Epilepsy A-Z: Common and Rare Types of Epilepsy (Part 2)

Oct 11, 2016 | Trends

Epilepsy is a chronic neurological disorder characterized by persistent seizures. Previously, we discussed epilepsy broadly covering what seizures are and how they manifest and develop. We also looked at some of the types of seizures in Epilepsy A-Z: Common and Rare Types of Epilepsy Part 1. In this Part 2 article, we will discuss some of the other types of epilepsy that have been described as a continuation of our Part 1 piece.

To recap, there are around 40 different types of epilepsy each with a different seizure profile. Additionally, each person with epilepsy will experience a pattern of seizures and triggers that are specific and unique to them but that falls within a set of criteria specific to a small subset of types of epilepsy. The various types of epilepsy can be grouped into 4 categories. These categories describe the electrical activity pattern in the brain present during a seizure. Diagnosis occurs using a combination of seizures descriptions, an EEG, an MRI and an analysis of family history. 

Note: For an outline of “1. Focal Epilepsy”, see our previous article. A future article will cover Progressive Myoclonic Syndromes and Reflex Epilepsy.

  1. Idiopathic Generalized Epilepsy (IGE): abnormal activity is found in both hemispheres of the brain simultaneously leading to immediate loss of consciousness. The entire brain may not be involved but both surface and/or deep areas of the brain in both hemispheres take part. The abnormal electrical firing starts in one or more areas of the brain and spreads and this pattern varies from individual to individual and even from one seizure to the next. As a result, the part of the brain affected is not always well-defined.

Acquired Epileptic Aphasia

Alternative names Features Include Triggers

Landau-Kleffner syndrome (LKS), Acquired Aphasia with Convulsive Disorder and Infantile Acquired Aphasia.

Varying degrees of aphasia (100% of patients), seizures (75%), cognitive and behavioral problems (75%). Seizure types: generalized tonic-clonic, focal motor, atypical absences and atonic seizures. Several may occur in sequence. Possible immune component.

Nighttime.

Prevalence Genetics Brain Area Affected Prognosis

Rare but twice as common in males.

Uncertain but there are several proposed candidates: GRIN2A, RELN, BSN, EPHB2 and NID2.

Temporal lobe which plays a role in behaviour, auditory comprehension and speech.

10% to 20% achieve complete normalization. Improvements in speech may occur.

 

Childhood Absence Epilepsy (CAE)

Alternative names Features Include Triggers

Pyknolepsy.

Seizures last from 10-20 seconds and result in periods of staring where a child is unresponsive and unaware of their surroundings (formally called a petit mal seizure). Eyes may roll and blink. Seizures may occur in the  hundreds per day. Around 30% of children may also have attention, concentration, and memory problems. Other seizure types may develop.

Exercise.

Prevalence Genetics Brain Area Affected Prognosis

2 to 8% of cases of epilepsy.

Strong genetic component but it’s complex polygenic

Starts in the thalamus which in involved in sleep, consciousness, alertness and processing of sensory and motor signals.

Around 70% of children respond to medication. Symptoms usually disappear by adolescence.

 

Epilepsy With Generalized Tonic-clonic Seizures Alone (EGTCS or GTCS)

Alternative names Features Include Triggers

Awakening Epilepsy (AE) and Epilepsy With Grand Mal Upon Awakening.

Generalized tonic-clonic seizures usually within 1-2 hours of waking up or while asleep and involve convulsive jerking and rigidity of the whole body. Can start in childhood or adulthood but teen years to young adult is most common. Aura are common. Typical tonic-clonic symptoms including muscle rigidity results in tongue biting, jaw-clenching, difficulty breathing, incontinence and blue skin. Seizures are followed by confusion, memory loss, muscle weakness and sleepiness.

Sleep deprivation, fatigue, alcohol use, fever, menstrual cycle, drug use, and flashing lights.

Prevalence Genetics Brain Area Affected Prognosis

Not known but estimated at 0.9-15% of IGE.

Strong genetic link with only CLCN2 gene and EJM1 loci confirmed thus far.

Very generalized.

Seizure remission with medication for around 75% of people.

 

Juvenile Myoclonic Epilepsy (JME)

Alternative names Features Include Triggers

Janz syndrome and Adolescent Myoclonic Epilepsy.

Emerges in mid-late childhood. Starts as absence seizures progressing to myoclonic seizures over time and often eventually tonic-clonic seizures. Seizures commonly occur upon awakening and manifest as sudden, irregular and arrhythmic movements of one or both arms and/or fingers. May only occur on one side of the body.

Fatigue, sleep deprivation, the period of time after awakening, complex activities, head injury and brain tumors.

Prevalence Genetics Brain Area Affected Prognosis

5-10% of all epilepsy cases. More common in females. Estimated to affect 1 in 1,000 people worldwide.

Complex. Includes GABRA1, EFHC1 CACNB4, CLCN2, EFHC1 and GABRD genes as well as others not yet discovered.

Very generalized.

Controllable with lifelong medication. Remission without medication is rare.

 

Lennox-Gastaut Syndrome (LGS)

Alternative names Features Include Triggers

None.

Intellectual disability, learning problems and medication resistance are common. Disability can increase over time when seizures are not well-controlled. Many seizure types may be present with tonic seizures accounting occurring in 75% of cases. Atypical absence seizures and drop (atonic) attacks also occur. Usually starts in early childhood.

Sleep. Also brain injury/trauma before or during birth.

Prevalence Genetics Brain Area Affected Prognosis

2-5% of childhood epilepsies. More common in males.

None yet but genetic link suspected for around 30 of cases.

Very generalized.

Lifelong medication use needed but low response to treatment is common.

 

West Syndrome

Alternative names Features Include Triggers

Infantile spasms. Called epileptic spasms if they occur in adult (very rare).

Typically occurs within the first year of life and may be misdiagnosed as colic. Tonic seizures with or without extensor spasms and range from bending at the waist to twitching. Babies may appear irritable and slow to develop. May develop LGS later in life (see above).

Sleep or brain trauma (70-75%).

Prevalence Genetics Brain Area Affected Prognosis

Occurs in one in 2,500-3,000 children.

Some cases are X-linked.

Very generalized.

May develop LGS later in life (see above).

In our previously article on epilepsy, we outlined some of the types of epilepsy with focal seizures. Focal seizures are characterized by aberrant brain activity in one defined part of the brain. Generalized epilepsy however is defined by abnormal activity in both hemispheres of the brain. In our next article, we’ll describe progressive myoclonic epilepsy and reflex epilepsy.

Some takeaways:

  1. Some forms of epilepsy have a strong genetic component while others do not appear to.
  2. Epileptic triggers may be specific to each type but general triggers include tiredness, lack of food, dehydration, alcohol use, drug use and trauma (both physical and mental).
  3. Some forms of epilepsies may present at an early age and disappear over time while others may be lifelong. Others manifest in later years and anywhere in between.
  4. Some forms of epilepsy are very rare while others are more common.
  5. Brain injuries and certain medications may provoke seizures.
  6. Some genes have been identified as having a role in epilepsy but more research is needed to cover all cases of all forms of the condition.
  7. People may have several different seizure types or just one type.

Do you have any questions you like to ask or topics you’d like covered? Comment below or send an email.


Article by Olwen Reina. Contact Olwen at olwen@tempobioscience.com.

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