Ictal electrocardiographic changes in children presenting with seizures.

BACKGROUND: The aim of this study was to determine electrocardiographic changes in children during seizures. METHODS: We assessed heart rate changes, RR intervals and QT changes during 47 seizures in children. Consecutive QT and RR intervals were measured for 60 s before the seizures, during the seizures and 60 s after the seizures during video electroencephalography monitoring. RESULTS: There were 47 seizures in 18 patients. Five patients had generalized seizures and 13 patients had focal seizures. Twelve patients were male. The mean age during monitoring was 10.1 years (range 4 months-19 years). Ictal tachycardia was seen in every seizure. No ictal bradycardia was noted. There was only one dropped beat in a patient. The mean ictal heart-rate-corrected QT (QTc) interval was significantly higher than the postictal measurements (P= 0.005). Mean ictal QTc variation tended to increase during seizures and then decreased below the pre-ictal measurements in the postictal period. However these changes were statistically insignificant (P > 0.05). RR variance was significantly decreased during seizures compared to the postictal period and the standard deviation of the RR intervals was significantly decreased in the ictal period compared to the pre-ictal period (P= 0.014 and P= 0.001, respectively). CONCLUSION: Tachycardia is the main finding in seizures in children. Ictal bradycardia and cardiac arrhythmias are very rare despite being more frequent in adults with seizures.

Prevention of brisk hyperactive response during selective dorsal rhizotomy in children with spasticity: isoflurane versus sevoflurane maintenance anesthesia.

In children with spasticity, deep tendon reflexes are hyperactive and even stimulation of normal dorsal rootlets can produce exaggerated full-strength, single-twitch responses in the muscles they innervate. This phenomenon is called the brisk hyperactive response (BHR). The aim of this study was to compare the efficacy of 2 volatile anesthetics, isoflurane and sevoflurane, for suppressing the confounding effect of BHR during selective dorsal rhizotomy (SDR) in children with spasticity. The subjects were 54 consecutive children of American Society of Anesthesiology physical status III who were scheduled for SDR. After tracheal intubation, each child was randomly assigned to Group I (isoflurane; n=27) or Group S (sevoflurane; n=27). There was no significant difference between the mean operation times in Groups I and S (200+/-40 vs. 220+/-35 minutes, respectively; p=0.0559). Thirteen patients in Group I (48.1%) and 5 in Group S (18.5%) exhibited BHR during stimulation of the dorsal rootlets (odds ratio 4.086; p=0.0418). Three of these 18 patients (2 in Group I and 1 in Group S) experienced hypertension and tachycardia simultaneously with BHR (odds ratio 4.086; p=1.0). The results suggest that sevoflurane is more effective at preventing BHR and might be a better choice for anesthetic management of children with spasticity undergoing SDR.

Microvessel density and vascular endothelial growth factor expression as predictors of childrens' survival from cerebellar medulloblastoma.

Cerebellar medulloblastoma is the most common malignant brain tumor of childhood. This neoplasm is highly vascular and has a high growth rate. We aimed to determine whether high microvessel density (MVD) and expression of vascular endothelial growth factor (VEGF) in medulloblastoma tissue is correlated with survival time in children with this tumor. Tissue from 32 cerebellar medulloblastomas in 14 girls and 18 boys was studied. The standard-risk group comprised patients older than 3 years, without metastases of medulloblastoma and a residual post-operative tumor with a surface area less than 1.5 cm(2). The patients assigned to a high-risk group had at least one of the following indicators: younger than 3 years, metastases, or a residual post-operative tumor with a surface area larger than 1.5 cm(2). For each tumor, MVD was determined and the expression of VEGF was assessed using immunohistochemical techniques. The 5-year survival rate for the 32 patients was 56.2%. Five-year survival rates were 70.6% and 40.0% for patients in the standard-risk and high-risk groups, respectively. The mean (+/-standard deviation, SD) MVD for all patients was 22.0+/-9.1 microvessels per 0.7 mm(2). There was no difference in the survival rate between the groups with above-average MVD and below-average MVD (66.7% and 50.0%, respectively). Testing revealed 7 tumors with VEGF expression and 25 without. The 5-year survival rates for these 2 groups were not significantly different (57.1% vs. 56.0%, respectively). The mean (+/-SD) MVD values for the VEGF-positive and VEGF-negative groups were not significantly different (19.1+/-6.5 vs. 22.9+/-9.7 microvessels per 0.7 mm(2), respectively, Mann-Whitney U-test=78.5, Z=-0.41, p=0.68). There were no significant correlations between risk groups and expression of VEGF or MVD. These results indicate that neither high MVD nor the expression of VEGF in tumor tissue predicts poor prognosis in children with cerebellar medulloblastoma.

Basal ganglia location of subependymal giant cell astrocytomas in two infants.

Subependymal giant cell astrocytomas are benign tumors that constitute one of the primary features of tuberous sclerosis. Two infants with tuberous sclerosis had very unusual subependymal giant cell astrocytomas, confirmed on biopsy in one of the infants. In both cases, contrast-enhanced cranial magnetic resonance imaging suggested a calcified intra-axial mass with diffuse basal ganglia involvement extending into the lateral ventricle. Computed tomography confirmed calcification in both cases. The first patient had right temporal lobectomy for intractable epilepsy. Biopsy of the basal ganglia lesion in that case suggested subependymal giant cell astrocytoma. In infants, subependymal giant cell astrocytomas can present with unusual morphology and may feature diffuse basal ganglia involvement and severe calcification.

Surgical treatment of polymicrogyria with advanced radiologic and neurophysiologic techniques.

INTRODUCTION: Coexistence of multiple seizure types, inclusion of the motor cortex in the epileptogenic zone, and poor delimitation of the abnormal cortex make most patients with polymicrogyria (PMG) unlikely candidates for epilepsy surgery (Guerrini R et al., Epilepsy and malformations of the cerebral cortex in Epileptic syndromes in infancy, childhood and adolescence, 2005). CASE REPORT: We present here a child with frontal PMG and intractable epilepsy evaluated with advanced magnetic resonance imaging (MRI) and neurophysiologic techniques. Diffusion tensor imaging and fiber tractography showed severe involvement of neighboring white matter tracts besides the cortex. The evaluation also included functional MRI, chronic subdural electroencephalogram monitoring, and intra-operative motor mapping. The patient had a decrease in seizure frequency and an increase in his developmental skills after the surgery. CONCLUSION: Advanced neuroradiologic and neurophysiologic techniques are required to provide an effective and safe resection of the epileptogenic cortex in cortical dysplasias.

Association between DNA content and tumor suppressor gene expression and aggressiveness of atypical teratoid/rhabdoid tumors.

OBJECTS: Atypical teratoid/rhabdoid tumors (AT/RT) are aggressive neoplasms that afflict infants and young children. The objective of this retrospective study was to determine the association between DNA content (DNA ploidy, cell cycle analysis), tumor suppressor gene (p53, pRb, p16, and MMAC/PTEN) expression and the biologic aggressiveness of these tumors. METHODS: Eight tumors from 7 patients (1 girl, 6 boys; median age 4+/-6.7 months) were studied. Two patients had DNA aneuploidy and 5 patients manifested diploid DNA content at diagnosis. The proliferative index of the tumors ranged from 10% to 28% (median, 12+/-6.4%). The single tumor with a low proliferative index (i.e., <10%) was aneuploid. Immunohistochemical evaluation of p53, pRb, p16, and MMAC/PTEN expression patterns showed that most of the tumors contained more cells with abnormal pRb and p16 expression than cells with abnormal p53 and MMAC/PTEN expression. Expression of tumor suppressor genes, however, was inhomogeneous. CONCLUSION: Our findings led us to conclude that AT/RT of childhood is characterized by a high proliferative index and DNA aneuploidy. The high expression of abnormal pRb and p16 and the low expression of abnormal p53 and MMAC/PTEN indicate alteration of the G1-to-S phase step in the cell cycle, which could be an explanation for the aggressive nature of these tumors.