Absence status epilepticus

Absence seizures Febrile seizures in children Status epilepticus Absence seizures Tonic-clonic seizures... 

Clonazepam, a typical 1 4 benzodiazepine, is effective in absence seizures, myoclonic jerks and tonic-clonic seizures and given intravenously it attenuates status epilepticus. It is less sedative than phenobarbitone but tolerance develops and its withdrawal, as... 

The benzodiazepines have many clinical indications and are discussed in Chapters 25, 30, 35, and 40. As AEDs, they have their major usefulness in the treatment of absence, myoclonic, and atonic seizures and in the emergency treatment of status epilepticus. 

Onset of unconsciousness is rapid but it is associated with a high incidence of excitatory effects, comparable to methohexitone, but these can be reduced by prior administration of an opioid. Analogous to the barbiturates, etomidate decreases CMR02, CBF and ICP but the haemodynamic stability of the drug will maintain CPP. Its well-known inhibition of adrenocortical function limits its clinical usefulness for long-term control of elevated ICP. While etomidate can produce convulsion-like EEC potentials in the absence of apparent convulsions, it has been used to terminate status epilepticus. 

Several members of the benzodiazepine group are effective in treating epilepsy, but most are limited because of problems with sedation and tolerance. Some agents such as diazepam (Valium) and lorazepam (Ativan) are used in the acute treatment of status epilepti-cus (see Treatment of Status Epilepticus ), but only a few are used in the long-term treatment of epilepsy. Clonazepam (Klonopin) is recommended in specific forms of absence seizures (e.g., the Lennox-Gastaut variant) and may also be useful in minor generalized seizures such as akinetic spells and myoclonic jerks. Clorazepate (Tranxene) is another benzodiazepine that is occasionally used as an adjunct in certain partial seizures. 

Therapeutic uses Phenytoin is highly effective for all partial seizures (simple and complex), for tonic-clonic seizures, and in the treatment of status epilepticus caused by recurrent tonic-clonic seizures (Figure 15.3). Phenytoin is not effective for absence seizures, which often may worsen if such a patient is treated with this drug. 

Phenobarbital has selective antiseizure activity at low doses and has a long half-life suitable for maintenance treatment in seizure disorders (for characteristics of barbiturates, see sedative-hypnotics). Clonazepam is usually a backup drug in absence and myoclonic seizures it causes marked sedation at anticonvulsant doses. IV lorazepam and diazepam are both used in status epilepticus. 

The combination of these drugs may induce absence status epilepticus. 

The concurrent administration of valproate and clonazepam rarely has been associated with the development of absence status epilepticus. 

List the major drugs used for partial seizures, generalized tonic-clonic seizures, absence and myoclonic seizures, and status epilepticus. 

Benzodiazepines Diazepam and lorazepam are preferred drugs for status epilepticus. Clonazepam is used for absence seizures. Described in tables 3.8A and 3.8C. 

Absence status epilepticus is a condition of impaired consciousness, perhaps including mild motor symptoms, that lasts from 30 minutes to 12 hours. It can be distinguished from ongoing seizures because of organic or toxic causes by the spike-and-wave EEC pattern that is characteristic of absence seizures. The usual pharmacological treatment of absence status employs diazepam or lorazepam, followed by ethosuximide. 

Phenytoin is indicated for initial monotherapy or adjunct treatment of complex partial or tonic-clonic seizures, convulsive status epilepticus, and prophylaxis. It often is selected for initial monotherapy because of its high efficacy and relatively low incidence of side effects (29). Phenytoin is not used in the treatment of absence seizures, because it may increase their frequency of occurrence (30,31). Phenytoin binds to and stabilizes the inactivated state of sodium channels, thus producing a use-dependent blockade of repetitive firing and inhibition of the spread of seizure activity to adjacent cortical areas. 

Osorio I, Reed RC, Peltzer JN. Refractory idiopathic absence status epilepticus a probable paradoxical effect of phenytoin and carbamazepine. Epilepsia 2000 41 887-894. 

Thomas P, Valton L, Genton P. Absence and myoclonic status epilepticus precipitated by antiepileptic drugs in idiopathic generalized epilepsy. Brain 2006 129 1281-1292. 

Valproic acid (Depakene or Depakote [divalproex sodium]) is a structurally unique anticonvulsant. It is used for the treatment of absence seizures, partial complex, and generalized seizure disorders and is a secondary agent for refractory status epilepticus. It is also commonly used for the prophylaxis and treatment of acute manic episodes and other affective disorders, migraine prophylaxis, and chronic pain syndromes. 

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