How can sodium channels cause epilepsy?
Excerpt. Voltage-gated sodium channels initiate action potentials in brain neurons, and sodium channel blockers are used in therapy of epilepsy. Mutations in sodium channels are responsible for genetic epilepsy syndromes with a wide range of severity.
How do SCN1A mutations cause epilepsy?
The SCN1A gene codes for a sodium channel protein that regulates brain cell activity. Changes in the DNA sequence of the gene (referred to as variants) alter the sodium channel protein and lead to the brain being more susceptible to seizures.
What is SCN1A epilepsy?
SCN1A is the major gene for Dravet Syndrome, a severe epilepsy of childhood most prominently characterized by fever-induced seizures.
How do sodium channel blockers work for epilepsy?
Sodium channel blockade is the most common and best-characterized mechanism of currently available antiepileptic drugs (AEDs). AEDs that target sodium channels prevent the return of the channels to the active state by stabilizing the inactive form. In doing so, repetitive firing of the axons is prevented.
Does salt affect epilepsy?
Many seizures take place when blood sugar is low. Stimulants such as tea, coffee, chocolate, sugar, sweets, soft drinks, excess salt, spices and animal proteins may trigger seizures by suddenly changing the body’s metabolism.
Is sodium good for epilepsy?
Since a small increase in the serum sodium concentration can substantially reduce cerebral edema, seizures induced by hyponatremia can be controlled by increasing the serum sodium concentration.
What is SCN2A epilepsy?
SCN2A-Developmental and Epileptic Encephalopathy Encephalopathy refers to a disease that affects the functioning of the brain. Children with SCN2A-developmental and epileptic encephalopathy often experience seizures that start early in infancy, sometimes even shortly after birth.
What are the symptoms of Dravet syndrome?
Dravet syndrome (DS) is a severe form of epilepsy characterized by frequent, prolonged seizures often triggered by high body temperature (hyperthermia), developmental delay, speech impairment, ataxia, hypotonia, sleep disturbances, and other health problems.
What happens when you block sodium channels?
The principal effect of reducing the rate and magnitude of depolarization by blocking sodium channels is a decrease in conduction velocity in non-nodal tissue (atrial and ventricular muscle, purkinje conducting system).
Does valproate block sodium channels?
There is also anecdotal evidence to suggest that sodium valproate and gabapentin have inhibitory effects on neuronal sodium channels. Voltage-gated sodium channels exist in one of three basic conformational states: resting, open, and inactivated.
What is the ILAE classification of the epilepsies?
ILAE Classification of the Epilepsies (2017) After diagnosis of the seizure type, the next step is diagnosis of epilepsy type, including focal epilepsy, generalized epilepsy, combined generalized, and focal epilepsy, and also an unknown epilepsy group. The third level is that of epilepsy syndrome, where a specific syndromic diagnosis can be made.
Which is the best definition of epilepsy?
Definition of epilepsy. Epilepsy is a disease of the brain defined by any of the following conditions: At least two unprovoked (or reflex) seizures occurring more than 24 hours apart One unprovoked (or reflex) seizure and a probability of further seizures similar to the general recurrence risk…
Which is a defining feature of familial partial epilepsy?
EEG findings are a defining feature of familial partial epilepsy with variable foci, which manifests as temporal and extratemporal seizures; the EEG focus is usually congruent with seizure type in individual cases.
How is the EEG used to diagnose epilepsy?
EEG has relatively low sensitivity in epilepsy, ranging between 25–56%. Specificity is better, but again variable at 78–98%. These wide ranges can be explained partly by diverse case selection and differences in clinical requirements for diagnosis of epilepsy in population studies of EEG specificity and sensitivity.
