THE EPILEPSIES

Defined by Sun et al. (2021) as a neurological disorder caused by abnormal brain activity, epilepsy has been noted as one of the most common neurological disorders in childhood, with potential to impact on physical, psychological, and social health (Fisher et al. 2005). Referred to as a disorder rather than a disease, epilepsy is a complex spectrum of symptoms which can manifest in up to 40 different types of seizure activity (Fisher et al. 2005). The main characteristic of epilepsy is recurrent, unprovoked seizures due to the presence of excess electrical activity in the brain, which causes a temporary disruption in the normal nerve impulses passing between brain cells (Epilepsy Research UK 2010; Glasper & Richardson 2020). Hauser and Banerjee (2008) further add that the recurrent seizures are separated by more than 24 hours. In some cases, it is possible for one person to have several types of seizure. Refer to Activity 15.1 for additional definitions.

NICE 2021 estimate the prevalence of epilepsy in the UK to be 5–10 cases per 1000 people and it is thought to affect approximately 63,400 children and young people under the age of 18 years in the UK (Joint Epilepsy Council (JEC) 2011). Those who have other neurological problems, for example a learning disability, show a higher incidence with risk of developing epilepsy increasing with the severity of learning disability (Whittaker 2004). Epilepsy is most commonly diagnosed during the first year, after a child has had two or more unprovoked seizures (Camfield & Camfield 2006) and although normally diagnosed in childhood, it can affect people of any age as a result of trauma to the brain such as injury or infection (Ricci & Kyle 2009).

The causes of epilepsy fall into three categories (National Society for Epilepsy (NSE) 2010a; Wolraich et al. 2008):

• Idiopathic epilepsy: has no apparent cause, but a genetic defect is thought to be involved. It is known that epilepsy can be inherited. In some cases, single or combinations of two or more genes can be involved, and environmental factors cannot be underestimated.
  
• Symptomatic epilepsy: has a definite cause, for example meningitis, birth trauma, anoxia, or congenital abnormalities, for example hydrocephalus.
  
• Cryptogenic epilepsy: has a likely cause, but for which nothing definite can be found.

According to Scheffer et al. (2007) there is growing evidence of the role of genes in symptomatic and cryptogenic epilepsies. Gene defects do not lead directly to epilepsy, but can affect the excitability of the brain, making it more susceptible to seizures. Each of us is born with a genetically inherited seizure threshold. Those with low thresholds are more susceptible to having a seizure when exposed to certain circumstances or triggers, for example sleep deprivation. Conversely, those with higher thresholds are less likely to have a seizure in similar circumstances. According to the NSE (2009a) anyone has the potential to have a seizure given the right circumstances, or a strong enough stimulus (Whittaker 2004).

Seizures are a clinical manifestation or symptom of epilepsy associated with a disturbance of the electrical activity in the brain; however, it is important to note that not all seizures are due to epilepsy. They may also be associated with other non-epilepsy conditions, such as infections of the central nervous system, hypoglycaemia, syncope, hyponatraemia, and hypoxia, which can disturb the neuronal environment. Dissociative seizures (previously known as pseudo seizures and also known as functional seizures or psychogenic seizure) are thought to be a severe reaction to emotional or psychological distress. Due to the unconscious nature of these and their similarity to epileptic seizures, these can initially be misdiagnosed as epilepsy. Whilst all seizure types may have much in common, they differ in their cause, and therefore must be investigated in order to make an accurate diagnosis.