Approximately 50% of people who have epilepsy have an unknown or undiagnosable cause of their seizures1. Epilepsy is a neurological condition that is diagnosed when someone is at risk for recurrent, unprovoked seizures. Epilepsy will typically be diagnosed when an individual has had two or more unprovoked seizures, at least twenty-four hours apart, or one seizure that fits specific criteria and there is concern that additional seizure activity may follow2.
A seizure is defined as a temporary change or disruption in the way the brain sends electrical signals3. A common first question when individuals hear this definition is “What causes the electrical signals to malfunction?”. Seizures are a sign that there is an abnormality within the brain interrupting the way that cells communicate with each other.
This abnormality could be caused by many different issues. In some cases, seizures are provoked by specific conditions within the body. Conditions can include high fever, drug overdose or withdrawal, blood sugar issues, lack of hydration, or nutritional deficiencies4. Provoked seizures can happen to anyone at any time given the “right” circumstances. Provoked seizures only occur when the body meets the conditions specified above and are typically easily prevented through managing regular healthy behaviors. Provoked seizures are not a type of seizure that would result in an epilepsy diagnosis, however, people with epilepsy can have provoked seizures.
In many cases, individuals living with epilepsy are doing everyday tasks and ordinary activities that they have done before, in the same conditions their body has experienced before with no issue. Despite the situation and conditions being familiar, for an unknown reason at that moment, an individual can still experience a seizure. This is what we could consider an unprovoked seizure.
In some cases of unprovoked recurrent seizures, a structural issue within the brain can be identified as the cause or area of seizure focus. These can include, cell death caused by a stroke, neurodegeneration as seen in people with dementias, brain tumors, brain lesions, abnormal development of the brain, or resulting from a traumatic brain injury5. All these conditions alter the structure of the brain, and in many cases cause malfunctioning in the otherwise carefully balanced electricity, therefore resulting in seizure activity.
As seizures can have many different underlying causes, neurologists may run various tests to detect the underlying issues. Tests may include:
- Magnetic Resonance Imaging (MRI)
- Computed Tomography (CT) Scan
- Blood Tests
- Genetic Panels
Other diagnostic tests to confirm the diagnosis of seizures may include different types of electroencephalogram’s (EEG’s).
Unfortunately, approximately 50% of the time seizures cannot be tied down to a specific cause or focus area6. This means that about half of individuals with epilepsy do not noticeably have any of the structural issues within the brain that were mentioned previously. In a large population of individuals who have seizures, many or all their tests may come back normal, with no noted abnormalities. In these cases, the cause of the seizures is unknown.
However, it is important to note that if a neurologist does not find an abnormality in the brain, this does not mean that the seizures are untreatable. Approximately 70% of people with epilepsy become “seizure-free” or go longer than one year without any seizure activity7. This is possible through modern medications and other treatment methods. In some epilepsy syndromes and diagnoses, brain scans and additional testing may not be necessary. Talk to your doctor about what tests are right for you. If you are concerned that you or a family member may be having seizures, please speak with your doctor. The information, including text, graphics, images, and other material on this website and provided by the Epilepsy Foundation of Northeastern New York, is for informational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis or treatment.
If you are interested in learning more about seizure recognition and first aid, please reach out to our team by calling (518) 456-7501 or visiting our website for additional resources.
References:
1, 2, 3, 5: Epilepsy and Seizures | National Institute of Neurological Disorders and Stroke, http://www.ninds.nih.gov/health-information/disorders/epilepsy-and-seizures. Accessed 30 Dec. 2024.
4: “Epilepsy.” AANS, 10 Sept. 2024, www.aans.org/patients/conditions-treatments/epilepsy/#:~:text=Brain%20injury%20or%20infection%20can,a%20seizure%20while%20on%20medication.
6: Huff, J. Stephen. “Seizure.” StatPearls [Internet]., U.S. National Library of Medicine, 7 Feb. 2023, http://www.ncbi.nlm.nih.gov/books/NBK430765/.
7: “What Is a Seizure?” CURE Epilepsy, 7 Nov. 2024, www.cureepilepsy.org/understanding-epilepsy/epilepsy-basics/what-is-seizure/#:~:text=Epilepsy%20is%20the%20most%20common,cases%2C%20the%20cause%20is%20unknown.
