Monday, April 18, 2016

Absence potpourri

11 yo male with a 2 years history of staring and unresponsiveness episodes noted several  times daily. These are now somewhat more frequent than they had been in the past.  A student.  EEG shows a typical absence seizure, provoked by hyperventilation. The remainder of the EEG is unremarkable. I am confident that I can eliminate the seizures and, probably, normalize the EEG with medication. What benefit will accrue to this patient from my doing so?

Correspondent A:  Medication intervention may very possibly promote vigilance along with increased attention, focusing and concentration especially at school where cognitive stress can provoke episodes. Headaches can be a difficult comorbidity. Given gender and age this is likely Juvenile Absence. No paroxysms during flash stimulation ? (best seen following sleep-deprivation). Would also be on alert for early presenting JME (Any AM jerks,e.g.?)

Correspondent B:  I am generally in agreement with Correspondent A’s answer. However, if the EEG is classic 3Hz without any polyspike features, this young man could certainly be classic childhood absence. The age criteria developed by Panayiotopoulos and others suit this child (cutoff for onset 10yo) and a long line of other excellent and meticulous electroencephalographers (Gibberd, Sato, Louiseau, etc.) have confirmed onset of the classic "childhood" pattern of absence rather than juvenile absence at even later ages, with the tendency to greater risk for prolonged persistence and for the occurrence of generalized consulsive seizures, hence some of the risks seen in juvenile absence may of course be present. Apropos of that one must weigh treatment against the risks of absence not only on vigilance in school, but in using a bicycle, later an automobile, playing sports, swimming and bathing, etc.

My response:  The EEG does seem to be that of childhood absence. The only EEG abnormalities, 3HZ S&W, are present during hyperventilation. Although the patient is 11 at presentation, the onset of his epilepsy seems to have been 2 years earlier. For 2 years, by the history given, he has gotten along just fine, albeit his observed seizures may be somewhat more frequent at the present. Would increased attention, focusing and concentration make him an A+ student, instead of an A student? His classmates have wondered why he might inexplicably halt during a dodge ball game. Perhaps his dodge ball performance could be improved. He has probably been riding a bicycle without mishaps, although who knows what might occur tomorrow. By the way, does anyone have additional information on the incidence of accidents in children with absence epilepsy specifically?

Correspondent C:  Any studies on
1. The Iikelihood of development of grand mal seizures without treatment?
2. The Iikelihood of outgrowing seizures treated v. non treated?

Correspondent A:  If "TA" w/ onset age 5-early childhood, female, the risk is very low for subsequent GTC. Later age onset absence is associated with much greater likelihood for GTC and lifelong therapy.
In JA the hv-induced SW tends to be longer than 3 Hz (3.5-4) and as Rob stated any clear multispike form presence is not "absence". While EEG is helpful and supportive of "absence" the clinical picture rules. Excellent history taking is a must. As we all know, epilepsy is a clinical diagnosis.

Me again:  A 2 yrs 4 mos girl was evaluated for staring episodes. An EEG showed 3HZ S&W associated with behavioral change. She was treated with ethosuximide.

An EEG on therapy 4 1/2 years later was normal. The last observed absence seizures had been 14 mos earlier. Ethosuximide therapy was tapered and discontinued. An EEG subsequent to ethosuximide discontinuation showed re-emergence of 3 Hz S&W with clinical change. The parents reported observing only one episode; none had been seen by her teachers. At 7 yrs of age she was doing superlative work in school and generally seemed brighter off pharmacotherapy. Medication was not restarted. On one occasion subsequently, she was observed to have 5 absence episodes at a time when she was tired. The parents preferred to try to keep her from getting unduly tired. She continues off pharmacotherapy at present and she was last reported as doing well.

Correspondent D:  i think you discontinued the drug early.

In absence seizure not only the clinical seizure must be controlled ,but the EEC must be normal And after the clinical seizure control led ,the patient must be evaluate in every visit with
hyperventilation test and every 3 mo with EEG.

after the drug discontinued, the patient must be followed with EEG and if the EEG was abnormal the AED must be restarted ,even if the patient is clinically seizure free.

My response:  My usual protocol for childhood absence which has been consistently successful (one instance of relapse requiring reinstitution of medication; the patient described above did not follow this protocol) has been to start an appropriate medication and then, when medication is at a reasonable dosage and no seizures are being observed, to obtain a repeat EEG, which generally is entirely normal. Presuming so, and presuming no one is observing seizures, the patient is maintained on medication for a minimum of 2 years. When a decision is made to taper and discontinue medication, presuming no observation of seizures, an EEG is repeated when the patient is medication free, which is generally normal.

The patient is then discharged from ongoing pediatric neurology care.

I would certainly be interested in others' thoughts, but the protocol described by Correspondent D  seems to me quite excessive. In general, childhood absence has seemed to be a disorder which is easy to treat. I still struggle, in certain instance, with what I am accomplishing by the treatment.

Correspondent E:  I use roughly the same protocol as you, but generally if things are going really well don't bother with the EEG when seizures aren’t being seen.

Correspondent E:  I am sure that most of us are aware of the fairly recent paper by Glauser et al in the New England Journal of Medicine (NEJM, 362(9), 03/04/2010, Ethosuximide, Valproic Acid, and Lamotrigine in Childhood Absence Epilepsy). The result of this large double blinded case controlled study showed that VPA and ethosuximide were as efficacious (about 50%) but ethosuximide was better tolerated, while lamotrigine had — 70% failure rate. One of the criteria for failure rate was the presence of a clinical electrographic seizure, defined as a spike and wave burst lasting more than 3 seconds.

Me again:  A girl with childhood absence was started on pharmacotherapy. Although pharmacotherapy was effective in eliminating observed seizures, she seemed to have noteworthy difficulties with medication toleration. She was then seen by an esteemed general pediatrician at a renowned medical institution. He obtained an EEG on the patient, while she was on therapy, which was normal. This being done, he contemptuously asserted that the diagnosis of absence epilepsy was erroneous from the start, and discontinued the patient's medication.

Correspondent C:  What happened?

My response:  The mother was extremely upset at the pediatric neurologist (me)who had "erroneously" diagnosed her daughter and subjected her to the noxious medications. No further follow-up information is available.

Correspondent F:  Wow! That story leaves me sputtering with disbelief and rage.

My response:  My letter to the mother in response to her irate phone call (this was better than 22 years ago) indicated: "The normalization of the EEG in a patient with absence epilepsy is deemed by many authorities a criterion of adequate treatment. Therefore, the normalcy of an EEG obtained on therapy is expected, not unusual. Whether your daughter continues to have a paroxysmal EEG will only be known when her EEG is repeated after discontinuation of her medication. It is possible that her generalized paroxysmal discharges are no longer present. However, it is likely that this is not the case."

Correspondent G:  This is an excellent example of what motivates non- compliance. Patients and families have reasons to be afraid or concerned or annoyed by taking pills regularly, growing pimples, spending so much money or whatnot. They may feel useless to try to get a hearing having tried before. Or they know their objections are unreasonable, or will be treated as such. It is a shady world of emotions hard to describe or sometimes to take seriously but a key to non- compliance despite rational choice and appropriate explanations on that choice.

My update regarding the 2yrs 4 mos girl described above: Parents continue to report patient as doing very well. They have no concerns. Off ethosuximide for 5 months.

Correspondent H:  With reference to absence seizures the worry is this. Is the child having more seizures than what we are observing? I have had "day dreamers" who were in absence status whose performance improved after treatment. It is of course an informed choice.

Me again:  This is one that I've heard more than once. I was speaking to the mother of a young boy seen in another state by another practitioner. Following the diagnosis of absence epilepsy brand-name Zarontin was started with excellent results. Insurance then dictated use of generic ethosuximide.

There was a rapid reemergence of absence, despite blood levels, dosage adjustment, etc. Resuming brand-name Zarontin did not resolve the problem. Valproate was then utilized, evidently without excellent results and complicated by a remarkable increase in appetite and weight gain.
Currently, levetiracetam is being utilized, not surprisingly, with lack of effect and, possibly, emerging behavioral issues. When I inquired regarding academic performance, I was told that he is a superlative student, as he always has been.

My most recent update regarding the 2 yrs 4 mos girl,  22 months after the prior update:

The patient's mother called to indicate that she was seeing seizures once again. I then recommended that ethosuximide be restarted and that arrangements be made for a follow-up evaluation. Later, the patient's mother reported that she was not really sure that she had observed seizures and, in any event, no further episodes of concern were observed, leading to neither ethosuximide nor follow-up evaluation. Yet later, the patient's mother observed two unambiguous seizures, with a protracted interval of confusion accompanying these. The patient was brought to an emergency department, at which time she was behaving normally. Once again, there was a recommendation that ethosuximide be restarted with arrangements for follow up. Before departing the emergency department, she had another evident seizure, again followed by protracted confusion. The patient was then given a loading dose of intravenous valproate and started on valproate maintenance. Despite the prolonged interval of non-treatment, the patient continues to be described as doing very well academically.

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