Seizure disorders: Types & causes | Pacific Medical ACLS

It can be terrifying to witness anyone, a loved one or stranger, having a seizure. Approximately one in 50 adults will have a seizure in their lifetime, but two-thirds will never have another episode. While many people only experience a seizure once or twice in their life, others may have recurring seizures that impact their daily routine.

Seizure disorders affect people of all ages, ethnicities, and countries. Understanding seizure disorders is crucial because they impact the quality of life of family, friends, or patients. Healthcare professionals diagnose and manage seizures with medication, lifestyle changes, and other treatments.

People with seizure disorders can lead productive and fulfilling lives with proper treatment and management. This article will help you to understand the basics of seizure disorders, including types, causes, symptoms, diagnosis, and treatment.

What are seizure disorders?

Seizure disorders are neurological disorders affecting the brain’s electrical activity. The type of seizure disorder impacts an individual’s symptoms, treatment, and long-term prognosis.

Neurons may release electrical discharges within an epileptogenic (seizure-causing) focus. A seizure occurs following an excessive electrical discharge in the brain that disrupts the brain’s typical function.

Where do seizure disorders occur?

Seizure disorders are complex conditions that can occur in various areas of the brain. The two significant areas where seizure disorders occur are the cortex and subcortex.

The cortex, the brain’s outer layer, enables higher thinking functions like critical thinking and language in this “gray matter.” Focal seizures originate in the cortex due to imbalances in the gray matter of the cortex.

The brain’s subcortex is underneath the cortex and controls primitive functions like autonomic regulation, sleep, and emotions. Parts of the subcortex are the “white matter.” The brain’s white matter in the subcortex communicates with the cortex, so disorders of the white matter may cause generalized seizures or other types of neurologic disorders.

Nerve fibers covered in myelin, a sheath covering nerves wrapped in phospholipids and proteins, connect the sides of the brain. For those experiencing epilepsy, seizures often worsen over time. Researchers believe that this is due to increasing myelination following epilepsy seizures, which leads to more episodes. As the number of bouts grows, so does the amount of myelination, and the cycle continues.

Seizure disorders can affect the brain’s deep structures, like the brainstem, thalamus, and basal ganglia. Together, these drugs control movement, sensation, and consciousness. Generalized and absence seizures may occur due to dysfunction in these areas.

What is the difference between a seizure disorder and epilepsy?

A seizure is a singular episode of abnormal electrical activity in the brain, whereas epilepsy is a neurological disorder with recurring seizures. This article describes other types of seizure disorders.

Types of seizure disorders

Many people assume that people who experience a seizure have epilepsy. However, there are many other types of seizures. The seizure type varies depending on the part of the brain affected and the electrical discharge severity. This article explores the most common type of seizure disorders and their characteristics.

What are the types of seizures?

The earliest prominent characteristics classify seizures. The initial classification of seizures splits insignificant or categories related to onset:

Healthcare providers also classify seizures by motor or nonmotor onset. Within these categories, there are many different types of seizures.

Seizure types that are generalized-onset motor seizures are:

Generalized-onset non-motor seizures include changes in consciousness without motor manifestations due to widespread electrical discharges in both brain hemispheres. This affects the entire brain and can be further categorized.

Generalized-onset nonmotor seizure types include:

Focal onset seizures originate in a specific area of the brain and one brain hemisphere, often in the subcortical structures. They were formerly known as partial seizures and can be widely distributed or localized. The patient’s level of awareness classifies focal onset seizures:

Focal onset motor seizures classify seizure types, including:

Atonic seizures and epileptic spasms often do not have an associated awareness level.

Focal onset nonmotor seizures are classified by their earliest prominent features, such as:

Other Types of focal onset seizures

Focal-onset seizures may evolve into generalized-onset tonic-clonic seizure that causes a loss of consciousness. The initial focal onset seizure may not be clinically apparent due to brevity.

Unknown-onset seizures

Seizures with an unknown origin refer to cases with an unknown cause and can be motor or nonmotor. Unknown-onset seizures are diagnosed when data about the onset is lacking but may be reclassified later.

Unknown-onset motor seizures include tonic-clonic seizures and epileptic seizures. A tonic-clonic seizure is obscure and often classified as an unknown onset seizure.

The diagnosis of unknown-onset nonmotor seizures may be given before identifying the specific disorder, such as epileptic spasms or behavior arrest seizures.


During pregnancy, those who have never experienced a seizure may experience seizure activity due to eclampsia, a hypertensive disorder. Eclampsia is a serious pregnancy complication with a sudden onset of seizures or convulsions in someone with preeclampsia between 20 weeks gestation and six weeks postpartum. Preeclampsia causes elevated blood pressure and organ damage. Symptoms include headaches, blurred vision, and abdominal pain. Less than one percent of people with preeclampsia have a seizure.

However, when it occurs, it can be fatal to both the patient and the baby and requires immediate medical attention. Prompt diagnosis and treatment are crucial to save the lives of both.


Epilepsy is the fourth most common neurological disorder. An estimated 50 million people have epilepsy worldwide1, and 3.4 million people (1.2% of the population) in the U.S. have epilepsy2.

Epilepsy is a chronic condition with recurrent seizures caused by these surges in electrical activity3. It affects people of all ages, but healthcare providers more commonly diagnose children and older adults. About 70% of people with epilepsy can control their seizures with medication, but 30% experience uncontrolled seizures1. Sudden unexpected death in epilepsy (SUDEP) is a rare but potentially fatal complication in 1 of 1,000 people with epilepsy annually.

Is there a cure for epilepsy?

There is no known cure for epilepsy, but people with epilepsy can manage the condition with medications and other treatments. People with epilepsy can often live relatively normal lives with medical management and lifestyle changes.

What causes seizure disorders?

You might wonder what causes someone to experience a seizure suddenly. What causes a person to experience seizures for the first time? While some chronic seizure disorders occur frequently, others occur only once or twice and happen suddenly.

Multiple factors cause seizures, including:

The causes of seizure disorders are often multifaceted and complex. Medical experts may not fully understand the multifactorial underlying causes behind seizures. For example, some causes of generalized-onset seizures sometimes result from genetic disorders.

Other causes of seizure disorders include:

While there is typically a clear underlying cause, there is seemingly no cause in some cases. However, knowing that seizures with an unknown cause are idiopathic is crucial.

Seizure mimics

A seizure mimic resembles a seizure but is not caused by abnormal electrical brain activity. Some conditions may cause convulsions, involuntary muscle movements, aura, or fainting that may be mistaken for a seizure.

Examples include:

Signs and symptoms

Seizure disorders cause some life-altering signs and symptoms. These signs and symptoms include:

Seizures may cause a loss of consciousness in some individuals. Individuals who lose consciousness may experience incontinence (urine or feces), prolonged confusion, or tongue biting.

Warning signs

Aura is a change in the individual that some experience before a seizure begins. It is subjective and may be sensory, autonomic, or psychic sensations or feelings. Auras may help individuals with seizure disorders anticipate the impending seizure and take appropriate safety methods.

What is an aura?

Aura is a simple type of seizure called focal aware seizure that occur before a more severe type of focal seizure. Auras can include many sensations, such as sights, sounds, smells, and pain.

An aura can take many different forms, such as:5

What is the after effect of seizures in adults?

The after-effects of seizures in adults vary based on the type, severity, and duration. When signs and symptoms continue after the completion of the seizure, this is considered the postictal state. Some individuals experience post-seizure effects, including disorientation, fatigue, and confusion in the postictal state. These effects can last between several minutes to many hours.

The period of time immediately following a seizure is known as the postictal phase. Common after-effects of seizures include:

Diagnosing seizure disorders

Just because someone experiences a seizure does not mean they have epilepsy. Accurate diagnosis enables healthcare providers to provide accurate therapy. Evaluate patients with seizures for possible causes.

Initial nursing assessments should include evaluating for:

It can feel challenging to get to the bottom of why these seizures are happening. However, there are medical tests that can explain what is occurring, whether it’s new onset seizures or to evaluate levels of antiseizure medications for patients with a seizure disorder who experience breakthrough seizures.

Healthcare providers can provide an accurate diagnosis and management plan from medical tests like neuroimaging, laboratory testing, and electroencephalograms. There are many diagnostic tests and procedures to review.

An electroencephalogram (EEG) measures brain electrical activity through electrodes attached to the scalp. It can help identify abnormal brain activity that may be causing seizures. Detailed EEG monitoring clarifies whether the seizure onset is focal or generalized. Determining the seizure onset is crucial because, in some cases, focal seizures are manageable. Managing a focal seizure can decrease the risk of long-term complications like mood disorders and cognition.

Computed tomography (CT) scan is a non-invasive test that uses ionizing radiation for brain imaging to identify abnormalities like bleeding or swelling5.

Magnetic resonance imaging (MRI) is a non-invasive medical test that uses a magnetic field and computer-generated radiofrequency waves to produce detailed brain images that can identify structural abnormalities that may cause seizures, such as brain tumors or cysts6. MRI machines are large tube-shaped magnets that patients lie inside.

Laboratory tests, including bloodwork, help identify or rule out underlying medical conditions causing seizures, like infections or metabolic disorders.

Video EEG monitoring combines EEG and video recording to capture and analyze seizures while they occur to identify the type and origin of the seizure.

Neuropsychological testing assesses cognitive function and emotional status that identify mental or emotional deficits. This can help with diagnosis, to establish a baseline for cognitive function, and to determine strengths and weaknesses.


First, the management goal is to eliminate any possible cause. After potential triggers have been removed from the individual’s life, managing seizure disorders includes lifestyle changes and treatment strategies. Medications and other treatments can control conditions and prevent seizures.

Seizure treatment includes:

Coping with seizure disorders

A seizure disorder can be life-altering to the person experiencing it. There are also considerations for family, friends, and colleagues. These include:


People with seizure disorders do not have to go through this alone. It is crucial to seek medical advice and support from your healthcare provider if you are experiencing any signs or symptoms of a seizure. People with seizure disorders have significant life changes, medication regimens, and other therapies crucial to staying healthy. This article covered all the essential ways to keep patients with seizure disorders healthy.

Works cited

  1. World Health Organization. Epilepsy. Accessed April 15, 2023.
  2. Centers for Disease Control and Prevention. Epilepsy data and statistics. Accessed April 15, 2023.
  3. Epilepsy Foundation. What is epilepsy? Published n.d. Accessed April 15, 2023.
  4. Centers for Disease Control and Prevention. Types of seizures. Accessed April 27, 2023.
  5. Merck Manual Professional Version. Seizure disorders. Published 2022. Accessed April 15, 2023.
  6. Assid P. CT Scan vs. MRI: Differences. Verywell health. Published 2023. Accessed April 15, 2023.
  7. Cleveland Clinic. Neuropsychological testing and assessment. Published 2020. Accessed May 8, 2023.

Written by on May 23, 2023

Caitlin Goodwin, DNP, RN, CNM, is a Board Certified Nurse-Midwife, Registered Nurse, and freelance writer. She has over twelve years of experience in nursing practice.

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