Neurology E-Book

• Herausgeber: Thieme
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 1452

Veröffentlichungsjahr: 2003

Beschreibung

Pocket-sized and affordable, this classic Thieme Flexibook provides a thorough and comprehensive review of clinical neurology. The fully revised fourth edition puts new emphasis on clinical relevance, and contains updated information on stroke, epilepsy, eye movements, headache, and more!

Key features:

• Nearly 1,000 pages of up-to-date clinical information
• More than 50% of the book has been totally revised and updated for this edition
• Easy-to-use index provides quick access to content
• Written by two experienced clinical neurologists and teachers

One of the best basic works to address the entire field of neurology, this practical book has become a major text and reference for neurology students and residents the world over. The book also appeals to general practitioners, neurology specialists, and even neurosurgeons needing a quick reference on an unfamiliar neurological problem.

Leseprobe

Robert Wyss

Neurology

Mark Mumenthaler, M.D.

Professor Emeritus of NeurologyFormer Head of the Department of NeurologyBerne University, InselspitalBerne, Switzerland

Heinrich Mattle, M.D.

Professor of NeurologyBerne UniversityInselspitalBerne, Switzerland

Translated and adapted byEthan Taub, M.D.

4th revised and enlarged edition

438 illustrations210 tables

Georg Thieme VerlagStuttgart · New York

Library of Congress Cataloging-in-Publication Data

This book is an authorized and revised translation of the 11th German edition published and copyrighted 2002 by Georg Thieme Verlag, Stuttgart, Germany. Title of the German edition: Neurologie

Translator: Ethan Taub, M.D.,Klinik Im Park, Zurich, Switzerland

1st German edition 19672nd German edition 19693rd German edition 19704th German edition 19735th German edition 19766th German edition 19797th German edition 19828th German edition 19869th German edition 199010th German edition 19971st English edition 19772nd English edition 19833rd English edition 19901st Czech edition 20011st French edition 19741st Greek edition 19901st Hungarian edition 19891st Indonesian edition 19951st Italian edition 19752nd Italian edition 19841st Japanese edition 19831st Polish edition 19722nd Polish edition 19793rd Polish edition 20011st Portuguese edition 19971st Spanish edition 19762nd Spanish edition 19821st Turkish edition 1984

© 2004 Georg Thieme Verlag,Rüdigerstrasse 14, 70469 Stuttgart,Germanyhttp://www.thieme.deThieme New York, 333 Seventh Avenue,New York, NY 10001 USAhttp://www.thieme.com

Cover design: Cyclus, StuttgartTypesetting by Mitterweger, PlankstadtPrinted in Germany by Grammlich,Pliezhausen

ISBN 3-13-523904-7 (GTV)ISBN 1-58890-045-2 (TNY)                        1 2 3 4 5

Important note: Medicine is an ever-changing science undergoing continual development Research and clinical experience are continually expanding our knowledge, in particular our knowledge of proper treatment and drug therapy. Insofar as this book mentions any dosage or application, readers may rest assured that the authors, editors, and publishers have made every effort to ensure that such references are in accordance with the state of knowledge at the time of production of the book. Nevertheless, this does not involve, imply, or express any guarantee or responsibility on the part of the publishers in respect to any dosage instructions and forms of applications stated in the book. Every user is requested to examine carefully the manufacturers' leaflets accompanying each drug and to check, if necessary in consultation with a physician or specialist, whether the dosage schedules mentioned therein or the contraindications stated by the manufacturers differ from the statements made in the present book. Such examination is particularly important with drugs that are either rarely used or have been newly released on the market. Every dosage schedule or every form of application used is entirely at the user's own risk and responsibility. The authors and publishers request every user to report to the publishers any discrepancies or inaccuracies noticed.

Some of the product names, patents, and registered designs referred to in this book are in fact registered trademarks or proprietary names even though specific reference to this fact is not always made in the text. Therefore, the appearance of a name without designation as proprietary is not to be construed as a representation by the publisher that it is in the public domain.

This book, including all parts thereof, is legally protected by copyright. Any use, exploitation, or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to prosecution. This applies in particular to photostat reproduction, copying, mimeographing, preparation of microfilms, and electronic data processing and storage.

For Regula, Sarah, and Sofia-Rebeccafrom M. Mumenthaler

For Rösly, Stephanie, Selina, and Regulafrom H. Mattle

Preface to the Fourth English Edition

Since this book first appeared in German in 1967, the reading and study habits of medical students and physicians have changed dramatically. As foreign travel is now commonplace, many young physicians take part of their training abroad and thereafter continue to enjoy a lively exchange of experiences with colleagues in different countries. International communication, of course, requires a common language, and English has gradually become the predominant language for this purpose. The authors and publisher therefore decided to arrange a translation of the 11th German edition into English.

The book is now 3 times its original length; since 1967, the number of illustrations has risen sixfold from 70 to 438, the number of tables from 30 to 210, and the number of references from 640 to about 2000. Its scope having widened over the years, this text, originally intended for beginning medical students, has come to be more suitable for advanced medical students with a special interest in neurology, for resident trainees, and for physicians in practice.

As a logical consequence of this development, the authors and publisher have decided to tailor the current edition for practicing physicians. Thus, we have omitted the sections concerning the basic neurological examination and ancillary tests in neurology, while introducing a substantial amount of new material and providing greater detail on many of the topics previously covered. We have entirely rewritten the chapters on epilepsy, disorders of cerebral perfusion, extrapyramidal motor disorders, polyneuropathies, and myopathies. We have also considerably enlarged the sections on treatment in each chapter, as requested by readers of previous editions.

In order to keep the book from becoming unwieldy through the addition of so much material, we have not printed the reference list in the book, but have published it instead on the Thieme Internet site (http://www.thieme.com/mm-refs), where the abstracts of most references can also be read. The didactic aspects of the text and its graphic presentation have been brought up to date with the help of Ms. Susanne Huiss of Georg Thieme Verlag.

We have tried to make the book comprehensive, though not complete (which would be impossible in any case), aiming at a clear and understandable presentation of what we think are the more important aspects of neurological disease. We encourage readers to consult the amply cited references for more detail on particular matters of interest.

Many of the illustrations show imaging studies of the kinds that are now indispensable in clinical neurology. Physicians should order such studies, in our opinion, mainly to confirm a diagnosis that has already been formulated on the basis of the case history and physical examination. It should be possible to arrive at a single diagnosis or a narrow differential diagnosis through a critical assessment and logical combination of these elements, in the light of an understanding of topical neurologic diagnosis and of the patterns of neurologic disease, which is what this book seeks to impart.

We have also written another, less comprehensive text, Grundkurs Neurologie (soon to be available in English as Fundamentals of Neurology), which provides an introduction to clinical neurology for medical students and allied health professionals. That text, unlike this one, includes introductory chapters on the neurological examination and on ancillary testing.

We are glad to have secured the collaboration of Dr. Ethan Taub, an American-trained and certified neurosurgeon practicing in Switzerland, for this English edition. He has not only produced an accurate translation of fine literary quality, but has also, through his familiarity with American medicine, succeeded in adapting this edition optimally to the standard practice and terminology of English-speaking physicians.

We would like to thank Dr. Thomas Scherb, Dr. Thorsten Pilgrim, Susanne Huiss, M.A., and Rolf Dieter Zeller of Georg Thieme Verlag for designing and producing the German edition with such great care, and Dr. Clifford Bergman and Gert Krüger of Thieme International for managing production the English edition. We also thank all of the readers and friends whose critical advice has helped us eliminate errors and maximize the accuracy of the text. We gratefully look forward to more such advice in the future.

Many people have helped us obtain references and illustrations, reviewed parts of the manuscript critically, and participated in the technical aspects of book production. We would like to express our particular thanks in this regard to Professor G. Schroth, Dr. L. Remonda, Dr. K. Lövblad, Dr. F. Donati, Dr. K. Gutbrod, Professor Ch. W. Hess, Dr. G.Jenzer, PD Dr. K. Rösler, PD Dr. J. Mathis, Prof. C. Bassetti, Dr. A. Nirkko, and Dr. P. Imesch, as well as Dr. sc.nat. Karin Hänni and Dr. phil. Annelies Blum.

We hope that this translation of the book into the lingua franca of modern medicine will make it accessible to a wider audience, in the English-speaking countries and throughout the world.

Mark MumenthalerHeinrich MattleZurich and Berne, SwitzerlandAutumn 2003

Translator's Note

This textbook of neurology has been translated into many languages since its original publication in German in 1967 and has earned the appreciation of generations of readers all over the world. It has covered the field of neurology in greater depth with each new edition, while incorporating the latest clinical and scientific advances, and has thus doubled in size since it last appeared in English (the 3rd edition of 1990, translated by E. H. Burrows from the 9th German edition). Yet, thanks to the skill of the authors, the book has not become unwieldy and remains eminently readable for both study and reference.

In translating and adapting the 11th German edition to produce this English version, I have worked directly from the current German text, but have occasionally borrowed words and phrases from the previous English edition when I found they could not be improved on. The text mostly corresponds to the German, paragraph by paragraph, and even page by page for long stretches toward the beginning of the book. I have sparingly added words of explanation wherever this might help the reader, especially in passages touching on my own specialty (neurosurgery), but have otherwise done my best to convey the sense of the original unaltered. Needless to say, the opinions and expert judgments expressed in the book are those of the authors. I have learnt much in the process of translation and am grateful to Professors Mumenthaler and Mattle, and to Georg Thieme Verlag, for the privilege of helping them put this book before an English-speaking audience.

Ethan Taub, M.D.Zurich, Switzerland, Autumn 2003

Contents

Clinical Syndromes

1Clinical Syndromes in Neurology

Differentiation of Central and Peripheral Paresis

Bodily Distribution of Paresis

Monoparesis

Hemiparesis

Para- and Quadriparesis

Lesions Affecting the Anterior Horn Ganglion Cells

Lesions Affecting a Spinal Nerve Root

Polyradiculopathy

Polyneuropathy

Plexus Lesions

Lesions of a Single Peripheral Nerve

Dysfunction of the Neuromuscular Junction

Myopathy

Clinical Neurology

2 Diseases Mainly Affecting the Brain and its Coverings

Characteristics of Diseases of the Brain

Congenital and Perinatally Acquired Diseases of the Brain

Traumatic Brain Injury

Intracranial Hypertension and Brain Tumors

Infectious Diseases of the Brain and Meninges

Disturbances of Cerebral Perfusion and Nontraumatic Intracranial Hemorrhage

The Comatose Patient

Extrapyramidal Syndromes

Cerebellar Syndromes

Metabolic Disorders with Cerebral Or Other Neurologic Involvement

Systemic Diseases Affecting the Nervous System

Dementing Disorders and Other Neuropsychological Syndromes

3 Diseases Mainly Affecting the Spinal Cord

Characteristics of Diseases of the Spinal Cord

Ancillary Tests in Diseases of the Spinal Cord

Classification of Spinal Cord Syndromes

Congenital and Perinatally Acquired Lesions of the Spinal Cord

Spinal Cord Trauma

Fundamentals of (Complete) Spinal Cord Transection Syndrome

Practical Approach to Acute Traumatic Spinal Cord Transection

Acceleration Injury of the Spine (Whiplash Injury)

Tumors and Other Masses Compressing the Spinal Cord

General Aspects

Types of Mass Compressing the Spinal Cord

Infectious, Allergic, and Toxic Diseases of the Spinal Cord and Its Coverings

Infectious Diseases of the Spinal Cord

Myelitis

Toxic Myelopathies

Circulatory Disorders of the Spinal Cord

Blood Supply of the Spinal Cord

Spinal Cord Ischemia Due to Deficient Arterial Blood Flow

Spinal Cord Ischemia Due to Venous Disturbances

Degenerative and Heredodegenerative Diseases Mainly Affecting the Spinal Cord

Diseases Affecting the Anterior Horn Cells

Spastic Spinal Paralysis

Amyotrophic Lateral Sclerosis (ALS)

Spinocerebellar Ataxias

Metabolic Disorders Mainly Affecting the Spinal Cord

Vitamin B12 Deficiency and Funicular Myelosis

Syringomyelia and Syringobulbia

Other Diseases of the Spinal Cord

Radiation-Induced Myelopathy

Decompression Myelopathy

4 Autonomic and Trophic Disorders

Acute Pandysautonomia

Familial Dysautonomia (Riley-Day Syndrome)

Botulism

Insensitivity to Pain

Congenital Insensitivity to Pain

Congenital Sensory Neuropathy with Anhidrosis

Sensory Radicular Neuropathy

Pain Asymbolia

Sympathetic Syndromes

Typical Manifestations

Trophic Disorders

5 Demyelinating Diseases

Multiple Sclerosis

Typical Clinical Features

Epidemiology

Clinical Features

Ancillary Tests

Prognosis

Pathologic Anatomy

Etiology and Pathogenesis

Treatment

Differential Diagnosis

Other Demyelinating Diseases

Concentric Sclerosis (Baló's Disease)

Diffuse Sclerosis (Schilder's Disease)

Acute Disseminated Encephalomyelitis (ADEM)

Neuromyelitis Optica (Devic's Disease)

Subacute Myelo-optic Neuropathy (SMON)

Hereditary Demyelinating Diseases

6 Injury to the Nervous System by Specific Physical Agent

Electrical Injury

Gas Embolism

Venous Gas Embolism

Arterial Gas Embolism

Injury Due to Ionizing Radiation

Radiation Injury to the Brain

Radiation Injury to the Spinal Cord

Radiation Injury to the Peripheral Nervous System

Hypothermic Injury

7 Epilepsy, Other Episodic Disorders of Neurologic Function, and Sleep Disorders

Epilepsy

History

Etiology and Pathogenesis

Epidemiology

Ancillary Diagnostic Tests in Epileptology

Classification of Epilepsy

Individual Seizure Types

Clinical Patterns of Epilepsy and Epileptic Syndromes

Partial (Focal) Seizures

Special Seizure Types and Seizure Etiologies

Procedure after a First Seizure or Multiple Seizures

Treatment of Epilepsy

Prognosis

Episodic Disturbances of Consciousness, Syncope, and Other Nonepileptic Episodes

Syncope and Drop Attacks

Disturbances of Consciousness of Metabolic Origin

Drop Attacks

Episodic Nonepileptic Motor Phenomena

Episodic Disorders that are Partly or Wholly Psychogenic

Neurological Findings in the Unconscious Patient and in Psychogenic Pseudo Neurological Conditions

Neurological Findings in the Unconscious Patient

The Neurological Examination in Psychogenic Pseudo Neurological Conditions

Sleep and Disturbances of Sleep

Sleep

Sleep Disorders

Hypersomnia

Sleep Apnea Syndrome

8 Polyradiculitis and Polyneuropathy

Polyradiculitis

Classic Acute Polyradiculitis (Guillain-barré Syndrome, Landry-Guillain-barré Syndrome)

Atypical Polyradiculitis

Polyneuropathy

General Features

Hereditary Polyneuropathy

Polyneuropathy Due to Metabolic Disorders

Polyneuropathy Due to Improper or Inadequate Nutrition

Polyneuropathy Due to Vitamin B12 Malabsorption

Autoimmune Polyneuropathy

Polyneuropathy Due to Infectious Disease

Polyneuropathy Due to Arterial Disease

Polyneuropathy Due to Sprue and Other Malabsorptive Disorders

Polyneuropathy Due to Exogenous Toxic Substances

Polyneuropathy of Other Causes

9 Diseases Affecting the Cranial Nerves

Disturbances of Olfaction

Anosmia

True Combined Anosmia and Ageusia

Cacosmia

Visual Disturbances of Neurologic Origin

Loss of Vision

Visual Field Defects and Perceptual Disturbances

Abnormal Findings in the Optic Disks

Oculomotor Disturbances

The Neuroanatomical Basis of Ocular Motility

Preliminary Remarks on the Examination of Ocular Motility

Ancillary Tests in Oculomotor Disturbances

General Principles of Ocular Motility

Some Diseases in which Oculomotor Disturbances are Prominent

Diseases that Mimic Supranuclear Disturbances of Eye Movement

Lesions of the Cranial Nerves Subserving Eye Movement and their Brainstem Nuclei

Ptosis

Treatment of Oculomotor Disorders

Pupillary Disorders

Anatomy and Clinical Examination of the Pupils

Abnormal Size and Shape of the Pupils

Abnormalities of Pupillary Reactivity

Trigeminal Disturbances

Facial Nerve Disturbances

Cryptogenic Peripheral Facial Nerve Palsy

Bilateral Facial Nerve Palsy

Melkersson-Rosenthal Syndrome

Other Causes of Peripheral Facial Nerve Palsy

Disturbances of Taste

Hemifacial Spasm

Facial Myokymia

Facial Tic

Progressive Facial Hemiatrophy

Disturbances of the Vestibulocochlear Nerve (Statoacoustic Nerve, Auditory Nerve)

Anatomy

Testing of Hearing

Cochlear, Retrocochlear, or Central Hearing Loss?

Diseases Causing Hearing Loss

Ancillary Tests in the Diagnostic Evaluation of Hearing Loss

Tinnitus and Other Abnormal Sounds

Vertigo

Diseases Causing Prominent Vertigo

Glossopharyngeal and Vagus Nerve Dysfunction

Accessory Nerve Palsy

Hypoglossal Nerve Palsy

Multiple Cranial Nerve Palsies

Cranial Polyradiculitis

(Recurrent) Multiple Cranial Nerve Palsies

Progressive Palsies of Multiple Cranial Nerves

Garcin Syndrome

Rarer Causes

10 Spinal Radicular Syndromes

General Symptoms and Signs

Intervertebral Disk Disease as a Cause of Radicular Syndromes

Cervical Disk Herniation and Spondylosis

Thoracic Radicular Syndromes

Lumbar Disk Herniation

Mass Lesions in and Adjacent to the Spinal Nerve Roots

Other Radicular Syndromes

Herpes Zoster

11 Lesions of Individual Peripheral Nerves

General Clinical Features

Ancillary Tests

Classification and Quantification of Peripheral Nerve Lesions

Peripheral Nerve Regeneration

Pain Syndromes due to Peripheral Nerve Lesions

Brachial Plexus Palsies

Traumatic Brachial Plexus Palsies

Other Causes of Brachial Plexus Palsy

Differential Diagnosis of Brachial Plexus Palsies

Long Thoracic Nerve

Axillary Nerve

Suprascapular Nerve

Musculocutaneous Nerve

Radial Nerve

Median Nerve

Ulnar Nerve

Lumbosacral Plexus

Genitofemoral and Ilioinguinal Nerves

Femoral Nerve

Lateral Femoral Cutaneous Nerve (Meralgia Paresthetica)

Obturator Nerve

Gluteal Nerves

Sciatic Nerve

Common Peroneal Nerve

Tibial Nerve

12 Headache and Facial Pain

General Aspects

History-Taking from Patients with Headache

Classification of Headache and Facial Pain

Examination of Patients with Headache

Pathogenesis of (Primary) Headache

The Major Primary Headache Syndromes

Tension-Type Headache

Post-Traumatic Headache

Migraine

Headache in Organic Vascular Disease

Cranial Arterial Occlusion

Aneurysmal Subarachnoid Hemorrhage

Arterial Hypertension

Pheochromocytoma

Temporal Arteritis

Spondylogenic Headache and Cervical Migraine

Neck-Tongue Syndrome

Other Symptomatic Forms of Headache

Headache Due to an Intracranial Mass

Headache Due to Intermittent Obstruction of CSF Flow

Syndrome of Low Cerebrospinal Fluid Volume (Hypoliquorrhea)

Pseudotumor Cerebri

Headache Due to Ocular Disorders

Headache Due to Disorders of the Ear, Nose, and Throat

Headache Due to Systemic Disease

Psychogenic Headache

Drug-Induced Headache

Facial Pain

Neuralgias

Other Types of Facial Pain

13 Pain Syndromes of the Limbs and Trunk

Pain in the Shoulder and Arm (Cervicobrachialgia)

Pain Syndromes of the Trunk and Back

Pain in the Trunk

Back Pain

Pelvic Pain and Pain in the Lower Limb

Other Regional and Generalized Pain Syndromes

14 Myopathies

General Aspects

Muscular Dystrophies

Myotonias and Periodic Paralyses

The Myotonias

Heterogeneous Syndromes Involving Excessive Muscle Fiber Activity

Periodic Paralyses

Metabolic Myopathies

General Aspects of Energy Metabolism in Muscle

Clinical Presentation and Diagnostic Evaluation of the Metabolic Myopathies

Specific Metabolic Myopathies

Myoglobinuria

Mitochondrial Encephalomyo-pathies

Congenital Myopathies

Myositis

Myopathy in Endocrine Diseases

Muscular Manifestations of Electrolyte Disturbances

Muscular Manifestations Due to Medications, Intoxications, and Nutritional Deficiencies

Disorders of Neuromuscular Transmission

Myasthenia Gravis (Myasthenia Gravis Pseudoparalytica, Erb-Goldflam Disease)

Lambert-Eaton Myasthenic Syndrome

Congenital Myasthenic Syndromes

Other Myasthenic Syndromes

Common Muscle Cramps

15 References

See also http://www.thieme.com/mm-refs

Appendix

Scales for the Assessment of Neurologic Disease

Detailed Instructions for the Unified Parkinson's Disease Rating Scale (UPDRS)

Simplified Scale for Evaluating the Severity of Individual Signs of Parkinson's Disease

Epworth Sleepiness Questionnaire

Barthel Index (of Disability)

Modified Rankin Scale (for Stroke)

Modified NIH Stroke Scale (adapted from Brett et al. and Lyden et al.)

Expanded Disability Status Scale (DSS) for Multiple Sclerosis

Major Neurogenetic Diseases

Glossary of Common Abbreviations in Neurology

Glossary

Index

ClinicalSyndromes

1Clinical Syndromes in Neurology

Because of the anatomical construction of the nervous system and the manner in which functions are assigned to its components, lesions in specific areas of the central or peripheral nervous system are regularly associated with characteristic symptoms and signs. An acquaintance with these recurring patterns allows one to trace individual findings or constellations of findings back to the responsible dysfunctional component of the nervous system (Table 1.1).

Table 1.

1

Components of the nervous system

Central

Peripheral

Brain (not including cranial nerve nuclei)

Cranial nerve nuclei

Spinal cord

(not including anterior horn ganglion cells)

Anterior horn ganglion cells

Nerve roots

Brachial and lumbar plexuses

Peripheral nerves

Motor end plates

Muscles

The following discussion will concern the most important typical constellations of findings (syndromes):

central paresis,

peripheral paresis,

monoparesis,

hemiparesis,

paraparesis,

quadriparesis,

anterior horn lesion,

radicular lesion,

polyradiculopathy,

polyneuropathy,

plexus lesion,

lesion of a single peripheral nerve,

dysfunction of the neuromuscular junction (motor end plate),

myopathy.

Differentiation of Central and Peripheral Paresis

Central and peripheral forms of paresis may be differentiated from each other by the criteria listed in Table 1.2.

Table 1.

2

Characteristics of central and peripheral paresis

Feature

Central paresis

Peripheral paresis

Proprioceptive muscle reflexes

Increased

Decreased

Exteroceptive muscle reflexes

Decreased

Decreased

Babinski sign

Present

Absent

Muscle atrophy

Absent (or mild atrophy of disuse)

Present

Muscle tone

Increased (i.e., spasticity; not yet present in acute phase)

Decreased

Bodily Distribution of Paresis

The distribution of paresis in the body enables a number of inferences to be made about the nature and anatomical localization of the responsible lesion.

Monoparesis

Monoparesis is defined as isolated weakness of an entire limb or of a major part of it. Possible causes are listed in Table 1.3.

Table 1.

3

Sites of lesions causing monoparesis, and corresponding clinical features

Site of lesion

Clinical features

Central nervous system

Spastic paresis (increased muscle tone, increased reflexes)

No muscle atrophy

Possibly a purely motor deficit

(e.g., contralateral leg paresis due to ischemia in the territory of the anterior cerebral artery)

Anterior horn of spinal cord(chronic lesion)

Paresis of individual muscles with accompanying atrophy and decreased tone

No sensory deficit

Possibly accompanied by fasciculations

Decreased proprioceptive muscle reflexes (but may be increased in amyotrophic lateral sclerosis)

Brachial or lumbar plexus

Mixed sensory and motor deficit

Decreased muscle tone

Muscle atrophy, decreased proprioceptive muscle reflexes

Sensory deficit for all modalities

Multiple peripheral nerves

Same as in plexus lesions in a single limb

Muscle

Hardly ever a pure monoparesis; if so, then flaccid

Purely motor deficit, sometimes with muscle atrophy

Hemiparesis

Hemiparesis may be due to any of the causes listed in Table 1.4.

Para- and Quadriparesis

Paraparesis is weakness affecting both lower limbs, and quadriparesis is weakness affecting all four limbs (but sparing the head). These may be due to any of the causes listed in Table 1.5.

Table 1.

4

Sites of lesions causing hemiparesis, and corresponding clinical features

Site of lesion

Clinical features

Cerebrum

Spastic hemiparesis, possibly also involving facial muscles, characterized by:

Increased muscle tone

Increased reflexes

Pyramidal tract signs

No atrophy

Usually associated with a sensory deficit

Brain stem

Spastic hemiparesis, as above

Face involved or not, depending on level of lesion

Cranial nerve deficits contralateral to hemiparesis

Upper cervical spinal cord

Spastic hemiparesis, as above

Face spared

Possible ipsilateral loss of position and vibration sense and contralateral loss of pain and temperature sense below the level of the lesion (Brown-Sequard syndrome)

Table 1.

5

Sites of lesions causing para- or quadriparesis,and corresponding clinical features

Site of lesion

Clinical features

Cerebrum (bilateral lesion)

Clinical picture of “bilateral hemiparesis,” or paraparesis due to a bilateral parasagittal cortical lesion

Corticobulbar pathways in the brain stem (bilateral lesion) (e.g., lacunar state, p. 178)

Bilateral spasticity with only mild weakness

Spastic, small-stepped gait

hyperreflexia, pyramidal tract signs

No sensory deficit

Usually accompanied by pseudobulbar signs (dysarthria, hyperreflexia of the facial musculature)

Corticospinal pathways in the spinal cord (bilateral lesion)

Para- or quadriparesis

Face spared

Hyperreflexia, pyramidal tract signs

No sensory deficit

Only mild weakness

Lesions Affecting the Anterior Horn Ganglion Cells

Lesions selectively affecting the efferent neurons (ganglion cells) of the anterior horn of the spinal cord (p. 425 ff.) produce the characteristic clinical findings listed in Table 1.6.

Table 1.

6

Clinical features of an isolated lesion of the anterior horn ganglion cells

Muscle atrophy

Weakness

Fasciculations (in chronic phase)

Intact sensation

Decreased or absent reflexes

But: hyperreflexia and pyramidal tract signs in amyotrophic lateral sclerosis, which involves not only the anterior horns but also the corticospinal pathways (thus the term “lateral” sclerosis, as these pathways are lateral in the spinal cord)

Lesions Affecting a Spinal Nerve Root

Lesions affecting a spinal nerve root (p. 717 ff.) always produce both motor and sensory deficits. Individual spinal nerve roots always supply more than one muscle, and no muscle is supplied exclusively by a single root. Thus, the motor deficit produced by a monoradicular lesion has the following characteristics:

There is always more than one affected muscle.

No affected muscle is ever totally paralyzed.

Nevertheless, certain muscles are predominantly supplied by a single root and are, therefore, weakened to a particularly severe degree by a corresponding monoradicular lesion. Proprioceptive muscle reflexes partially subserved by the affected root may be decreased or even absent (cf. Table 1.4). The sensory deficit lies within the corresponding sensory dermatome (cf. Table 1.1) and thus usually has a band-like cutaneous distribution. Pain, if present, is referred into the dermatome of the affected root. Although the deficit is mixed (both motor and sensory), the clinical picture may be dominated by either the motor deficit or the sensory deficit in individual cases. Atrophy of the affected muscles is evident about 3 weeks after the onset of weakness.

Fig. 1.1a-g Cutaneous sensation.

Fields of sensory innervation of peripheral nerves and spinal nerve roots, depicted on the left and right sides of the body, respectively.

1 Trigeminal n.

2 Great auricular n.

3 Transverse cutaneous n.

4 Supraclavicular nn.

5 Anterior cutaneous branches of the intercostal nn.

6 Superior lateral cutaneous n. of the arm (a branch of the axillary n.)

7 Medial cutaneous n. of the arm

8 Lateral cutaneous branches of the intercostal nn.

9 Posterior cutaneous n. of the arm (a branch of the radial n.)

10 Posterior cutaneous n. of the forearm

11 Medial cutaneous n. of the forearm

12 Lateral cutaneous n. of the forearm

13 Superficial branch of radial n.

14 Palmar branch of median n.

15 Median n.

16 Common palmar digital nn.

17 Palmar branch of ulnar n.

18 Iliohypogastric n. (lateral cutaneous branch)

19 Ilioinguinal n. (anterior scrotal nn.)

20 Iliohypogastric n. (anterior cutaneous branch)

21 Genitofemoral n. (femoral branch)

22 Lateral femoral cutaneous n.

23 Femoral n. (anterior cutaneous branches)

24 Obturator n. (cutaneous branch)

25 Lateral sural cutaneous n.

26 Saphenous n.

27 Superficial peroneal n.

28 Sural n.

29 Deep peroneal n.

30 Tibial nerve (calcanean branches)

1 Frontal n. (V1)

2 Greater occipital n.

3 Lesser occipital n.

4 Great auricular n.

5 Dorsal branches of the cervical nn.

6 Supraclavicular nn.

7 Superior lateral cutaneous n. of the arm (a branch of the axillary n.)

8 Dorsal branches of the cervical, thoracic, and lumbar spinal nn.

9 Lateral cutaneous branches of the intercostal nn.

10 Posterior cutaneous n. of the arm

11 Medial cutaneous n. of the arm

12 Posterior cutaneous n. of the forearm

13 Medial cutaneous n. of the forearm

14 Lateral cutaneous n. of the forearm

15 Superficial branch of radial n.

16 Dorsal branch of ulnar n.

17 Median n.

18 Iliohypogastric n. (lateral cutaneous branch)

19 Superior cluneal nn.

20 Middle cluneal nn.

21 Inferior cluneal nn.

22 Lateral femoral cutaneous n.

23 Posterior femoral cutaneous n.

24 Obturator n. (cutaneous branch)

25 Lateral sural cutaneous n.

26 Sural n.

27 Saphenous n.

28 Lateral plantar n.

29 Medial plantar n.

Fig. 1.1c Radicular innervation: lateral view.

Fig. 1.1d Peripheral innervation: lateral view.

1 Ilioinguinal n.

2 Iliohypogastric n.

3 Genitofemoral n. (femoral branch)

4 Lateral femoral cutaneous n.

5 Dorsal n. of penis (pudendal n.)

6 Ophthalmic n. (V1)

7 Mandibular n. (V3)

8 Lesser occipital n.

9 Maxillary n. (V2)

10 Greater occipital n.

11 Dorsal branches of cervical nn.

12 Great auricular n.

13 Transverse cutaneous n.

14 Anterior cutaneous branches of the intercostal nn.

15 Supraclavicular nn.

16 Superior lateral cutaneous n. of the arm (a branch of the axillary n.)

17 Intercostobrachial nn. (intercostal nn.)

18 Dorsal branches of the thoracic nn.

19 Posterior cutaneous n. of the arm

20 Lateral cutaneous n. of the arm

21 Posterior cutaneous n. of the forearm (a branch of the radial n.)

22 Superior lateral cutaneous n. of the forearm

23 Medial cutaneous n. of the forearm

24 Lateral cutaneous branch of the iliohypogastric n.

25 Superior cluneal nn.

26 Superficial branch of radial n.

27 Autonomous area of superficial branch of radial n.

28 Dorsal branch of ulnar n.

29 Inferior cluneal n.

Fig. 1.1e, f

1 Cutaneous branch of obturator n.

2 Posterior femoral cutaneous n.

3 Lateral sural cutaneous n.

4 Ilioinguinal n. and genital branch of genitofemoral n.

5 Anterior cutaneous branches of femoral n.

6 Medial cutaneous branches of the saphenous n.

7 Medial dorsal cutaneous n. (superficial peroneal n.)

8 Medial calcaneal branches

9, 10 Medial plantar n.

11 Lateral plantar n.

12 Medial cutaneous branches of the saphenous n.

13 Sural n.

14 Medial calcaneal branches

Fig. 1.1g

1 Dorsal n. of the penis or clitoris (pudendal n.)

2 Posterior scrotal or labial nn.

3 Anterior cutaneous branches of the femoral n.

4 Obturator n.

5 Posterior femoral cutaneous n.

6 Superior cluneal nn.

7 Inferior cluneal nn.

8 Middle cluneal nn.

9 Anococcygeal nn.

10 Ilioinguinal n. and genital branch of genitofemoral n.

Polyradiculopathy

Polyradiculopathy (p. 575 ff.) is manifested by a rapidly progressive and symmetric bilateral paresis, which usually begins in the lower limbs. The motor deficits dominate the clinical picture in most forms of polyradiculopathy. The affected muscles are flaccid, and reflexes are absent. Micturition is not impaired.

Polyneuropathy

The clinical picture of polyneuropathy (p. 582 ff.) usually develops very slowly, over the course of several years. The initial symptoms are practically always confined to the lower limbs. Only sensory abnormalities are present at first:

paresthesiae and formication in the toes,

abnormal sensation in the soles of the feet,

burning sensations,

(occasionally) the feeling of walking on cotton wool.

Shortly after these symptoms arise, the Achilles reflex disappears, furnishing the first objective clinical sign. Vibration sense is impaired, more so distally than proximally. Weakness first manifests itself as an inability to spread the toes, and, when the toes are dorsiflexed, the examiner feels no contraction of the extensor digitorum brevis muscles on the dorsum of the foot. Later, cutaneous sensation to touch is impaired, and the proximal calf muscles become weak. Finally, severe bilateral foot drop appears and leads to a characteristic bilateral steppage gait.

Plexus Lesions

Plexus lesions (p. 749 and 780 ff.) always give rise to a mixed motor and sensory deficit. The involved muscles and the distribution of the sensory deficit do not correspond to the field of innervation of a single peripheral nerve, but rather to that of a combination of nerves. There is a flaccid paresis, and the reflexes subserved by the affected nerves are absent. The sensory deficit is sharply delimited and complete and involves all modalities. Sweating is absent in the area of the sensory deficit. Muscle atrophy becomes evident a few weeks after the onset of weakness.

Lesions of a Single Peripheral Nerve

A lesion of a single peripheral nerve (p. 741 ff.) produces a characteristic motor deficit in the muscles it supplies, and a characteristic sensory deficit in its field of sensory innervation. Lesions of purely motor or purely sensory nerves (or nerve branches) will obviously produce purely motor or purely sensory deficits. Sweating is absent in the area of a sensory deficit, and any reflex that is subserved by the affected nerve is absent. There is a flaccid paresis, and muscle atrophy becomes evident 2–3 weeks after the onset of weakness.

Dysfunction of the Neuromuscular Junction

In dysfunction of the neuromuscular junction (motor end plate) (pp. 875 ff.), there is a purely motor paresis of variable severity. However, as in the (other) myopathies (see below), sensation remains intact. There is no muscle atrophy.

Myopathy

Myopathy (p. 815 ff.) is characterized by paresis in the absence of a sensory deficit, because the lesion lies within the striated muscle itself. The clinical picture is thus comparable to that of an anterior horn lesion (see above). Most myopathies progress very slowly and affect both sides of the body symmetrically. The paresis is flaccid and the muscles become atrophic, albeit usually less severely than is seen with anterior horn or peripheral nerve lesions. The corresponding reflexes are decreased or absent in advanced stages of the illness. Fasciculations do not occur, in contrast to anterior horn lesions.

Clinical Neurology

2Diseases Mainly Affecting the Brain and its Coverings

Characteristics of Diseases of the Brain

Definition:

Diseases of the brain are characterized by both general and localizing manifestations. General symptoms and signs include headache, disturbances of consciousness, (generalized) epileptic seizures, an organic mental syndrome, meningism, and signs of elevated intracranial pressure (vomiting, bradycardia). Localizing signs include focal neurological and neuropsychological deficits, visual disturbances, cranial nerve deficits, and focal epileptic seizures. None of these features are obligatory for diagnosis, and they may be present in varying combinations and degrees of severity.

Congenital and Perinatally Acquired Diseases of the Brain

Definition:

Both genetic defects and disturbances occurring during pregnancy may lead to developmental disorders of the brain (and of the remainder of the nervous system, as well as other organs of the body). These may already be evident in the newborn infant (e.g., microcephaly), or they may become evident only in the course of further development. The same is true of brain injuries occurring during delivery, which are of two types: hemorrhages, and more or less diffuse hypoxic injuries. The more common modes of presentation in the early postnatal phase are abnormalities of muscle tone and pathological reflexes. Later manifestations include delayed psychomotor development, motor deficits (para- or hemiparesis) and involuntary movements (e.g., athetosis). Epileptic seizures in children and adolescents are not uncommonly an expression of a congenital or perinatally acquired disease of the brain.

The Neurological Examination in Infancy and Early Childhood

Techniques used in the neurological examination of adults are generally not applicable to infants and very young children. Information about the child's functional state is more usefully derived from observation of spontaneous behavior and of complex motor reflexes (104, 311).

In the infant, spontaneous posture should be noted, as well as any bodily asymmetries or constantly maintained postures. It should also be noted whether the head is asymmetric (plagiocephalic) or otherwise abnormal in shape (p. 44). The head circumference, body weight, and body length should be measured, entered into a table for future reference, and compared with normal values for age and sex (Fig. 2.1).

Primitive motor function in children is initially governed by a number of reflex mechanisms. These are listed in Table 2.1, and their temporal development and clinical significance are briefly described.

The stages of normal motor development are shown in Fig. 2.2.

In the initial months of life, the following motor abnormalities may indicate the presence of a cerebral movement disorder (cerebral palsy):

feeding problems,

hypotonia,

paucity of movement,

spastic extension of the legs when the child is lifted,

intense adductor spasms—e.g., during diaper changes,

absence of head lifting while prone persisting into the 3rd month of life,

an abnormally brisk hand grasp reflex,

increased tonic reflexes,

increased neck reflexes,

en bloc rotation on testing of the trunk postural reflex and the head- on-trunk reflex.

By the end of the 4th month, the infant should be able to control its head while sitting, lift its head while prone, and use both hands for play. The Moro reflex fades, and the Landau and parachute reflexes make their first appearance. The phenomena listed above are pathological in this stage also.

By the end of the 6th month, the following findings are highly suggestive or, if pronounced, definitely indicative of a cerebral movement disorder: retained tonic neck reflex and Moro reflex, and absent Landau, labyrinthine positional, and parachute reflexes. The child should be able to lift its head while supine, turn from supine to prone, sit up with support, turn toward an external noise, and use the whole hand, including the thumb.

By the end of the 9th month, the child should be able to sit unaided, and the lumbar kyphosis becomes less pronounced. The following findings are suggestive of a cerebral movement disorder, in addition to the pathologic reflexes already mentioned: absence of the body righting and limping reactions, and presence of a trunk postural reflex.

Fig. 2.1a-h Head circumference, body length, and weight in childhood and adolescence. (Adapted from:Berner Datenbuch der Padiatrie: Praktische Richtlinien, Therapie, Ernährungsgrundlagen, Referenzwerte, 4th ed., Stuttgart: Fischer, 1992).

Fig. 2.2 Normal motor development in infancy and early childhood.

Cerebral Movement Disorders, Infantile Cerebral Palsy, Psychomotor Retardation (311, 661, 926)

Definition:

These terms are used more or less synonymously to denote any delay of motor development that becomes evident in early childhood, regardless of etiology. In most cases, such disorders are already evident in the first year of life and are accompanied by delayed mental development.

Etiology and Pathogenesis

Problems during pregnancy and delivery, premature birth, and birth weight under 2000 g or over 4000 g often cause hypoxic injury to the brain and thereby lead to a cerebral movement disorder. The Apgar scale is a measure of the infant's neurological and general medical condition at birth (Table 2.2). Congenital malformations (p. 32), infectious and toxic conditions affecting prenatal development of the brain (p. 36), and severe neonatal jaundice (p. 38) are further causes of cerebral movement disorders.

Clinical Features

A cerebral movement disorder may be manifested at birth by cyanosis or a delayed first cry, or in the first few weeks of life by feeding difficulties, hypotonia or a fixed arching of the back, a tendency to opisthotonus, and spasticity, which may make diaper changes difficult. Strabismus and lefthandedness are also more common in infants with cerebral movement disorders.

For a discussion of the clinical features of cerebral movement disorders in the first year of life, see p. 15. Motor development in infancy and early childhood is depicted in Fig. 2.2, and reflexes in infancy and early childhood (104) are described in detail in Table 2.1.

Findings on Examination

At first, hypotonia may be present, for as long as 6 months (“floppy infant”). There follows a period of several months characterized by dystonic, fluctuating, position-dependent and stimulus-related increasing muscle tone, after which true spasticity appears. Involuntary movements (athetosis, chorea, choreoathetosis, torsion dystonia, tremor), ataxia, and rigidity are also frequently present, with or without spasticity. Epileptic seizures occur in some cases.

Intellectual ability may be more or less severely impaired. The term oligophrenia denotes a significant impairment of intellectual ability that is either congenital, or acquired in early childhood.

In some children, varying degrees of agnosia and apraxia may produce disturbances of fine motor control, of drawing, and of the appreciation of spatial relationships. These children are often not only clumsy, but also restless and hyperkinetic. They often have choreiform movements, which can, however, be suppressed at will or by voluntary movement. Poor performance on tests of practical manual skills contrasts with relatively high verbal intelligence. There is a complex relationship to dyslexia. The mental status examination is normal, but the EEG is almost always diffusely abnormal. The term “clumsy child” is sometimes used as a shorthand description of this condition, which is also called “débilité motrice” (motor debility).

This condition is almost always due to a relatively minor congenital abnormality of, or perinatal injury to, the brain. Some of its clinical features may reflect an abnormality of cortical organization occurring during fetal development. Table 2.3 provides an overview of cerebral movement disorders.

Course

About 25% of cases improve spontaneously, and a further 50% can be helped to a greater or lesser extent by early therapeutic intervention. Early detection is, therefore, essential. Much can be achieved at present with exercise therapies (e.g., those of Bobath or Vojta) that are specifically tailored to the abnormal reflex activity of these children. 25% do, however, remain severely impaired.

Malformations of the Brain

Most of the conditions listed in Table 2.4 become evident at birth or shortly thereafter.

Table 2.

4

The most important malformations of the brain

Dysgenesis or agenesis of parts of the brain:

• Micropolygyria

Focally abnormal gyral pattern: gyri abnormally narrow and abnormally numerous

• Pachygyria

Abnormally few secondary convolutions

• Agyria

Absence of convolutions (smooth brain)

• Lissencephaly

(See agyria)

• Double cortex syndrome (348a)

Cortical cells in two layers (genetically determined)

• Arrhinencephaly

Absence of olfactory nerves and tracts, (sometimes) agenesis of the corpus callosum, other abnormalities

• Cyclopia

Single orbit

• Holotelencephaly

Single ventricle in rostral portion of cerebrum

• Dandy-Walker syndrome

Cystic dilatation of the fourth ventricle, hydrocephalus

• Arnold-Chiari malformation

Caudal displacement of the cerebellar tonsils, sometimes associated with syringomyelia and other anomalies of the craniocervical junction

Microcephaly

Small head and brain

Neural tube defects:

Incomplete closure of the neural tube

• Spina bifida occulta

• Meningocele

• Myelomeningocele

• Myelomeningocystocele

• Open anencephaly

Sinus pericranii

Vascular malformation communicating with a venous

Cranial dermal sinus

In the midline, usually occipital, often associated with a dermoid cyst

Phakomatoses

Malformations affecting multiple systems including the central nervous system (see Table 2.5)

Agenesis or Dysgenesis of Parts of the Brain

See Table 2.4.

Microcephaly

A variety of prenatal influences can result in microcephaly, particularly cytomegalovirus (p. 37), but also genetic factors in 15% of cases.

Meningoencephalocele and Meningomyelocele

The following defects of the brain and spinal cord may occur:

Incomplete closure of bone over the central nervous structures: cranium bifidum occultum (spina bifida occulta).

Emergence of the meninges through the bony defect, covered by skin: meningocele.

Emergence of the meninges and of brain or spinal cord parenchyma through the bony defect: encephalomeningocele (myelomeningocele).

The emerging portion of the central nervous system includes part of the fluid-filled ventricular system: encephalomeningocystocele (myelomeningocystocele).

The neural tube has failed to close, so that the malformed primordial brain lies uncovered as an open neural plate: anencephaly (complete rachischisis).

Phakomatoses

The abnormalities associated with the phakomatoses (Table 2.5) are found not only in the brain, but also in the skin, the peripheral nerves, and other internal organs.

Tuberous Sclerosis (Bourneville's Disease)

Genetics and Pathogenesis

This multifaceted disorder of histogenesis is transmitted in an autosomal-dominant inheritance pattern with a high rate of spontaneous mutation.

Clinical Features

The illness is clinically characterized by feeblemindedness, cutaneous manifestations (particularly adenoma sebaceum), nodular tumors of the heart, kidneys, and retina, epileptic seizures, and nodular intracranial tumors (“tubers”), which are frequently calcified.

The intellectual deficit becomes evident within the first 2 years of life. Hypopigmented macules (“white spots”) are seen in only three-quarters of cases; the presence of more than 54 such spots should arouse clinical suspicion of the disease. Adenoma sebaceum (Pringle's nevus) often becomes visible at some time in early childhood. Intracranial calcifications are often visible on radiological images from the age of 2–4years onward.

Prevention and Treatment

The risk of an open neural tube defect is reduced by 70% or more if the mother takes at least 0.4 mg of folic acid around the time of conception, and other vitamins and minerals may also be protective (124b, 200a). Of the malformations of the brain listed above, only meningocele and encephalomeningocele are, in principle, operable; for myelomeningocele, see p. 393. If a surgical repair is to be performed, it should be done in the first few hours after birth. The decision whether to operate should be based on careful consideration of what is likely to be achieved thereby for the newborn and its family. The parents' attitude, and any accompanying spinal malformations or hydrocephalus, should be taken into account.

Prenatal detection of malformations of the brain and spinal cord is at least as important as treatment. The concentration of fetally derived protein (α-fetoprotein) in maternal blood is measured. A normal αFP level is associated with a risk of only one in 10,000 that the newborn will have a neural tube defect. If the αFP level is elevated, the risk rises to 1 in 15.

Seizures practically always begin in the first 2 years of life, at first often as salaam spasms (p. 515).

Nodular tumors are found in the heart, kidneys, and retina, and so called tubers in the brain (subependymal giant-cell astrocytomas), which are often calcified. When the diagnosis is suspected, it should be confirmed by CT or MRI of the brain in the first few months of life, to enable appropriate genetic counseling of the parents.

Encephalofacial Angiomatosis (Sturge-Weber Disease)

Genetics

This disease is mostly found in individuals without relevant family history, but is probably transmitted in autosomal-dominant fashion with variable penetrance.

Clinical Features

It is characterized by the combination of a facial nevus (“nevus flammeus”) in the distribution of one or more branches of the trigeminal nerve with (focal) epilepsy, intellectual deficiency, and sometimes contralateral hemiparesis.

Diagnosis

Radiologic studies reveal “railroad-track” calcifications of the cerebral cortex, corresponding to abnormal, serpentine vessels (mostly capillaries and small veins) in the meninges covering the parieto-occipital convexity.

Von Hippel-Lindau Disease

Genetics

Von Hippel-Lindau disease is of simple autosomal dominant inheritance.

Clinical Features

Retinal angiomatosis is found in combination with a single or, rarely, multiple hemangioblastoma of the cerebellum. Syringomyelia may also be present. The cerebellar tumor usually arises in middle age and consists of a cyst with a mural nodule. It may become manifest through cerebellar dysfunction, signs of intracranial hypertension, or signs of syringomyelia.

Treatment

The treatment consists of the complete neurosurgical removal of the mural nodule of the cerebellar hemangioblastoma. Early diagnosis and treatment confer a good prognosis.

Fig. 2.3 Neurinoma () of the sciatic nerve in von Recklinghausen's neurofibromatosis. CT of the pelvis. The star indicates the piriformis muscle, which divides the sciatic foramen into supra- and infrapiriform compartments.

Neurofibromatosis (von Recklinghausen's Disease)

Clinical Features

This phakomatosis is characterized by the presence of numerous neurofibromas, which develop from connective tissue nerve sheaths. These may affect either peripheral nerves or nerve roots, giving rise to progressive mononeuropathies or radiculopathies, respectively (Fig. 2.3).

Neurofibromas with in the spinal canal may lead to signs of spinal cord compression and paraplegia. A neurofibroma growing within an intervertebral neural foramen assumes a characteristic dumbbell shape because of the combination of intraand extraspinal tumor mass (see Fig. 3.5). The intraspinal portion of the tumor causes neurologic symptoms and signs. Enlargement of the neural foramen itself may be demonstrable on plain roentgenograms of the spine (oblique view).

The most common intracranial tumor in this disease is a schwannoma affecting the vestibulocochlear nerve, usually (but inaccurately) termed “acoustic neuroma.” These tumors are often bilateral and give rise to the typical clinical signs of a mass in the cerebellopontine angle (p. 68). Tumors are also found in association with the optic nerve and the retina, leading to visual disturbances, and occasionally within the brain itself, leading to epilepsy and other signs of space-occupying lesions. Neurofibromas may undergo malignant degeneration. Meningiomas are also found with increased frequency in this patient group.

Cutaneous lesions include neurofibromas, which may be very large, and pigmented patches (café-au-lait spots, freckles). Axillary freckling is typical. The pattern of inheritance is autosomal dominant, and 90% of cases represent new mutations.

Ataxia Telangiectasia

Ataxia telangiectasia may be considered one of the phakomatoses and is discussed on p. 280.

Infectious and Toxic Conditions Affecting Prenatal Development of the Brain (Table 2.6)

Table 2.

6

Infectious and toxic conditions affecting prenatal development of the brain

Rubella embryopathy

Congenital toxoplasmosis

Congenital cytomegalovirus

Congenital syphilis

Congenital HIV infection

Alcohol embryopathy

Rubella Embryopathy

Rubella in the mother in the first trimester of pregnancy carries an approximately 10% risk of damage to the fetus; the later the maternal illness, the lower the risk. The more common defects are:

cataract,

deafness (abnormal development of the inner ear),

microcephaly, and

cardiac anomalies.

Congenital Toxoplasmosis

A maternal infection with toxoplasmosis in early pregnancy is followed in late pregnancy by generalized infection of the fetus, and then by florid encephalitis with general cerebral symptoms and signs, seizures, and hydrocephalus. The cerebrospinal fluid is abnormal (for serologic diagnosis, see p. 108).

Congenital Cytomegalovirus

This disease causes:

premature birth and other disturbances of delivery,

microcephaly (the leading sign),

hydrocephalus,

seizures,

paralysis,

intracerebral calcifications, particularly around the ventricles.

Congenital Syphilis

This form of neurosyphilis is more common when the mother is affected with an early stage of the disease. The syphilis-related serologic reactions in blood and cerebrospinal fluid are usually positive. Chorioretinitis is often seen. Tertiary manifestations, such as general paresis or tabes dorsalis, may appear years later (p. 112).

Congenital HIV Infection

Approximately 25 % of HIV-positive pregnant women transmit the infection to their children either in utero, during labor, or through breastfeeding. The risk is much lower when delivery is by caesarean section and when antiretroviral therapy is given (p. 124). Documentation of infection is complicated by the presence of maternal HIV antibodies in neonatal blood, and therefore a direct demonstration of the virus itself should be attempted. The polymerase chain reaction (PCR) reveals infection at the age of 3 months in almost all cases. The manifestations are highly variable and include delayed psychomotor development and spasticity (with mortality over 50% in the first 3years) and immunodeficiency. Infants with immunodeficiency but without encephalopathy have a better prognosis and may survive into the second decade of life.

Alcohol Embryopathy

Alcohol embryopathy is damage to the fetus caused by maternal alcohol consumption during pregnancy. The manifestations include small stature, psychomotor retardation, microcephaly, facial dysmorphia (small nose, thin lips, micrognathia), and a number of other structural abnormalities.

Brain Disorders Due to Birth Trauma

Subdural Hematoma

Subdural hematoma is the most common hemorrhagic complication resulting from trauma during delivery. The source of bleeding is either a torn venous sinus (often the transverse sinus) or one or more bridging veins.

Treatment

The treatment is neurosurgical and consists of repeated puncture with aspiration, and/or craniotomy.

Intracerebral and Intraventricular Hemorrhage

These hemorrhages are usually fatal, but the patient may survive a smaller hemorrhage (single or multiple) and develop the clinical picture of a cerebral movement disorder. The manifestations are comparable to those of diffuse brain damage from neonatal asphyxia. The pathological changes arising in such cases include thinning and sclerosis of the cerebral convolutions (ulegyria), the formation of large cystic spaces (porencephaly), and status marmoratus of the basal ganglia. The last-named is due to an excess of myelinated fibers and is associated with athetosis or athetose double.

Severe Neonatal Jaundice (“Icterus Gravis Neonatorum”)

Definition:

Maternal-fetal Rh-incompatibility leads to deposition of bilirubin in the brain, particularly in the basal ganglia, and thereby to paresis, dystonia, athetosis, deafness, and intellectual deficiency.

Pathoanatomy and Pathophysiology

When an Rh-negative woman has formed anti-Rh antibodies through previous pregnancy with an Rhpositive fetus (or transfusion of Rhpositive blood) and then becomes pregnant with another Rh-positive fetus, the anti-Rh antibodies cross the placenta and induce the immunologic destruction of fetal erythrocytes. So-called “kernicterus” develops (German for “jaundice of the [deep cerebral] nuclei”), in which bilirubin is deposited in various portions of the basal ganglia.

Clinical Features

The neonate suffers from edema, anemia, erythroblastosis, and jaundice that rapidly worsens with in a few days of birth. Kernicterus develops in about 20% of cases with erythroblastosis. Two to five days after the onset of jaundice, the neonate becomes apathetic, does not drink, and develops clonic movements, opisthotonus, and irregular breathing. Death ensues in severe cases in 3–7 days, but most of these children survive to suffer from a form of cerebral palsy with motor abnormalities, pareses, involuntary dystonic or athetotic movements, deafness, and intellectual deficiency.

In recent years, hemolytic disease of the newborn due to maternal-fetal Rh-incompatibility has become a preventable illness through the administration of anti-Rh immunoglobulin injections during pregnancy.

Diagnosis

The diagnosis is made by measurement of the serum bilirubin level.

Treatment

In milder cases (bilirubin concentration 10–20 mg/100mL), phototherapy. In severe cases (greater than 20mg/100mL), exchange transfusion.

Hydrocephalus

Definition:

Enlargement of the internal and/or external cerebrospinal fluid spaces (see Table 2.7).

Table 2.

7

Types and terminolcgy of hydrocephalus

Internal hydrocephalus

Enlargement of the ventricles:

• Obstructive

Due to obstruction of CSF flow within the ventricular system (e.g., aqueductal stenosis) or at its exits (e.g., obstruction of foramina of Magendie and Luschka)

• Communicating

Nonobstructive internal hydrocephalus

• Malresorptive

A subtype of communicating hydrocephalus due to impaired CSF resorption (e.g., cisternal adhesions or dysfunction of the pacchionian granulations)

External hydrocephalus

Enlargement of the subarachnoid space over the cerebral convexities and/or in the cisterns

External and internal hydrocephalus

Combination of the above

Hydrocephalus ex vacuo

Widening of sulci and ventricles secondary to brain atrophy

Normal Physiology

The cerebrospinal fluid (CSF) is produced in the choroid plexus of the lateral, third, and fourth cerebral ventricles. It flows from the lateral ventricles through the interventricular foramina of Monro into the third ventricle, through the cerebral aqueduct of Sylvius into the fourth ventricle, and through the medial foramen of Magendie and lateral foramina of Luschka into the basal cisterns (cerebellomedullary cistern and lateral pontine cisterns, respectively) (Fig. 2.4). Having thus arrived in the perimedullary subarachnoid space, it flows over the entire surface of the brain and spinal cord and finally enters the bloodstream through the Pacchionian granulations (arachnoid villi) of the superior sagittal sinus. CSF is probably also independently produced within the subarachnoid space itself.

Pathogenesis

Hydrocephalus arises when the flow of CSF is impeded at any point along its pathway. A distinction is drawn between communicating hydrocephalus, in which the ventricles communicate with each other and with the subarachnoid space, and obstructive (noncommunicating) hydrocephalus, in which the flow of CSF is blocked at some point at or above the level of the fourth ventricular outflow. Causes of the latter include agenesis, gliosis, stenosis, or malformation of the cerebral aqueduct, posterior fossa tumors, and blockage of the foramina of Luschka and Magendie.

Congenital and Infantile Hydrocephalus

Clinical Features

Congenital and infantile hydrocephalus are characterized by an abnormally large and progressively increasing head circumference (see Fig. 2.1). The fontanelles are wide and may bulge. Percussion of the skull may yield a cracked-pot sound. The forehead bulges outward and the orbital plates are pushed downward, so that the sclera is visible above the iris of both eyes, which thus appears to dip below the lower lid (“setting-sun sign”).

Fig. 2.4 Circulation of the cerebrospinal fluid (adapted from Gardner).

Ancillary Tests

Suspected hydrocephalus should be initially evaluated by ultrasound, as long as the fontanelle is still open. The diagnosis is revealed in other cases by CT or MRI. The only possible contraindication to further evaluation and treatment of hydrocephalus is a demonstrated, severe accompanying malformation of the brain.

Prognosis

Untreated hydrocephalus in childhood confers a mortality of more than 50%. Only a small minority of the surviving untreated individuals will develop normally. CSF shunting has reduced the overall mortality at 10 years after diagnosis to less than 10%, with an operative mortality under 1 %. More than two-thirds of all children with treated isolated hydrocephalus (i.e., without accompanying malformation of the brain) go on to develop normally, both physically and mentally. If the brain parenchyma is less than 1.5 mm thick at the time of diagnosis, however, the prognosis for normal development is poor.

Differential Diagnosis

A large head frequently reflects familial microcephaly. Such children, who are typically larger and heavier than usual, are otherwise healthy and exhibit normal psychomotor development. The setting-sun phenomenon is absent, and the CT scan is normal. Serial measurement reveals tracking of the larger-than-normal head circumference along its percentile curve.

Treatment

The findings of the imaging studies determine the type of treatment. In rare cases, a direct reopening of a blocked passageway may be attempted (e.g., atresia of the foramina of Luschka and Magendie), but, much more commonly, a shunt operation will be performed.

Occlusive hydrocephalus was once most commonly treated by ventriculocisternostomy (the Torkildsen shunt), in which CSF was redirected through permanently implanted tubes from the posterior horns of the lateral ventricles into the cerebellomedullary cistern. This operation has now been entirely supplanted by the ventriculoperitoneal shunt.

Ventriculoatrial shunting, once commonly performed for communicating hydrocephalus, has also been largely replaced by ventriculoperitoneal shunting.

In recent years, neuroendoscopic surgery has been introduced for the treatment of occlusive hydrocephalus. A hole is made in the floor of the third ventricle to enable flow of CSF from the ventricles into the subarachnoid space (endoscopic third ventriculostomy). A permanent, indwelling foreign body (shunt catheter) is thus unnecessary. Further experience with this technique, and long-term followup of treated patients, will reveal whether it truly provides comparable or better results than the conventional ventriculoperitoneal shunt.

Otitic Hydrocephalus

This rather imprecise term denotes an elevation of intracranial pressure caused by thrombosis of a venous sinus, usually the transverse sinus, which impedes the resorption of CSF from the subarachnoid space into the bloodstream. This syndrome may occur as a consequence of otitis media (more commonly on the right side) or of other primary processes. It is characterized by:

headache,

vomiting,

papilledema, and

abducens palsy, often bilateral.

Most of the affected patients are children. The prognosis is good if the primary process is appropriately treated.

Normal-Pressure Hydrocephalus (Nonresorptive Hydrocephalus, Malresorptive Hydrocephalus)

Clinical Features

Normal-pressure hydrocephalus affects adults, but is considered in this section along with the other hydrocephalus syndromes. Its clinical features are listed in Table 2.8.

Causes

Adhesions in the subarachnoid space or impaired CSF resorption through the Pacchionian granulations leads to the development of normal-pressure hydrocephalus. Common etiologies include a previous traumatic or aneurysmal subarachnoid hemorrhage, meningitis, and, more rarely, borreliosis (Lyme disease). The syndrome may also arise without any discernible cause.

Ancillary Tests

CT and MRI scans reveal symmetrical enlargement of the cerebral ventricles with normal, or constricted, external CSF spaces. A typical MRI finding is abnormal signal intensity adjacent to the poles of the lateral ventricles, so-called “polar capping.” A characteristic clinical feature is rapid and dramatic improvement after lumbar puncture and withdrawal of CSF.

Radioisotope cisternography with labeled albumin may be used to trace the abnormally slow flow of CSF from the subarachnoid space into the ventricles.

An important diagnostic aid is continuous monitoring of intracranial pressure or of lumbar CSF pressure. A constant or intermittent mild elevation of pressure distinguishes so-called normal-pressure hydrocephalus from hydrocephalus ex vacuo (in which the pressure is truly normal). A CSF infusion test can provide a direct measure of resorptive capacity.

A further aid to differential diagnosis is the glycosphingolipid (sulfatide) concentration in CSF, which is elevated in hydrocephalus ex vacuo on an atherosclerotic basis, but not in normal-pressure hydrocephalus (956a).

Diagnosis

In the last 30years, this syndrome has been too frequently diagnosed, and too many shunt operations have been performed. Surgical treatment should only be considered when typical signs, such as gait ataxia, are present (though the associated dementia may be no more than mild), when the CT or MRI findings are consistent, and when an appropriate etiology can be determined (974, 974a).

Treatment

Treatment is highly beneficial in properly selected cases and consists of a ventriculoperitoneal or ventriculoatrial shunt operation (see above). Those patients benefit most who exhibit the full neurological and psychopathological syndrome and in whom a prior etiological event can be clearly identified. Only one-third to two-thirds of patients will actually improve after the operation. Shunting should not be performed in cases of progressive psycho-organic syndrome or progressive spasticity without identifiable cause, even if the radioisotope cisternogram is abnormal.

Craniostenosis (Craniosynostosis)

Premature closure of one or more cranial sutures upsets the coordinated enlargement of the skull in step with the growing brain (218). The clinical subtypes of craniostenosis are listed in Table 2.9. At first, the proportions of the growing skull are distorted. Later, in many cases, intellectual development is impaired, and there may be seizures and signs of intracranial hypertension.

Treatment

The treatment is neurosurgical and consists of excision of strips of bone incorporating the abnormally closed suture(s). For best results, surgery should be performed early, before the age of 4months if possible.

Anomalies of the Craniocervical Junction

Classification

The following malformations may be present, singly or in combination:

atlanto-occipital assimilation,

osodontoideum,

atlantoaxial instability,

occipital vertebra,

spina bifida of the atlas,

platybasia,

basilar impression.

In basilar impression, the lateral skull roentgenogram shows the tip of the dens projecting more than 5mm above either Chamberlain's line (from the posterior rim of the hard palate to the posterior rim of the foramen magnum) or McGregor's line (from the posterior rim of the hard palate to the most caudal point of the occiput).

Block vertebrae (the Klippel-Feil anomaly) may be present in the cervical spine. These skeletal anomalies are sometimes accompanied by anomalies of the brain itself, such as the Arnold-Chiari malformation (p. 32).

Clinical Features

Patients with anomalies of the craniocervical junction often nave a short neck and a low hairline. Neurological symptoms generally begin in adulthood and progress slowly. The typical clinical picture is a combination of lower cranial nerve palsies, brainstem signs (nystagmus) and long tract signs (bilateral pyramidal tract signs and sensory disturbances, which may be dissociated).

Treatment

The optimal form of treatment has yet to be defined. It is not yet clear whether wide occipital decompression or a shunt operation is beneficial. If a bony decompression is performed for this indication (in the presence or absence of an associated Arnold-Chiari malformation), a duraplasty should be performed as well to enlarge the space available for the brain, and retroflexion of the head should be avoided during the procedure (271).

Traumatic Brain Injury(253)

Definition: