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

Infantile spasms are generalized seizures specific to early infancy, and are believed to result from complex cortical-subcortical interactions during a critical period of development. We used positron emission tomography (PET) to determine local cerebral metabolic rates for glucose (1CMRG1c) in 44 infants with spasms, in an attempt to define the neuroanatomical substrates that mediate these seizures. All infants were studied in the awake state during continuous electroencephalographic monitoring. The most consistent abnormality on PET, seen in 32 infants, was the symmetrical increase in 1CMRG1c in the lenticular nuclei, compared to age-matched normal infants (p less than 0.05). In 21 infants, even though the brain stem appeared to be visually more prominent compared to normal infants, statistically significant differences could not be demonstrated. Relative hypermetabolism of the lenticular nuclei (1) occurred irrespective of whether the spasms were cryptogenic or symptomatic, (2) was associated with focal cortical hypometabolism in 22 and focal cortical hypermetabolism in 5 of the 44 infants, and (3) was not characterized by any specific electroencephalographic abnormality during PET. These findings suggest that the lenticular nuclei may contribute to the pathophysiological state that predisposes to infantile spasms, and is consistent with the observation that spasms are clinically symmetrical even when focal cortical lesions are present. A scheme describing the neuronal circuitry likely to be involved in the generation of infantile spasms is proposed.
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PMID:Infantile spasms: II. Lenticular nuclei and brain stem activation on positron emission tomography. 157 60

Refractory status epilepticus (RSE) is defined as status epilepticus that continues despite aggressive treatment. A 9.8-year-old boy with a past history of daily left focal motor seizures was transferred to University of California at Los Angeles (UCLA) Hospital in pentobarbital coma after 4 days in RSE. The RSE was treated with very high doses of all appropriate antiepileptic drugs (AEDs), alone and in combination. The pentobarbital was titrated to burst suppression on EEG, but whenever pentobarbital was decreased, the seizures recurred. An ictal positron tomography scan of glucose metabolism demonstrated a right frontal area of hypermetabolism corresponding to an epileptic focus on EEG and magnetic resonance lesion. Eight days after the boy was admitted to UCLA, the right frontal focus was surgically removed, with immediate control of the status epilepticus. Whereas before onset of RSE, he had daily focal seizures, the boy has been seizure-free postoperatively for greater than 1 year. Operative treatment should be considered in patients with RSE in whom a focus of seizure onset can be demonstrated and who are reasonably considered surgical candidates.
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PMID:Neurosurgical treatment of refractory status epilepticus. 159 35

A total of 2248 infants born at All India Institute of Medical Sciences Hospital, New Delhi were selectively screened for hypoglycemia over a period of 15 months. Hypoglycemia (blood glucose less than 30 mg/dl) was diagnosed in 107 cases (4.8%). Preterm babies had three times increased risk (12.8%) as compared to term babies (3.6%). Small-for-dates (SFDs) and large-for-dates (LFDs) infants were at increased risk of manifesting hypoglycemia (7 and 10 times, respectively) as compared to the appropriate-for-dates (AFDs) babies (2.7%). Approximately two-thirds of the hypoglycemic babies (67.3%) had one or more risk factors including birth asphyxia (24.2%), diabetic mothers (23.8%), respiratory distress (13.9%) and septicemia (11.6%). A total of 59.8% cases were asmyptomatic while the rest had one or more symptoms. The most common symptom observed was lethargy (81.4%), followed by jitteriness (67.4%), respiratory abnormalities (41.9%), hypotonia (39.5%) and seizures (30.2%). The amount of glucose (mg/kg/min) needed to maintain a stable blood sugar in various categories of hypoglycemic babies was observed to be in the following decreasing order of amount; symptomatic babies with seizures (Gp IV), IGDM's/IDM's and symptomatic babies with other features (Gp III), SFDs and LFDs (Gp II) and AFDs (Gp I). Such a categorization of hypoglycemic babies will help to treat them more precisely.
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PMID:Neonatal hypoglycemia--clinical profile and glucose requirements. 159 96

Seizure is a common problem evaluated in pediatric emergency departments. Serum chemistry analysis is often performed as a routine part of the diagnostic evaluation of children who arrive in the ED with seizure. From this retrospective study, we sought to determine 1) how often serum electrolytes (Na, K, Cl, CO2), total calcium, magnesium, ammonia, and glucose chemistries were performed, 2) the frequency of abnormalities detected, and 3) whether abnormalities resulted in a change in patient care. Three hundred eight ED charts from 12 consecutive months were reviewed. Data collected included age, sex, ED diagnosis, medical history, and physical examination. Charts were also reviewed for diagnostic tests ordered and patient management. Children were classified as having febrile (FS) or nonfebrile seizures (NFS) to establish diagnostic evaluation practices for each group as well as to determine rates of laboratory abnormalities. Three hundred eight children were enrolled, 108 (35%) FS and 200 (65%) NFS. The mean ages of FS and NFS patients were 2.1 and 5.7 years, respectively (P less than 0.05, t-test). One hundred twenty-four of 308 (40%) children had at least one test performed; no abnormal test was thought to have caused seizure; none was treated. One hundred five of 308 (34%) were experiencing their first seizure. There was no difference in the likelihood of having a test ordered for children with a first seizure, regardless of seizure category. We concluded that 1) abnormal serum electrolytes, total calcium, magnesium, and glucose rarely cause seizure in children and 2) routine use of these tests in the ED is costly and does not contribute to seizure therapy.
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PMID:Emergency department laboratory evaluation of children with seizures: dogma or dilemma? 160 83

To determine the utility of the routine practice of obtaining serum chemistry values on children presenting after a seizure, we reviewed the emergency department records of 241 episodes of seizures in pediatric patients. One hundred fifty-five nonfebrile (49 initial, 106 recurrent) and 86 febrile (53 initial, 33 recurrent) convulsive episodes were analyzed. At least one serum chemistry value was obtained in 149 (64%) patients. Clinically significant abnormalities were found in 0/149 serum sodium, 0/148 glucose and blood urea nitrogen, 0/86 calcium, and 0/61 magnesium studies. We concluded that routine determination of serum chemistry values in pediatric patients presenting with a seizure is unnecessary unless specific clinical data strongly suggest otherwise.
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PMID:Absence of serum chemistry abnormalities in pediatric patients presenting with seizures. 160 2

The acute secretion of glucocorticoids is critical for responding to physiological stress. Under normal circumstances these hormones do not cause acute neuronal injury, but they have been shown to enhance ischemic and seizure-induced neuronal injury in the rat brain. Using fetal rat hippocampal cultures, we asked whether hypoxic and hypoglycemic cell damage in vitro could be exacerbated by direct exposure to corticosterone (CORT). Each of these insults alone damaged neuronal cells, whereas 4-6 h of hypoxic treatment could damage age-matched astrocytes if glucose was reduced or omitted. Ischemic-like injury to both cell types could be attenuated by pretreatment with high (30 mM) glucose. Exposure to 100 nM CORT did not affect cell viability under control conditions but enhanced both hypoxic and hypoglycemic neuronal injury. In both cases, pretreatment with high glucose abolished this CORT-mediated synergy. In astrocyte cultures, CORT exacerbated both hypoxic and hypoglycemic injury and this effect was also attenuated by high-glucose pretreatment. Identical 24-h CORT treatment caused a 13% reduction in glucose uptake in astrocytes and a 38% reduction in glycogen content, without affecting the level of intracellular glucose. Thus, CORT could endanger both neurons and astrocytes in mixed hippocampal cultures and this effect emerged only under conditions of substrate depletion. The metabolic disruption in astrocytes by CORT further suggests that the ability of CORT to exacerbate neuronal injury may be due in part to impaired glial cell function.
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PMID:Glucocorticoids exacerbate hypoxic and hypoglycemic hippocampal injury in vitro: biochemical correlates and a role for astrocytes. 161 95

Regional cerebral blood flow (CBF) and regional cerebral glucose utilization (CGU) were studied by quantitative autoradiographic techniques in rats. Animals were treated either with a toxic dose of soman, an irreversible organophosphorus cholinesterase inhibitor, that produced convulsions or with saline as controls. An increased arterial blood pressure (mean increase = 41% of control) always preceded onset of convulsions. Convulsive activity was associated with an increase of plasma glucose concentration and marked increases over controls of CGU [average of all regions: control = 75 +/- 5 mumol.100 g-1.min-1, n = regions/animals (304/8); seizures = 451 +/- 20 mumol.100 g-1.min-1, n = 190/5] and CBF [average of all regions: control = 135 +/- 6 ml.100 g-1.min-1, n = 190/5; seizures = 619 +/- 29 ml.100 g-1.min-1, n = 190/5). Regional distribution of these effects revealed a greater proportional increase of CBF over CGU in cingulate, motor, and occipital cortex and caudate-putamen. In contrast, a lower proportional increase of CBF over CGU in CA3 region of hippocampus, dentate gyrus, medial thalamus, and substantia nigra was observed, implying the existence of a relative ischemia in these brain areas. These findings may be relevant to the pathogenesis of brain lesions associated with soman-induced convulsions.
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PMID:Cerebral blood flow and metabolism in soman-induced convulsions. 161 57

Changes in blood-brain barrier (BBB) permeability and cerebral metabolic activity following intravenous injection of kainic acid (KA; 6, 12 mg/Kg) in rats were assessed by calculating respectively a blood-to-brain transfer constant (Ki) for [14C]alpha-aminoisobutyric acid and local cerebral glucose utilization (LCGU) values, at different times (1 h, or acute seizures phase, and 48 h, or chronic pathology phase) after the induction of seizures. A significant increase in the local permeability of the BBB was observed 1 h after the injection of KA 6 mg/Kg (eliciting no significant changes in cerebral metabolic activity, except within the frontal cortex and the hippocampus) and 12 mg/Kg (which induced a marked and widespread enhancement of LCGU). On the contrary, during the pathology phase, persistent regional increases in Ki values were evidenced in rats treated with the lowest dose of the convulsant, but not in rats injected with KA 12 mg/Kg (a dose able to cause extensive neuronal damage). Thus one can speculate that: 1) KA-induced regional changes in the permeability of the BBB are not correlated with changes in neuronal activity; 2) opening of the BBB is not reliably associated with neuronal injury.
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PMID:Blood-brain barrier dysfunctions following systemic injection of kainic acid in the rat. 164 Jul 96

Alterations in a variety of neurotransmitter systems have been identified in experimental models of epilepsy and in brain tissue from patients with intractable temporal lobe seizures. The availability of new high-affinity radioligands permits the study of some neuroreceptors in vivo with positron emission tomography (PET). We previously characterized the in vivo binding of 11C-carfentanil, a potent and selective mu opiate receptor agonist, and described increases in 11C-carfentanil binding in the temporal neocortex of patients with unilateral temporal lobe epilepsy. These studies have been extended to 11C-diprenorphine, which labels mu, kappa, and delta opiate receptor subtypes. Paired measurements of opiate receptor binding were performed with PET using 11C-carfentanil and 11C-diprenorphine in patients with unilateral temporal lobe seizures. Carfentanil binding, reflecting changes in mu opiate receptors, was increased in the temporal neocortex and decreased in the amygdala on the side of the epileptic focus. Diprenorphine binding, reflecting mu as well as non-mu opiate subtypes, was not significantly different among regions in the focus and nonfocus temporal lobes. Regional glucose metabolism, measured using 18F-2-fluoro-2-deoxyglucose, was decreased in the mesial and lateral aspects of the temporal lobe ipsilateral to the epileptogenic focus. The variation in pattern of carfentanil and diprenorphine binding supports a differential regulation of opiate subtypes in unilateral temporal lobe epilepsy.
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PMID:Quantification of mu and non-mu opiate receptors in temporal lobe epilepsy using positron emission tomography. 165 46

The diagnosis of nesidioblastosis was established in a 9-month-old male child with a history of recurrent convulsive seizures and hypoglycemia. After unsuccessful subtotal pancreatectomy, treatment was started with the long-acting somatostatin derivative Sandostatin (Octreotide, Sandoz) at a dosage of 25 micrograms t.i.d. spaced between carbohydrate-enriched meals. With this regime, blood glucose was maintained at the low normal range and seizures ceased. During a 30-month observation period, growth velocity and weight progression were well within the predicted limits. A 24-hour hormone profile recorded at the end of the observation period revealed the following: (1) failure to improve blood glucose with carbohydrate-enriched food due to reactive hyperinsulinemia; (2) hyperglycemic reaction after administration of Sandostatin caused by a reduction of plasma insulin; this effect was particularly marked during sleep; (3) low mean GH, decreased spiking frequency and reduced area covered by the nocturnal peaks by recognized standards, and (4) normal somatomedin C levels for age. Interpretation of growth hormone (GH) data is hindered by the lack of pertinent information from the patient's age group. Recording of normal growth progression in the case illustrated here can only be explained by the capability of a reduced GH secretory rate to maintain full biological activity as shown by the normal plasma level of somatomedin C. Indeed, recent evidence has been provided elsewhere for normal growth progression in the presence of low GH secretion, although other factors unrelated to this hormone may also be operative at this early age. Further reports concerning the treatment of non-GH-dependent conditions with somatostatin derivatives will certainly contribute to the better understanding of the mechanisms governing growth in the postnatal period.
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PMID:Growth progression and 24-hour hormone profile in an infant treated chronically with a long-acting somatostatin derivative. 168 92


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