Recurrence after first seizure

[French guidelines on electroencephalogram]

Electroencephalography allows the functional analysis of electrical brain cortical activity and is the gold standard for analyzing electrophysiological processes involved in epilepsy but also in several other dysfunctions of the central nervous system. Morphological imaging yields complementary data, yet it cannot replace the essential functional analysis tool that is EEG. Furthermore, EEG has the great advantage of being non-invasive, easy to perform and allows control tests when follow-up is necessary, even at the patient's bedside. Faced with the advances in knowledge, techniques and indications, the Société de Neurophysiologie Clinique de Langue Française (SNCLF) and the Ligue Française Contre l'Épilepsie (LFCE) found it necessary to provide an update on EEG recommendations. This article will review the methodology applied to this work, refine the various topics detailed in the following chapters. It will go over the summary of recommendations for each of these chapters and underline proposals for writing an EEG report. Some questions could not be answered by the review of the literature; in those cases, an expert advice was given by the working and reading groups in addition to the guidelines.

Single unprovoked seizures

Unprovoked seizures are common, affecting approximately 4% of the population by age 80. Only approximately 30% to 40% of patients with a first seizure will have a second unprovoked seizure (ie, epilepsy). Treatment with antiepileptic drugs (AEDs) should not be initiated unless the diagnosis of a seizure is firm. Decisions regarding treatment of single unprovoked seizures must balance seizure recurrence risk, the potential impact of a recurrent seizure, the likelihood of adverse effects of treatment, and patient preference. Risk factors for seizure recurrence include a history of remote neurologic insult, epileptiform abnormalities on electroencephalogram, focal structural lesion on neuroimaging, and family history of epilepsy. Adult patients with these risk factors have a recurrence risk of 60% to 70% and usually should be treated with an AED to prevent seizure recurrence. Without risk factors, the recurrence risk is 20% to 30%, and treatment depends on individual risk-to-benefit ratios and patient preference. Treatment of a first unprovoked seizure is often not necessary in childhood, especially if the seizure is part of a benign self-limited syndrome, such as benign Rolandic epilepsy of childhood. Treatment with an AED reduces the risk of seizure recurrence after a single unprovoked seizure. This must be balanced against the risk of adverse effects of AEDs. Treatment of the first seizure does not appear to affect the long-term prognosis of epilepsy. The choice of an AED should be guided by the seizure type and likely epilepsy syndrome diagnosis. Monotherapy is preferable. Standard AED options include phenytoin, carbamazepine, valproate, and phenobarbital. The newer AED, including gabapentin, lamotrigine, topiramate, oxcarbazepine, levetiracetam, and zonisamide, have good efficacy, favorable pharmacokinetic profiles, and often fewer adverse effects, supporting their use early in treatment. Not all of the newer AEDs are approved for use as monotherapy. Patients with single seizures should be counseled about seizure first aid and general safety measures, including precautions regarding swimming alone, engaging in high-risk activities, driving, possible seizure precipitation by photic stimuli (in generalized epilepsy), sleep deprivation, and alcohol.

The prognosis of epilepsy

The cardinal question for a person developing seizures is 'What is the likelihood that they will go away?' 'Prognosis' refers to the possible outcomes of a disease and the frequency at which they can be expected to occur. Prognostic factors may include demographic features, disease-specific indicators (e.g. seizure frequency, aetiology of epilepsy) or co-morbidity. Such factors do not necessarily cause the outcome, but they are associated strongly with the outcome measured. They are distinct from risk factors--which are associated with the initial development of the disorder. Ideas about the outcome for epilepsy have been altered radically in the past century by study of its epidemiology. The prognosis for epilepsy comprises a number of measurable end-points: the prediction of recurrence after a single unprovoked seizure, the chance of remission after the diagnosis of epilepsy and the risk of premature death.

Failure of salmeterol to inhibit circulating white cell responses and bronchoconstriction induced by platelet activating factor

BACKGROUND

Platelet activating factor (PAF) is a potent mediator of inflammation. Inhalation of PAF causes acute bronchoconstriction and a transient fall in white blood cell count in humans. Salmeterol inhibits pulmonary inflammation induced by PAF in guinea pigs.

METHODS

The effect of salmeterol on effects induced by PAF was investigated in eight normal subjects who inhaled salmeterol (50 micrograms) twice daily or a matched placebo for one week before challenge with PAF. Blood samples were taken from a forearm catheter for total white cell and neutrophil counts before and for 30 minutes after administration of PAF (48 micrograms) through a Mefar dosimeter. Blood films were stained for unsegmented neutrophils before and after treatment with PAF on a placebo day.

RESULTS

Mean baseline total white cell counts and neutrophil counts did not differ on the two days. Mean baseline sGaw was significantly higher after inhaled salmeterol (1.84 (95% C1 1.45-2.23) s-1kPa-1) than after placebo (1.53 (1.24-1.82)). After placebo mean total white cell counts, neutrophil counts, and sGaw were reduced to 60 (43-78)%, 39 (14-64)%, and 82 (71-93)% of baseline respectively five minutes after inhaled PAF. After salmeterol treatment mean reductions five minutes after inhaled PAF were 59 (45-73)%, 40 (19-61)%, and 82 (71-93)% of baseline respectively. At 30 minutes after treatment with PAF the neutrophil count rebounded to 143 (82-204)% of baseline after placebo and to 127 (93-161)% after inhaled salmeterol. There was no significant difference in the percentage of immature neutrophils before and after treatment with PAF (2.0 (0.5-2.6)% compared with 3.9 (2.2-5.6)%.

CONCLUSIONS

Treatment with salmeterol did not inhibit reduction in total white cell count or neutrophil count, rebound neutrophilia, acute bronchoconstriction, or transient flushing after inhalation of PAF. These results conflict with the inhibitory effect of salmeterol on lung inflammation in guinea pigs but are consistent with the lack of effect of salbutamol in humans. Salmeterol does not have an anti-PAF effect in vivo in humans.

Formoterol compared with beclomethasone and placebo on allergen-induced asthmatic responses

Formoterol is a new long-acting beta 2-agonist. We compared the protective effect of 24 micrograms formoterol with 200 micrograms beclomethasone and placebo on inhaled allergen-induced asthmatic responses in mild stable asthmatic subjects. We measured airflow rates, histamine airway responsiveness, cell counts from sputum and peripheral blood, and markers of lymphocyte and eosinophil activation. Adjustments were made for the confounding effect of bronchodilatation produced by formoterol in comparisons using a control inhalation of normal saline. Formoterol caused bronchodilation and inhibition of histamine airway responsiveness for at least 24 h. It completely inhibited the early asthmatic responses when beclomethasone had no effect. Control comparisons of the effect of formoterol and beclomethasone on the allergen-induced late asthmatic response and increase in histamine responsiveness showed each to be equally effective but not to inhibit the responses completely. Formoterol caused bronchodilation in addition to preventing bronchoconstriction. Both drugs inhibited the rise in serum eosinophil cationic protein 24 h after allergen, but neither inhibited the allergen-induced increases in sputum or blood eosinophils or CD25+ lymphocytes. These results suggest that formoterol modifies allergen-induced airway responses through functional antagonism rather than the inhibition of inflammatory cell infiltration.