Clinical imitators of infantile spasms

Electroclinical Features of Infantile Epileptic Spasms Syndrome

Epileptic spasms are a unique, age-dependent manifestation of epilepsies in infancy and early childhood, commonly occurring as part of infantile epileptic spasms syndrome. Developmental stagnation and subsequent decline may occur in children with epileptic spasms, partly due to the abundant high-amplitude interictal epileptiform and slow wave abnormalities. Early recognition and treatment of epileptic spasms, along with the reversal of the electroencephalography (EEG) findings, are critical for improving outcomes. Recognizing hypsarrhythmia and its variations is key to confirming the diagnosis. The various patterns of hypsarrhythmia are not etiology specific, but could indicate the severity of the disease. Several scoring systems have been proposed to improve the inter-rater reliability of recognizing hypsarrhythmia and to assess EEG progress in response to treatment. Ictal patterns during spasms are brief and composed of slow waves, sharp transients, fast activity, and voltage attenuation, either in isolation or more commonly as a combination of these waveforms. Ictal patterns are commonly diffuse, but may be lateralized to one hemisphere in children with structural etiology. A subset of patients with epileptic spasms has a surgically remediable etiology, with readily identifiable lesions on neuroimaging in most cases. Asymmetry in epileptic spasms, concurrent focal seizures, and asymmetric interictal and ictal EEG findings may be present, but a lack of focality in electrophysiological findings is not uncommon. Intracranial EEG features of epileptic spasms have been described, but the utility of intracranial EEG monitoring in surgical candidates with overt focal epileptogenic lesions on magnetic resonance imaging is questionable, and surgery could be performed using noninvasive data.

Transient benign paroxysmal movement disorders in infancy

This review summarizes the current empirical and clinical literature on benign paroxysmal movement disorders in infancy most relevant to practitioners. Paroxysmal benign movement disorders are a heterogeneous group of movement disorders characterized by their favourable outcome. We pay special attention to the recognition and management of these abnormal motor conditions strongly suggestive of epileptic disorders. They include: neonatal jitteriness; benign neonatal sleep myoclonus; benign paroxysmal tonic upgaze; paroxysmal tonic downgaze, benign paroxysmal torticollis and benign polymorphous movement disorder of infancy.

Misdiagnosis of gastroesophageal reflux disease as epileptic seizures in children

BACKGROUND

Gastroesophageal reflux disease (GERD) can mimic epileptic seizure, and may be misdiagnosed as epilepsy. On the other hand, GERD can be more commonly seen in children with neurological disorders such as cerebral palsy (CP); this co-incidence may complicate the management of patients by mimicking refractory seizures.

OBJECTIVE

The purpose of our study was to evaluate the clinical features, definite diagnoses and treatment approaches of the patients with clinically suspected GERD who were referred to the division of pediatric neurology with a suspected diagnosis of epileptic seizure. We also aimed to investigate the occurrence of GERD in children with epilepsy and/or CP.

METHODS

Fifty-seven children who had a final diagnosis of GERD but were initially suspected of having epileptic seizures were assessed prospectively.

RESULTS

All patients were assigned to 3 groups according to definite diagnoses as follows: patients with only GERD who were misdiagnosed as having epileptic seizure (group 1: n=16; 28.1%), those with comorbidity of epilepsy and GERD (group 2: n=21; 36.8%), and those with the coexistence of GERD with epilepsy and CP (group 3: n=20; 35.1%). Five patients (8.8%) did not respond to anti-reflux treatment and laparoscopic reflux surgery was performed. The positive effect of GERD therapy on paroxysmal nonepileptic events was observed in 51/57 (89.5%) patients.

CONCLUSIONS

GERD is one of the important causes of paroxysmal nonepileptic events. In addition, GERD must be kept in mind at the initial diagnosis and also in the long-term management of patients with neurological disorders such as epilepsy and CP.

Contrast sensitivity is reduced in children with infantile spasms

PURPOSE

To investigate whether visual deficits in children with infantile spasm (IS) are the result of seizure activity or of treatment with the anticonvulsant drug vigabatrin (VGB).

METHODS

Vision function was determined in three experiments by determining peak contrast sensitivity (CS) and grating acuity (GA) with the sweep visual evoked potential. Cross-sectional study A: 34 children, including 11 patients with childhood epilepsy with exposure to VGB for at least 6 months, 10 with childhood epilepsy exposed to antiepileptic drugs other than VGB, and 13 normally developing children. Cross-sectional study B: 32 children, including 16 with IS naïve to VGB and 16 normally developing children. Longitudinal study: seven children with IS naïve to VGB, with subsequent follow-up 5 to 10 months after starting VGB.

RESULTS

In cross-sectional study A, the median CS was reduced by 0.5 log units (P = 0.025) in children with epilepsy exposed to VGB compared with those exposed to other antiepileptic drugs and normally developing children. In cross-sectional study B, the median CS was reduced by 0.25 log units (P = 0.0015) in children with IS (VGB naïve) compared with normally developing children. Longitudinal assessment showed no decrease in CS in children with IS who were followed up 5 to 10 months after starting VGB. There was no difference in GA among groups in any of the experiments.

CONCLUSIONS

Patients with IS have CS deficits, but a sparing of GA. This deficit is present before VGB treatment and does not worsen with treatment onset. Results suggest that visual dysfunction is largely the result of the seizures themselves.

Does epilepsy influence the outcome of antireflux procedures in neurologically impaired children?

In neurologically impaired patients (NIP), surgical management of gastroesophageal reflux disease (GERD) has become a widespread standard. Several follow-up studies have shown a high incidence of complications and recurrent reflux. As one of the possible causes epilepsy is mentioned repeatedly in the literature. The aim of this study was to determine the effective impact of epilepsy on the postoperative outcome by comparing results of our patients suffering from epilepsy to those without this disorder. From 1984 to 1999, a total of 45 NIP underwent antireflux surgery, including 20 patients suffering from epilepsy (EP) and 25 patients without this disorder (nEP). The existence of epileptic disorders, incidence of epileptic seizures and administration of anticonvulsatory drugs as well as results of diagnostic procedures, postoperative complications and incidence and time of recurrence of pathologic GER were recorded and analysed retrospectively. Preoperatively all patients had pathologic results in 24 h pH-monitoring. Median RI was 15.75 (EP, range 5.2-28.6) and 17.55 (nEP; range 7.2-26.5). 12-months-postoperative 24 h pH-monitoring showed a median RI of 3.8 (EP; range 1.3-25.6) versus a median RI of 3.3 (nEP; range 0.7-26.3). During the long-term follow-up evaluation of 3.9 years, 17 EP suffered from persistent epileptic seizures despite medical treatment. 19 patients (42%) developed recurrent reflux. This included seven EP (35%) and 12 nEP (48%). The necessity of reoperation was higher in nEP (n = 5, 20%) than in EP (n = 1, 5%). This analysis did not show a significant correlation between recurrence of pathologic GER after fundoplication and the incidence of epileptic seizures. We consider our findings to strongly question the widespread opinion considering this correlation. We conclude, that cerebral seizures alone do not alter the operative outcome of antireflux surgery in NIP.

Infantile spasms and Lennox-Gastaut syndrome

Infantile spasms and Lennox-Gastaut syndrome are rare but are important to child neurologists because of the intractable nature of the seizures and the serious neurologic comorbidities. New antiepileptic drugs offer more alternatives for treating both infantile spasms and Lennox-Gastaut syndrome. Selected children with infantile spasms are candidates for epilepsy surgery. Vagus nerve stimulation, corpus callosotomy, and the ketogenic diet are all options for selected children with Lennox-Gastaut syndrome. The epidemiology, clinical manifestations of the seizures, electroencephalographic characteristics, prognosis, and treatment options are reviewed for infantile spasms and Lennox-Gastaut syndrome. Additional therapies are needed for both infantile spasms and Lennox-Gastaut syndrome as many children fail to achieve adequate seizure control in spite of newer treatments.

Infantile spasms

Infantile spasms constitute both a distinctive seizure type and an age-specific epilepsy syndrome that have been extensively described for over a century. Standardization of the classification of infantile spasms has evolved, culminating in recent recommendations for separately recognizing and distinguishing the seizure type (spasms or epileptic spasms) and the epilepsy syndrome of infantile spasms (West syndrome). More-detailed descriptions of the clinical and electrographic features of epileptic spasms and hypsarrhythmia have emerged. Advances in neuroimaging techniques have revealed clues about pathophysiology and increased the etiologic yield of the diagnostic evaluation of patients with infantile spasms. Adrenocorticotrophic hormone remains the treatment of choice for many neurologists. Recent controlled studies support vigabatrin as first-line therapy, and open-label studies suggest that topiramate, lamotrigine, and zonisamide may be useful in treating spasms. Recent reports of visual-field constriction with vigabatrin may limit its use. Surgical treatment has been used successfully in a select subgroup of patients with secondarily generalized spasms from a single epileptogenic zone. Although the prognosis for most patients with infantile spasms remains poor, further studies identifying predictors of favorable prognosis and recent advances in understanding the pathophysiology of infantile spasms offer hope of safer and more-effective therapies that improve long-term outcome.

Effective utilization of home-video recordings for the evaluation of paroxysmal events in pediatrics

In young children, differentiating seizures from nonepileptic "spells" by history alone can be difficult, even for the specialist. Nonepileptic spells may be psychogenic (rare in the young child) or physiologic in origin. Physiologic spells misidentified as epileptic may be treated with antiepileptic medication where none is needed. Recording spells on video provides a potentially valuable supplement to the clinical history in arriving at a correct diagnosis. In practice, however, most home-video recordings prove difficult to interpret. Simple instructions to parents on the manner in which spells should be recorded will greatly increase the usefulness of home-video recordings. A systemic analysis of precipitating factors and the evolution and resolution of the spell will very often exclude seizures. The widespread availability of home-video recordings provides the pediatrician with an opportunity to visually examine a child's spells, often avoiding unnecessary investigations and referrals and allowing the physician to more confidently offer reassurance to the parents.

Long-term EEG monitoring for difficult seizure problems

Long-term electroencephalographic (EEG) monitoring, initially popular in the form of 24-hour video-EEG telemetries developed for the evaluation of patients who were candidates for epilepsy surgery, is now possible in diverse configurations. Studies can be designed to evaluate a variety of diagnostic problems and can be individualized to address specific clinical questions for each patient. A great variety of severe epilepsies present in infancy and childhood with daily seizures, often presenting difficult diagnostic problems. Extending the benefits of long-term EEG monitoring to these patients early in the course of the epileptic process can be expected to result in more accurate diagnoses, more effective treatment, and improved prognoses. Long-term EEG monitoring is needed to improve our understanding of the nosology of infant epilepsy, which is incomplete.

Treatment of infantile spasms

OBJECTIVE

To summarize and evaluate the literature regarding the clinical features, epidemiology, etiology, pathophysiology, and treatment of infantile spasms.

DATA SOURCES

A literature search of articles from January 1966 to July 1993 using MEDLINE, EM-Base, and Current Concepts/Life Sciences, as well as bibliographies of relevant articles.

STUDY SELECTION

All identified original and review publications regarding the clinical features, epidemiology, etiology, pathophysiology, and treatment of infantile spasms were reviewed. Emphasis was placed on original studies published since 1975.

DATA EXTRACTION

Data from published research were extracted and evaluated according to study design, sample size, dosing regimen, outcome measures, and treatment efficacy and safety.

DATA SYNTHESIS

Infantile spasms constitute a rare epileptic syndrome with a poor long-term prognosis for normal intellectual development. The spasms are characterized by a brief symmetric contraction of the muscles of the neck, trunk, and/or extremities, often occurring in a series of 2 to more than 100 spasms during a single episode. The disorder is age-specific, with the peak onset of symptoms occurring between 2 and 8 months of age. Spasms of no identifiable cause in infants with normal development prior to the onset of infantile spasms are classified as cryptogenic or idiopathic, whereas those with an identifiable cause are classified as symptomatic. Long-term prognosis is best in cryptogenic cases, with 30-70 percent attaining normal intellect compared with 5-19 percent in symptomatic cases. The etiology and pathophysiology are not well understood. Recent theory postulates that infantile spasms may be caused by an excess of corticotropin-releasing hormone activity during infancy. The suspected association between the whole-cell pertussis vaccine and infantile spasms is coincidental. Few well-designed, prospective, controlled clinical trials for the treatment of infantile spasms have been conducted.

CONCLUSIONS

Standard anticonvulsants such as phenytoin, the barbiturates, carbamazepine, and the succinimides have been ineffective. Of the anticonvulsants, only the benzodiazepines, valproic acid, and vigabatrin have shown efficacy in reducing spasm frequency and severity. Hormonal therapy with adrenocorticotropic hormone (ACTH) and/or prednisone has been the most frequently studied treatment modality and appears to be the most effective. Hormonal therapy achieves complete spasm control in 50-75 percent of infants within four weeks of initiation. Opinions differ regarding the relative efficacy between ACTH and prednisone, the need for early initiation of hormonal treatment, and the benefits of high dosages of ACTH (> 40 units/d). No treatment has been shown conclusively to improve the long-term intellectual development of these infants. Neurosurgery may be the treatment of choice in select cases when a localized central nervous system abnormality can be demonstrated. Well-designed, blind, prospective clinical trials are needed to answer definitively many lingering questions regarding the treatment of infantile spasms.