What is Epilepsy?
Seizure disorder is a neurologic condition characterized by spontaneous firing of neurons in the cerebral cortex, which may lead to impaired consciousness, convulsions, and other neurologic deficits. Some patients have a genetic predisposition to developing seizures and have recurrent seizure activity – this condition is termed epilepsy. A subset of patients with seizure disorder develop seizures due to other conditions – such as stroke, meningitis, brain tumor, traumatic brain injury, electrolyte abnormalities, and low glucose.
Severe seizures or tonic-clonic (grand mal) seizures are potentially life threatening – this is especially true in a condition called status epilepticus which is characterized by a prolonged and refractory seizure. Repeat seizures can lead to cumulative brain injury.
What Causes Epilepsy?
Seizure disorder is typically caused by genetic and environmental factors. Seizures have a tendency to run in families and close relatives. This is particularly true of epilepsy syndromes. Seizures may also be provoked by certain factors such as:
- Meningitis or encephalitis – brain infection
- Traumatic brain injury
- High fever – temp >101
- Electrolyte abnormalities – elevated or low potassium, calcium, sodium, or magnesium
- Alcohol withdrawal
- Cocaine or amphetamine intoxication
- Certain medications can lower seizure threshold
These factors lead to spontaneous firing and activity of neurons located in the cerebral cortex. This may occur on one side of the brain or both sides of the brain simultaneously. Seizure starting on one side of the brain and remaining there is called partial seizure. Seizures starting in both hemispheres at onset are called generalized seizures. Seizures accompanied by preserved consciousness are called simple, whereas those associated with loss of consciousness are called complex. Those that start in both hemispheres at onset tend to be associated with loss of consciousness (generalized complex seizure) – this is a grand mal or tonic-clonic type seizure.
The terminology of seizure disorder continues to evolve and recently new changes were implemented; however, neurologists and neuroscientists still frequently use traditional terminology in practice.
How Common is Epilepsy?
Seizure disorder is common neurologic disease that leads to numerous emergency department visits in the United States annually. The disease typically requires long-term management by a neurology specialist.
Seizure disorder affects approximately 8-10% of people over their lifetime and is responsible for 1%-2% of all emergency department visits. Approximately 1% of children and adolescents in the United States with develop one or more afebrile seizure by 14 years of age.
Signs and Symptoms
Symptoms and signs of seizure disorder often include:
- Postictal confusion (recovery period following “black out”)
- Tongue biting
- Urinary or bowel incontinence
- Loss of consciousness
- Sensory loss
- Muscle weakness
- Myoclonus or muscle jerking
Patients may drop suddenly to the ground and convulse – grand mal seizure. Others will have a blank stare in which they have lost consciousness – these types of seizures frequently affect children and are called absence seizures.
Symptoms typically last for seconds or minutes. Sometimes they may be prolonged and unresponsive to first-line therapy – this is called status epilepticus. Prolonged refractory seizures can result in brain injury as well as hypoxia (low oxygen levels). Patients may also aspirate vomitus or food in the mouth. Death is a serious complication of seizure.
The diagnosis of seizure disorder is clinical – meaning it is made based on based on symptoms, and physical examination. Your doctor will typically order neuroimaging with a head CT or brain MRI to evaluate for structural diseases such as tumor or stroke. If you have signs of meningitis – fever, still neck, headache – your doctor may perform a lumbar puncture (spinal tap). Your neurologist will usually obtain an electroencephalogram (EEG) to monitor your brain waves – occasionally they will capture a seizure as it is happening. The absence of epileptiform activity on an EEG does not preclude the possibility of seizure disorder.
Other commonly ordered blood tests include a CMP (comprehensive metabolic panel), CBC (complete blood cell count), creatine phosphokinase (CPK), and thyroid function tests (TSH, free T4). Your doctor may also obtain a urine analysis and urine drug screen. Women who are of childbearing age may also be tested with a urine pregnancy screen.
Epilepsy Medication and Treatment
Seizure disorder is treated with anticonvulsant medications - these are generally categorized as broad- and narrow-spectrum. Broad-spectrum anticonvulsants successfully treat most seizure types (e.g., focal or generalized at onset) and typically include:
In contrast, narrow-spectrum anticonvulsants are generally favored for focal-onset seizures. The most commonly prescribed narrow-spectrum agents include:
- Huff JS, Morris DL, Kothari RU, et al. Emergency department management of patients with seizures: a multicenter study. Acad Emerg Med 2001; 8:622. - https://www.ncbi.nlm.nih.gov/pubmed/11388937
- Brodie MJ, Perucca E, Ryvlin P, et al. Comparison of levetiracetam and controlled-release carbamazepine in newly diagnosed epilepsy. Neurology 2007; 68:402. - https://www.ncbi.nlm.nih.gov/pubmed/17283312
- Bonnett LJ, Tudur Smith C, Donegan S, Marson AG. Treatment outcome after failure of a first antiepileptic drug. Neurology 2014; 83:552. - https://www.ncbi.nlm.nih.gov/pubmed/24994842
The above information is an educational aid only. It is not intended as medical advice for individual conditions or treatments. Talk to your doctor, nurse or pharmacist before following any medical regimen to see if it is safe and effective for you.