Understanding the types of epilepsy conditions

The Comprehensive Epilepsy Center at Texas Children’s Hospital has curated a multidisciplinary team that has the experience necessary to care for children and families with many different seizure disorders. Whether you’re seeking a second opinion or looking for more advanced care, we welcome you to Texas Children’s.

What is a seizure?

A seizure occurs when one or more parts of the brain has a burst of abnormal electrical signals that interrupt normal brain signals, which results in changes in muscle tone, movement, sensations, behaviors or states of awareness. Seizures in children can have a variety of causes, such as an imbalance in brain chemicals, a brain tumor or lesion, infection, fever, stroke, brain damage, alcohol or drug withdrawal, abnormal blood sugar levels or concussion.

When a child has 2 or more seizures of any type without a known cause, he or she is diagnosed with epilepsy.

One way to categorize seizures is to divide them into generalized seizures, which affect both sides of the brain, and focal seizures, which affect only one side of the brain.

Generalized seizures

When both sides of the brain are affected by a seizure, a child will typically lose consciousness and be sleepy and possibly confused once the seizure is over. Types of generalized seizures include:

  • Absence seizures, which cause staring and a brief change in consciousness that typically lasts 30 seconds.
  • Atonic seizures, which cause loss of muscle tone that can result in a sudden fall.
  • Generalized tonic-clonic seizures, which cause symptoms most commonly recognized as seizure: flexion, extension and trembling of the limbs followed by generalized contraction and relaxation of the muscles.
  • Myoclonic seizures, which cause quick movements or sudden jerking of a specific group of muscles, most commonly the upper body.

Focal (partial) seizures

Focal seizures occur when the abnormal electrical activity that causes seizures comes from one or more locations that are only on one side of the brain.

  • Simple focal seizures are one type of focal seizure. The symptoms depend on which area of the brain is affected. If the abnormal electrical brain function is in the part of the brain involved with vision, your child’s sight may be altered. Alternatively, an isolated muscle group, such as fingers on one hand or one arm can be affected. Your child may also have sweating, nausea or become pale. Your child won’t lose consciousness in this type of seizure.
  • Complex focal seizure is the other type of focal seizure. This type of seizure often occurs in the temporal lobe of the brain, which controls memory and emotion. Your child will likely lose consciousness but may not pass out and fall to the ground. Losing awareness of one’s surroundings is a common symptom. Your child may look awake, but have a variety of unusual behaviors, including gagging, lip smacking, running, screaming, crying or laughing.

Specific seizure causes

Angelman syndrome is characterized by developmental delay, intellectual disability, small head size, severe speech impairment, sleep difficulty and problems with movement and balance. Most affected individuals also have epilepsy.

Brain tumors can cause seizure activity based on the location of the tumor. Neurologists and epileptologists from the Comprehensive Epilepsy Center commonly work with oncologists at the Texas Children’s Cancer and Hematology Center to decrease the number and severity of seizures in children with cancer.

Dravet syndrome is also known as severe myoclonic epilepsy of infancy. It’s a very rare disorder that causes dozens or hundreds of seizures a day starting in infancy. These children are at high risk for status epilepticus and unexplained death in epilepsy.

Epileptic encephalopathies are age-specific syndromes characterized by aggressive seizure activity that begins in infancy or early childhood. These children may have associated developmental delays characterized by cognitive, behavioral or neurological deficits.

A hypothalamic hamartoma is a benign (noncancerous) tumor located in the hypothalamus, an area of the brain that governs hunger, thirst, body temperature, heart rate, blood pressure and hormone regulation. Symptoms of this condition vary greatly, but commonly include seizures.

Malformations of cortical development are irregularities in the way the cortex of the brain, which controls higher thought, speech and decision making, developed in utero. Seizures and developmental delay are hallmarks of this condition.

Anti-seizure medications are the first step of epilepsy treatment for most children. Some, however, will continue to have seizures despite trials with 2 or more medications. These children have medically refractory epilepsy and may receive referrals for surgical or procedural therapies.

Mesial temporal lobe epilepsy is the most common type of epilepsy and is often characterized by the sense of an aura immediately preceding the seizure, followed by a seizure lasting 30 seconds to 2 minutes, followed by a state of sleepiness or confusion.

Neonatal seizures often present within the first 72 hours of life and may include subtle twitching or full-body convulsions. They’re caused by a lack of oxygen and blood to the brain.

Rasmussen’s encephalitis is a very rare disorder characterized by an aggressive brain inflammation that peaks in childhood and then spontaneously decreases or resolves. The inflammation causes seizures and irreversible brain damage.

Rett syndrome is a genetic disorder in girls that causes seizures and developmental milestone regression starting around 6 months of age. Texas Children’s has been internationally recognized for our research on and treatment of Rett syndrome.

Status epilepticus is a medical emergency that occurs when a seizure lasts more than 5 minutes without any pauses. Most commonly, children in status epilepticus will have generalized tonic-clonic seizures, but seizures in which the child has an altered mental status are also possible.

TSC is a rare autosomal dominant condition in which benign masses grow on any organ of the body and may or may not significantly disrupt that organ’s function. The kidneys, eyes, skin and heart are all commonly affected, but 90% of children with TSC will have brain lesions and epilepsy, with many experiencing infantile spasms as their first symptom.