الفهرس 
Definition and types of EpilepsyOnly 14 pages are availabe for public view
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Abstract
Epilepsy is the most common serious neurological disease, with a prevalence commonly quoted as 5-10 cases per 1000 persons. Incidence varies due to a number of factors. In developed countries, it has been found to be around 50 cases per 100,000 persons per year. In developing countries, the incidence is higher (of the order of 100-190/100,000/year) for reasons which are not entirely clear. Thus from an anesthetic perspective, it is important to understand the issues of safe management of epileptics in the peri-operative period.
A seizure is any abnormal clinical event caused by electrical discharge from the brain, while epilepsy is a tendency to have seizures and considered as a symptom of the brain rather than a disease itself. A single seizure is not epilepsy but an indication for investigation. The recurrence of attacks after the first one approach about 70% in the first year mainly occurs in the first or second month .
Approximately 10% of the population has a single convulsive episode during their lifetime. In this situation, the use of anticonvulsants is not indicated. After the occurrence of a second seizure, the diagnosis of epilepsy is confirmed, initiating then the routine treatment with antiepileptic drugs .
The choice of the anticonvulsant should be made according to the type of crisis, the effectiveness and side effects, and used as monotherapy whenever possible, i.e. the goal of pharmacological treatment is to control seizures without side effects .
It is important to understand the mechanisms of action and the pharmacokinetics of antiepileptic drugs (AEDs) so that these agents can be used effectively in clinical practice, especially in multidrug regimens.
In the perioperative management of epileptic patients, it is important for the anesthesiologist in the preoperative evaluation to identify the type of epilepsy, frequency, intensity and the triggers to the epileptogenic episodes, the use of anticonvulsant drugs and possible interactions with drugs used in anesthesia as well as the presence of other treatments such as Vagus nerve stimulator and Ketogenic diet and its implications in anesthetic techniques. The anesthesiologist must know the properties of pro- and anticonvulsant drugs used in anesthesia, minimizing the risk of seizure activity during surgery. Finally, although an uncommon event, it is important to outline the diagnosis and, where necessary, establish the treatment of perioperative seizures, which would allow lower morbidity and mortality in patients with epilepsy .
Medications works for about 70% of patients with epilepsy. When they do not work, surgery is a well-accepted option for some types of epilepsy. A candidate for epilepsy surgery must have not attained acceptable seizure control with sufficient trials of AEDs and must have a reasonable chance of benefiting from surgery.
Surgery is generally considered when medications fail to control the seizures. How many medications should be tried before looking into surgery? The answer to this question has recently become clear: it is now known that if one fails 2 medications, then the chance of future success with any medications are less than 20%. If 3 or more medications have failed, then the chances of future suc¬cess with any medications are less than 10%.
The choice of anesthetic technique – local versus general anesthesia, rests predominantly on the choice of surgical technique – standardized versus customized resection. Even among centers with extensive experience performing craniotomy under local anesthesia, the use of general anesthesia typically provides a less stressful environment for the patient, surgeon and anesthetist. Although a variety of general anesthetic techniques can be used during temporal lobe surgery, the adequacy of intraoperative ECoG recording remains controversial and the opportunity to tailor the resection, based on intraoperative ECoG studies, is eliminated. Recent additions to the repertoire of anesthetic drugs and equipment have renewed enthusiasm for developing and evaluating anesthetic techniques that improve patient safety and comfort during these procedures .
With general anesthesia technique , a combination of nitrous oxide, opioid and low dose volatile anesthetic agent are typically used. Since each of the volatile anesthetic drugs (i.e., isoflurane, enflurane, halothane, desflurane and sevoflurane) are known to suppress epileptiform activity, even at low to moderate doses, general anesthesia using these drugs carries a risk of obscuring intraoperative ECoG spike activity. Since the level of surgical stimulation is low during ECoG studies, the depth of anesthesia can be reduced to a minimum. The decision to reduce administration of anesthetic drugs to achieve artifact-free recordings is balanced against the risk that some patients may experience intraoperative awareness and recall. In view of the fact that ECoG recording is not associated with discomfort, many patients, appropriately counseled and forewarned, may find this option acceptable.