Absences (generalised seizures)
This type of generalised seizure is localized in the central region of the brain in the thalamus and spreads over both hemispheres.
The most probable mechanism of an absence (also called petit mal) is abnormal synchronization of thalamocortical and cortical cells.
The absence is characterized by activation of T-type calcium channels on the thalamic relay neurons. The pathophysiological process begins with a certain signal from the cortex towards the thalamic area. This can include increased cellular potassium, increased GABAergic input or decreased excitatory input. This stimulus evokes hyperpolarisation
A 9-year-old girl is diagnosed with absences. Which of the following drugs is NOT an appropriate choice to treat the patient?
Extra info: Ethosuximide is the drug of choice, valproic acid secondary, and phenobarbital with refractory cases. There is clinical evidence that carbamazepine may increase the incidence of absences.