Epilepsy Flashcards
What does the term epilepsy refer to
The term epilepsy refers to a disorder of brain function characterized by the periodic and unpredictable occurrence of seizures.
Paroxysmal alteration in brain activity- time limited- clinically detectable event (seizure).
What is meant by a seizure
The term seizure refers to a transient alteration of behaviour due to the disordered, synchronous, and rhythmic firing of populations of brain neurones.
What are drugs that treat seizures termed
The pharmacological agents in current clinical use for inhibition of seizures are referred to as anticonvulsant or antiepileptic drugs.
What is important to remember about seizures
More than one seizure
Seizures must occur in the absence of abnormal metabolic states (most people will seizure if they are hyponatraemic).
Highest incidence in early and late life
Are febrile convulsions in childhood classed as epilepsy
No, but if prolonged, they may predispose to epilepsy.
Where do seizures arise from and what can they be classified into
Seizures are thought to arise from the cerebral cortex and they can be classified into partial seizures, those beginning focally at a cortical site, and generalized seizures, those that involve both hemispheres widely from the outset. The behavioural manifestations of a seizure are determined by the functions normally served by the cortical site at which the seizure arises.
Describe what may occur in a seizure involving the motor cortex
Thus, for example, a seizure involving the motor cortex is associated with clonic jerking of the body part controlled by this region of the cortex.
Describe the difference between simple and complex partial seizures
A simple partial seizure is associated with preservation of consciousness, whilst a complex partial seizure is associated with impairment of consciousness (temporal lobe).
Describe simple partial seizures
May arise from an intracerebral structural defect and causes motor or sensory symptoms localised to one body part
May spread to adjacent areas as the electrical activity spreads to contiguous regions of the cortex (Jacksonian march).
An underlying structural defect may be found.
Describe seizures arising in the medial temporal lobe
May cause disturbances in smell and taste, visual hallucinations and a sense of déjá vu.
May evolve to tonic-clonic (secondary generalisation)
weakness following the event can last from minutes to hours (Todd’s paresis).
What type of seizures are included in primary generalised epilepsy
Examples of generalized seizures include absence, myoclonic and tonicclonic seizures.
Describe the potential causes of epilepsy
Epilepsy is a neurological disorder associated with abnormal neurotransmitter function in the brain. A decrease in GABAmediated inhibition or an increase in glutamate-mediated excitation in the brain may result in seizure activity. Indeed, both glutamate and GABA are thought to play key roles in the brain mechanisms causing epilepsy in man.
What is meant by generalised epilepsy
whole brain engulfed simultaneously by abnormal electrical activity
Describe tonic-clonic seizure
tonic maintained muscle contraction - holding still after collapse to floor; clonic rhythmic contractions 20-30s after the tonic contraction; followed by laboured breathing - grand mal
Sudden tonic contraction of muscles- with upward eye deviation
Initial EEG changes are bilateral.
Describe absence seizures
usually children, lose concentration and gaze rises.
AKA petit mal
Brief interruption of activity sometimes with complex motor activity (fumbling clothes)
No collapse
EEG shows 3 p/s spike-and-wave activity.
