Post-Traumatic Epilepsy Explained: What to know about head injuries and seizures
This month on Epilepsy Explained we focus on Post-Traumatic Epilepsy (PTE) with guest expert Dr. Pavel Klein, Neurologist, PTE Researcher, and Director of the Mid-Atlantic Epilepsy and Sleep Center. Dr. Pavel explains PTE, seizures that result from traumatic brain injury (or TBI), who is most at risk for PTE following head trauma, how it is treated, what we know about the development of PTE, and the research that is being done to prevent it.
In Post-Traumatic Epilepsy Explained, Dr. Klein answers the following questions.
0:16 What is post-traumatic epilepsy and how does someone get it?
1:24 Who is at risk to get post-traumatic epilepsy?
2:54 Do we understand how a traumatic brain injury causes post-traumatic epilepsy?
5:04 What are the treatments for post-traumatic epilepsy and how effective are they?
7:00 If a person suffers a head trauma, do they have to worry about developing seizures for the rest of their lives?
8:23 I’ve recovered from a brain injury, but I’m concerned about post-traumatic epilepsy. Are there symptoms of PTE that I should be looking for and is there anything I can do to help prevent seizures?
11:00 As someone living with post-traumatic epilepsy, the medications I’ve been prescribed for depression have not worked. Are there certain medications that may be more effective at treating depression in people with PTE?
12:30 What research is currently being done on post-traumatic epilepsy?
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Episode Transcript
What is post-traumatic epilepsy and how does someone get it?
Dr. Pavel Klein:
Post-traumatic epilepsy are recurrent seizures that can be tracked to a head injury that occurred before the seizures start. The condition arises out of head injury, but not everybody with head injury gets it by any manner of means. You can think of head injuries in three categories, minor, moderate, and severe. By and large, it is the patients who have severe or moderate head injury that have an increased risk of developing post-traumatic epilepsy. By severe, we mean bleeding into the head, either outside of the brain or inside of the brain, and usually quite bad bleeding that, for instance, may require surgery to drain the hemorrhage. That is probably one of the highest risks of developing post-traumatic epilepsy. At the other end of the spectrum, if you have a minor concussion, it is relatively unlikely that you will be at risk for developing epilepsy. The risk is slightly higher than in the general population, but not by much.
Who is at risk to get post-traumatic epilepsy?
Dr. Pavel Klein:
Patients with head injury, but it’s stratified by the severity of the head injury. So again, patients with minor concussion may have a one in 100, two in 100 risk of developing epilepsy. The greatest risk is in patients who have bleeding inside the head. If the bleeding is mild and resolves by itself, the risk may be maybe five in a 100, so 5% or 8%. If the bleeding is bigger, or there’s several bleeds, or the bleeding requires surgery to drain the blood, the risk goes up. And it may be 20%, so 20 out of 100 patients. Or in patients who require surgery, it may go even higher, 30 or 40%. So it depends on the severity of the bleeding primarily.
There’s a couple of other categories. Patients who have seizures very early after the head injury also had an increased risk of, let’s say, 20 or 25% risk. And then patients who have complicated fracture of the skull also have roughly 20% risk of developing epilepsy after head injury. So overall in patients with severe head injury, the risk is maybe 20, 25%, maybe 30%. In patients with milder injury, it’s less.
Do we understand how a traumatic brain injury causes post-traumatic epilepsy?
Dr. Pavel Klein:
That’s an excellent question. And broadly speaking, the answer is no. But with that caveat, we have a lot of understanding of the processes that are likely involved from work with animals and cell cultures and so on. So you’ve got several parts of the injury. The first part is the death of the part of the brain that has been impacted. That has consequences in that some of the cells are more likely to die than others. Then in response to that, the system tries to clean up. When that happens, you’ve got inflammation. You also, as a result of the injury, have disruption of the barrier between blood and brain, and some of the blood may get into the brain and cause consequences that may also put you at risk for developing seizures.
And then a little later, you have the brain’s response to the damage where it tries to regain the function that may have been impaired as a result of the damage. In doing that, the brain tries to rewire itself. And as a result of the rewiring, changes happen that may be beneficial, but may also have side effects that may not be so beneficial.
Broadly speaking, when a seizure happens, you’ve got more of the nerve cells working than they should be, that’s called increased excitability, and you’ve got more of the nerve cells working together than they should be, and that is called hypersynchronization. And in the rewiring of the brain, the rewiring may happen in such a way that you’ve got increased excitability and increased hypersynchronization that leads to seizures. So we have a fair amount of understanding of how it happens in animals. We don’t know how all of these things that I mentioned work together, and we have very little understanding of what happens in humans.
What are the treatments for post-traumatic epilepsy and how effective are they?
Dr. Pavel Klein:
The treatments for post-traumatic epilepsy don’t really differ from treatments for other causes of epilepsy. So the mainstay of treatments are anti-seizure medications. There are, give or take, 30 of those. And you will choose the medication depending on the patient’s circumstances, whether they have other diseases, whether they have other medications and so on. The anti-seizure medications work overall in roughly two-thirds of patients with epilepsy. In post-traumatic epilepsy, we’re not quite certain whether that’s the case, but let’s say that they work in at least half to two-thirds of patients.
For those patients in whom anti-seizure medications don’t work, there are other options. One of them would be surgery. It’s paradoxical that surgery, which may contribute to the cause of the epilepsy if you have to remove the blood that happened after head trauma, might also be treatment. So why would that be? Because if you have epilepsy after head trauma that’s localized to one part of the brain, and you can determine that that part of the brain can be removed safely without causing any damage, then removing that part of the brain may remove the source of focus of epilepsy and may either improve seizures or sometimes cure the epilepsy.
You also have other surgical modalities for those patients in whom medications don’t work completely, such as neurostimulation, either by stimulating the vagal nerve, or stimulating inside of the brain with the response neurostimulation or with deep brain stimulation. And then you have also the possibility of dietary treatment, for instance, with ketogenic diet.
If a person suffers a head trauma, do they have to worry about developing seizures for the rest of their lives?
Dr. Pavel Klein:
That is another excellent question. So it depends again on the severity of the head injury, as well as time since the head injury. So for those patients who have the minor concussion that we spoke about earlier, you have 1 or 2% risk of developing epilepsy. You don’t really need to worry about it. It’s not much higher than the rest of the population.
If you’ve got the more moderate or severe head injury, and you have a higher risk of developing epilepsy, then the risk goes down with time since injury. Roughly one-third of epilepsy develops within the first six months after a head injury, roughly a half of it within one year, and roughly 80% of epilepsy after head injury starts within two years. So if you’ve gone for two years without seizures, the likelihood of your developing post-traumatic epilepsy has gone down. It doesn’t go down to zero. You can develop post-traumatic epilepsy 10 years after head injury, 15 years after a head injury, but it goes down very significantly if you’ve gone that period of, let’s say, two years after head injury.
I’ve recovered from a brain injury, but I’m concerned about post-traumatic epilepsy. Are there symptoms of PTE that I should be looking for and is there anything I can do to help prevent seizures?
Dr. Pavel Klein:
Seizures after head injury can be similar to seizures after other causes of epilepsy. And they’re, broadly speaking, divided into three kinds. Seizures where you retain consciousness. Let’s say that you’ve had injury to the left frontal part of the brain, and let’s say that you may develop shaking of the right hand. Don’t look out for it. If it happens, you’ll see it. Or you may have similar thing that you may have abnormal sensation in part of the body, reflecting the part of the brain that’s been involved.
You have second type of seizures when you may have impairment of consciousness, and then you may have a third type of seizures when either you start with impaired consciousness or without impaired consciousness, and the seizure progresses to the what’s called convulsions. The symptoms depend on the part of the brain that has been injured. Again, I would not go out of your way to look for symptoms. If something abnormal happens, contact your physician and discuss it with them.
Now, the second part of the question, whether you can do anything to protect yourself from developing it. You can’t do anything about the initial injury. However, it is possible that certain things down the road may put you at more risk. What would those things be? Primarily, repeated head contact. So to give you an example, if you’re a hockey player and you suffered major injury in a game, you have bled into the brain, you had surgery, and you’ve had no seizures for two years, you could potentially increase risk of more seizures by being on ice again and hitting your head against the panel. Or if you’re a soccer player, doing heading and so on. So minor head injury has the potential of possibly lowering seizure threshold if you’ve had a head injury. So in so far as you can avoid that, the instances that I chose were elective instances of playing sports where you have a head contact, then avoid those things.
As someone living with post-traumatic epilepsy, the medications I’ve been prescribed for depression have not worked. Are there certain medications that may be more effective at treating depression in people with PTE?
Dr. Pavel Klein:
That’s a very difficult question. So depression is common after head injury. Depression is common in epilepsy. Depression is more common in epilepsy that does not respond to treatment. There isn’t really any antidepressant treatment that is selective for type of epilepsy such as post-traumatic epilepsy. So the treatment would be similar in post-traumatic epilepsy as it would be in other types of epilepsy.
You use the standard antidepressants. The ones that are commonly used in epilepsy would be the SSRIs medications, such as Zoloft or Celexa or Lexapro. It is worth remembering that some anti-seizure medications may make depression worse. Those medications include levetiracetam or Keppra, phenobarbital, perampanel. Those would be the main ones. It’s also worth remembering that very few antidepressants may also make seizures worse. The chief amongst those would be Wellbutrin. All of these things are not specific to post-traumatic epilepsy. They are generic to all epilepsy, but they’re worth bearing in mind.
What research is currently being done on post-traumatic epilepsy?
Dr. Pavel Klein:
There’s a lot of research being done, but as with much medicinal research, not enough. So I would describe the research that’s being done into several categories. One is simple description of what happens in patients after head injury, patients who develop post-traumatic epilepsy. The second category is how does the epilepsy develop both in the animals, and to a lesser degree in humans. And there’s a lot of research that we touched upon earlier that’s trying to figure out how the epilepsy develops.
That is related to the third line of research, which is trying to prevent the condition from happening. So you have a situation where you’ve got a cause that is well-defined, the patients with a head injury come to us healthcare providers quickly, and there is a time between the head injury and the development of epilepsy. And during that time, theoretically, we could apply treatment that will change the development of epilepsy so that it doesn’t develop. So prevention of post-traumatic epilepsy is the holy grail.
In animals, we’re trying to understand how the disease happens, and we’re looking at interventions, primarily medications, that might prevent the condition from happening. We’ve had a number of interesting insights over the last 15, 20 years, and have to figure out how to apply them in studies in humans. Those studies of prevention of epilepsy in humans are not easy because not everybody develops epilepsy after head injury.
So we are also looking at what’s called biomarkers to figure out what are the risk factors for epilepsy after head injury, other than what we discussed earlier, the blood in the brain that we can see with CAT scans and MRIs. So is there anything in genetics that may increase the risk of epilepsy? Is there anything that we can see on EEG that will give us an increased understanding of who is at higher risk for developing epilepsy? So these biomarkers, we’re trying to identify to be able to focus more on those patients who are at very high risk for developing epilepsy, and target the studies of new treatments to prevent epilepsy after head injury at patients who are at most risks.
