Handbook of Epilepsy Treatment

431 Pages·2010·15.58 MB·English

by  Simon D. Shorvon

Handbook of Epilepsy Treatment
Handbook of Epilepsy Treatment, Third Edition Simon Shorvon
© 2010 Simon Shorvon. ISBN: 978-1-405-19818-9
Handbook of
Epilepsy Treatment
Simon Shorvon,
MA, MB BChir, MD, FRCP
Professor of Neurology and Clinical Subdean, UCL Institute of Neurology, University College London
Consultant Neurologist, National Hospital for Neurology and Neurosurgery, Queen Square London
THIRD EDITION
A John Wiley & Sons, Ltd., Publication
This edition fi rst published 2010 © 2000, 2005, 2010 by Simon Shorvon
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Library of Congress Cataloging-in-Publication Data
Shorvon, S. D. (Simon D.)
Handbook of epilepsy treatment / Simon Shorvon. – 3nd ed.
p. ; cm.
Includes bibliographical references and index.
ISBN 978-1-4051-9818-9
1. Epilepsy–Handbooks, manuals, etc. 2. Anticonvulsants–Handbooks, manuals,
etc. I. Title.
[DNLM: 1. Epilepsy–therapy. WL 385 S559h 2010]
RC372.S528 2010
616.8′5306–dc22
2010015320
A catalogue record for this book is available from the British Library.
Set in 9.25 on 11.5pt Minion by Toppan Best-set Premedia Limited
Printed and bound in Singapore
01 2010
Contents
Preface to the Third Edition, ix
Acknowledgements, xii
1 Defi nitions and Epidemiology, 1
Defi nitions, 1
Frequency and population features of epilepsy, 3
2 Seizure Type and Anatomical Location of Seizures, 6
Seizure type, 6
Classifi cation of partial seizures by anatomical site of seizure onset, 12
3 Epilepsy Syndromes, 19
ILAE Classifi cation of the Epilepsies and Epilepsy Syndromes, 19
The epilepsy syndromes, 21
4 The Causes of Epilepsy, 33
Idiopathic epilepsy, 33
Symptomatic epilepsy of genetic or congenital origin, 36
Symptomatic epilepsy due to acquired causes, 54
Provoked seizures, 67
5 Principles of Treatment, 75
Why treat epilepsy? The aims of treatment, 75
The risks of epilepsy and its treatment, 76
Choice of antiepileptic drug therapy based on seizure type, 81
Treatment of specifi c epilepsy syndromes, 89
Principles of treatment of newly diagnosed patients, 96
Principles of treatment of patients with established active epilepsy, 101
Treatment of patients with epilepsy in remission, 104
Psychiatric disorders in epilepsy, 107
Life-threatening idiosyncratic reactions, 116
Complementary and alternative therapy in epilepsy, 118
Genetic counselling in epilepsy, 121
6 Treatment of Epilepsy in Specifi c Groups, 127
Treatment of epilepsy in children, 127
Treatment of epilepsy in patients with additional handicaps, 129
Epilepsy in elderly people, 132
Treatment of epilepsy in women, 136
7 Pharmacokinetic Principles of Antiepileptic Drug Treatment, 147
Drug absorption, 147
Drug distribution, 148
v
vi Contents
Drug elimination (metabolism and excretion), 150
Blood level measurements, 153
8 The Antiepileptic Drugs, 158
Carbamazepine, 158
Clobazam, 170
Clonazepam, 174
Eslicarbazepine acetate, 177
Ethosuximide, 181
Gabapentin, 185
Lacosamide, 189
Lamotrigine, 192
Levetiracetam, 199
Oxcarbazepine, 205
Phenobarbital, 210
Phenytoin, 218
Pregabalin, 229
Primidone, 232
Rufi namide, 235
Tiagabine, 238
Topiramate, 244
Valproate, 252
Vigabatrin, 261
Zonisamide, 267
Other drugs used in the treatment of epilepsy, 272
Acetazolamide, 273
Benzodiazepines, 275
Corticosteroids and ACTH, 278
Felbamate, 278
Piracetam, 281
Stiripentol, 285
9 The Emergency Treatment of Epilepsy, 287
How to deal with a seizure, 287
Status epilepticus, 288
Antiepileptic drugs used in status epilepticus, 307
10 The Surgical Therapy of Epilepsy, 314
Presurgical assessment – general points, 315
Surgery in epilepsy arising in the mesial temporal lobe, 321
Surgery in epilepsy arising in extratemporal regions and the
temporal neocortex, 339
Cortical dysplasia (malformations of cortical development), 349
Surgery where no lesion is apparent on neuroimaging
(‘MRI-negative cases’), 351
Hemispherectomy, hemispherotomy and other large resections, 352
Corpus callosectomy (corpus callosum section, corpus callosotomy), 356
Multiple subpial transection, 358
Vagal nerve stimulation, 359
Other functional surgical procedures, 362
Contents vii
The organization of epilepsy surgery care: the epilepsy
surgery centre, 364
Pharmacopoeia, 365
Antiepileptic drugs – indications in epilepsy, 367
Antiepileptic drugs – dose, average adult values, 369
Antiepileptic drugs – dose, interactions, 370
Antiepileptic drugs – dose, in children, 371
Antiepileptic drugs – summary of side effects, 372
Antiepileptic drugs – summary of metabolism, 374
Antiepileptic drugs – summary of pharmacokinetic values (typical adult values), 376
Antiepileptic drugs – modes of action, 377
Further Reading, 378
Index, 409
Preface to the Third Edition
This monograph is part of the series of handbooks that epilepsy in the clinic. The internet, by its all inclusive
are produced to accompany the large multi - authored nature, cannot take such a singular approach.
reference books published by Wiley - Blackwell. The third This is the justifi cation for embarking on a third
edition of the reference text Treatment of Epilepsy was edition. The fi rst two editions of the handbook were
published in 2009 (edited by myself, Emilio Perucca and published 10 and 4 years ago, were both generously
Jerome Engel), and this handbook is now also in its third received and, I hope, fulfi lled at least in part their purpose
edition. of informing and improving epilepsy therapy. However,
As we now enter the second decade of the age of the in epilepsy, as in all of medicine, treatment moves on,
internet, the fi rst question to address when contemplat- knowledge has increased and fashions have changed and,
ing a writing project is a fundamental one – are books of in the short span of these handbooks, much new
this nature still required? In an age where information is information has arrived on the desks of physicians. The
now readily available at a click of a Google button, does writing of a third edition is an opportunity to refl ect these
a book have a function frozen as it is in form and in changes, and also, sad to say, to correct the all too obvious
content, not unlike, some would argue, the fossilized defi ciencies of the previous editions.
remains of past life forms? This is a question that is As I noted in the previous edition, this book contains
already central to medical publishing. My own opinion pretty much everything I know about epilepsy therapy.
on this matter is, however, clear – books that concentrate It is a worrying thought that all one ’ s professional knowl-
and fi lter information are both necessary and desirable, edge can be compressed into a couple of megabytes (the
in the fi eld of epilepsy treatment, as much as anywhere draft manuscript of the whole book amounted to less
else, for at least three reasons: than fi ve megabytes, and could be saved onto a memory
1 Accuracy of information: comprehensive as the inter- stick smaller than my fi ngernail, but this is the rather
net is, accurate it is not. There exists on the web much humbling reality). Another concern is that this is a single
information that is phoney, wild and irresponsible, many author text, with the danger of bias and prejudice. My
data that are inaccurate or uncorroborated, and much defence is that the disadvantages of single-authorship
opinion that has more to do with kite - fl ying than medical need to be weighed against the advantages of coherence
science. A book can avoid these snake - pits. and lack of omission, repetition or inconsistency.
2 Condensation of information into a short and concise Avoiding these in the writing of this book has been a
form, in one easily accessible place: this I have tried to constant preoccupation.
do here, avoiding repetition, redundancy or excessive The aim of this edition is exactly the same the aim of
verbiage. Whether this is successfully achieved is a judge- the previous editions, and so is cited verbatim from the
ment for the reader, but the condensation of data in the second edition:
book is surely an overwhelming advantage over the
diffuse nature of the information highway (now less of a The aim is to summarize the many and various treatments
discrete path than a horizonless moor). of epilepsy in a clear yet comprehensive, and concise yet
3 Consistency of perspective and approach: this book is balanced and practical manner. Surgical as well as medical
written from a single perspective – that of the practising therapy is included, as is the treatment of epilepsy in adults
neurologist who specializes in epilepsy. This is not a sci- and children. Rare as well as common clinical problems are
entifi c, theoretical or populist, but a medical, text. Its covered, and rarely – as well as commonly - used therapies.
audience is the practising doctor who sees patients with It is intended to be a hands - on text which will guide clinical
ix
x Preface to the Third Edition
practice and rational therapy, and to be a source of ready rize and extract data. Second, since the last edition there
reference; a catalogue of epilepsy therapy. There is an have been licensed at least fi ve new antiepileptic drugs
emphasis on factual information, which I have tried to give and a large range of novel drugs is also in the process of
in a parsimonious and easily - digested form, but one that development. The widely predicted famine in the fi eld of
still gives the reader a clear idea of the scientifi c basis of epilepsy therapy that so many foresaw in the past decade
current practice. This scientifi c perspective is important has resolutely failed to materialize. Indeed, it is probably
and, where possible, the text has endeavoured to be science - true to say that there have been more novel and exciting
and evidence - based. In some areas of therapy an evidence therapies in current development since the publication of
base, however, is lacking (perhaps especially in the area of the last edition than at any time in the history of epilepsy
epilepsy surgery), and data informing longer - term therapy. It is not, I hope, too panglossian to think that
outcome, risk and benefi t in particular are missing. In these these have incrementally improved treatment of many
areas the book inevitably refl ects the author ’ s own preju- patients. Finally, the scientifi c information about drug
dices and anecdotal experience. therapy has again improved, due to advances in clinical
and molecular chemistry, and this is also incorporated
The book is embedded in the experience gained from where possible in this book. Developments in the surgical
my own clinical practice, now over 30 years of specializa- therapy of epilepsy have been less impressive, but there
tion in epilepsy at the National Hospital for Neurology are some areas of incremental change that I hope also to
and Neurosurgery, Queen Square, London, and is heavily have recorded.
infl uenced by this. The book also refl ects the work of the As in the last edition, a number of editorial decisions
International League Against Epilepsy, on whose execu- have been made that should be noted here. The summary
tive committee I have served now for more than 17 years. of factual information in table form (for easy reference)
These infl uences provide the context and a distinctive is a deliberate policy, but it should be recognized that,
perspective, which I hope adds coherence and interest. especially in relation to pharmacological and pharmaco-
I mentioned, in the previous edition, three develop- kinetic data, confl icting information commonly exists.
ments in epilepsy therapy that had occurred in the years This can lead to contention, and the tables include
leading up to 2005, and that I considered to deserve what I consider to be the most reliable data. It is
special mention. The fi rst was molecular genetics – but important also to recognize that data do vary, and in
now 5 years later one has to admit that in the therapeutic some places the data in the tables are not universally
arena the impact has been less than hoped for. The goal applicable. Second, the contentious decision has been
of therapy tailored to an individual ’ s genomic make - up, made, in the interests of readability and clarity, to omit
which 5 years ago was trumpeted by colleagues and citations to the literature from the text. In the age of
seemed within reach, now seems entirely unrealizable in PubMed and Medline, literature is now easily tracked,
the foreseeable future. The second was the plethora of and citations can also be found in the relevant chapters
guidelines – this torrent continues to fl ow, and now, in of the associated textbook. In place of this, a ‘ further
my personal opinion, the downsides of this outweigh reading ’ section, listing key articles, books and review
the advantages. This fashion for guidelines risks bland articles, with an emphasis on recent publications, has
uniformity and guideline fatigue. Does the wearying been included; this seemed to me to be of more general
audience really need the further imposition of more of utility. Finally, the reader should know that this
these? The third thread of contemporary therapy identi- book, like its predecessor, is conceptually, and in many
fi ed in the last edition was the importance of patient places actually, a condensation of the multi - authored
involvement in medical decisions. This remains an textbook ( Treatment of Epilepsy , edited by Shorvon SD,
important prerogative and in this edition too the impor- Perucca E, Engel J, Blackwell Publishing Ltd, Oxford,
tance of two - way communication and of patient choice 2009). Much of the information in this handbook
is emphasized. has its basis in the textbook (that indeed is a rationale of
There are a series of signifi cant changes to this edition, this handbook) and the borrowing has often been
which it is hoped will improve the book. First, the struc- heavy, sometimes word for word, and the infl uence
ture has changed, which refl ects the greater attention to great. I would like to acknowledge here my debt of
the causes of and the syndromes of epilepsy (now sepa- gratitude to my co - editors of this textbook, Professor
rate chapters), as well as more detail on principles Emilio Perucca and Professor Pete Engel, and also to all
of therapy, and a greater emphasis on tables to summa- the contributors to the multi - authored textbook (listed
Preface to the Third Edition xi
in the acknowledgement section), for without their work Finally, I repeat the health warning of the second
this book would not exist. The textbook remains a land- edition: although every effort has been made in the prep-
mark in the bibliography of epilepsy therapy. aration of this book to ensure that the details given are
Finally, thanks too are due to the production crew at correct, it is possible that errors have been overlooked
Wiley - Blackwell, Rebecca Huxley and Martin Sugden for (e.g. in pharmaceutical or pharmacokinetic data). The
their expert guidance and assistance, and Lynne and reader is advised to refer to published information from
Matthew, for whom the writing of this book has meant the pharmaceutical companies and other reference works
lost time and the smoke of much midnight oil. to check accuracy.
Simon Shorvon
London 2010