Muscles, Nerves, and Pain

Muscles, Nerves, and Pain

Wilfred A. Nix Muscles, Nerves, and Pain A Guide to Diagnosis, Pain Concepts, and Therapy Second edition With 102 figures 123

Nix, Wilfred A. Professor of Neurology Department of Neurology University Medical Center Johannes Gutenberg University Mainz, Germany ISBN 978-3-662-53718-3 978-3-662-53719-0 (ebook) DOI 10.1007/978-3-662-53719-0 Springer Springer-Verlag GmbH Germany 2012, 2017 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Cover Design: deblik Berlin Graphic design and layout: Berthold Matthäus, Mühltal Cover illustration: Prof. Nix, Mainz Illustrations: Fotosatz-Service Köhler GmbH Reinhold Schöberl, Würzburg Printed on acid-free paper This Springer imprint is published by Springer Nature The registered company is Springer-Verlag GmbH Germany The registered company address is: Heidelberger Platz 3, 14197 Berlin, Germany

V Acknowledgments I would like to thank all those who encouraged me to write this book and who helped in editing and getting it published. For the first edition I would particularly like to thank Dr. Dieter Bonke, who coordinated much of the work that had to be done, and Berthold Matthäus for the graphic design and layout. For the second edition I thank the continuing support of Springer represented by Diana Kraplow, Astrid Horlacher, and Isabella Athanassiou. Their help guided me through the book s revision. I am also indebted to my patients, who were a constand motivation while writing the book. Finally I would like to thank my wife, Brigitte, for her patience and constant support and care.

Contents Introduction.................................................... 1 1 Basics of anatomy.......................................... 3 1.1 Motor system............................................... 4 1.2 Sensory system.............................................. 4 1.3 Vegetative system............................................ 7 1.4 Neuron................................................... 7 1.5 Peripheral nerve............................................. 8 1.6 Regeneration of the peripheral nerves.............................. 10 1.7 Denervation and reinnervation................................... 12 1.8 Sequelae of nerve injuries on the sensory system and pain................. 14 2 Examination process........................................ 17 2.1 Motor function.............................................. 19 2.1.1 Muscle tests of the upper extremity................................. 19 2.1.2 Muscle tests of the lower extremity.................................. 22 2.2 Reflexes.................................................. 23 2.2.1 Examination of reflexes......................................... 23 2.3 Sensitivity................................................. 23 2.3.1 Methods of testing sensitivity..................................... 25 2.4 Vegetative nervous system...................................... 32 2.4.1 Sympathetic skin innervation..................................... 33 3 Electrophysiology.......................................... 37 4 Radicular lesions........................................... 41 4.1 Segmental innervation......................................... 42 4.2 Remarks on terminology....................................... 44 4.3 Overuse and disc herniation..................................... 46 4.4 Diagnostics................................................ 46 4.5 Therapy of a herniated disc...................................... 49 4.5.1 Conservative or operative therapy.................................. 50 4.5.2 The failed back syndrome....................................... 51 4.6 Cervical root syndromes........................................ 52 4.6.1 Cervical myelopathy........................................... 53 4.7 Lumbar root syndromes........................................ 56 4.7.1 Conus/cauda lesion............................................ 59 4.7.2 Spondylolisthesis............................................. 60 5 Lesions of single nerves...................................... 63 5.1 Trigeminal nerve............................................. 65 5.1.1 Corneal reflex............................................... 65 5.1.2 Sense of smell............................................... 65 5.1.3 Bulbar and pseudobulbar paralysis.................................. 65

Contents VII 5.1.4 Masseter reflex.............................................. 65 5.1.5 Trigeminal neuralgia........................................... 66 5.2 Facial nerve................................................ 68 5.2.1 Anatomy.................................................. 68 5.2.2 Peripheral facial nerve paresis..................................... 70 5.2.3 Central facial nerve paresis....................................... 70 5.2.4 Facial nerve spasm............................................ 71 5.2.5 Therapy................................................... 71 5.3 Brachial plexus.............................................. 72 5.3.1 Traumatic damage............................................ 72 5.3.2 Damage from inflammation...................................... 75 5.3.3 Entrapment syndromes......................................... 78 5.3.4 Pancoast syndrome, radiation sequelae............................... 80 5.4 Shoulder nerves............................................. 80 5.4.1 Long thoracic nerve........................................... 80 5.4.2 Suprascapular nerve........................................... 80 5.5 Axillary nerve............................................... 83 5.6 Musculocutaneous nerve....................................... 83 5.7 Radial nerve................................................ 83 5.8 Ulnar nerve................................................ 88 5.8.1 Ulnar groove and loge de Guyon................................... 89 5.9 Median nerve............................................... 90 5.9.1 Carpal tunnel syndrome......................................... 93 5.10 Volkmann s contracture........................................ 98 5.11 Lumbosacral plexus........................................... 98 5.11.1 Diabetic plexopathy........................................... 101 5.11.2 Gluteal nerves, injection paralysis................................... 102 5.12 Cutaneous femoral nerve....................................... 103 5.13 Femoral nerve.............................................. 103 5.14 Sciatic nerve................................................ 107 5.15 Tibial nerve................................................ 107 5.16 Peroneal nerve.............................................. 109 5.17 Anterior tibial nerve syndrome................................... 110 6 Acute and chronic pain....................................... 111 6.1 Pain concepts over time........................................ 112 6.2 Aspects of physiology and pain pathways............................ 114 6.2.1 Prespinal level............................................... 114 6.2.2 Spinal level................................................. 115 6.2.3 Brain level.................................................. 115 6.2.4 Sensitization................................................ 120 6.2.5 Pain memory................................................ 121 6.3 Nociceptors in muscles and joints................................. 122 6.4 Neurogenic inflammation....................................... 122 6.5 Nociceptive pain............................................. 123 6.6 Neuropathic pain............................................ 124 6.7 Mixed pain concept........................................... 126

VIII Contents 7 Pain mechanics............................................ 129 7.1 First and second neuron pathways................................. 131 7.2 Impulse propagation in the normal nerve: the diseased nerve and cross-talk..... 131 7.3 Ectopic impulse generation and peripheral sensitization.................. 132 7.4 Central sensitization and anatomical plasticity......................... 133 7.5 Central sensitization and descending inhibition........................ 134 7.6 Sympathetic afferent coupling................................... 134 8 Polyneuropathies.......................................... 137 8.1 Demyelinating neuropathies..................................... 139 8.1.1 Polyneuritis and polyradiculitis.................................... 141 8.2 Axonal degeneration.......................................... 142 8.2.1 Sensory Neuronopathies........................................ 142 8.2.2 Axonopathies............................................... 143 8.3 Combined axon and myelin damage................................ 144 8.4 Diabetic neuropathy.......................................... 144 9 Clinical aspects of painful conditions............................ 147 9.1 Complex regional pain syndrome.................................. 148 9.2 Root avulsions.............................................. 150 9.3 Referred pain............................................... 151 9.4 Myofascial syndrome.......................................... 153 9.5 Pain states in the trunk and extremities.............................. 154 9.5.1 Cervical pain syndromes......................................... 156 9.5.2 Whiplash trauma............................................. 161 9.5.3 Paravertebral pain............................................ 162 9.5.4 Low back pain, sciatica.......................................... 163 9.5.5 Intercostal neuralgia........................................... 166 9.5.6 Scapulocostal syndrome........................................ 166 9.5.7 Frozen shoulder.............................................. 166 9.5.8 Brachialgia................................................. 168 9.6 Herpes zoster............................................... 168 9.7 Muscle cramps.............................................. 173 10 General therapeutic guidelines................................ 175 10.1 Nerve-muscle interaction....................................... 176 10.1.1 Electrotherapy of the muscle...................................... 176 10.1.2 Electrotherapy of the regenerating nerve.............................. 177 10.1.3 Physical therapy.............................................. 178 10.1.4 Voluntary activation........................................... 178 10.1.5 Motivating the patient.......................................... 179 10.2 Regeneration-promoting substances............................... 179 10.3 Pain therapy................................................ 180 10.3.1 Neuropathic pain treatment..................................... 181 10.3.2 Non-steroidal anti-inflammatory drugs............................... 184 10.3.3 Anticonvulsants.............................................. 186

Contents IX 10.3.4 Antidepressants.............................................. 186 10.3.5 Opioids................................................... 187 10.3.6 Neuroleptics................................................ 187 10.3.7 Miscellaneous............................................... 187 10.3.8 The mixed pain concept and its impact on pain therapy..................... 188 Subject Index................................................... 191

Introduction 1

2 Introduction Diagnosing nerve and muscle lesions and the pain associated with them is generally considered difficult, as they display a wide variety of symptoms and the mere thought of the extensive anatomical details is a deterrent. However, these reservations are unfounded. A targeted patient history and prac tical examination techniques that can be learned make it possible to recognize many lesions. This is also necessary because disorders such as back pain, sensory disorders, and muscle weakness are not rare, and since many patients suffer from them, they demand a diagnostic response. Nerves and muscles are at the forefront of diagnostic interest in peripheral neurological disorders. This is understandable, as muscle paralysis is always a dramatic symptom and nerves are exposed to a great deal of potential damage along the long course from the spinal cord to muscle or skin. This yields a great variety of lesion sites that must be considered in daily practice. For example, we have to decide whether muscle paralysis is caused by disc damage or only by a nerve lesion. Very frequently, for example, pain brings the patient to the doctor, who then must differentiate between myogelosis in the arm or entrapment syndrome in the carpal tunnel. It is necessary to distinguish between acute and chronic pain, as different peripheral or central nerve mechanisms are involved and they determine the required therapy options. Pain can be nociceptive or neuropathic. Occasionally both components play a role a mixed pain concept that is described here. Depending on the suspected diagnosis, differ ent procedures are required and at different speeds. For example, immediate medication is needed for trigeminal neuralgia before any further examination. By contrast, the suspicion of an acute herniated disc requires targeted, technical diagnos tics before any therapy. Diagnosing peroneal nerve paresis, on the other hand, is not as urgent. But since it can be mistaken for a herniated disc, care ful differentiation must first be made between these two lesions in the peripheral area. Back or neck pain in the form of lumbago or a cervical syn drome is a very frequent acute or chronic symptom in which the mixed pain concept can be helpful in understanding the illness as well as treating it. Facial nerve paralysis can also make a differential diagnosis difficult when you need to decide between a peripheral or central facial nerve paresis. In every case, the first physician to see the patient sets the course with his suspected diagnosis by planning and arranging further tests. In making his diagnosis, he is aided by the fact that damage to peripheral nerves always occurs systematically depending on the location of the lesion. The loss of motor, sensory, and vegetative function is different for root damage than for a lesion in the plexus or fur ther toward the periphery. This can be helpful in solving the problem cycle caused by the damage. More difficult are painful disorders in the functional relation between joints and their associ ated muscles, which can imitate nerve irritations. This book will also offer assistance in these situa tions by presenting the newest ideas on how symp toms arise and the ensuing knowledge of diagnos tics and therapy. Furthermore, familiar know-how is refreshed in pictures and practice-related texts. This book is not intended as a textbook, but rather as a guideline for routine practice, and its numer ous illustrations can be helpful for explaining the situation to the patient. Wilfred A. Nix