When Seizure Types Change: Part I

Shahin Nouri, M.D.

Change in the Course and Pattern of Seizures

Many people with epilepsy can experience changes in the pattern, frequency and nature of their seizures. Such changes might mean worsening of the disorder, improvement of the condition, or have no consequences.

A change might have various causes and various consequences for each person. The epileptologist (epilepsy neurologist) can help make this distinction with the help of an accurate history and by using diagnostic methods, e.g. electroencephalogram (EEG) or imaging.

Epilepsy Types and Seizure Types

To develop a better understanding of a change, it is wise to review the different types of epilepsy and different types of seizures. Basically there are two main types of epilepsy. Eighty percent of people have Localization-Related Epilepsy (LRE) and 20 percent have Primary Generalized Epilepsy (PGE).

In LRE, seizures start in one focus in the brain. This focus can cause a brief and simple partial seizure (SPS), which manifests in different ways, depending on what part of the brain is involved. If a SPS affects alertness, it is called a Complex Partial Seizure (CPS). CPS’s are the most common manifestation of epilepsy. Both SPS’s and CPS’s can propagate to involve the whole brain and cause a generalized seizure, also known as a “Grand mal” seizure.

People with PGE experience generalized seizures, which involve the whole brain at the same time. These can be tonic-clonic (grand mal), tonic, myoclonic, atonic, or absence (petit mal) seizures.

It should be noted that a generalized tonic clonic seizure, also known as a grand mal; can be the result of secondary generalization of a partial (or focal ) seizure, or the manifestation of primary generalized epilepsy.

Patterns of Change

Increase in frequency and severity of seizures:

Increase in frequency of seizures might be a sign of worsening of the condition. Refractory epilepsy (please refer to previous blogs) needs to be identified and addressed properly. Basically, in about 40 percent of people with epilepsy the seizures cannot be controlled with two or more anti-seizure medications. So a progression of the condition, as the epileptic brain gets used to the medications; is the number one and most important situation to identify. People with refractory epilepsy might be candidates for epilepsy surgery. The earlier such people undergo surgery, the better the outcome will be.

-It is also possible that the level of anti-seizure medications have declined.  This might cause an increase in frequency and severity of the seizures. Multiple causes are possible:

  1. This might be due to a change from the brand to generic formulations. Generic versions can deliver medications to the brain 10-20 percent less effectively.
  2. A new drug interaction might also explain a decline in drug levels. For example, starting a patient on female hormones or birth-control pills can cause a drop in Lamotrigine blood level.
  3. Absorption of anti-seizure medications might have become impaired. Diarrhea and vomiting are possible causes.

-Many hormones have various effects on the brain. Therefore, changes in the hormonal balance of the body can cause changes of seizures. Specifically, one of the female hormones, “estrogen” can worsen seizures, while another hormone, “Progesterone” improves the seizures. If the balance of these two hormones changes in favor of estrogen, e.g. around the time of menstruation, seizures can become more frequent and more severe. This condition is called “Catamanial Seizures”. Pregnancy and menopause can change this balance as well.

-New concomitant conditions could have emerged. Some conditions can make epilepsy worse, eg: Obstructive Sleep Apnea, strokes, head traumas, alcohol and recreational drug use.

-Certain medications lower seizure threshold in brain and should be avoided in people with epilepsy, e.g.: some antibiotics including ciprofloxacin or levofloxacin.

-Rarely, psychological stresses and possibly a problem in coping with these stresses can cause psychogenic non-epileptic seizures (PNES) that can super-impose on epileptic seizures.

-Extremely rarely, starting a new anti-seizure medication can worsen seizures. This is an unusual reaction and only an experienced clinician should make that distinction.

-Finally, the course of certain types of epilepsy changes with age. Some types of PGE, for example absence epilepsy, only rarely continue beyond the age of 20 years.

Change in Seizure Type

-Localization-Related Epilepsy can cause SPS, CPS and GTC. If a person once had brief seizures with or without change in mental status and loss of consciousness, he/she has had SPS or CPS. Now, if this person starts experiencing GTC, this is a sign of worsening of the condition. However, if he/she used to experience GTC, and now is experiencing only SPSs and CPSs, then it might be a sign of improved control of the seizures. This can occur after starting a new medication.

-Primary Generalized Epilepsies can present with various generalized seizures. A new pattern of generalized seizures in such a case might not necessarily signify worsening of the condition.

-It is very rare, but at times people can have two different types of epilepsy causing both focal seizures and generalized seizures.

What to do? What to do?

-It is advisable to use a seizure calendar at all times. Certain characteristics of a seizure might be fresh in person’s memory or the witnesses’, but be forgotten later on. Documenting the events in as much detail as possible, and as soon as possible, helps the clinicians manage the condition better. In addition to description of seizures, other events, e.g.: menstruation, sleep deprivation and extreme stresses should be documented. A correlation between these events and the seizure frequency can help identify the provoking factors.

-The American Association of Epilepsy Centers recommends: if the seizures are not controlled after management by a general practitioner after three months, and by a general neurologist after six months, then the patient should be referred to an Epilepsy Center for work up and management.

-It is imperative that refractory epilepsy be diagnosed and addressed as soon as possible. Typically, if seizures aren’t controlled after proper use of two anti-seizure medications, a work-up should be attempted to evaluate whether the person is a candidate for epilepsy surgery, Vagal Nerve Stimulator or other alternative treatments.

-The gold standard in characterizing the seizures is capturing an event while a person is undergoing video-EEG epilepsy monitoring. Under very controlled circumstances and close supervision epileptologists record a seizure to examine and characterize its nature in EEG and to correlate these findings with the video recordings.

-A comprehensive history and the above-mentioned procedures assist in interpreting any changes in the frequency, severity or pattern of the seizures in every individual.