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

This study examines the possibility that changes of cerebral extracellular pH (PH e) or adenosine concentration may provide coupling mechanisms of a general nautre, adjusting cerebral blood flow (CBF) to metabolic demands. Although there is considerable indirect evidence that CBF varies inversely with pHe, results obtained during the last few years indicate that large increases in flow may occur in the absence of a fall in pHe. Thus, induction of hypoxia or epileptic seizures leads to maximal increase in CBF before pHe falls or even when there is initial alkalosis due to concomitant hypocapnia. Furthermore, CBF increases in hypoglycaemia and after administration of amphetamine, two conditions unassociated with tissue acidosis. The possibility that adenosine may be a coupling factor was examined in hypoxia and during epileptic seizures in rats. In both conditions a four- to fivefold increase in CBF occurs in spite of the fact that tissue adenosine concentrations remain at or below 1 mumolkg-u. It is concluded that adenosine accumulates first when there is a perturbation of cerebral energy state with a rise in AMP concentration. It seems unlikely that adenosine, formed by breakdown of AMP, acts as a general coupling factor.
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PMID:Coupling of cerebral metabolism and blood flow in epileptic seizures, hypoxia and hypoglycaemia. 2 37

70 chronic alcoholics in the withdrawal state, 45 with convulsions and 25 controls without convulsive seizures, were tested with respect to electrolyte changes and acid base balance in serum or blood and cerebrospinal fluid (CSF). It was of special interest to note that there was a partial independence between magnesium levels in serum and CSF. Thus the serum level has only a limited liability as to magnesium depletion suggested to be responsible for seizure precipitation. In the seizure group a slightly but significantly lower magnesium, potassium and calcium in CSF and a significant decrease of potassium and calcium in serum were revealed. In the nonzeizure controls a similar decrease of magnesium in serum and potassium in CSF was observed while serum potassium and calcium in CSF and serum remained in low normal range. In both groups there was a prominent respiratory alkalosis. The role of magnesium depression for seizure precipitation is discussed with respect to the concomitant changes of other electrolytes and acid base disturbances.
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PMID:Electrolyte changes and acid base balance after alcohol withdrawal, with special reference to rum fits and magnesium depletion. 6 5

In idiopathic or generalized epilepsy, serum glucose and cholesterol concentrations tend to be low, especially just before the seizure. Glucose tolerance curves are abnormal and variable. The electrolyte balance is disturbed, and epileptics tend to go readily into alkalosis. Serum [Na+] is usually unaffected, but [K+] is normal to low between attacks and increases during and after the seizure. Serum [Cl-] is usually high just before the seizure. Epileptics are generally mildly hypocalcemic, especially in the period before the seizure. Serum urea and nonprotein nitrogen values are low between paroxysms but increase after the seizure. Serum protein concentration is usually normal. Stress, which releases epinephrine and corticotropin, results in high serum citrate concentration, which probably contributes to decreased serum [Ca2+] just before a seizure. In the healthy individual, any increase in serum citrate is accompanied by increasing [Ca2+]. In the rabbit, convulsions can be induced with corticotropin, a result of increased serum citrate concentration coupled with a decrease in [Ca2+]. The net result is severe hypo-ionic-calcemia. A similar phenomenon has been reported in a few humans. Administration of insulin causes serum citrate concentrations to decrease. Apparently, the dynamic system that controls glucose and lipid metabolism, and thus electrolyte balance, through the hormones epinephrine, corticotropin, insulin, glucagon, calcitonin, and parathormone, is abnormal in the epileptic.
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PMID:Clinical biochemistry of epilepsy. I. Nature of the disease and a review of the chemical findings in epilepsy. 22 Nov 36

In order to determine the effects of acetate on signs and symptoms of hypoglycemic seizures, Swiss Webster albino mice were injected intraperitoneally with solutions of NaCl, NaHCO3, NH4Cl, Na-acetate, or NH4-acetate, followed by subcutaneous injection of 7 U of insulin/kg body wt. Administration of Na- or NH4-acetate delayed and reduced the incidence of hypoglycemic reactions. Reinjection with Na-acetate or repeated injections with NH4-acetate caused a return to normal behavior patterns for 60 and 75%, respectively, of the affected hypoglycemic experimental animals. Injections of control animals with NaHCO3 or NH4Cl showed that the results were not due to alkalosis or acidosis. Acetate administration significantly increased plasma acetate and citrate, but not glucose, lactate, beta-hydroxybutyrate, or acetoacetate concentrations. The results indicate that intraperitoneal administration of acetate directly acted to prevent signs of hypoglycemia from occurring and reversed its manifestations when they were present. The protective effect of acetate suggests that it may serve as a fuel for the brain.
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PMID:Effect of acetate on hypoglycemic seizures in mice. 48 41

An encephalopathy may occur following treatment of chronic pulmonary failure and is manifested by multifocal seizures, mild focal motor signs, and coma. The encephalopathy seems to be a multifactorial illness resulting from cerebral ischemica and hypoxia. The more important factors appear to be cerebral alkalosis, administration of aminophyline, and associated hypotension.
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PMID:Encephalopathy following treatment of chronic pulmonary failure. 94 91

Acid-base changes in arterial blood and lumbar cerebrospinal fluid were correlated with simultaneously determined lactate levels in patients admitted after alcohol withdrawal seizures. Arterial and cerebrospinal fluid lactate was elevated in association with a marked respiratory alkalosis in 13 patients studied 5 to 12 hours after the seizure. Similar elevations of arterial and cerebrospinal fluid lactate were found in five patients during delirium tremens without antecedent withdrawal seizure. The cerebrospinal fluid lactate determined on admission appeared to correlate best with the length and severity of the alcohol withdrawal syndrome that developed in patients after a withdrawal seizure.
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PMID:Cerebrospinal fluid acid-base and lactate changes after seizures in unanesthetized man II. Alcohol withdrawal seizures. 123 4

Rett' syndrome is a progressive disorder that occurs in females and is characterized by autistic behavior, dementia, ataxia, loss of purposeful use of the hands, and seizures. Patients with Rett' syndrome have been observed to have stereotyped hand movements (hand-washing) and to exhibit intermittent hyperventilation. To characterize more precisely the respiratory pattern associated with this disorder, SAO2 and pH studies were made during sleep and wakefulness in a girl with this syndrome. These studies showed abnormal respiratory pattern during wakefulness characterized by hyperventilation periods (SAO2 98%, alkalosis) and ipo-apnea (SAO2 80%); during the sleep, ventilation became regular (SAO2 94-96%). The occurrence of disorganized breathing and compensatory hyperpnea during wakefulness with regular, continuous breathing during sleep suggests an altered or impaired voluntary/behavioral respiratory control system.
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PMID:[Rett's syndrome: description of a case with abnormal respiratory pattern]. 129 42

Clonic and tonic seizure-like movements of the extremities were observed during induction of anaesthesia with sevoflurane in a 9-yr-old girl. The tonic movements were associated with respiratory alkalosis and were not abolished by an i.v. injection of thiamylal 75 mg. Arterial pressure, heart rate and body temperature remained normal during the episode. Ventilation was assisted easily and then controlled via a face mask. No neurological abnormalities were obvious after the anaesthesia. The movements may have been the result of seizure activity in the central nervous system, or myoclonus of the extremities.
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PMID:Seizure-like movements during induction of anaesthesia with sevoflurane. 154 Apr 67

To investigate alterations of brain metabolism associated with temporal lobe epilepsy, [31P]MRS studies were performed on the anterotemporal lobes of patients with medically refractory complex partial seizures. Interictally, the pH was significantly more alkaline in the temporal lobe ipsilateral to the seizure focus (7.25 vs. 7.08, p less than 0.05), and the inorganic phosphorous concentration was greater on the side of the epileptogenic focus (1.9 vs. 1.1 mM, p less than 0.05). These changes in pH and inorganic phosphate may represent metabolic alterations secondary to seizures. Alternatively, because alkalosis enhances neural excitability and may enhance seizure activity, the increased pH of the seizure focus may provide insight into the pathophysiologic mechanism of epileptic seizures.
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PMID:Increased pH and inorganic phosphate in temporal seizure foci demonstrated by [31P]MRS. 162 74

The patient with theophylline overdose commonly presents with gastrointestinal, cardiovascular, neurologic, and electrolyte abnormalities. Respiratory alkalosis is the most common acid-base alteration, but mild metabolic acidosis has been reported. Two cases of severe lactic acidosis (pH 6.67 and 6.63) in patients without hypoxemia, shock, or prolonged seizure activity are reported. Possible causative mechanisms and aspects of therapy are discussed. Theophylline toxicity should be considered when an unconscious patient with concurrent severe metabolic acidosis presents to the emergency department.
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PMID:Severe lactic acidosis following theophylline overdose. 165 19


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