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Query: UMLS:C0036572 (seizures)
 80,221 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neonatal seizures remain an emergent clinical problem in the neonatal intensive care unit that requires prompt diagnosis and treatment. The electroencephalogram is the preferred tool by which a surface-recorded seizure can be documented. While a number of etiologic possibilities may occur, overlapping mechanisms result in a lower seizure threshold. The susceptibility to seizures shortly after birth, efficacy of antiepileptic medications to control seizures, as well as the prediction of outcome in patients with neonatal seizures remains controversial. Prospective studies are required to assess interactions among maternal, fetal, and neonatal conditions that contribute to the occurrence of neonatal seizures.
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PMID:Seizures in the newborn infant. Diagnosis, treatment, and outcome. 939 61

Neonatal seizures can be difficult to classify according to partial vs generalized onset based on clinical appearance, electroencephalogram (EEG) or other adjunctive imaging techniques. Single-photon emission computed tomography (SPECT) has proven to be useful in adults; however, its use is limited in the paediatric age group, particularly in neonates. A case of a 12-d-old infant with intractable seizures is reported, on whom an interictal Tc-99m HMPAO SPECT showed an area of hypoperfusion in the left temporal cortex, whereas the ictal SPECT revealed prominent hyperperfusion in the same area. The EEG of the infant demonstrated generalized epileptiform activity, while computed tomography and magnetic resonance (MR) imaging findings were normal. This case indicates that the use of SPECT may provide valuable data in evaluation of neonatal seizures, particularly with poorly localized EEG changes and normal MRI scans.
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PMID:Ictal and interictal SPECT in a newborn infant with intractable seizure. 947 21

This study analyzes the relative frequency and age of onset of the different seizure types in a 20-year cohort of a pediatric neurology outpatient clinic of an urban hospital that serves the majority of the city's population (Tel Aviv Medical Center). Only patients with two or more unprovoked seizures were included. Neonatal seizures were excluded from the analysis. The different seizure types in descending order of frequency were: partial seizures secondarily generalized (20.6%), complex partial seizures (12.5%), West syndrome (9%), simple partial seizures (8.6%), benign rolandic epilepsy of childhood (8%), absence seizures (7%), generalized tonic-clonic seizures (6.6%), generalized tonic seizures (5%), myoclonic seizures (2.2%), benign occipital epilepsy of childhood (2%), mixed type seizures (1.8%), Lennox-Gastaut syndrome (1.5%), juvenile myoclonic epilepsy (0.9%), atypical absence (0.6%), Landau-Kleffner syndrome, Ohtahara syndrome, myoclonic astatic epilepsy, electrical status epilepticus in sleep and startle epilepsy (0.2% each), and unclassified seizures (12%). The findings of this study confirm that there are more pediatric patients with partial seizures (52%) than primary generalized seizures (33%) and that partial seizures secondarily generalized is the most frequent seizure type in this age group.
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PMID:Epidemiology of epilepsy in childhood: a cohort of 440 consecutive patients. 949 91

Neonatal seizures are frequently manifested by subtle movements that are referable to brain stem structure, ie, nystagmus, conjugate eye movements, posturing, sucking movements, and so forth. Electroencephalogram (EEG) confirmation of abnormal movements is essential in diagnosing seizures in the neonate. Clinical seizure signs are often a clue to etiology. Metabolic abnormalities must always be considered, and blood gases, calcium, magnesium, glucose, and ammonia obtained. Neonatal seizures are an indication for cerebrospinal fluid examination. Specific metabolic abnormalities are treated with metabolic approaches, not conventional anticonvulsant drugs. Hypertensive encephalopathy is treated by controlling blood pressure, and not through anticonvulsant drugs. Critically ill infants bind anticonvulsants in an unpredictable fashion, and unbound or free anticonvulsant drug concentrations should be used to guide therapy. Phenobarbital is the most commonly used drug in treating nonmetabolic seizures. Doses to achieve free concentrations of at least 35 mg/L should be used. Use in vitro binding determinations with this formula to calculate loading doses. Dose is 25 mg/kg multiplied by volume and distribution (1 L/kg) divided by % free. Phenytoin is the second most commonly used agent, and doses should be calculated to achieve, but not exceed, 3 mg/L. Dose is 3 mg/kg multiplied by volume and distribution (1 L/kg) divided by % free. Benzodiazepines, notably lorazepam and diazepam are used at doses of 0.15 mg/kg and 0.3 mg/kg, respectively.
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PMID:Neonatal Seizures. 1128 39

The neonatal period is defined as the first 28 days of life of a term infant; for premature infants the limit of this period is 44 completed weeks of the infant's conceptional age (CA)-defined as the chronological age plus gestational age (GA) at birth. The clinical and electroencephalographic (EEG) manifestations of seizures during this period are determined primarily by the development features of the immature brain at the time of seizure onset, but are also related to the type and diversity of etiologies and risk-factors for seizures neonates may face early in life. Neonatal seizures may be strikingly different from the clinical and electrical seizures of older children and adults. In addition, findings from basic science investigations suggest that immature animals are more likely to experience seizures in response to injury than more mature animals, although the developing brain is less susceptible to seizure-induced injury.
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PMID:Neonatal seizures and neonatal epileptic syndromes. 1135 51

Adenylosuccinate lyase deficiency is an autosomal-recessive disorder of the purine de novo synthesis pathway, diagnosed up to now in approximately 40 patients. The clinical presentation is characterized by severe neurologic involvement including seizures, developmental delay, hypotonia, and autistic features. Neonatal seizures and a severe infantile epileptic encephalopathy are often the first manifestations of this disorder. The existence of genetic heterogeneity for the adenylosuccinate lyase defect could account for variability of the clinical presentation. Deficiency of purine nucleotides, impairment of energy metabolism, and toxic effects are potential mechanisms of cerebral damage. Laboratory investigations show the presence in urine and cerebrospinal fluid of succinylpurines, which are normally undetectable. Currently, no effective treatment is available for adenylosuccinate lyase deficiency. A search for this disorder should be included in the screening program of children with unexplained neonatal seizures or severe infantile epileptic encephalopathy.
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PMID:Neurologic aspects of adenylosuccinate lyase deficiency. 1139 13

Neonatal seizures caused by hypoxia can be refractory to conventional anticonvulsants. Currently, there is no effective postnatal intervention for newborn infants with hypoxic encephalopathy to prevent brain injury and long-term neurologic sequelae. We previously developed a rat model of perinatal hypoxia-induced seizures with subsequent long-term increases in seizure susceptibility and showed that these epileptogenic effects are selectively blocked by the alpha-amino-3-hydoxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor antagonist 6-nitro-7-sulfamoylbenzo(f)quinoxaline-2,3-dione. Using this model of perinatal seizures, we evaluated the efficacy of topiramate, a structurally novel anticonvulsant drug recently shown to attenuate AMPA/kainate currents. Topiramate effectively suppressed acute seizures induced by perinatal hypoxia in a dose-related manner with a calculated ED50 of 2.1 mg/kg, i.p. Furthermore, in animals that had seizures suppressed by topiramate during acute hypoxia, there were no long-term increases in susceptibility to kainate-induced seizures and seizure-induced neuronal injury. Our results suggest that topiramate may have clinical potential as a therapeutic agent for refractory seizures in human neonates.
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PMID:Topiramate blocks perinatal hypoxia-induced seizures in rat pups. 1155 93

To evaluate prenatal and perinatal risk factors for early neonatal seizures, we conducted a case-control study including 100 newborns with neonatal seizures in the first week of life and 204 controls randomly selected from a list of healthy newborns born in the same hospital during the study period. Generalized tonic seizures were the most common seizures observed (29%), although the majority of newborns (71%) experienced more than one type of seizure. The most frequent presumed etiology of neonatal seizures was hypoxic-ischemic encephalopathy (30%). A history of epilepsy in first-degree relatives was found only for cases. Neonatal seizures were found to be associated with maternal disease in the 2 years before pregnancy, mother's weight gain > 14 kg during pregnancy, placental pathology, preeclampsia, low birthweight, low gestational age, and jaundice in the first 3 days of life. The need for cardiopulmonary resuscitation was found only for cases (37%). The causal pathways for neonatal seizures often begin before birth, and some of the factors identified may be preventable.
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PMID:Prenatal and perinatal determinants of neonatal seizures occurring in the first week of life. 1157 4

Neonatal seizures are frequently associated with cognitive impairment and reduced seizure threshold. Previous studies in our laboratory have demonstrated that rats with recurrent neonatal seizures have impaired learning, lower seizure thresholds, and sprouting of mossy fibers in CA3 and the supragranular region of the dentate gyrus in the hippocampus when studied as adults. The goal of this study was to determine the age of onset of cognitive dysfunction and alterations in seizure susceptibility in rats subjected to recurrent neonatal seizures and the relation of this cognitive impairment to mossy fiber sprouting and expression of glutamate receptors. Starting at postnatal day (P) 0, rats were exposed to 45 flurothyl-induced seizures over a 9-day period of time. Visual-spatial learning in the water maze and seizure susceptibility were assessed in subsets of the rats at P20 or P35. Brains were evaluated for cell loss, mossy fiber distribution, and AMPA (GluR1) and NMDA (NMDAR1) subreceptor expression at these same time points. Rats with neonatal seizures showed significant impairment in the performance of the water maze and increased seizure susceptibility at both P20 and P35. Sprouting of mossy fibers into the CA3 and supragranular region of the dentate gyrus was seen at both P20 and P35. GluR1 expression was increased in CA3 at P20 and NMDAR1 was increased in expression in CA3 and the supragranular region of the dentate gyrus at P35. Our findings indicate that altered seizure susceptibility and cognitive impairment occurs prior to weaning following a series of neonatal seizures. Furthermore, these alterations in cognition and seizure susceptibility are paralleled by sprouting of mossy fibers and increased expression of glutamate receptors. To be effective, our results suggest that strategies to alter the adverse outcome following neonatal seizures will have to be initiated during, or shortly following, the seizures.
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PMID:Timing of cognitive deficits following neonatal seizures: relationship to histological changes in the hippocampus. 1171 38

Seizures in the newborn period constitute a medical emergency. Subtle seizures are mild paroxysmal alterations in motor or autonomic activity and are unique to the neonatal period. They are likely to be missed or confused with benign movements observed commonly in preterm children. Focal clonic seizures have a better prognosis as compared to myoclonic seizures for long-term neuro-developmental outcome. Seizures due to sub-arachnoid hemorrhage and late onset hypocalcemia carry a better prognosis as compared to seizures due to hypoglycemia, meningitis and cerebral malformations. Hypoglycemia and hypocalcemia are common causes and should be excluded in all neonates with seizures. Multiple etiologies can co-exist in neonatal seizures and a comprehensive approach for management of neonatal seizures has been described.
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PMID:Seizures in the newborn. 1175 35


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