Reversible non-metabolic triphasic waves.
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Biomedical subjects
Publications and source records attributed to P Jallon.
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The prevalence of epilepsy is about 1%. Only two thirds of these patients respond satisfactorily to an antiepileptic drug (AED) treatment. New AED did not clearly improve this overall efficacy, but often show a better tolerability as compared to old AED. This may allow a more targeted choice, especially in some delicate clinical situations, such as for the treatment of women in childbearing age, or patients receiving other drugs with possible pharmacokinetic interactions. Invasive approaches should be considered early in the course of treatment-resistant epilepsy, and may offer a complete seizure remission in selected cases. On the background of recent acquisitions from the literature, the pros and cons of different treatment options are presented. This is followed by the discussion of some clinical relevant situations.
During the last two decades, there has been a renewed interest in studying epidemiology of epilepsy in developing countries. While there are data on prevalence of epilepsy from many developing countries, there is very little information on the mortality of epilepsy in these same populations. This is because incidence studies of epilepsy are difficult to perform, death certificates are unreliable and often unavailable, and the cause of death is difficult to determine. We report on several studies of mortality in epilepsy in developing countries: Ecuador; the Parsi community of Bombay; a semiurban community in Vasai, India; Mali; Martinique; and Africa. Overall, these studies in general illustrate excess mortality among people with epilepsy when compared with the general population.
BACKGROUND: To evaluate the incidence and the prevalence of drug-resistant epilepsies and risk factors in relation with this condition. METHODS: The epidemiological approach of drug-resistant epilepsies come up against two major difficulties: the lack of a rigorous and consensus definition of this condition and its elusive evaluation which is indirectly appreciated with many studies concerning the remission of seizures in heterogeneous population of patients with or without treatment. RESULTS: The majority of papers on this topic report a hard core of 20 p. 100 of patients who continue to have seizures under treatment. This percentage has to be discussed because many factors can influence the exact number of patients with refractory epilepsy: the age of the first seizure, the seizure type, the cause of the seizures, the effective therapeutic interventions. This percentage did not seem to have been modified since the use of "new" anti-epileptic drugs and the development of epilepsy surgery. The main problem is to appreciate when refractoriness is really present and how long does it takes to declare that this condition has a self-perpetuating progression. Thank to the data from an abundant literature we can put forward that nearly 10 p. 100 of the incident cases could become refractory and that 1 to 2 /1 000 persons are drug resistant epilepsies, of which partial epilepsies represent 60 p. 100 of the cases. This rate allows to think that in France 5 000 to 12 000 patients may require a surgical evaluation and that annual need for surgery would be 500 patients per year. CONCLUSIONS: Data on drug-resistant epilepsies in France are lacking and it seems essential to put in place in our country a population-based incidence study including the risk factors of intractability in order to confirm these epidemiological data. The results of such a study would help to convince the political authorities to encourage the development of surgical structures.
OBJECTIVE: To highlight the role of EEG in the diagnosis of SSPE. METHODS: EEG was performed in an 18 month old girl who had a 1 week history of repeated episodes of sudden flexion of the head and trunk and frequent falls. RESULTS: EEG abnormalities consisted of stereotyped, generalized and synchronous high amplitude periodic complexes. These abnormalities correlated with brief episodes of axial and upper limb atonia on electromyogram examination. They persisted during sleep although abnormal movements disappeared. Biological results and cerebral MRI confirmed the diagnosis of subacute sclerosing panencephalitis. CONCLUSIONS: This case is exceptional because of the age of the patient, the clinical presentation and the mode of contamination and it highlights the role of EEG in this diagnosis.
This 71 years old women without any history of epilepsy had diabetes mellitus. She was admitted for repetitive giratory seizures in relation with non-ketotic hyperglycaemia. The EEG showed right centro-parietal paroxysmal slow activity. Symptomatology disappeared within 48 hours after insulin therapy. One month later, she presented with a left hemiplegia in relation with a right sylvian infraction. The role of focal transitory ischaemia in connection with hyperglycaemia is discussed.
PURPOSE: We describe first unprovoked seizures and newly diagnosed epilepsies at initial presentation, with a special emphasis on epilepsy syndromes, in a large cohort recruited in the mid-1990s in France. METHODS: The French Foundation for Research on Epilepsy set up a network to conduct a prospective study of patients with newly diagnosed unprovoked seizures. Information was provided by 243 child or adult neurologists. Four neurologists classified each case according to the International League Against Epilepsy (ILAE) criteria. First-seizure patients and patients with previously undiagnosed seizures were compared. RESULTS: Between May 1, 1995, and June 30, 1996, 1,942 patients aged from 1 month to 95 years were identified: 926 (47.7%) with a single seizure and 1,016 (52.3%) with newly diagnosed epilepsy. All but 17 patients had EEGs. In the first-seizure and newly-diagnosed-epilepsy groups, neuroimaging studies were performed in 78.2 and 68.3% of patients, and medication prescribed in 54.1 and 89.6%, respectively. There were significant differences between the two groups with respect to age at onset and diagnosis, sex, etiology, several specific syndromes, as well as the type and presentation of initial seizure. In patients for whom the first seizure was convulsive, only sex, multiple seizures in a day or status epilepticus, and cryptogenic localization-related syndrome differed between the two groups. CONCLUSIONS: Approximately half of patients who first came to attention for an unprovoked seizure already met epidemiologic criteria for epilepsy. There were significant differences between the types of patients with a first seizure and those with newly diagnosed epilepsy. One or several seizures at diagnosis did not influence the diagnostic assessment of the patients but had a strong influence on the initiation of treatment.
This report describes a patient with complex partial seizures arising from the right temporal lobe who developed symptomatic sinus arrest following the end of his seizure activity. A ventricular pacemaker was implanted and was documented to function appropriately, preventing development of bradycardia associated symptoms during subsequent seizures. Possibly relevant cerebral structures are briefly discussed.
Periodic lateralized epileptiform discharges (PLEDs) are a well defined electroencephalographic entity but whether PLEDs represent an ictal condition or not remains debated. Much work has been done using electroencephalography (EEG) but new approaches using cerebral perfusion imaging may give more information about this question. We aimed to evaluate if PLEDs were associated with high regional cerebral blood flow (rCBF). We studied 18 patients with PLEDs and different pathologies, and performed brain single-photon-emission computed tomography (SPECT) during and, for three cases, after the disappearance of PLEDs. Qualitative variations and locations of rCBF were compared with PLEDs. Association with seizures and type of seizures were also assessed. SPECT showed high rCBF in 18/18 patients (100%). The location of PLEDs and high rCBF matched in 17/18 cases (94%). In the three cases where SPECT was performed after PLEDs disappeared, the high rCBF had cleared (100%). Eighteen cases (100%) presented seizures before recording of PLEDs, mainly motor (partial motor or generalized tonic-clonic). Where there was a decreased rCBF (related to a lesion) there was little relationship to PLEDs and all patients with decreased rCBF had an adjacent increased rCBF. These results confirm preliminary case reports. Hyperperfusion adds further to the argument that PLEDs may be related to a form of partial status epilepticus.
Bodyweight gain is a common and frequent undesirable effect associated with the use of anticonvulsant drugs. This has been observed for many years with valproic acid (sodium valproate) and carbamazepine, and also, more recently, with some of the newer anticonvulsants such as vigabatrin and gabapentin. Very often bodyweight gain in children, adolescents and adults with epilepsy taking such anticonvulsants results in cosmetic adverse effects. On the other hand, bodyweight gain is disturbing to general health, with a possible increase in the risk of diabetes mellitus or heart disease. Other potential adverse effects, such as the association of obesity with polycystic ovaries, have been reported with the use of valproic acid. Potential mechanisms of anticonvulsant-associated bodyweight gain are not yet clear and differ between drugs used. The involvement of lowered blood glucose level, which may stimulate eating through an effect on the hypothalamus, constitutes one of the possible mechanisms. Lowered blood glucose levels may result from a competition between the binding of the drug and long chain fatty acids. An increased availability of the latter stimulates insulin production and lowers the serum glucose levels. Another possible explanation for lowered blood glucose may be a deficiency in carnitine directly caused by the drug, that would result in a reduction of fatty acid metabolism and an increase in glucose consumption. An enhancing effect of gamma-aminobutyric acid-mediated neurotransmission may increase appetite for carbohydrates and reduce energy expenditure. An antidiuretic hormone-like effect or effects on norepinephrine (noradrenaline) or serotonin-mediated neurotransmission are more rarely considered. Many studies on anticonvulsant-associated bodyweight gain illustrate how we could better define the risk factors for the development of anticonvulsant-induced bodyweight gain and uncover the mechanisms behind it.
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BACKGROUND: To determine the incidence, risk factors, and case fatality rate of status epilepticus (SE) in the French-speaking part of Switzerland. METHODS: Between October 1, 1997 and September 30, 1998 all cases of SE referred to all the hospitals in the six cantons of the French-speaking part of Switzerland were identified by physicians working in emergency rooms, intensive care units, and electroencephalography departments; neurologists; and pediatricians from all hospitals in the area. Each case was validated and classified according to seizure type and etiology. RESULTS: Over 1 year, 172 cases were identified, of whom 74 had a history of epilepsy (42.4%). The crude and standardized annual incidence rate were 9.9/100,000 (95% CI, 8.4 to 11.4) and 10.3/100,000 (95% CI, 8.7 to 11.9). The incidence rate was higher among children < 1 year of age and adults > 65 years, and among men than women. There were 108 cases of acute symptomatic SE (incidence: 6.2 per 1000), 49 cases of remote symptomatic SE, and 15 cases of unknown etiology. Case fatality rate was 7.6%. CONCLUSIONS: The standardized incidence rate of SE in the French-speaking part of Switzerland was lower than that reported in Rochester, MN (18.3/100,000) and in the white population of Richmond, VA (20/100,000). The discrepancy may stem from the lack of a homogeneous, rigorous, and pragmatic definition of SE and the efficient management of acute repetitive seizures in this area.
Refractory epileptic state (RES) is defined by severe seizures that are resistant to antiepileptic drug treatment. Diagnostic errors such as pseudo-seizures and encephalopathies with triphasic waves must be distinguished at an early stage from cases of RES. The latter are symptomatic of a focal brain lesion or severe systemic disease, most frequently metabolic in origin. The treatment of such conditions is aimed at correction of the underlying cause. A nosographic issue that is still a subject of discussion and which requires further study, i.e., PLEDS, will also be discussed in this article.
Status epilepticus (SE) can theoretically be described using a simple definition based on physiopathological mechanisms: any seizure of epileptic nature, partial or generalized, convulsive or non-convulsive, lasting over a period of more than 30 minutes; or repeated seizures lasting for a period of over 30 minutes without recovery of consciousness. In the context of a historical review of various definitions, the validity of this definition is assessed and questioned. The heterogeneous nature of this condition is evidenced in daily clinical practice and by the results of epidemiologic studies. In the present study, the authors propose a more pragmatic and heuristic classification, taking into account not only clinical but also electroencephalographic data, as well as the particular nature of the epileptic syndrome when this is known.
In this study, a report has been made of 19 cases of severe encephalopathy in patients with renal impairment who were treated during the last three years for various infections with cefepime, a new parenteral cephalosporin antibiotic. All patients (aged 57 to 91 years) presented a prolonged confusional state associated with diffuse rhythmic non-reactive triphasic sharp waves on the EEG. All the electroclinical symptomatology disappeared within 24-48 hours after discontinuation of drug administration. A clear relation was found between encephalopathy and cefepime intake. These observations underline the fact that the cefepime dosage should be reduced in renally impaired patients.
OBJECTIVE: To determine the prognostic significance of spindle coma (SC) according to etiology and EEG reactivity. METHODS: We reviewed 15 patients with SC due to various causes within 8 days of coma to determine the prognostic significance of this EEG pattern. RESULTS: The outcome among survivors was favorable: among 13 survivors, 9 were independent in all activities of daily living (ADLs) at 6 months; 3 were dependent in all ADLs; and one remained in coma. EEG reactivity to noxious stimuli best predicted outcome: All patients (whatever the coma etiology) with EEG reactivity survived; conversely, not all patients without EEG reactivity died. CONCLUSION: In our patients, EEG reactivity independent of etiology predicted survival, neurological examination did not predict outcome. Most SC survivors had a meaningful recovery achieving all ADLs. From the literature, the cause of SC was predictive of outcome: encephalopathy, seizures and trauma had the best prognosis while hypoxia, CRA and structural lesions carried the worst. Literature review revealed that 23% of patients [56/242] died or remained in a persistent vegetative state (PVS). Best outcomes occurred when SC was due to drugs, encephalopathy or seizures: (0/14 died or were in a PVS). With trauma 15% [25/169] died or were in a PVS). Intermediate outcomes occurred with hypoxia and cardio-respiratory arrest (CRA): 33% [7/21] died or were in a PVS. The gravest outcomes occurred with brain-stem and cerebral infarctions, and tumors: 73% [22/30] died or were in a PVS.