Symptomatic Epilepsies

00:01 Now, let's move to some of the important symptomatic epilepsies.

00:04 Symptomatic epilepsy or secondary epilepsies.

00:07 It's epilepsy secondary to some type of problem.

00:11 And there are a few really important conditions that you should know.

00:15 The first is West syndrome.

00:16 This is a combination of epilepsy in someone in a patient who has other neurodevelopmental abnormalities.

00:24 The classic triad is infantile spasms, hyparrhythmia on the EEG, and psychomotor delay on clinical exam.

00:32 So what is West syndrome? What do we see? The peak onset is early in life.

00:37 Within the first 4 to 7 months, patients begin to develop seizures.

00:41 That characteristic seizure is an epileptic spasm.

00:45 We also call that an infantile spasm.

00:47 And those cluster during sleep transitions.

00:50 So typically, when a patient is waking up, we can see a number of seizures, or sometimes when a patient is going to sleep.

00:56 Epileptic spasms have a very characteristic clinical appearance.

01:00 The patient's arms extend out.

01:03 Their head often can go down, and then the arms and head go back to the normal posture.

01:08 And that brief episode is a seizure, with the arms extended head down, and then slowly returning back to normal posture.

01:15 And seeing that in a child should raise suspicion for a possible epileptic phenomenon, which would be confirmed by EEG.

01:22 In addition, the EEG also shows an important interictal abnormality.

01:26 And abnormality that's there at all times.

01:29 And this is called hypsarrhythmia, which we'll look at on a subsequent slide.

01:33 We see both the hypsarrhythmia interictally, and an electrodecrement ictally.

01:40 So that clinical epileptic spasm is associated with a spike.

01:43 And then as the spasm is resolving, we see a decrement where the EEG resolves down and is suppressed for a short period of time.

01:51 And that discharge tips us off that we may be dealing with West syndrome or infantile spasms.

01:57 This is a secondary epilepsy.

01:59 It's caused by some type of problem and there are numerous etiologies, or insults that can lead to this.

02:06 Perinatal hypoxic-ischemic injury, brain malformations, tuberous sclerosis, Down syndrome, and other metabolic disorders are inherited and genetic metabolic disorders, all can result in the presentation of West syndrome.

02:20 So many different underlying pathologies or problems with the brain can present with a common epileptic syndrome.

02:27 The prognosis depends on the underlying etiology, upwards of 75 or more percent of patients will be severely delayed with neurodevelopmental abnormalities and dysfunction.

02:40 What is the EEG look like in West syndrome? Well, here again, we're looking at a normal EEG from front to back and left to right, odd numbers indicate the left side of the brain, and even numbers the right side of the brain.

02:53 When we look at an EEG for someone who has an infantile spasm, this is what we tend to see.

02:58 You can see on the left side of the tracing, we see a chaotic rhythm.

03:03 There is no organization.

03:04 It looks dramatically different from the normal EEG, which has some characteristic waves in the back part of the brain that's called an alpha rhythm, and otherwise, is a low amplitude and irregular tracing.

03:17 This is irregular and chaotic. It's also disorganized.

03:20 We can't pick out individual lines or individual waves.

03:24 And in the middle of this tracing, we see that all that disorganization calms into a smooth line that comes back down to the baseline and that is called an electrodecrement.

03:37 And in some cases can be associated with an infantile spasm or seizure.

03:42 This disorganized and chaotic pattern is characteristic of a hypsarrhythmia.

03:47 Again, we see chaos, irregularity, and disorganization of the EEG.

03:51 And this is an interictal pattern that occurs without any clinical seizure activity.

03:58 The second very important symptomatic generalized epilepsy is Lennox-Gastaut syndrome.

04:03 There are a lot of similar features to West syndrome to Lennox-Gastaut, but some important differences.

04:09 The first is its age of onset.

04:11 West syndrome begins very early.

04:14 A perinatal or early injury to the brain or neurodevelopment results in early onset West syndrome.

04:22 Lennox-Gastaut patients tend to present a little bit later, in the first 2 to 8 years of life.

04:28 We see multiple seizure types: tonic, atonic, absence or a typical absences is a myoclonic seizures.

04:36 All of these are generalized onset seizures, and most patients have multiple seizure types.

04:42 The EEG shows a 1.5 to 2.5 hertz, polyspike and wave discharge, which we call a slow spike and wave discharge.

04:51 What that looks like is not as important as the name slow spiking wave discharge.

04:56 And that's characteristic of a diagnosis of Lennox-Gastaut syndrome.

05:00 There are multiple etiologies, multiple underlying insults that can contribute to the development of Lennox-Gastaut.

05:07 Two-thirds of patients are symptomatic, and 1/3 have a history of infantile spasms.

05:12 Early in life that then develops into full blown Lennox-Gastaut syndrome.

05:17 Patients frequently have medically refractory seizures for their lifetime, and severe developmental delay.

05:23 Some being nonverbal and fully dependent on others for complete care.

05:28 In Lennox-Gastaut as well as West syndrome underscores the way that we make a diagnosis of a symptomatic epilepsy.

05:35 And the things we're looking at clinically and in vignettes with these patients.

05:38 Were characterizing the seizures And with Lennox-Gastaut, 30% of patients have infantile spasms, and will progress on to Lennox-Gastaut syndrome.

05:47 That seizure type is important in making this epilepsy diagnosis.

05:51 We're also evaluating the neurologic status of the patient.

05:54 And 80% of patients with Lennox-Gastaut will have cognitive dysfunction, the second key pillar of this triad.

06:02 And the last we're incorporating EEG findings.

06:05 And with Lennox-Gastaut, we see that slow spike and wave activity.

06:08 And that triad of infantile spasms, cognitive dysfunction or neurodevelopmental delay, and slow spike and wave is what establishes this diagnosis of Lennox-Gastaut syndrome.

06:19 There are specific medications that are approved to treat Lennox-Gastaut vaigabatrin is one of those as well as others.

06:26 And we can use this information to prognosticate for patients and Lennox-Gastaut is associated with long-term difficult to treat epilepsy and significant neurodevelopmental delay.

06:38 This is an example of an EEG for a patient with Lennox-Gastaut.

06:42 We see it's quite different from that hypsarrhythmia pattern for West syndrome.

06:46 We see spike and wave. And this is very slow.

06:49 The hertz is about 1.5 to 2.5 hertz.

06:52 That's how many bumps, spikes, and waves you see each second of this tracing.

06:57 And this slow spike and wave activity, which we see generalized throughout the entire brain is characteristic of Lennox-Gestaut.

07:06 And last, let's finish by talking about temporal lobe epilepsy.

07:09 This is one of the most common forms of symptomatic focal onset epilepsy.

07:14 It's one of those epilepsies we see in adults and a diagnosis that sometimes we make in adults.

07:20 The onset can be between 10 and 20 years.

07:23 That we can see patients that present even after the age of 20 with their first time seizure.

07:29 This is the most common form of focal onset or partial epilepsy.

07:34 Patients have that typical description of a focal onset epilepsy coming from the temporal lobe.

07:39 The aura often begins with déjà vu, or a rising nausea, or other temporal lobe localization symptoms.

07:48 This progresses to alteration and awareness.

07:51 During that altered awareness patients may have automatisms, motor automatisms, like lip smacking or chewing, or other automatisms in their behavior.

08:01 And this ultimately will progress to generalize convulsions and postictal confusion.

08:06 The EEG shows temporal lobe spikes interictally or sharp waves interictally, and we can see a seizures arising out of the temporal lobe, ictally.

08:16 And the treatment begins with antiepileptic medications.

08:20 Typically, we start with one medication and titrate to the maximum dose.

08:24 If the patient fails, we would consider a second medication.

08:28 In this syndrome is important for understanding the definition of medically refractory epilepsy.

08:34 Treatment refractory epilepsy, or medically refractory epilepsy is a patient with epilepsy who has failed two medications at maximum doses.

08:43 And in those patients they should be considered for a surgical evaluation.

08:47 One of the reasons to consider that is temporal lobe epilepsy.

08:50 This can be highly amenable to temporal lobe resection.

08:54 Removing that epileptic nidus Some patients will be able to reduce their medicines and others may be able to come off of all antiepileptic medications as a result of that surgery.

09:05 Importantly, seizure surgery must happen early before one epileptic focus co ops another.

09:11 and a patient develops multi-focal epilepsy that would not be amenable to surgery.

09:16 And that's why we think about this at the time of failing two medications at maximum doses or medically refractory epilepsy.

09:26 Here we see the characteristic imaging of a patient with temporal lobe epilepsy.

09:30 This is associated with scarring of the temporal lobe, which we call mesial temporal sclerosis.

09:37 We're looking at a coronal picture at T2 looking back through a patient's eyes.

09:42 And again, the patient is flipped as we look at this image.

09:46 The left temporal lobe is over on the right side of the screen and the right temporal lobe is on the left side of the screen.

09:54 The green arrow is pointing to the temporal lobe.

09:57 We can see it's smaller than the right side.

09:59 The left hippocampus is smaller.

10:02 It's a little bit brighter and scarred compared to the right side.

10:05 And this is a good example of mesial temporal sclerosis, which is a cause of temporal lobe epilepsy.

10:12 This underscores that the symptomatic epilepsies have a cause we need to go looking for them.

10:17 And a high resolution MRI is important for looking at temporal lobe sclerosis, a cortical dysplasia, or some other underlying nidus and cause of the patient's epilepsy.

10:28 Surgically, we would target this and by removing that scar, we're removing the nidus for epilepsy and can cure the patient's seizures.