Epilepsy comes in a range of conditions and is not just one ‘condition’. In short it is a form of brain disorder which cause convulsive or not convulsive seizures.
There are many types of Epilepsy and many types of seizures.
10% of the population will experience a seizure while 3-4% will go on to be diagnosed with epilepsy.
There are seizures that are not epileptic. These include those that result from diabetes, kinked blood vessels and a range of other health conditions.
Who gets epilepsy?
Epilepsy is a common condition and can develop at any age, regardless of gender or ethnic group. Research suggests that 3-4% of the Australian population will develop epilepsy at some stage. Epilepsy was one time considered a condition that the young suffered from. It was believed that most people experienced their first seizure before the age of 20. However, the over 55 years age group is now recognised as being the most vulnerable group.
What causes epilepsy?
There are many causes of epilepsy, which vary with age. In around 50% of cases, the cause is unknown.
There are a number of causes and these include:
- Structural abnormalities in the developing brain,
- Infections such as meningitis or encephalitis,
- Lack of oxygen to the brain during birth or after a stroke
- Brain injury
- A tumour
- Alzheimer’s disease
- Genetics
What is a seizure?
Our thoughts, feelings and actions are controlled by brain cells. These communicate through regular electrical impulses. They travel along the network of nerve cells, called neurons. A seizure occurs when the brains nerve cells misfire. This causes a sudden, uncontrolled burst of electrical activity in the brain. The communication becomes scrambled. Our thoughts, feelings or movements become confused or uncontrolled.\
Seizures can be subtle. They may cause momentary lapses of consciousness, causing sudden loss of body control. Seizures are unpredictable, and may occur every day, or occasionally in a lifetime.
While seizures can be frightening, in most instances they stop without intervention. Once the seizure is over the person gradually regains control. They re-orient themselves to their surroundings, generally without any ill effects.
How is epilepsy diagnosed?
Epilepsy is not one condition. There are numerous epilepsy syndromes. Each has its own symptoms, seizure types, causes, methods of diagnosis, outcomes and management.
In diagnosing epilepsy, the presence of seizures is often the determining factor. An eyewitness report of the event and the person’s own description of what happened are vital. These can be the doctor’s best diagnostic tools. All the tests the doctor might order are to gather specific data on the kind of seizures experienced.
A neurological examination will be conducted. It will include a test to measure the electrical activity of the brain. This will determine where in the brain the activity that is generating the seizure is happening. Specialised imaging tests may be required, along with blood tests.
Diagnosing epilepsy in a child can be a harrowing experience. Many a parent has observed seizures at home that are not subsequently picked up in hospitals by the most sophisticated scanning. This is a frustrating situation for a parent to be in. Most doctors will now listen to parents and treat them as a primary information source in helping to diagnose their children’s health.
With mobile phone technology, many handsets now have excellent video capabilities. Capturing the event or behaviour when it occurs on video, parents/carers can provide their doctor with recorded evidence to support their observations. Such recordings can be extremely helpful to the doctor when determining a diagnosis.
Types of seizures
Generally, seizures fall into two categories: primary generalised seizures and focal seizures. The difference between these two types is in how they begin.
Primary generalised seizures involve the whole brain and involve the whole body.
Focal seizures start in one part of the brain and affect that part of the body controlled by that part of the brain.
The most common seizure types:
Primary Generalised Seizures
There are many types of generalised seizures, some convulsive, others non-convulsive.
Absence seizure
This is a brief, repetitive, non-convulsive event, usually occurring in the young, and involves the whole brain. With this type, the persons awareness and responsiveness are impaired. They simply stare, their eyes might roll back or their eyelids flutter.
It can be difficult to tell the difference between absence seizures and daydreaming. However, absence seizures start suddenly. They cannot be interrupted, last a few seconds, and then stop suddenly and the person goes on with what they were doing. Although these seizures usually last less than 10 seconds, they can occur many times daily, and thus be very disruptive to learning.
Atonic seizure
Atonic seizures are generalised seizures that affect muscle tone causing the person to collapse to the ground. The person will usually remain conscious. Often called drop attacks, these seizures can cause head or facial injury. Protective headwear is advisable to avoid constant injury. Recovery is generally quite quick.
Myoclonic seizure
Myoclonic seizures are brief, shock-like jerks of a muscle or a group of muscles. They usually last no more than a second or two. There can be just one, but sometimes many will occur within a short time.
Tonic seizure
The body’s muscle tone is greatly increased and the body, arms, or legs make sudden stiffening movements. These seizures most often occur during sleep. Seizures can occur when the person is awake. Seizure duration is usually less than 20 seconds and consciousness is generally preserved. If appropriate it is advisable for the person to wear a protective helmet to avoid injury.
Tonic-clonic seizure
Tonic-clonic seizures generally last 1 to 3 minutes.
During a tonic-clonic seizure a persons body stiffens and they fall to the ground. Air being forced past the vocal cords causes a cry or groan. The tongue or cheek may be bitten, so bloody saliva may come from the mouth. Their limbs then begin to jerk in strong, symmetrical, rhythmic movements. The person may dribble from the mouth, go blue or red in the face, or lose control of their bladder and/or bowel. The seizure generally stops after a few minutes. As consciousness returns the person may be confused, drowsy or irritated. They may have a headache and want to sleep. This drowsiness can last for a number of hours.
This seizure type is the one most people think of when they think of epilepsy.
Although this type of seizure can be frightening to watch, the seizure itself is unlikely to seriously harm the person. They may however vomit or bite their tongue and can sometimes injure themselves if they hit nearby objects as they fall or convulse.
Focal Seizures
Focal seizures start in one part of the brain and affect the part of the body controlled by that part of the brain. The seizure may involve the involuntary movement or stiffening of a limb. A feeling of déjà vu, an unpleasant smell or taste, or sensations in the stomach such as ‘butterflies’ or nausea may also be experienced. The seizure usually lasts less than two minutes.
People can have different levels of consciousness during focal seizures. Sometimes the person remains alert throughout.
Focal seizures can also affect a person’s level of consciousness. The person may appear confused and dazed. They may do strange and repetitive actions. Fiddling with their clothes, making chewing movements or uttering unusual sounds are not unusual.
The seizure usually lasts for one or two minutes. The person may be confused and drowsy for some minutes to several hours afterwards and have no memory of the seizure or the events just before or after. This type of seizure can be mistaken for drug/ alcohol affected behaviour or psychiatric disturbance.
Secondarily generalised seizures
Secondarily generalised seizures are so called because they only become generalised after the initial or primary event, a focal seizure, has begun. These occur when a burst of electrical activity in a focal area of the brain spreads throughout the brain. This event can be so brief that the person does not recall or recognise it. The generalised convulsive stage of these seizures usually lasts no more than a 1-3 minutes, similar to primary generalised seizures. Secondarily generalised seizures occur in more than 30% of people with focal seizures.
If you are concerned or have any questions relating to Epilepsy then contact your Doctor.
