Evolutional changes and outcome of West syndrome: correlation with magnetic resonance imaging findings

Treatment of preterm infants with West syndrome: differences due to etiology

BACKGROUND

This study was conducted with a particular focus on preterm infants with West syndrome (WS) to evaluate differences in the first responses to oral medication based on etiology.

METHODS

Medical records of 53 patients with WS, treated at five institutions between 2005 and 2009, were reviewed retrospectively. Patients were divided into six groups based on the time of brain insult, and evaluated for short-term outcomes using oral anti-epileptic agents and synthetic adrenocorticotropic hormone.

RESULTS

The sample consisted of 15, six, 14, two, four, and 12 patients classified, on the basis of apparent time of acquisition of etiology, into the prenatal, term, preterm, postnatal, other, and no identified etiology groups, respectively. Average age of onset in the term group was 3.3 ± 1.0 months, significantly earlier than in the prenatal, preterm, postnatal and no identified etiology groups (P < 0.05). All patients in the term group had experienced seizures before the onset of WS. Only patients in the preterm group had only experienced neonatal seizures, and responded better to treatment. Patients in the preterm group had better responses to treatment, especially oral medication, compared with those in the prenatal and term groups. The prevalence of relapse of seizures in the preterm group (14%) was significantly lower than that in the prenatal group.

CONCLUSIONS

Preterm WS patients responded well to treatment. Distinguishing WS patients on the basis of different etiologies is important for evaluating the effectiveness of treatment.

Model of cryptogenic infantile spasms after prenatal corticosteroid priming

Infantile spasms (IS) is a devastating epilepsy syndrome of childhood. IS occurs in 3-12-month-old infants and is characterized by spasms, interictal electroencephalography (EEG) hypsarrhythmia, and profound mental retardation. Hormonal therapy [adrenocorticotropic hormone (ACTH), corticosteroids] is frequently used, but its efficacy is tainted by severe side effects. For research of novel therapies, a validated animal model of IS is required. We propose the model of spastic seizures triggered by N-methyl-d-aspartate (NMDA) in infant rats prenatally exposed to betamethasone. The spasms have remarkable similarity to human IS, including motor flexion spasms, ictal EEG electrodecrement, and responsiveness to ACTH. Interestingly, the spasms do not involve the hippocampus. Autoradiographic metabolic mapping as well as tagging of the areas of neuronal excitation with c-fos indicates a strong involvement of hypothalamic structures such as the arcuate nucleus, which has significant bilateral connections with other hypothalamic nuclei as well as with the brainstem.

Popliteal angle in infants with west syndrome

The aim of this study was to clarify the relationship between neurologic findings and outcome of patients with West syndrome, focusing on the popliteal angle. The complete neurologic examination, including an assessment of the popliteal angle and muscle tone, was performed on 45 patients with West syndrome. A tight popliteal angle was determined when it was 120 degrees or less. In all 45 patients, abnormal muscle tone was not correlated with any variables. A tight popliteal angle was correlated with seizure persistence, cerebral palsy, and abnormality on magnetic resonance imaging (MRI), as well as severe developmental delay. When limited to the patients with developmental delay, a tight popliteal angle was correlated with severe developmental delay, cerebral palsy, and MRI abnormality, although abnormal muscle tone was not correlated with any items. In the delay group, eight patients had a tight popliteal angle with normal muscle tone. Among them, severe developmental delay was seen in seven (88%), seizure persistence in five (63%), and MRI abnormality in five (63%). These results suggest that a tight popliteal angle might be an indicator of poor neurologic outcome in patients with West syndrome.

Magnetic resonance imaging findings in infantile spasms: etiologic and pathophysiologic aspects

An etiologic evaluation of 86 patients with infantile spasms is presented and the place of cranial magnetic resonance imaging (MRI) findings within this spectrum is discussed. A total of 103 cranial MRIs, performed between 4 and 72 months of age, were analyzed and classified according to the etiologic and pathophysiologic aspects. Ninety-one percent of cases were diagnosed as symptomatic infantile spasms, and hypoxic-ischemic encephalopathy was the primary cause (30%). The most common involvement was thinning of the corpus callosum in 43 patients (50%), followed by dilation of cerebral ventricles in 32 (36%), delayed myelination in 23 (26.7%), lesions of diencephalic deep gray matter in 17 (19.7%), and enlargement of the subarachnoid space in 12 (14%). Thin corpus callosum and diffuse atrophy were changes mainly associated with hypoxic-ischemic encephalopathy, whereas delayed myelination seemed to be independent from a specific etiology. The results showed that cranial MRI may provide considerable information regarding not only the etiology but also the pathophysiology of infantile spasms.

Informative value of magnetic resonance imaging and EEG in the prognosis of infantile spasms

PURPOSE

To investigate the informative value of EEG and cranial magnetic resonance imaging (cMRI) in the prognosis of infantile spasms (ISs); 86 patients with ISs were included in this study.

METHODS

All cases had epileptic spasms, psychomotor retardation, and hypsarrhythmia in at least one of their EEGs. cMRIs and laboratory tests necessary for etiologic diagnosis were completed in all cases. Patients were followed up periodically both clinically and by video-EEGs for >1 year. Clinical information was categorized on the basis of four spheres as epilepsy, psychosocial development, motor development, and overall clinical condition, with each category being evaluated under three levels of involvement as good, moderate, and severe, depending on selected parameters. A similar scale was applied for the EEG results and for the cMRI findings. Clinical parameters were correlated to EEG and cMRI results, by Spearman test. Other statistical tests used were Kruskal-Wallis chi(2) and Mann-Whitney U analysis as multiple comparison by post hoc Bonferroni correction.

RESULTS

A severe overall clinical course was observed in 64% of patients, whereas this incidence was 58% and 44% in the EEG follow-up and cMRI parameters, respectively. In regard to prognosis, a significant correlation was determined between the clinical and the EEG course. This relation was the most prominent in psychosocial developmental parameters and least prominent in the motor development. cMRI findings, however, were correlated only with motor development.

CONCLUSIONS

cMRI and repeated EEG recordings, especially when assessed together, may provide complementary information regarding the prognosis in ISs.

Visual field defects and other ophthalmological disturbances associated with vigabatrin

Vigabatrin has been an important anticonvulsant drug for over 10 years with a reputation for high efficacy and excellent tolerability. However, since 1997, there have been over 25 reports in the literature of visual field defects attributable to the use of this agent. Most are case reports and many have only been reported as abstracts or posters or as letters or short communications. Only a small number of papers give details of patient characteristics. Typically, case reports detail ophthalmological tests such as visual acuity, funduscopic examination, integrity of colour vision, and the nature of the field cut. Many also include various electrophysiological tests which were performed in an attempt to further describe the nature of the visual changes. In order to shed light on the mechanism underlying these visual field changes, many investigators also tested various electrophysiological parameters. However, because electrophysiological testing requires considerable expertise on the part of the technician, this could be a source of variability in results and may also pose a challenge with data interpretation. The magnitude of the problem is difficult to assess. The manufacturer's estimate of incidence of visual field defects with vigabatrin was approximately 0.1%, but incidences estimated in the literature range from 6 to 30%. Since the majority of the published data are in case report form, proof of causation is also very difficult. Two papers that used proper scientific methodology to investigate this condition suggest that vigabatrin causes these changes; however, there needs to be further studies with larger populations to answer this question definitively. There is a lack of data on the dose-response characteristics of vigabatrin and the development of visual field defects. The only available data are reports of trends that implicate duration of therapy or cumulative dose. Perhaps the most important area to elucidate is whether or not the visual field defects are reversible. Data are scare on this subject, but we can hope that data will emerge as follow-up periods become more substantial. There is a need for more complete information regarding several aspects of the mechanistic basis of visual field defects associated with vigabatrin that will allow rational clinical decision making. The treatment choices, both pharmacological and nonpharmacological, for patients with refractory epilepsy have grown substantially in the last few years. Thus, it is doubtful that the clinical positioning of vigabatrin is likely to change in the future from that of a very valuable 'niche drug', with emphasis on paediatric usage.

West syndrome--The University of Hong Kong experience (1970-2000)

OBJECTIVE

To study the clinical pattern of West syndrome (WS) in a university based hospital.

METHODOLOGY

The database of children seen in the Epilepsy Clinic of Queen Mary Hospital and Duchess of Kent Children's Hospital during a 30-year period (1970-2000) was reviewed.

RESULTS

A total of 105 cases had WS (1.9%). The number of new cases of WS admitted per year ranged from one to eight. The range of annual incidence of WS to newly diagnosed epilepsy was 0.8-4.8%. The etiology included idiopathic (N=19, 18%), cryptogenic (N=23; 22%), symptomatic (N=56; 53.3%) and unknown (N=7; 5.7%). Adrenocorticotropic hormone (ACTH) and/or prednisone were given to 42 children (40%). Most were effective in controlling WS on an all-or-none fashion. Seizure outcome included 12 with remission, persistent in the same form in two and persisting but changed to another form in the rest. Neurological outcome at the last follow up in 2000 December included multiple disabilities (N=16), cerebral palsy (N=22), mental retardation (N=94) and Lennox-Gastaut syndrome (N=13). We analysed the following risk factors in relation to poor outcome: age of onset, age of presentation, time lag before treatment, etiology, family history of epilepsy and hormonal treatment. Only etiology of WS has a positive correlation with poor outcome (P<0.0005).

CONCLUSIONS

WS is an uncommon epileptic syndrome. The majority had poor outcome, especially those with causes identified. Infantile spasm is a specific epileptic phenomenon in a maturational stage of a child when heterogeneous disorders can present with the same clinical epileptic and electroencephalographic phenomenon.

Epidemiological and clinical studies of West syndrome in Nagasaki Prefecture, Japan

Recent advances in diagnostic and therapeutic techniques may have changed incidence and etiologies of West syndrome (WS). We performed a retrospective epidemiological study of WS that occurred in 47 children in Nagasaki Prefecture during a recent 10-year period from 1989 to 1998. The incidence of WS was 3.1/10,000 live births. Thirty-nine patients (83%) had symptomatic WS, in which the prenatal causes were most frequent, followed by low-birth weight (LBW) infants, perinatal and postnatal. Such high frequency of LBW may have been due to a relative increase in survivors of premature babies because of recent advances in perinatal care. The brain computerized tomography/magnetic resonance imaging performed in 41 patients revealed congenital brain malformation (10 patients), destructive brain disorders (13 patients), and no structural abnormalities (18 patients). The seizure outcome was worse in the symptomatic WS than in the cryptogenic WS. The developmental outcome was very poor in both symptomatic and cryptogenic WS. The mean developmental quotient (DQ) in all patients was 25, and only four patients (11%) had a normal DQ (>70). DQ was lower in patients with developmental delay before the onset of WS, symptomatic group, relapse and/or persistence of seizure. Developmental delay seen in WS patients seems to be related to the two major factors, that is, underlying brain abnormalities and the persistent seizures as a result of the former. Therefore, every effort should be made to control seizures, including medical and early surgical treatment, as well as prevention of brain damage through perinatal care.

Clinico-electrical evolution in pre-hypsarrhythmic stage: towards prediction and prevention of West syndrome

We investigated serial electroencephalographic (EEG) changes before the onset of spasms in patients with West syndrome (WS) due to perinatal injury in order to determine whether one can predict WS or not. In preterm infants with periventricular leukomalacia (PVL), depression of EEG activities is commonly followed by disorganized pattern during the early neonatal period. Disorganized patterns persist until the late neonatal period, but epileptiform discharges do not appear. Epileptiform discharges usually appear during early infancy in infants who later develop WS. As the onset of WS was relatively later in preterm infants with PVL, it may be possible to select the patients at risk for secondary prevention of WS with sufficient treatment period. In term infants with hypoxic-ischemic encephalopathy, all EEGs during the neonatal period did not reveal epileptiform discharges in the majority of patients. Multifocal spikes were very likely to be observed during early infancy, but hypsarrhythmia was observed immediately after their appearance. It is not always easy to select patients for prevention of WS with sufficient treatment period.