First seizure of life
Don’t freak out, but 8-10% of Americans will have at least one seizure in their lifetime. That being said, there is a less than 3% chance of developing epilepsy. The question is, who makes up that 5-7% of the American population who have a seizure but won’t develop epilepsy, how do you know they won’t, and what should you do when you meet them? By the end of today’s episode, you should be able to answer these questions and confidently approach this scary situation of first seizure of life.
We open this episode with a case presentation, with a discussion by Dr. Brian Hanrahan of the University of Pittsburgh Medical Center. The patient is a young man in his twenties who had a witnessed convulsive event starting with right facial twitching that secondarily generalized. He had received intravenous midazolam in the field already and is a bit sleepy from this but arousable. Basic labs and toxicology screening were normal, and a head CT showed no acute process. Obviously we will get to treatment soon, but first what is the risk of recurrent seizures in this patient?
- Single unprovoked seizure: 34 – 71% over 2 years
- No risk factors, normal EEG, normal MRI: ~ 20%
- Abnormal EEG (meaning epileptogenic phenomena): ~ 60-70%
- Abnormal imaging (structural lesion): ~ 60-70%
- Two unprovoked seizures: ~ 70%
Dr. Hanrahan begins his discussion by recognizing the key difference between a provoked and an unprovoked seizure. The fact that a seizure could be triggered by an event, such as head injury, meningitis, or markedly abnormal electrolytes may mean that the patient has a lower risk of developing epilepsy in the long term when compared to the same patient who has an unprovoked seizure–meaning no obvious trigger, that patient’s brain just wanted to seize. But even having an unprovoked seizure doesn’t mean the patient has epilepsy.
According to the International League Against Epilepsy, kind of the Avengers of the neurophysiology world, a patient has epilepsy if any of the following criteria are met:
- Two unprovoked seizures more than 24 hours apart
- A diagnosed epilepsy syndrome
- A single unprovoked seizure and a probability of further seizures similar to the general recurrence risk (at least 60%) after two unprovoked seizures, occurring over the next 10 years
That 3rd statement always confuses me. So Dr. Hanrahan fleshes it out a little more and talks about the value of neuroimaging and EEG. If the MRI shows a cortical lesion, like a focal cortical dysplasia, primary or metastatic tumor, or old cerebral infarct, then that raises the risk of subsequent seizures quite a bit. And if the EEG demonstrates epileptogenic phenomena, then you probably have enough to support a diagnosis of epilepsy. But what are epileptogenic phenomena?
- Sharp spike and wave complexes, more so these than simple spike discharges
- Periodic lateralizing discharges
- Generalized periodic discharges
- Focal slowing
- Rhythmic temporal delta activity
- Other specific interictal abnormalities (e.g., hypsarrhythmia in West syndrome, continuous spike-wave discharges in Landau-Kleffner syndrome, burst-suppression in Otohara syndrome)
And this can be challenging to distinguish from non-epileptogenic abnormalities of the EEG. So we’ve summarized this from a paper on the subject:
One of the major points of discussion in today’s episode has to do with driving safety. Brian has spent a great deal of his recent career studying healthcare policy, and he shares some of this experience with us on the show. In particular, for this case, he discusses the legal requirements for healthcare providers to report patients with particular seizure types to their State Department. Six states in the US have MANDATED reporting of drivers whose
health could compromise their safety. Those include
- New Jersey
- Pennsylvania, where both Brian and I practice
And once you have reported the driver, most states have a 3-12 month interval where seizure freedom is required before a license can be restored. But how was this interval decided upon? Based on some limited data, if you compare studies, we get numbers like this: Consider that nearly 3 million people have epilepsy in the US. That’s a lot of people. Now consider that 86 people die per year in motor vehicle accidents that are attributed to seizures. Compared to motor vehicle deaths due to alcohol, over 13,000 per year, that doesn’t sound like a lot. But still, it’s 86 potentially preventable deaths.
So now lets imagine the timeline. If you restrict an epileptic patient from driving for 12 months after their last seizure, you could prevent about 80% of all crashes associated with seizures—preventing almost 70 deaths per year. Which is a pretty great save. But it also would prohibit driving for about 50% of all those with epilepsy who would not crash. 1 and a half million people. Now let’s suppose you cut down the seizure-free interval to 3 months for drivers. This would prevent only 50% of crashes, about 43 deaths, but at the cost of keeping 25% of seizure-free drivers off the road—about 750,000 people. Ultimately, more time of driving restriction may prevent slightly greater number of deaths, but at a significantly greater socioeconomic cost. So 6 months may be a happy medium to prevent more crashes without significantly interfering with the day-to-day activities of epileptic patients who may end up not seizing while driving.
For more information on counseling the patient with first seizure of life, I’d recommend you check out the final cut of the show. Seize the day!
Brainwaves audio and online content are intended for medical education purposes only and should not be used for routine clinical decision making. I am not responsible for your MRI or EEG bills no matter how much you think I’m telling you to get these studies for your patients.
- Maganti RK and Rutecki P. EEG and epilepsy monitoring. Continuum (Minneap Minn). 2013;19:598-622.
- Smith SJ. EEG in the diagnosis, classification, and management of patients with epilepsy. Journal of neurology, neurosurgery, and psychiatry. 2005;76 Suppl 2:ii2-7.
- Sofat P, Teter B, Kavak KS, Gupta R and Li P. Time interval providing highest yield for initial EEG in patients with new onset seizures. Epilepsy Res. 2016;127:229-232.
- Krumholz A, Shinnar S, French J, Gronseth G and Wiebe S. Evidence-based guideline: Management of an unprovoked first seizure in adults: Report of the Guideline Development Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology. 2015;85:1526-7.
- Richards KC. Patient page. The risk of fatal car crashes in people with epilepsy. Neurology. 2004;63:E12-3.
- Krumholz A. Driving issues in epilepsy: past, present, and future. Epilepsy Curr. 2009;9:31-5.
- Temkin NR, Dikmen SS, Wilensky AJ, Keihm J, Chabal S and Winn HR. A randomized, double-blind study of phenytoin for the prevention of post-traumatic seizures. The New England journal of medicine. 1990;323:497-502.
- Thompson K, Pohlmann-Eden B, Campbell LA and Abel H. Pharmacological treatments for preventing epilepsy following traumatic head injury. The Cochrane database of systematic reviews. 2015:CD009900.
- Deutschman CS and Haines SJ. Anticonvulsant prophylaxis in neurological surgery. Neurosurgery. 1985;17:510-7.
- van Breemen MS, Wilms EB and Vecht CJ. Epilepsy in patients with brain tumours: epidemiology, mechanisms, and management. The Lancet Neurology. 2007;6:421-30.
- Hemphill JC, 3rd, Greenberg SM, Anderson CS, Becker K, Bendok BR, Cushman M, Fung GL, Goldstein JN, Macdonald RL, Mitchell PH, Scott PA, Selim MH, Woo D, American Heart Association Stroke C, Council on C, Stroke N and Council on Clinical C. Guidelines for the Management of Spontaneous Intracerebral Hemorrhage: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Stroke; a journal of cerebral circulation. 2015;46:2032-60.