Track the duration of the crisis. Call 911 if an attack lasts longer than 5 minutes or if the person is injured during the seizure. Antiepileptic drugs (AEDs) are the mainstay of treatment for most patients with seizures. First-line drugs are valproic acid, lamotrigine and topiramate. [13] Each of these medications has side effects that treating physicians should be aware of. Valproic acid poses a risk of hepatotoxicity, teratogenicity and pancreatitis. [13] Valproate is contraindicated in patients suspected of having mitochondrial disease due to the high risk of liver failure. Valproate can cause neural tube defects and decreased IQ scores and autism after uterine exposure. Therefore, valproate should not be given to women of childbearing potential unless the seizures are refractory to other antiepileptic drugs. When valproate is used in women of childbearing potential, folic acid supplementation and effective contraception should be used. Lamotrigine has a warning box that it can cause severe rashes. The incidence of these rashes, including Stevens-Johnson syndrome, is approximately 0.08% to 0.3% in the adult population.
The incidence of rash is higher in pediatric patients. These life-threatening rashes usually appear 2 to 8 weeks after starting treatment. [13] Co-administration of lamotrigine and valproate, higher than the recommended starting dose of lamotrigine, or a more rapid increase in the dose of lamotrigine may increase the risk of rash. Lamotrigine should be discontinued at the first sign of a rash unless the rash is clearly not related to the drug. There is a new safety warning regarding a life-threatening immune reaction called hemophagocytic lymphohistiocytosis (HLH) associated with lamotrigine. Common features of HLH include fever and rash, enlarged spleen, cytopenia, elevated triglyceride or fibrinogen, elevated ferritin levels, hemophagocytosis identified by biopsy of the bone marrow, spleen or lymph nodes, absence or denaturation of natural killer (NK) cell activity, or elevated CD25 levels with prolonged activation of immune cells. Absences, the second most common form of generalized seizures, are classified as typical or atypical (see Table 375-3). In typical absence crises, patients experience an abrupt onset and end of momentary loss of consciousness. Patients have no perception of any aspect of the event and may not realize that some time has been lost, although individuals often lose their train of thought. Since consciousness is abruptly lost and regained immediately, there are no initial symptoms or residual postictal symptoms.
These seizures begin in childhood and teachers are often the first to notice them. In the absence of seizures, patients stop abruptly, stare at them, may have brief blinks or myoclonic movements, especially if the event lasts longer than 10 seconds (as assessed by EEG) and immediately regain function (see video 375-1). These attacks can occur several times a day, but are not associated with progressive neurological disease. Absences may also occur in a more continuous form such as the resulting non-convulsive status epilepticus with confusion. The first-line treatment for epilepsy is medical, with a variety of antiepileptic drugs currently available in clinical practice and with new pharmacological studies. Most patients with generalized seizures respond to antiepileptic therapy. Although about 30% of patients with partial seizures are resistant to medical treatment, other treatment options are available, the most effective of which is surgical resection of the region/brain injury causing the seizures. A randomised trial comparing surgical treatment with medical treatment found that early epilepsy surgery is a cure for drug-resistant epilepsy in children and adolescents. Generalized seizures, including tonic, myoclonic, akinetic, atonic, absent and tonic-clonic, are observed in conjunction with an EEG pattern of multifocal spikes and complexes of irregular, atypical or slow spikes and waves (also known as petit mal variants) with slow and poorly organized background activity for the patient`s age.
Epileptiform activity is enhanced by sleep, often with disruption of normal sleep activity, but is little modified by intermittent photic stimulation of hyperventilation. These electroclinical features have been called Lennox and Gastaut encephalopathic syndrome (Gastaut et al., 1966) (Fig. 11.14). There is a strong clinical association with intellectual disability, including “autistic” characteristics. Hypsarrhythmia and infantile seizures may, but not necessarily, precede these seizures and EEG patterns. Seizures are common and difficult to control despite near-toxic doses of anticonvulsants. Long-term prognosis is also poor for normal mental development and seizure stoppage. The age of onset and highest disability range from infancy to 7 years, although seizures and EEG abnormalities sometimes persist into adolescence and early adulthood (Noriega-Sanchez & Markand, 1976; Markand, 1977). After a GTCS, treatment depends on the type of epileptic syndrome identified. Generalized epilepsy is treated differently than focal epilepsy. With an accurate diagnosis, most seizure disorders respond to treatment. A generalized tonic-clonic seizure is a type of seizure identified by specific clinical and electroencephalographic criteria.
[1] International League Against Epilepsy. Proposal for a revised clinical and electroencephalographic classification of epileptic seizures. Epilepsy. 22(4)August 1981:489-501. www.ncbi.nlm.nih.gov/pubmed/6790275?tool=bestpractice.com Clinically, this type of seizure typically involves loss of consciousness and phasic tonic stiffening of the limbs (symmetrical or asymmetrical), followed by repeated clonic shaking. The vast majority of these types of crises are self-limiting without intervention. The observed manifestations of seizure are correlated on the electroencephalogram with bisynchronous epileptiform activity in both cerebral hemispheres. These seizures can occur either primary (with onset in a generalized or bilateral distribution) or secondary (with onset in a hemisphere or region). In addition, the distinction between focal and generalized seizures becomes somewhat blurred; Seizures can begin by concentrating and turn into generalized seizures as activity spreads from one hemisphere to another. Such development occurs when the initial seizure focus is localized to the frontal lobes of the brain.
The behavioral representation is essentially indistinguishable from that of a generalized seizure, and the development of focal crisis to generalized seizure usually occurs so quickly that an EEG analysis is needed to detect it.