A seizure or epileptic attack is the consequence of a paroxysmal uncontrolled discharge of neurons within the central nervous system. The clinical manifestations range from a major motor convulsion to a brief period of lack of awareness.
The prodrome refers to mood or behavioural changes which may precede the attack by some hours.
The aura refers to the symptom immediately before a seizure and will localise the attack to its point of origin within the nervous system. The ictus refers to the attack or seizure itself.
The postictal period refers to the time immediately after the ictus during which the patient may be confused, disorientated and demonstrate automatic behaviour.
The stereotyped and uncontrollable nature of the attack is characteristic of epilepsy.
Epilepsy has been described since ancient times. The 19th century neurologist Hughlings-Jackson suggested 'a sudden excessive disorderly discharge of cerebral neurons' as the causation of the attack. Berger (1929) recorded the first electroencephalogram (EEG) and not long after, it was appreciated that certain seizures were characterised by particular EEG abnormalities.
Recent studies in animal models of focal epilepsy suggest a central role for the excitatory neurotransmitter glutamate. This produces a depolarisation shift by activating receptors which in turn facilitate cellular influx of Na + , K+ and Ca2+. Gamma amino butyric acid (GABA) has an important inhibitory influence in containing abnormal cortical discharges and preventing the development of generalised seizures.
All humans have a biological tendency to seizures and genetic factors play a role in susceptibility.
Incidence and course
Epilepsy usually presents in childhood or adolescence but may occur for the first time at any age.
5% of the population suffer a single seizure at some time.
Though there is considerable variability depending on seizure type, 6 years after diagnosis 40% of patients have had a substantial remission; after 20 years - 75%.
0.5% of the population have recurrent seizures
70% - well controlled with drugs with
0.5% of the population have recurrent seizures few seizures and prolonged remissions
30% - epilepsy at least partially resistant to drug treatment.
EPILEPSY IS A SYMPTOM OF NUMEROUS DISORDERS, BUT IN THE MAJORITY OF SUFFERERS THE CAUSE REMAINS UNCLEAR DESPITE CAREFUL HISTORY TAKING, EXAMINATION AND INVESTIGATION.
Was this article helpful?
This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.