigation. Nevertheless, brain MRI must be performed in emergency when CT scan is not conclusive despite a severe clinical condition or in case of cerebral venous thrombosis. Imaging modalities depend on clinical data, patient age and suspected epilepsy type.

Does sleep or sleep deprivation increase epileptiform discharges in pediatric electroencephalograms?

OBJECTIVE

Sleep deprivation before obtaining an electroencephalogram (EEG) is believed both to increase the likelihood of sleep during an EEG and to increase the detection of interictal epileptiform discharges. However, depriving a child of sleep poses a burden on both the parent and the child. The objective of this study was to compare the effects of sleep, standard sleep deprivation, partial sleep deprivation, and no sleep deprivation on the odds of an epileptiform abnormality in outpatient pediatric EEGs.

METHODS

Data were collected from all pediatric EEGs performed at a busy, university-based neurologic practice during two 2-month periods. During the first period, all EEGs were performed as ordered, either standard sleep-deprived (SSD) or non-sleep-deprived (NSD). During the second 2 months, SSD EEGs were performed per routine. However, non-SSD families were instructed to keep their children awake 2 hours later the night before the EEG. Those who complied were classified as partially sleep-deprived (PSD). Patient characteristics across protocols were compared with chi(2) and analysis of variance tests as appropriate. The odds of epileptiform and abnormal findings associated with sleep, NSD, PSD, and SSD EEGs were calculated using logistic regression.

RESULTS

Of 820 eligible EEGs, sleep occurred in 22% of NSD, 44% of PSD, and 57% of SSD EEGs. The sample size of this study allowed for an 85% power, with alpha of.05, to detect an absolute increased EEG yield of 10%. Neither the presence of sleep (odds ratio [OR]: 0.99; 95% confidence interval [CI]: 0.69-1.42) nor the use of PSD (OR: 0.90; 95% CI: 0.50-1.62) or SSD (OR: 0.96; 95% CI: 0.63-1.47) protocols increased the odds of epileptiform EEGs.

CONCLUSIONS

Sleep deprivation should not be used routinely to increase the yield of pediatric EEGs.

Autonomic seizures and autonomic status epilepticus peculiar to childhood: diagnosis and management

Autonomic seizures and autonomic status epilepticus in children have a high prevalence, manifest with dramatic clinical symptoms, and have important clinical and management implications. They probably affect approximately 13% of children aged 3-6 years with one or more nonfebrile seizures, or 6% in the age group 1-15. The primary cause is an idiopathic age-dependent epileptogenic susceptibility (Panayiotopoulos syndrome), but 10-20% are due to cerebral pathology. Autonomic seizures and autonomic status epilepticus have been best studied in Panayiotopoulos syndrome, which has been confirmed worldwide in more than 800 cases and recently recognized in the new classification scheme of the International League Against Epilepsy. Seizures start with autonomic symptoms, mainly emesis, while the child is usually fully conscious. Other more conventional seizure manifestations often ensue, but autonomic manifestations commonly predominate to the end of the seizure. Ictal syncope (transient loss of consciousness and postural tone) is an intriguing common symptom. Half of the seizures last longer than 30 minutes, constituting autonomic status epilepticus. Prognosis is invariably excellent except for the symptomatic cases. The interictal EEG shows great variability from normal to severely epileptogenic, often with multifocal spikes. Pathophysiology of Panayiotopoulos syndrome is unknown, but it is likely that they are due to diffuse maturation-related epileptogenicity activating susceptible-for-children emetic centers and the hypothalamus. Thus, Panayiotopoulos syndrome is not occipital epilepsy, with which it is often erroneously equated. Autonomic seizures and autonomic status epilepticus are frequently misdiagnosed and often treated as encephalitis, atypical migraine, cardiogenic syncope, or other unrelated medical conditions such as gastroenteritis. This review examines the existing evidence, provides a means of improving diagnostic yield, and proposes practice parameters and guidelines for the diagnosis and management of autonomic seizures and autonomic status epilepticus in children.

Evaluating new onset of seizures in children

Children who present either to the pediatrician's office or the emergency department with seizures should undergo a careful and detailed history and physical examination. This is done to distinguish between epileptic and nonepileptic events and to characterize among acute symptomatic, remote symptomatic, and idiopathic etiologies. An EEG is obtained both to assist in this differentiation and to help with medication selection and syndrome diagnosis. Brain imaging, where obtained, should be with a MRI scan except in specific incidences of acute symptomatic seizures. Most patients with idiopathic benign epilepsy will not require a brain image and may not require anticonvulsant medication. Prognosis is based on the etiology and syndrome and is usually excellent in acute symptomatic epilepsy (based on the source), very favorable in idiopathic epilepsy, and less favorable in remote symptomatic cases.

Clinical policy: Critical issues in the evaluation and management of adult patients presenting to the emergency department with seizures

This clinical policy focuses on critical issues in the evaluation and management of adult patients with seizures. The medical literature was reviewed for articles that pertained to the critical questions posed. Subcommittee members and expert peer reviewers also supplied articles with direct bearing on this policy. This clinical policy focuses on 6 critical questions: What laboratory tests are indicated in the otherwise healthy adult patient with a new-onset seizure who has returned to a baseline normal neurologic status?Which new-onset seizure patients who have returned to a normal baseline require a head computed tomography (CT) scan in the emergency department (ED)?Which new-onset seizure patients who have returned to normal baseline need to be admitted to the hospital and/or started on an antiepileptic drug?What are effective phenytoin or fosphenytoin dosing strategies for preventing seizure recurrence in patients who present to the ED after having had a seizure with a subtherapeutic serum phenytoin level?What agent(s) should be administered to a patient in status epilepticus who continues to seize after having received benzodiazepine and phenytoin?When should electroencephalographic (EEG) testing be performed in the ED? Recommendations for patient management are provided for each 1 of these topics on the basis of strength of evidence (Level A, B, or C). Level A recommendations represent patient management principles that reflect a high degree of clinical certainty; Level B recommendations represent patient management principles that reflect moderate clinical certainty; and Level C recommendations represent other patient management strategies based on preliminary, inconclusive, or conflicting evidence, or based on consensus of the members of the Clinical Policies Committee. This clinical policy is intended for physicians working in hospital-based EDs.

Clinical and electroencephalographic follow-up after a first unprovoked seizure

We studied the role of clinical and electroencephalographic factors in the follow-up of children and adolescents after a first unprovoked seizure, and their correlation with recurrence and risk for epilepsy. We conducted a 24-month follow-up of 109 patients aged 1 month to 16 years who had a first unprovoked seizure. We analyzed the characteristics of the first seizure, perinatal history, family history of seizures, electroencephalographic patterns and their influence on seizure recurrence, and calculated risk for subsequent epilepsy. Fifty-six patients (51.4%) had recurrent seizures. The bivariate statistical analysis revealed that maternal prenatal disease (relative risk = 2.02, P = 0.03) and an abnormal electroencephalogram (relative risk = 2.89, P = 0.0003) were significantly associated with seizure recurrence. Other factors (male sex, partial first seizure, vaginal delivery, family history of seizures, and sleep state) approached statistical significance. Logistic regression revealed that the only variable significantly associated with recurrence was an abnormal electroencephalographic pattern on the first examination (relative risk = 2.48, P = 0.003). Cumulative risk ranged from 50-68% at 24 months when the first electroencephalogram was abnormal, and from 26-36% when it was normal. We concluded that the electroencephalogram may have an important diagnostic value in the prognosis of epileptic seizure recurrence in children and adolescents.

Risk of seizure recurrence after a first unprovoked seizure: a prospective study among Jordanian children

PURPOSE

There is wide variation in the reported recurrence rate after a first unprovoked seizure in children. We investigated the risk of recurrence after a first unprovoked seizure in Jordanian children and the risk factors associated with increased recurrence rate.

METHODS

All consecutive patients aged 3 months-14 years who presented with their first unprovoked seizures between January 1997 and 2000, were included in a prospective study and followed up for 3 years for possible recurrence. Of the patients studied, there was slight male predominance (56.6%) and 55% of them were 2-9 years of age. Generalised seizures were reported in 75% and the remaining 25% had partial seizures. The duration of seizure was 1-4 minutes in 59%. Family history of epilepsy was positive in 31% and parental consanguinity in 32%. The role of these factors in increasing the risk of recurrence was also investigated.

RESULTS

Two hundred sixty-five patients were included in the study and continued follow up for 3 years. Ninety-eight (37%) of them experienced seizure recurrence. Among the predictor factors for recurrence, partial seizure (P = 0.003) and positive family history (P = 0.000) were associated with a statistically significant increased risk. Sex, age, duration of seizure and consanguinity were not associated with increased risk of recurrence.

CONCLUSION

Thirty-seven percent of the children studied experienced a second attack after a first unprovoked seizure over the 3 years follows up period. The risk of recurrence was significantly higher in children with a partial seizure (55%) and among those with a positive family history of epilepsy (59%). Age at first seizure, sex, duration of seizure and consanguinity were not significantly related to the risk of recurrence.

Evidence-based medicine: neuroimaging of seizures

Evidence-based medicine is useful in epilepsy and neuroimaging (Figs. 1 and 2). An understanding of the pretest probability suggests that focal neurologic deficits are important in predicting the outcome of neuroimaging examinations. In cases of nonacute symptomatic seizures, confusion and postictal deficits should prompt MR evaluation. In remote symptomatic seizures, MR imaging should be performed in a child with unexplained cognitive or motor delays or a child less than 1 year of age. Patients with partial seizures, abnormal EEG, or generalized epilepsy also should be imaged. Acute seizures should be imaged with CT to exclude hemorrhage and because of the availability and speed of the modality. Ictal SPECT is the best neuroimaging examination to localize seizure activity. MR imaging can offer prediction of surgical outcome and may hold promise in the future for dimensional localization of seizure focus. Evidence-based medicine can only work if there is physician communication. The pretest probability is helpful only when an accurate history is provided to the consulting physician. This field will flourish if physicians can develop accurate methods of collating information and reporting it in a timely fashion in the literature.

Classification of seizures and epilepsy

The management of seizures and epilepsy begins with forming a differential diagnosis, making the diagnosis, and then classifying seizure type and epileptic syndrome. Classification guides treatment, including ancillary testing, management, prognosis, and if needed, selection of the appropriate antiepileptic drug (AED). Many AEDs are available, and certain seizure types or epilepsy syndromes respond to specific AEDs. The identification of the genetics, molecular basis, and pathophysiologic mechanisms of epilepsy has resulted from classification of specific epileptic syndromes. The classification system used by the International League Against Epilepsy is periodically revised. The proposed revision changes the classification emphasis from the anatomic origin of seizures (focal vs generalized) to seizure semiology (ie, the signs or clinical manifestations). Modified systems have been developed for specific circumstances (eg, neonatal seizures, infantile seizures, status epilepticus, and epilepsy surgery). This article reviews seizure and epilepsy classification, emphasizing new data.

The role of emergent neuroimaging in children with new-onset afebrile seizures

OBJECTIVES

The objectives of this study were 1) to determine the frequency of clinically significant abnormal neuroimaging in children coming to the emergency department (ED) with new-onset afebrile seizures (ASZ), and 2) to identify children at high or low risk for clinically significant abnormal neuroimaging.

DESIGN/METHODS

Five hundred consecutive cases of new-onset ASZ seen in the ED of a tertiary care children's hospital were reviewed. Neuroimaging reports were categorized as normal, clinically insignificant abnormal, or clinically significant abnormal. Recursive partition analysis was used to identify clinical variables that separated children into high- and low-risk groups for clinically significant abnormal neuroimaging.

RESULTS

Ninety-five percent of patients (475/500) with new-onset ASZ had neuroimaging. Clinically significant abnormal neuroimaging was noted in 8% (95% confidence interval [CI]: 6, 11; 38/475) of patients. Recursive partition analysis identified 2 criteria associated with high risk for clinically significant abnormal neuroimaging: 1) the presence of a predisposing condition, and 2) focal seizure if <33 months old. Of the high-risk patients, 26% (95% CI: 17, 35; 32/121) had clinically significant abnormal neuroimaging compared with 2% (95% CI: 0.6, 3.7; 6/354) in the low-risk group.

CONCLUSIONS

In this large, retrospective review of children with new-onset ASZ, clinically significant abnormal neuroimaging occurred with relatively low frequency. Emergent neuroimaging should be considered, however, for children who meet high-risk criteria. Well-appearing children who meet low-risk criteria can be safely discharged from the ED (if follow-up can be assured) without emergent neuroimaging, because their risk for clinically significant abnormal neuroimaging is appreciably lower.

Role of neuroimaging in the management of seizure disorders

Neuroimaging is one of the most important advances made in the past decade in the management of seizure disorders. Magnetic resonance imaging (MRI) has increased substantially the ability to detect causes of seizure disorders, to plan medical or surgical therapy, and to prognosticate the outcome of disorders and therapy. However, MRI must be performed with techniques that will maximize the detection of potentially epileptogenic lesions, especially in candidates for epilepsy surgery. Functional imaging has an established role in evaluating patients for epilepsy surgery. It is relied on when results from standard diagnostic methods, such as clinical information, electroencephalography, and MRI, are insufficient to localize the seizure focus. Also, functional imaging is a reportedly reliable alternative to invasive methods for identifying language, memory, and sensorimotor areas of the cerebral cortex. Despite the availability of multimodality imaging, the epileptogenic zone is not determined solely by a single imaging modality. Evidence and experience have shown that concordance of results from clinical, electrophysiologic, and neuroimaging studies is needed to identify the epileptogenic zone accurately. With modern techniques in image processing, multimodality imaging can integrate the location of abnormal electroencephalographic, structural, and functional imaging foci on a "map" of the patient's brain. Computer image-guided surgery allows surgically exact implantation of intracranial electrodes and resection of abnormal structural or functional imaging foci. These techniques decrease the risk of morbidity associated with epilepsy surgery and enhance the probability of postsurgical seizure control.

Do occasional brief seizures cause detectable clinical consequences?

Seizures, particularly when prolonged or frequent, have been associated with a variety of adverse outcomes. However, epidemiological data provide little evidence for adverse effects of isolated brief seizures per se. Even the animal data is mostly for prolonged or frequent seizures. Febrile seizures lasting < 10 min have not been associated with adverse seizures or cognitive outcomes. Treating either febrile seizures or other acute symptomatic seizures does not reduce the risk of subsequent epilepsy. In subjects with a first unprovoked seizure, seizure duration does not influence recurrence risk. Furthermore, treatment after a first unprovoked seizure reduces recurrence risk, but does not alter long-term prognosis. In epidemiological studies of newly diagnosed epilepsy, the number of seizures prior to therapy does not influence prognosis. There are a variety of specific epilepsy syndromes associated with poor cognitive outcomes and with progressive loss of function. However, the poor outcomes in these syndromes do not appear to be the result of seizures per se but rather to the specific syndrome and to the frequent interictal spike activity seen in these patients. Antiepileptic drugs, while effective in reducing seizure recurrence are also associated with a variety of potential adverse effects. On a risk-benefit basis, the available epidemiologic data do not justify starting treatment after the first seizure to attempt to influence long-term prognosis.

Common emergent pediatric neurologic problems

Although there are a variety of neurologic disease processes that the emergency physician should be aware of the most common of these include seizures, closed head injury, headache, and syncope. When one is evaluating a patient who has had a seizure, differentiating between febrile seizures, afebrile seizures, and SE helps to determine the extent of the work-up. Febrile seizures are typically benign, although a diagnosis of meningitis must not be missed. Educating parents regarding the likelihood of future seizures, and precautions to be taken should a subsequent seizure be witnessed, is important. The etiology of a first-time afebrile seizure varies with the patient's age at presentation, and this age-specific differential drives the diagnostic work-up. A follow-up EEG is often indicated, and imaging studies can appropriate on a nonurgent basis. Appropriate management of SE requires a paradigm of escalating pharmacologic therapy, and early consideration of transport for pediatric intensive care services if the seizure cannot be controlled with conventional three-tiered therapy. Closed head injury frequently is seen in the pediatric emergency care setting. The absence of specific clinical criteria to guide the need for imaging makes management of these children more difficult. A thorough history and physical examination is important to uncover risk factors that prompt emergent imaging. Headaches are best approached by assessing the temporal course, associated symptoms, and the presence of persistent neurologic signs. Most patients ultimately are diagnosed with either a tension or migraine headache; however, in those patients with a chronic progressive headache course, an intracranial process must be addressed and pursued with appropriate imaging. Syncope has multiple causes but can generally be categorized as autonomic, cardiac, or noncardiac. Although vasovagal syncope is the most common cause of syncope, vigilance is required to identify those patients with a potentially fatal arrhythmia or with heart disease that predisposes to hypoperfusion. As such, all patients who present with syncope should have an ECG. Additional work-up studies are guided by the results of individual history and physical examination.

Update on the epidemiology and prognosis of pediatric epilepsy

Epilepsy is among the most common serious neurologic disorders in childhood. Epidemiologic studies over the past few decades have greatly increased current knowledge of the incidence and prognosis of seizures. Newer epidemiologic studies have used population- or community-based cohorts, and careful attention has been given to etiology and specific epilepsy syndromes, the two most important factors affecting prognosis. Risk of epilepsy is highest in patients with an associated serious neurologic abnormality, such as mental retardation or cerebral palsy. More than two thirds of patients with childhood-onset epilepsy ultimately achieve remission. Of those attaining remission on medications, approximately 70% remain seizure free when medications are discontinued. Mortality is increased in patients with epilepsy, but the increased mortality risk in childhood-onset epilepsy is primarily seen in patients with neurologic abnormalities or intractable epilepsy. Although long-term seizure outcomes are generally favorable, childhood-onset epilepsy is associated with adverse long-term psychosocial outcomes, even in patients attaining remission. This review summarizes recent data on the epidemiology and prognosis of pediatric epilepsy.

Factors affecting the yield of pediatric EEGs in clinical practice

Clinical factors affecting the yield of 2,500 pediatric electroencephalograms were analyzed. Electroencephalograms were interpreted as epileptiform in 40% of children with epilepsy. Most electroencephalograms were ordered for seizure in children not taking anti-epileptic drugs; just 15% showed epileptiform features. Six percent of electroencephalograms were epileptiform in non-seizure patients. The neurologist significantly influenced the odds of epileptiform interpretation (P = 0.022) and the recommendation to repeat the electroencephalogram (P < 0.001). In practice most electroencephalograms ordered for seizure are actually for non-seizure. In routine pediatric practice, electroencephalography has a low yield and appears to be over-used.

Initiation and discontinuation of antiepileptic drugs

The issues of when to initiate and discontinue antiepileptic drugs (AEDs) are reviewed using an approach that emphasizes weighing the relative risks and benefits of the therapeutic decisions. The majority of children and adults who present with a first unprovoked seizure will not experience further seizures. Treatment reduces recurrence risk but does not alter long-term prognosis. Treatment should be deferred until a second seizure has occurred. The majority of children and adults who are seizure free for two or more years on medications will remain so when medications are withdrawn. The risk of reoccurrence is somewhat higher in adults. The consequences of recurrence are much more significant in adults. Most children who are seizure free on medications should have at least one attempt at medication withdrawal. In adults, the decisions need to be individualized based on a variety of factors including age, sex, occupation, and the presence or absence of risk factors for reoccurrence.

Neuroimaging abnormalities in children with an apparent first unprovoked seizure

OBJECTIVE

To determine the incidence and type of neuroimaging abnormalities in children presenting with a first seizure.

METHODS

In a prospective observational study, 411 children with a first afebrile seizure were seen between 1983 and 1992. Imaging studies were performed in 218 (53%). For this analysis we examined the most sensitive neuroimaging study performed which included 159 computed tomography scans and 59 magnetic resonance imagings (MRI).

RESULTS

Four children were found to have lesions requiring intervention (brain tumor in two, neurocysticercosis in two). The remaining 407 were enrolled in a follow-up study of children with a first unprovoked seizure. After a mean follow-up of >10 years, none have developed clinical evidence of a tumor. In these 411 children, 45 (21%) of 218 imaging studies were abnormal. The most common abnormalities were focal encephalomalacia (n=16) and cerebral dysgenesis (n=11). Although children with partial seizures were more likely to be imaged (64%) than children with generalized seizures (43%) (P<0.001), the fraction of abnormal imaging studies was similar in both groups. Six children with a normal neurological examination who were initially classified as cryptogenic were subsequently found to have errors of cerebral migration on MRI. The incidence of lesions requiring acute intervention in children presenting with a first seizure is low. A significant proportion will have neuroimaging abnormalities particularly on MRI.

CONCLUSIONS

Neuroimaging should be considered in any child with a first seizure who does not have an idiopathic form of epilepsy.