What is a Breakthrough Seizure?
Breakthrough seizure is a bout of seizures, which develop suddenly and unexpectedly in an individual who has achieved considerable control on his/her seizures or is stable while taking medications for seizures. Breakthrough seizure is a seizure which occurs when the patient is already suffering from a seizure disorder and is taking anti-seizure or antiepileptic medicines and suddenly experiences a seizure for no apparent reason or cause. Breakthrough seizures occur in a patient where the seizures are assumed to be under control with the medication blood levels within the therapeutic range.
The patient will have control over his/her seizures for most of the time, but suddenly experiences a seizure without any known cause. There is a cause, however, for breakthrough seizures and it differs from patient to patient. Knowing and understanding the causes and triggers of breakthrough seizures will help in preventing further episodes.
Breakthrough seizures can occur if the patient forgets taking the anti-seizure medication or takes less than the prescribed dose for sometime, which results in slowly decreasing level of medicine in the blood that allows a seizure to occur once the levels have reached a sub-therapeutic mark. Breakthrough seizures can also occur if a person has been ill or is withdrawing from excessive alcohol use. A person who has been ill can suffer from seizures in different manners. Patient can experience a sudden drop in level of medication in the blood due to the inability to retain medicine from vomiting, which can be related to any illness. Fever can also decrease the seizure threshold. Interaction of seizure medication with other medications which are taken for illness can also cause breakthrough seizures.
Causes of Breakthrough Seizures
Breakthrough Seizure Caused as a Result of Non-Compliance: A patient needs to be compliant with his/her medication and the care plan formulated by the doctor for maintaining control over their seizures. There are a number of anti-epileptic medications prescribed by the doctor for treating breakthrough seizures; however, for these medicines to be effective, they need to accumulate or must build up in the patient’s blood. If the patient is not compliant with taking the medicine in the manner which the doctor has dictated, then it is possible to suffer from breakthrough seizure. Other than this, different medications which the patient is taking along with anti-epileptic medications can interfere with the process of buildup of medication in the patient’s bloodstream. A patient should always consult with his/her doctor before starting any new medicine and always follow the time and dosage of the antiepileptic medicine as the doctor has advised.
Breakthrough Seizure Caused as a Result of Discontinuing Medication: In some cases, the patient may discontinue his/her anti-seizure medication because they cannot tolerate the side effects, or are not able to take the required amount of pills each day or because the patient feels confident that they have gotten rid of their seizures, as they have been seizure-free for some time now. Stopping or discontinuing the anti-seizure medicine abruptly causes confusion in the patient’s body and result in breakthrough seizures. If the patient is having a problem with their medicine because of the side effects, then he/she should inform their doctor who will change to a new medication or will stop the medicine by tapering it gradually in order to give the body sufficient time to adjust to the change.
Breakthrough Seizure Caused Due to Personal Triggers: Triggers for seizures differ from patient to patient. Some of the common triggers for any seizure including breakthrough seizures include sleep deprivation, emotional stress, video games and flashing lights. Medications will help in such cases, but it is the duty of the patient to avoid such personal triggers.
Breakthrough Seizure Caused Due to Hormonal Fluctuations: Women are at an increased risk for developing breakthrough seizures from hormone fluctuations. Women will tend to have increased number of seizures during their mid-menstrual cycle and can also experience breakthrough seizures before the commencing of her menstrual cycle. The cause of this is hormonal changes, such as the hormone estrogen, which increases the risk of seizures; and the hormone progesterone, which inhibits the seizures. The level of progesterone is at its lowest in the middle of a menstrual cycle and just before a menstrual cycle.
Breakthrough Seizure Due to Other Causes: Fever, Infection, sleep deprivation, missed meals, dehydration, electrolyte disturbances, intake of toxins including alcohol which lowers the seizure threshold in a person are some of the other causes of breakthrough seizure. One more thing could be that it may not be a breakthrough seizure and that the patient is having a new type of seizure due to a new cause or pathology, such as some trauma/injury to the brain etc.
Signs & Symptoms of Breakthrough Seizures
People who have had a previous history of epileptic attacks/ seizures and who are on medications for it will experience breakthrough seizures. This is due to abrupt stoppage or decreased level of medication level in the blood. Breakthrough seizures occur suddenly and catch the patient unawares. The signs and symptoms of a breakthrough seizure are similar to that of other type of seizures. Some patients may experience a mild breakthrough seizure and will have an early recovery. When the patient has had a breakthrough seizure, they have impaired consciousness from the start of the attack. The patient does not respond when spoken to. Many episodes of breakthrough seizures will be less than 10 seconds. Patient will have clonic movement of the mouth and eyelids and the jerks can be irregular and asymmetrical. Patient can also have simultaneous rigid contraction of their muscles.
Diagnosis of Breakthrough Seizures
- Detailed medical history and physical examination of the patient is taken.
- Tests are done to calculate the blood concentration of antiepileptic medicines.
- Estimation is also done of blood electrolytes.
- Urine analysis is also done.
- If the patient has fever, then blood count is done.
- Chest x-ray can be done.
- In some cases, EEG, MRI or CT scan of the brain will be done.
Treatment of Breakthrough Seizures
Treatment of a Breakthrough Seizure depends on the precipitative factor of the breakthrough-seizure. In patients with a sub therapeutic AED level, treatment comprises of boosting up the level by giving additional dose of antiepileptic medicine and by increasing the maintenance dose. If the AED level is therapeutic; but not quite near the upper normal range or if the patient is not experiencing any side-effects with the current dose of the antiepileptic medicine, then the dose is increased further.
Treatment of the cause of the breakthrough seizure should be done accordingly. Patient may still need optimization of the medicine dose along with treating the other causes of breakthrough seizure. If the causative factor of the breakthrough seizure is identified and is fully reversible, then the dosage of the anti-seizure medicine can be temporarily increased.
Some patients may need addition of another anti-seizure medicine or change to a new medicine. All these treatment decisions vary from patient to patient. Neurology consultation is often needed in the care and management for patients suffering from breakthrough seizures.
- Title: “Breakthrough Seizures: Definition, Mechanisms, and Management.” Authors: Privitera M, Brodie M, Mattson RH, Chadwick D, Neto W, Wang S. Journal: American Journal of Medicine. 2009 Jun;122(6A):S3-13. DOI: 10.1016/j.amjmed.2009.04.015 Link: https://pubmed.ncbi.nlm.nih.gov/19464421/
- Title: “Characteristics of Breakthrough Seizures in a Large Cohort of Patients with Epilepsy.” Authors: Brigo F, Lattanzi S, Trinka E, Nardone R. Journal: Seizure. 2018 Feb;55:51-56. DOI: 10.1016/j.seizure.2017.12.002 Link: https://pubmed.ncbi.nlm.nih.gov/29216448/
- Title: “Breakthrough Seizures in Epilepsy Patients: A Review of Nomenclature, Definition, and Classification.” Authors: Sillanpää M, Schmidt D. Journal: Epilepsia. 2006;47(3):Suppl 1:86-91. DOI: 10.1111/j.1528-1167.2006.00473.x Link: https://pubmed.ncbi.nlm.nih.gov/16981860/
- Title: “Breakthrough Seizures: Causes and Management.” Authors: Fisher RS. Journal: CNS Drugs. 2002;16(5):331-334. DOI: 10.2165/00023210-200216050-00005
- Title: “Hormonal Factors in Women with Epilepsy: Strategies for Providing Enhanced Care.” Authors: Herzog AG. Journal: Epilepsy & Behavior. 2006 Oct;9(2):S1-6. DOI: 10.1016/j.yebeh.2006.05.018 Link: https://pubmed.ncbi.nlm.nih.gov/16920098/