What is the difference between epilepsy and seizure?

Answer: Epilepsy is the long term chronic neurological disorder, while a seizure is an occurrence that may indicate epilepsy or another underlying neurological condition.

Electrical activity as measured by an EEG of atypical activity patterns that may predict epilepsy

Often times, people confuse the words epilepsy and seizure. They may mistakenly use the two interchangeably, but they are very different things. To accurately describe a patient, it is critical to know which to use and when.

Epilepsy is a chronic neurological disorder. People with epilepsy experience recurrent seizures, which vary in type and severity. The cause of epilepsy is complex, and many forms of epilepsy are a result of genetics. These genetic changes lead to a dysregulation of the electrical properties of neurons. 

For example, some forms of epilepsy are due to genetic mutations in the voltage-gated sodium channel protein. In these mutations, the channels are more likely to remain active instead of inactivating periodically, as healthy channels do.

Seizures, on the other hand, are the main symptom of epilepsy. In a seizure, unusual electrical activity of neurons lead to muscle spasms, a temporary loss of consciousness, and unusual behavior. There are many different categories of seizures, with generalized vs. partial seizures being the main types.

In people with epilepsy, treatment is mostly with anti-epileptic medications. Many of these drugs dampen overall brain activity, which helps limit the excessive firing that produces the seizure symptoms. However, some of these drugs interfere with other cognitive processes, including memory formation.

Causes of seizures without epilepsy

The difference between epilepsy and a seizure is important because people may have seizures without the diagnosis of epilepsy. These are called acute symptomatic seizures. When non-epilepsy conditions cause seizures, treatment requires a different approach.

In people with severe alcohol use disorder, a sudden withdrawal can lead to a seizure.It is theorized that chronic exposure to alcohol causes a cellular level tolerance to happen, resulting in upregulation of excitatory glutamate receptors. When alcohol is no longer present to decrease excitation, the brain circuits fire too much, which may lead to seizures. Because of this risk, it is important that people with alcohol use disorder do not quit cold turkey, but rather taper off their exposure.  Alcohol withdrawal seizures may be treated with benzodiazepine drugs (including lorazepam and alprazolam), which mimic alcohol’s effect on the cellular level

Brain tumors are known to cause seizures. In these cases, clinical brain imaging tools such as a CT scan, MRI, or EEG may reveal the location of the tumor. From there, treatment of the tumor may be surgery, targeted radiation, or chemotherapy.

A sudden blow to the head resulting in traumatic brain injury (TBI) or concussion can result in seizures. In these cases, diagnostic imaging may also be helpful, but they may not be able to detect anything relevant. Henry Molaison, one of the most famous case studies in neuroscience, may have developed his debilitating seizures after an injury sustained during a bicycle accident. 

An infection of the brain, such as neurocyticersosis, can also cause seizures. This is a rare condition where an infection with the parasitic tapeworm Taenia solium forms cysts in the brain. The tapeworm comes from raw pork and poor sanitation conditions. Treatment for this condition involves anti-helminthic drugs, which are drugs such as praziquantel (PZQ), which helps destroy the tapeworm.

Other short-term conditions, ranging from excessive fever, dangerously low blood sugar, and hyponatremia (electrolyte imbalance, typically from drinking excessive amounts of water) can cause seizures. 

In all of these examples of acquired seizures, treatment is best by figuring out the underlying cause. Treatment is best done under the support from health care professionals. Therefore, it is always a good idea to visit a neurologist as soon as you have a first time seizure.