Pediatric epilepsy surgery

Determination of levetiracetam by GC-MS and effects of storage conditions and gastric digestive systems on drug samples

Background: Epilepsy is a neurologic condition that is occurs globally and is associated with various degrees of seizures. Levetiracetam is an approved drug that is commonly used to treat seizures in juvenile epileptic patients. Accurate quantification of the drug's active compound and determining its stability in the stomach after oral administration are important tasks that must be performed. Results & methodology: Levetiracetam was extracted from drug samples and quantified by gas chromatography mass spectrometry using calibration standards. Stability of levetiracetam was studied under various storage conditions and in simulated gastric conditions. The calibration plot determined for levetiracetam showed good linearity with a coefficient of determination value of 0.9991. The limits of detection and quantification were found to be 0.004 and 0.014 μg·ml^-1, respectively. The structural integrity of levetiracetam did not change within a 4-h period under the simulated gastric conditions, and no significant degradation was observed for the different storage temperatures tested. Discussion & conclusion: An accurate and sensitive quantitative method was developed for the determination of levetiracetam in drug samples. The stability of the drug active compound was monitored under various storage and gastric conditions. The levetiracetam content determined in the drug samples were within ±10% of the value stated on the drug labels.

Patterns of anti-seizure medication (ASM) use in pediatric patients with surgically managed epilepsy: A retrospective review of data from Boston Children's Hospital

OBJECT

Up to 30 % of patients with epilepsy are medically intractable, defined as persistent seizures despite 2 or more appropriate anti-seizure medications (ASMs) at therapeutic doses. Such patients require non-pharmacologic management that often includes epilepsy surgery. This paper aims to assess the pre-operative ASM use patterns of patients who were surgically managed.

METHODS

Retrospective review of children who underwent surgery for epilepsy at Boston Children's Hospital between January 2010 and December 2014 were performed. Patient demographics, covariates, etiology, surgery type and ASM use patterns were assessed. Patient characteristics were displayed using descriptive statistics, correlation between ASM use and patient covariates were calculated with the Spearman coefficient, and univariate analysis was performed with Cox regression analysis.

RESULTS

141 consecutive records of children were reviewed. All underwent one of four surgical procedures: focal resection, hemispherectomy, corpus callosotomy, or magnetic resonance-guided laser interstitial thermal therapy (MRgLITT). In this cohort, at the time of surgical evaluation the average number of pre-operative ASMs trialed was 5.2 and the average number of current ASMs was 2.6. The mean age of seizure onset was 4.4 years, the mean age at the time of surgery was 11.1 years, and the average time from seizure onset to surgery was 6.7 years. The number of total pre-operative ASMs was significantly related to longer time to surgery. Focal resection was associated with decreased ASM use and corpus callosotomy was associated with increased ASM use. Patients with radiographic findings that confer better surgical candidacy did not use fewer pre-operative ASMs or undergo earlier surgical referral.

CONCLUSIONS

Despite guidelines that encourage early surgical referral and evaluation for drug-resistant epilepsy, a delay in surgical referral was seen in clinical practice, as evidenced by an average trial of 5.2 ASMs prior to referral, and an average lag of 6.7 years between time of seizure onset and surgery. Increased medication trials was directly correlated with increased time to definitive surgery. Improved education amongst neurologists for earlier surgical referral is required, especially for pathologies associated with good surgical outcome.

Longitudinal brain functional and structural connectivity changes after hemispherotomy in two pediatric patients with drug-resistant epilepsy

The main focus of the present study was to explore the longitudinal changes in the brain executive control system and default mode network after hemispherotomy. Resting-state functional magnetic resonance imaging and diffusion tensor imaging were collected in two children with drug-resistnt epilepsy underwent hemispherotomy. Two patients with different curative effects showed different trajectories of brain connectivity after surgery. The failed hemispherotomy might be due to the fact that the synchrony of epileptic neurons in both hemispheres is preserved by residual neural pathways. Loss of interhemispheric correlations with increased intrahemispheric correlations can be considered as neural marker for evaluating the success of hemispherotomy.

Seizure clustering during presurgical electroencephalographic monitoring in children

BACKGROUND

Presurgical evaluation with antiseizure medication tapering in patients with refractory epilepsy places them at risk for seizure clustering or prolonged seizures. We looked at the occurrence of seizure clustering (3 or more seizures within 24h) and prolonged seizures and the factors that influence seizure clustering and affect length of stay (LOS) in pediatric patients during presurgical monitoring.

METHODS

We retrospectively reviewed the medical records of all consecutive admissions to the epilepsy monitoring unit (EMU) and included patients undergoing noninvasive presurgical evaluation. Data were extracted regarding demographics, seizure history, details of the EMU admission including occurrence of seizure clusters, prolonged seizures, status epilepticus, treatment, and LOS.

RESULTS

Sixty-nine patients met our inclusion criteria. Seizure clustering during monitoring was observed in 33 patients (48%). Prolonged seizures lasting >5min was observed in 14 (20%) patients including 2 with status epilepticus (3%). Seizure clusters necessitated rescue treatment in around 30%. History of seizure clustering at home was the only factor associated with the occurrence of seizure clustering during the EMU stay (p<0.0001). The LOS did not differ significantly between patients who had seizure clustering during monitoring versus those who did not (p=0.369).

CONCLUSIONS

Seizure clustering was common in children undergoing presurgical monitoring and seen especially in those with a history of seizure clustering at home. Occurrence of seizure clustering did not prolong the LOS but necessitated the use of rescue medications in about a third of the patients with seizure clusters due to multiple seizures.

Alterations in Spontaneous Brain Activity and Functional Network Reorganization following Surgery in Children with Medically Refractory Epilepsy: A Resting-State Functional Magnetic Resonance Imaging Study

For some patients with medically refractory epilepsy (MRE), surgery is a safe and effective treatment for controlling epilepsy. However, the functional consequences of such surgery on brain activity and connectivity in children remain unknown. In the present study, we carried out a longitudinal study using resting-state functional magnetic resonance imaging in 10 children with MRE before and again at a mean of 79 days after surgery, as well as in a group of 28 healthy controls. Compared with the controls, children with epilepsy exhibited abnormalities in intrinsic activity in the thalamus, putamen, pallidum, insula, hippocampus, cerebellum, and cingulate gyrus both before and after surgery. Longitudinal analyses showed that the amplitude of low frequency fluctuations (ALFF) increased in the parietal–frontal cortex and decreased in the deep nuclei from pre- to post-surgery. The percentage changes in ALFF values in the deep nuclei were positively correlated with the age of epilepsy onset. Functional connectivity (FC) analyses demonstrated a reorganization of FC architecture after surgery. These changes in brain activity and FC after surgery might indicate that the previously disrupted functional interactions were reorganized after surgery. All these results provide preliminary evidence that the age of epilepsy onset may have some potential to predict the outcome of brain functional reorganization after surgery in children with MRE.

Outcomes of resective surgery in children and adolescents with focal lesional epilepsy: The experience of a tertiary epilepsy center

OBJECTIVE

This study aimed to investigate the efficacy of resective surgery in children with focal lesional epilepsy by evaluating the predictive value of pre- and postsurgical factors in terms of seizure freedom.

METHODS

This study included 61 children aged between 2 and 18years who were admitted to the pediatric video-EEG unit for presurgical workup. Each patient was evaluated with a detailed history, video-EEG, neuroimaging, and postsurgical outcomes according to Engel classification to predict postsurgical seizure freedom. All the possible factors including history, etiology, presurgical evaluation, surgical procedures, and postsurgical results were analyzed for their predictive value for postoperative seizure freedom.

RESULTS

Of the 61 patients, 75% were diagnosed as having temporal lobe epilepsy (TLE), and 25% were diagnosed with extra-TLE. Two years after the surgery, 78.6% were seizure-free, of which 89% had TLE, and 50% had extra-TLE (p<0.05). Patients were more likely to have a favorable outcome for seizure freedom if they had rare seizure frequency, focal EEG findings, and focal seizures; had a temporal epileptogenic zone; or had TLE and hippocampal sclerosis. On the other hand, patients were more likely to have unfavorable results for seizure freedom if they had younger age of seizure onset, frequent seizures before the surgery, a frontal or multilobar epileptogenic zone, secondarily generalized seizures, extra-TLE with frontal lobe surgery, or focal cortical dysplasia.

SIGNIFICANCE

Resective surgery is one of the most effective treatment methods in children with intractable epilepsy. A history of young age of seizure onset, frequent seizures before surgery, secondarily generalized seizures, a multilobar epileptogenic zone, frontal lobe surgery, and focal cortical dysplasia (FCD) are the most important predictive factors indicating that a patient would continue having seizures after surgery. On the other hand, focal seizure semiologies, temporal lobe localization, and hippocampal sclerosis indicate that a patient would have better results in terms of seizure freedom.