Epilepsy

• Motor seizure: Involuntary jerking of one or more parts of the body (focal motor seizures). Jerking may begin in a small area of the body and spread sequentially to arms, legs, or face on the same side. Jerking may also spread to the opposite side, causing a generalised convulsive seizure. Motor seizures may also present with bizarre movements such as paddling, jumping and or violent random movements of the arms and legs (hypermotor seizure). These often occur upon waking from sleep. They may be very short, occurring many times a day.

• Some people experience abnormal hearing, vision, taste, smell or tingling sensations. They may feel unexplained fear, sadness, joy or nausea. While an adult can describe these clearly, children who are preverbal or nonverbal may act strangely. Parents may notice that the child suddenly stops normal activities and become unresponsive. They may look pale, sweaty or have dilated pupils. They may return to normal after seconds or a few minutes.

• Seizures can start with or without an aura (an awareness of an impending seizure). The person may stare blankly, followed by repetitive movements such as chewing, lip smacking, swallowing, or grunting. The person will appear unaware of their surroundings; they may seem dazed and mumble; their actions may be clumsy and not focused. The person may pick at their clothing or objects; or even try to take clothes off. They may run, appear afraid, and may flail their arms and legs.

• Post-seizure confusion can last substantially longer than the seizure itself. The individual will have no memory of what happened during the seizure. At times, focal seizures can progress to bilateral tonic-clonic seizure, causing muscle stiffening and jerking.

Approximately one third of babies with TSC will develop infantile spasms. For some, this will be the first symptom that leads doctors to a diagnosis of TSC. Infantile spasms are clusters of brief stiffening movements that typically start between 3 and 18 months of age.  They usually peak between 4-6 months of age, but can start anytime in the first two years of life. 

The most frequent and common characteristic is a sudden forward movement of the neck (head nod) and the arms and shoulders jerk upwards and towards midline. They may look like they are doing a ‘sit up’. Extensor type spasms are less common and are characterised by sudden extension of the neck and the arms move away from the midline. In other cases, the spasms may be subtle, and only abrupt head nods occurring in clusters are noticed. In many cases, infantile spasms are a mix of characteristics.

 Spasms tend to cluster, meaning they occur repeatedly  3-10 times in a row with a few seconds in between. At the end of a cluster the baby will often be very upset and will then be irritable. Spasms usually occur soon after the baby has woken up from sleep, or shortly after going to sleep.

Infantile spasms can difficult to diagnose and can be mistaken for normal body movements, colic/gastroesophageal reflux or startle reflex. As they can cause poor development, early correct diagnosis is important. Infantile spasm should be promptly treated.

Further information about infantile spasms can be found at TSC Alliance and Infantile Spasms Action Network.

Tonic seizures involve sudden lifting up and stiffening of arms, associated with stiffening of the neck and/or body. The legs can also show straightening and stiffening. In milder forms, these seizures can have subtle stiffening of the neck only.

During atonic seizures, the individual suddenly loses postural tone, resulting in a head nod or jaw drops (milder form), or falling to the ground (stronger form). Consciousness is usually impaired. The individual usually recovers after a few seconds to a minute.

Myoclonic seizures involve a sudden, involuntary, brief shock-like muscle contraction that usually involves both sides of the body, with synchronous jerks most often affecting the neck, shoulders, upper arms, body, and upper legs and may cause the person to spill what they were holding or fall off a chair.

Atypical absence seizures involve a prolonged stare or cessation of activity. They may begin and end gradually, usually last 5-30 seconds and are not generally provoked by hyperventilation. The person having the seizure may be partially responsive during episode. Eye-blinking or slight twitching movements of the lips may be seen. People with this type of seizure often have global cognitive impairment; therefore, it may be difficult to distinguish a seizure from the person’s usual behaviour. Electroencephalogram (EEG) is helpful to confirm the diagnosis of atypical absence seizures.

These are the most serious type of seizures and require prompt medical attention. Bilateral tonic-clonic seizure may occur with or without preceding aura/warning or complex partial seizure. Careful observation may reveal a seizure starting on one side with stiffening, jerking or head turn. There is often rapid progression to bilateral stiffening following by jerking. The seizure may last for many seconds to minutes.

A febrile seizure is a convulsion associated with a significant rise in body temperature. The incidence of febrile seizures is higher in TSC affected people (approximately 10%) than in the general population (5%). They are particularly common in children with TSC.

A person with TSC may suffer from both epileptic seizures and PNES.  Unlike epileptic seizures, PNES present differently on each occasion and may last for minutes to hours. Patients are often at rest, lying or sitting with the eyes closed, or slowly drop to the floor and usually do not sustain any injuries. A detailed history of the symptoms and home videos of any episodes are helpful for a diagnosis. An absence of epileptic activity in EEG rules out an epileptic seizure.

It is reassuring to know that PNES does not occur as a result of abnormal electrical activity in the brain and therefore does not require antiseizure medications. A prompt referral to a psychiatrist and a psychologist is required for early intervention. Some antiseizure medications like Sodium Valproate and Lamotrigine are used in epileptic seizures and as mood stabilisers in PNES. Some people with PNES may find these medicines helpful. 

Another way of describing the type of epilepsy a person has is as a syndrome. Diagnosis of an epilepsy syndrome is based on clinical and EEG characteristics. The two syndromes commonly diagnosed in people with TSC and epilepsy are:

1. Infantile Epilepsy Spasm Syndrome (IESS, previously known as West syndrome)

This is diagnosed on the basis of infantile spasms, the age at onset of spasms (under 12 months of age) and a typical EEG appearance – called hypsarrhythmia.

2. Lennox-Gastaut syndrome

This is diagnosed on the basis of multiple seizure types that occur in a person with TSC (particularly tonic, tonic-clonic and focal seizures), the age at onset of the different types of seizures (between 1 and 6 years of age) and a typical EEG appearance (slow spike and slow wave).

There have been many different studies looking to understand the link between epilepsy and other symptoms of TSC such as intellectual impairment, autism and mental health. Research has found that epilepsy starting early in life, infantile spasms and epilepsy that cannot be controlled may all increase the risk of intellectual disability and autism.

Although more research is needed to understand this better, the current research available does suggest that controlling seizures as early as possible may help to improve neurological outcomes. This is why many doctors will be aggressive in treating seizures, especially during the first 2 years of life.

Status epilepticus occurs when a seizure lasts too long, or when seizures occur close together without the person recovering between seizures.

*Status epielepticus is a medical emergency and requires immediate medical attention.*

1. Convulsive status epilepticus

This is defined as five or more minutes of continuous or repetitive tonic-clonic seizures without recovery of consciousness. Convulsive status epilepticus is a medical emergency and needs emergency treatment. If it is not treated urgently and successfully within 30 minutes, long term consequences with permanent brain damage or death may occur.

2. Focal status epilepticus with impaired awareness

This is defined as focal seizures of any type lasting for 10 minutes or more. 

3. Absence or Non-convulsive status epilepticus

This is defined as continuous absence seizures lasting for 10-15 minutes. EEG is necessary for making a diagnosis of non-convulsive status epilepticus. Although it is not as severe as convulsive status epilepticus, it does require urgent treatment.

Anyone with epilepsy and TSC is at risk of status epilepticus. Possible triggers for this include an infection that results in a high temperature (fever), brain trauma, or missing doses of anticonvulsant medications.

There are different types of status epilepticus which may present with or without prominent motor symptoms and are defined by the duration of the seizures.

People living with seizures have a 1 in 1000 risk of SUDEP per year, although the risk is lower in children. Each individual with epilepsy will have a different risk depending on their seizure types, the frequency of seizures and other factors. You can discuss the risk of SUDEP with your neurologist.

The best way to reduce the risk of SUDEP is by improving seizure control.