Degenerative and Compressive Structural Disorders

History and Definitions Degenerative Structural Disorders Degenerative Disc Disease Cervical Spondylosis Ankylosing Spondylitis Compressive Structural Disorders Fibrous Dysplasia Paget's Disease Other Compressive Disorders Compressive Neuropathies Reviews and Selected Updates References A variety of neurological disorders result from abnormalities of bones, ligaments, muscles, and other mesenchymal tissue that compress the nervous system. In many instances the result is a focal disorder of...

Isaacs Disease

In this syndrome, neuromyotonia or hyperexcitability of the peripheral nerves results in spontaneous and continuous muscle electrical activity. Although in some cases the disease is inherited, in the majority it is acquired. The continuous discharges may originate anywhere along the length of the peripheral nerve. There is some association between Issac's syndrome and autoimmune disease, and it is thought that the acquired varieties are autoimmune in origin. In support of this idea, antibodies...

Directed Neurological Examination Cranial Nerve Xi

The examination of cranial nerve (CN) XI consists of two parts observation (at rest and during action) and palpation. Abnormal findings include atrophy fasciculations neck or shoulder deviation and limitations in range, strength, or speed of motion. Examiners should observe the neck and back while the patient is seated or standing, paying particular attention to the SCM muscle and the upper portion of the trapezius muscle. Atrophy or asymmetry should be noted. Fasciculations may be present with...

Clinical History

Common complaints encountered with visual loss include so-called negative phenomena such as blurry vision or gray vision. Patients with higher cortical disorders often have nonspecific complaints such as I'm having trouble seeing or difficulty focusing. Patients with lesions of the afferent visual pathway may also complain of positive phenomena, such as flashing or colored lights (phosphenes or photopsias), jagged lines, or formed visual hallucinations (illusions of something that is not...

Progressive Aphasia

The degenerative focus centers on anterior perisylvian language cortices (Broca's area). Neuropathology of progressive aphasia has included (1) nonspecific degenerative changes, including increased neuronal lipofuscin, y neuronal loss, astrocytosis, and peri- neuronal microvacuolation in superficial laminae with or without occasional amyloid plaques y (2) nonspecific degenerative changes with focal accumulations of achromatic BLE 12-2 -- ASYMMETRICAL CORTICAL DEGENERATION...

Other Positive Visual Phenomena

Phosphenes are flashes of light witnessed in patients with a blow to the eye, traction on the retina, optic nerve compression, or optic neuritis. y More complex positive visual phenomena include palinopsia (persistence of visual images), polyopia (multiple images), micropsia (shrunken images), macropsia (enlarged images), metamorphopsia (distortion of shape), and Alice-in-Wonderland syndrome (distortion of bodily image). All of these may occur during migraine aura. Metamorphopsia is a much more...

Dorsal Root Radiculopathy

Radiculopathy is generally associated with back or neck pain radiating into an extremity. The pain is poorly localizing for nerve root level but typical in the fact that it is radiating. There will generally be a loss of all modalities of sensation in a dermatomal distribution, a corresponding weakness in a myotomal distribution (i.e., with ventral root involvement as well), and segmental hyporeflexia. The most common cause is a herniated disc or osteophyte compressing on a nerve root. A...

REM Sleep

The anatomical substrates for the different components of REM sleep are as follows 1. An important substrate is cortical desynchronization. The origin of the mixed frequency activity is the mesencephalic reticular formation. The reticular cells fire about 15 seconds before activation of cortex, and their projections extend to the intralaminar nuclei of the thalamus with widespread projections to cortex. 2. Hippocampal theta activity is highly synchronous activity with a frequency of 5 to 10 Hz,...

References

Haymaker W, Baer K The Founders of Neurology. Springfield, il, Charles c Thomas, 1953, pp 356-35 . 2. Levinson, A Cerebrospinal Fluid in Health and Disease. St. Louis, c.v. Mosby, 1929 3. Dandy WE, Blackfan KD Internal hydrocephalus. An experimental, clinical and pathological study. Am j Dis Child 1914 8 406-482 4. Cushing H Studies on cerebrospinal fluid. j Med Res 1914 31 1-19 5. Ames A, Sakanoue M, Endo S Na, K, Ca, Mg and Cl concentrations in the choroid plexus fluid and the cisternal fluid...

Unknown Inheritance Patterns

Sturge is credited with the first report of this syndrome, which appeared in a 6-year-old girl who had a facial angioma, buphthalmos, and contralateral partial seizures.y Sturge surmised that she had an underlying cerebral angioma, but it was not until 18 years later that a cerebral angioma affecting the leptomeninges of these patients was first described. Weber reported the presence of intracranial calcifications in skull radiographs of these patients, Dimitri noted double serpentine...

Abnormal Findings and Clinical Uses of the Blink Reflex

The blink reflex may be helpful in revealing the presence of a subtle trigeminal or facial nerve lesion. Ipsilateral trigeminal nerve lesions lead to responses that are either lost or have a prolonged latency bilaterally. A unilateral facial nerve lesion, by contrast, leads to a delayed or absent response on the affected side regardless of which side is stimulated. The blink reflex may be abnormal with polyneuropathies, thereby indicating the extent of the disorder. Abnormalities may also occur...

Etiology Percent

Jejunal diverticula 2 Dietary cobalamin malabsorption Intrinsic factor antibodies present, or, correction of abnormal Part I Schilling test with intrinsic factor Evidence of achlorhydria (elevated serum gastrin) with abnormal Part I Schilling test in some, but evaluation incomplete. Evidence of achlorhydria (elevated serum gastrin) with abnormal Part I Schilling test. Reprinted with permission from Healton EV, Savage DG, Brust JCN, et al Neurologic aspects of cobalamin deficiency. Medicine...

DNA viruses

Adapted from Bale JF Viral encephalitis Med Clin North Am 1993 77 2542. may enter the host through the mucosal surfaces of the gastrointestinal or respiratory tract. Enteroviruses are acquired most commonly by fecal-oral contamination and, less commonly, via aerosolized respiratory droplets. Enteroviruses

Measles

Measles is one of the three major infectious diseases worldwide and causes about 1.5 million childhood deaths per year. y In the 1960s, prior to routine childhood immunization, more than 400,000 cases of measles were reported annually in comparison, less than 4000 cases were reported annually in the early 1980s. From 1988 to 1990, the incidence of measles increased eightfold. y Between 1987 and 1990, 52,846 cases of measles were reported to the CDC.y This marked...

Other Peripheral Nerve Tumors

Benign tumors of the peripheral nerves are often localized to single sites and are related to pressure or trauma. For example, Morton's neuroma is commonly associated with increased pressure or tight-fitting shoes and represents fibrotic swelling of the nerve in response to repeated insult. Located on the plantar surface of the foot, it is treated with excision or observation. Symptoms include localized pain, tenderness, and weakness of the distally affected muscles innervated by the nerve....

Functional Visual Loss

Nonphysiological or functional visual loss can be either subconscious (hysteria) or deliberate and willful (malingering). Commonly encountered neuro-ophthalmic complaints include visual impairment or complete loss of vision, visual field defects such as constricted fields, and monocular diplopia. When confronted with a patient whose complaints and examination do not seem to correlate (subjective objective mismatch) or whose visual deficit is nonphysiological, there are several clinical tools...

Associated Neurological Findings

Because the basal ganglia circuits include the cortex and because the caudate nucleus is particularly involved with cognition, the cerebral examination can have important contributory findings in patients with hypokinesia or hyperkinesia. Bedside screening tests of dementia and depression are very useful, and an assessment of aphasia and apraxia indicates likely cortical lesions. Cranial Nerves. Most cranial nerve functions are retained in hypokinesia and hyperkinesia. Ocular saccades...

Anatomy Of Mood Emotion And Thought

The neuroanatomic structures related to human mood, emotion, and thought function are complex, and research in this area is still under development. The association of various brain regions with particular functions is based primarily on studies of lesions and, more recently, on functional neuroimaging. Although generalizations based on these isolated cases are somewhat precarious, extended observations based on series of cases are somewhat more reliable. Additionally, although the findings of...

History And Definitions

The glossopharyngeal and vagus nerves have been described since antiquity. Galen of Pergamus (131 to 201 AD) included them in his descriptions of neuroanatomy, grouping together cranial nerves IX, X, and XI as a single nerve. 11 Centuries later the anatomy of the glossopharyngeal and vagus nerves was elucidated in greater detail by the Prussian anatomist Samuel Thomas von Soemmering (1755-1830) in his treatise on the 12 cranial nerves. Although study of the glossopharyngeal nerve in isolation...

Evaluation Guidelines Table156

A wide variety of tests are now available to the neurological clinician. The work-up must be tailored to the situation and guided by a careful analysis of the neurological examination and history. The findings on the neurological examination localize the lesion to the nervous system and to the area where the attention should be focused. They also narrow the possible causes of the disorder. The list of possible causes is narrowed further by the history, which gives the clinician the temporal...

Neurological Applications in Diagnosis and Treatment

One of the primary uses of MRA is the evaluation of the lesions in the carotid artery bifurcation. Atherosclerotic lesions within the carotid bulb and proximal internal carotid artery are major factors contributing to the development of cerebrovascular ischemia. The appropriate treatment of patients with asymptomatic and symptomatic carotid stenosis remains controversial. The North American Symptomatic Carotid Endarterectomy Trial y and the European Carotid Surgery...

Anatomy of Arousal

Arousal requires the interplay of both the reticular formation and the cerebral hemispheres. The reticular components necessary for arousal reside in the midbrain and diencephalon the pontine reticular formation is not necessary for arousal. The midbrain may be viewed as a driving center for the higher structures loss of the midbrain reticular formation (MRF) produces a state in which the cortex appears to be waiting for the command or ability to function. This is manifested...

Discriminative Touch Vibration and Conscious Sense of Joint Muscle Movement

There are three elements of proprioception with separate peripheral receptor representation (1) the perception of limb movement is mediated by muscle spindle receptors, cutaneous mechanoreceptors, and joint receptors (2) the perception of limb position is mediated by muscle spindle receptors and cutaneous mechanoreceptors and (3) the perception of force of muscular contraction is mediated by corollary discharges and tendon organ receptors. y Specific mechanoreceptors that have been implicated...

Gastrointestinal Dysmotility

The principles of management of any gastrointestinal motility disorder include restoration of hydration and nutrition by the oral, enteral, or parenteral route, suppression of bacterial overgrowth, use of prokinetic agents or stimulating laxatives, and resection of localized disease. Bowel Hypomotility. The first line of treatment of bowel hypomotility is to increase dietary fiber as well as water intake and exercise. Psyllium or methylcellulose with a concomitant increase in fluid intake may...

Reviews And Selected Updates

Leigh JR, Zee DS The Neurology of Eye Movements, 2nd ed. Philadelphia, F.A. Davis Company, 1991. Miller NR Walsh and Hoyt's Clinical Neuro-Ophthalmology, 4th ed, Vol 2. Baltimore, Williams & Wilkins, 1985. Pierrot-Deseilligny C, Rivaud S, Gaymard B, et al Cortical control of saccades. Ann Neurol 1995 37 557-567. Pierrot-Deseilligny C Saccade and smooth-pursuit impairment after cerebral hemispheric lesions. Eur Neurol 1994 34 121-134. Pierrot-Deseilligny C Brainstem control of horizontal gaze...

Neuropathy Ataxia Retinitis Pigmentosa Syndrome

The neuropathy, ataxia, retinitis pigmentosa (NARP) syndrome is due to a point mutation at bp8993 in the ATPase 6 gene (MTATP6*NARP8993), which changes a highly conserved leucine at position 156 to an arginine. The exact incidence is unknown, but this is a rare, functionally recessive, with variable systemic expression, adult-onset progressive disease. Presentation is with neuropathy or neurogenic weakness, ataxia, and pigmentary retinopathy. It can also be associated with dementia, generalized...

Abnormal Findings and Clinical Uses of the SEP

Somatosensory evoked potentials are helpful in detecting and localizing lesions of the somatosensory pathways within the CNS but provide no indication about the nature of the underlying pathological processes. They are of little value in evaluating the peripheral nervous system, except when there is concern about the functional integrity of nerves Figure 24-14 Median-elicited somatosensory evoked potential elicited A, a normal subject by right-sided stimulation, anB, a patient with multiple...

Spinal Cord Tumors

Although rare, spinal cord tumors continue to carry a grave prognosis for patients. They are difficult to resect and treat. Both the tumor itself and the treatment often lead to profound physical and neurological disability due to spinal cord damage. Spinal cord tumors represent about 7 percent of all primary tumors of the CNS and are seen more commonly in children, in whom they represent up to a fourth of all intra-axial tumors by location. The most common histological type is that of the...

Demyelinating Disorders of the Central Nervous System

Noseworthy History Role of Myelin Multiple Sclerosis Neuromyelitis Optica Isolated Inflammatory Demyelinating CNS Syndromes Experimental Allergic Encephalomyelitis Acute Disseminated Encephalomyelitis Bookmark URL MD Consult L.L.C. http www.mdconsult.com

Dorsal Root Ganglion Dorsal Horn Lesions Tabes Dorsalis

Generalized sensory neuropathies should be distinguished from subacute sensory neuronopathies, which are characterized by pain, paresthesia, and numbness in the limbs. The latter demonstrate a marked loss of proprioception and vibration, ataxia, and areflexia in an entire limb with a loss of pain and temperature to a lesser degree. The sensory loss may be more pronounced in the upper extremities than the lower extremities therefore, it is not strictly length dependent, distinguishing it from a...

Epstein Barr Virus

Epstein-Barr virus (EBV) is a human B-lymphotropic virus, the causative agent of infectious mononucleosis. The major route of transmission of EBV is through saliva, and EBV infects the epithelial cells of the oropharynx and adjacent structures as well as those of the uterine cervix. Epithelial cells may play a major role in the persistence of EBV by allowing chronic viral replication and release of infectious particles throughout the lifetime of a virus-infected...

Comments

Normally, the cerebral cortex triggers another breath within 10 seconds regardless of the PaCO2 1. Periods of apnea are actually times when the respiratory amplitude is too low to measure, but the respiratory rhythm is unchanged 2. Congestive heart failure prolongs the reflex are (blood leaving the lungs takes longer to reach the brain stem than is normal) and may produce this finding without any neurologic dysfunction When present in patients with brain stem lesions or subarachnoid hemorrhage,...

Normal and Pathological Findings see Tables262 263 and 264

The general appearance of CSF is clear and colorless, because it is more than 99 percent water. Color of CSF is observed only in pathological circumstances. Whereas the term xanthochromia means yellow color, it has been used for the presence of other colors as well. Because of this practice, the actual color of the CSF should be stated and a gradation of its magnitude (from 1+ to 4+) should be noted. A yellowish tinge can be found with any cause of a markedly increased protein (greater than 200...

Calcium Disorders

Ninety-nine percent of total body Ca is contained in bone, making the skeleton a Ca reservoir the remaining 1 percent is distributed in the intracellular and ECF compartments. Because 1 percent of skeletal Ca is freely exchangeable with the ECF, it can help buffer acute changes in the serum Ca, whereas the kidney regulates calciuresis.y Total serum Ca reflects dietary intake, GI absorption, calciuresis, and transfer from the bone to the ECF. Parathyroid hormone (PTH),...

History

Multiple sclerosis (MS) is now known to be a common malady even though it was first recognized as a distinct clinicopathological entity less than 150 years ago. y The lack of reports before the early 1800s is sometimes interpreted as evidence that MS is a relatively new disease. However, it is more likely that the evolution of medicine as a science, which began at approximately the same time, led to more precise observation and description of human diseases. This view is strengthened by the...

Limbic System

The term limbic lobe was coined by Broca in 1878 to describe a series of structures that envelop the brain stem. The word limbic is derived from limbus, meaning border in Latin, 5 and the limbic system encompasses the amygdala, hippocampus, septum, cingulate gyrus, cingulate cortex, hypothalamus, epithalamus, anterior thalamus, mammillary bodies, and fornix. The limbic system has rich connections throughout the brain, particularly with the primary sensory cortices, including the rhinencephalon...

Spinal Cord Strokes

Spinal cord infarcts are most often caused by interruption of the blood flow in one or more of the arteries that feed into the anterior spinal arterial system. A large anterior spinal artery runs in the ventral midline from the medullospinal junction rostrally to the conus medullaris and the filum terminale caudally. This anterior spinal artery system is supplied by five to 10 single radicular arteries. The cervical region is supplied by the anterior spinal...

Metachromatic Leukodystrophies

The metachromatic leukodystrophies (see Ta.bJe30.-6 ), also known as sulfatide lipidoses, are a group of lysosomal storage disorders recognized by the accumulation of excessive amounts of sulfatide. The term metachromatic, as a description of the diseases, derives from the staining properties of the stored lipid sulfatides, which develop a brown or gold hue with toluidine blue rather than the usual blue of myelin. The enzymatic defect involves arylsulfatase-A or cerebroside sulfatase-A. A...

Spinocerebellar Ataxia Type

The SCA1 locus in this autosomal dominant disorder was found on chromosome 6p in both Japanese and American families using serological markers of the human leukocyte antigen (HLA) system. In 1993, Orr and colleagues isolated the SCA1 gene and showed that the mutation was an unstable CAG trinucleotide repeat expansion within a translated region of the gene. '24 Although the repeat length in normals varies from 6 to 39 trinucleotides, SCA1 patients have one...

Reasoning and Problem Solving Through Concept Formation

Reasoning and problem solving are highly related to intellectual functioning. Similar to intellectual function, these abilities tend to be impaired following damage to the CNS. Specific location of injury appears to be less important to reasoning impairments, as does the presence of CNS disturbance. Impairments in reasoning and problem solving result in difficulties in all areas of daily functioning. Patients may be not be able to form generalizations from a given situation and interpret events...

Aminoacidopathies and Organic Acidopathies

Disorders of Later Infancy with Recurrent Metabolic Crises Progressive Diseases of Infancy and Childhood Mitochondrial Enzyme Defects Subacute Necrotizing Encephalomyelopathy (Leigh's Disease) Progressive Infantile Poliodystrophy (Alpers' Disease) Lethal Infantile Mitochondrial Disease or Congenital Lactic Acidosis Myoclonic Epilepsy and Ragged Red Fibers Syndrome Mitochondrial Encephalopathy, Lactic Acidosis, and Strokelike Episodes Chronic Progressive External Ophthalmoplegia and Kearns-Sayre...

Cognititve Function Assessed

Reasoning, problem solving, concept formation Reasoning, problem solving, concept formation Spatial reasoning Motor function Processing speed Construction Praxis sample of IQ scores (Verbal, Performance, and Full Scale) are a mean performance of 100, with a standard deviation of 15. In addition, individual subtest performance can be converted to standard scores with associated variability. Thus, the clinician is able to classify individual performance for both summary IQ measures and individual...

Distal Myopathies

The distal myopathies are a rare heterogeneous group of disorders characterized by progressive muscular weakness and atrophy beginning in the hands or feet ( . Table.36-7,). Several types of distal myopathies have been differentiated clinically, distinguished either by site of onset or mode of inheritance or by differences seen on muscle biopsy. The late adult-onset distal autosomal dominant myopathy that first appears in the hands, also called Welander distal myopathy or Swedish-type distal...

Disorders of Memory

A disorder of declarative memory is defined as amnesia. A pure amnesia refers to a relatively circumscribed disorder of declarative memory that cannot be accounted for by nonmnemonic deficits such as attention, perception, language, or motivation. Anterograde amnesia refers to the inability to acquire new declarative memories. Retrograde amnesia refers to the loss of memories acquired prior to the onset of the amnesia. Retrograde amnesias are described as flat when they extend back uniformly...

Clinical Syndromes

Vocal Cord Dysfunction or Paralysis Spasmodic Dysphonia Flaccid Dysarthria Spastic Dysarthria Mutism Hypokinetic and Hyperkinetic Dysarthria Mixed Dysarthrias Broca's Aphasia Wernicke's Aphasia Conduction Aphasia Global Aphasia Transcortical Motor Aphasia Transcortical Sensory Aphasia Mixed Transcortical Aphasia Subcortical Aphasia Nonlocalizing Aphasic Syndromes Alexia without Agraphia Alexia with Agraphia Frontal Alexia Agraphia Psychiatric Disorders Right Hemisphere Disorders

The Suprachiasmatic Nucleus

The anatomical structure serving as the internal circadian rhythm generator is the suprachiasmatic nucleus (SCN) of the anterior hypothalamus. y , y Lesions of the SCN in rodents abolish circadian rhythmicity, and disconnection of the SCN from the rest of the brain also results in a loss of circadian rhythms in the brain in spite of continued fluctuations within the SCN. Furthermore, in animals with ablations of the SCN, transplantation of fetal SCN tissue restores circadian rhythm. Entrainment...

Craniosynostosis

Craniosynostosis refers to the premature fusion of one or more of the cranial sutures. The premature fusion of one or more sutures results in abnormal and often asymmetrical growth of the cranium with resulting effects on both the underlying brain and the outward appearance of the head. In patients with craniosynostosis, the brain may show a nonprogressive hydrocephalus. Intracranial pressure may be elevated even in the absence of hydrocephalus and also in...

Location of Lesion Pattern of Weakness Reflexes and Associated Signs

Bilateral cerebral Tetraparesis, spastic dysarthria, dysphagia with hyperreactive jaw and facial jerks (pseudobulbar palsy), decorticate posturing (large Tetraparesis, coma, mid-size poorly reactive pupils, decerebrate posturing Locked-in syndrome tetraparesis, paralysis of horizontal eye movements, jaw, face, pharynx, and tongue muscles preservation of eye blink, vertical eye movements, consciousness Tetraparesis with or without weakness of pharynx and tongue Tetraparesis, no cranial nerve...

Pelizaeus Merzbacher Syndrome

Pelizaeus-Merzbacher syndrome occurs in a particular type of demyelinating sudanophilic leukodystrophy and has many subtypes. y In all, sudanophilia is produced when neutral fat stains such as Sudan black react with the neutral fat breakdown products of myelin. Since this breakdown of myelin is the result of a variety of metabolic or acquired insults, sudanophilia provides no useful information about the pathogenic origin of the insult. Most of the early reports were based on the pathological...

Third Order Neuron

The fibers of the medial lemniscus terminate in the ventroposterolateral (VPL) nucleus of the thalamus. This pathway is organized somatotopically such that the fibers from the nucleus gracilis end most laterally within the VPL nucleus and those from the nucleus cuneatus end in the larger, medial part of the VPL nucleus. The VPL nucleus is the origin of the third-order sensory afferent neuron that sends projections to somatosensory cortex (Fig. 19-1 (Figure Not Available) ). Primary...

Clinical Environment

Asthma skin, kidney, encephalopathy, peripheral nerves Peripheral nerves and plexus, encephalopathy, palpable purpura Sinuses, respiratory tract, kidneys, cranial and peripheral nerves Peripheral nerves, muscle, eyes, lungs, skin, lymph nodes, brain granulomas Eyes, peripheral nerves, occasional strokes Syncope, light-headedness, headache, absent arm pulses (strokes rare) Aphthous oral ulcers, genital ulcers, eye inflammation, meningitis, brain stem lesions Interstitial keratitis of eye,...

Primary Small Brain Size

Nongenetic insults (prenatal, perinatal, postnatal) Infectious Vascular disruption, hypoxic-ischemic insult Irradiation Trauma (including shaken baby syndrome) Metabolic and degenerative conditions with onset before completion of brain growth Infantile neuronal ceroid lipofuscinosis Chromosomal instability and premature aging disorders Nijmegen chromosome breakage syndrome Monogenic or sporadic syndromic disorders Cornelia de Lange's syndrome Meckel's syndrome Rubinstein-Taybi syndrome Also

Organic Mercury

Organic mercury readily crosses the blood-brain barrier, and its turnover in the brain is slow. In cases of chronic exposure, approximately 10 percent of the body burden localizes in the brain. Less than 3 percent is degraded into inorganic mercury. In a single case study, histological changes and high mercurial content were noted in the corpus callosum. Excretion occurs primarily through the gastrointestinal tract, mostly through biliary secretion, and the...

T2Wl

Extracellular methemoglobin Cerebrospinal fluid Edema Neoplasms Abscess Demyelination Dysmyelination Acute to subacute infarcts Calcifications Deoxyhemoglobin Intracellular methemoglobin Hemosiderin Flow void in vessels Fat TABLE 23-5 -- MR SIGNAL CHANGE OF HEMORRHAGE TABLE 23-5 -- MR SIGNAL CHANGE OF HEMORRHAGE Extracellular Met-Hb and hemosiderin ring* *After slow reabsorption of the extracellular methemoglobin only decreased signal hemosiderin persists. *After slow reabsorption of the...

Syndromes of Overactivation

This movement disorder is characterized by unilateral, involuntary, episodic tonic and clonic contraction of muscles innervated by CN VII. It usually begins as twitches around the eye and progresses to involve the remaining ipsilateral facial muscles, even during sleep. The spasms are painless, can be provoked by voluntary facial motion and emotional stress, and occur most often in middle-aged women. The exact etiology is unknown, but many believe that compression of the motor nerve root at the...

Exirapulmonary Causes

Central nervous system (parenclymal disorders, increased intracranial pressure, sleep apnea) Neuromuseular disorders Spinal cord tetanus, trauma Anterior horn cell amyotrophic lateral sclerosis poliomyelitis, rabies Nerve Guillain-Barre syndrome, diphtheria, porphyria, ciguatoxin, saxitoxin, tetrodotoxin, thallium intoxication, acute hyperkalemic paralysis, buckthorn polyneunapathy Neuromuscular junction myasthenia gravis, congenital myasthenic syndromes, botulism, hypermagnesemia,...

Fabrys Disease

This X-linked lipidosis is characterized biochemically by the accumulation of two glycosphingolipids, globotriaosylceramide and galabiosylceramide. The enzymatic deficiency is alpha-galactosidase A. The molecular structure of the gene encoding the enzyme was first identified as the full-length cDNA clone and is localized to Xq21.33-q22.yi Twenty different mutations have been described for this gene and include deletions or duplications. The majority of the glycosphingolipids are synthesized in...

Acute Intoxication

In the nervous system, alcohol acts as a depressant, and small doses may lead to disinhibition or a slight euphoria. The toxic effects of alcohol become more prominent with rising blood levels, yet through repeated consumption, humans can become habituated rapidly. Although blood levels of 100 mg dl typically cause drunkenness in occasional imbibers, chronic alcohol abusers can tolerate levels up to 500 mg dl without any apparent effects. The toxic effects of alcohol can be produced in any...

Rubella

Since the rubella vaccine became available in 1969, rubella and the neurological complications of rubella have been due primarily to periodic outbreaks of the disease. Ihe neurological syndromes associated with rubella virus infection include (1) the congenital rubella syndrome, (2) acute encephalitis complicating rubella, (3) postrubella polyradiculoneuritis, and (4) progressive rubella panencephalitis. y , y Acute encephalitis is a rare complication of rubella...

Extracranial Steal Syndromes from Disease of the Aortic Branches

Occlusive disease in the subclavian arteries or the innominate artery can give rise to extracranial steal syndromes. The most defined syndrome is the subclavian steal syndrome. In this condition, occlusive disease in the proximal subclavian artery can lead to a siphoning of blood away from the brain by a reversal of flow down the vertebral artery on the affected side to the ischemic limb. The pulse and blood pressure are diminished in the affected limb. The symptoms may include headache,...

Anatomy of Cranial Nerves Iii Iv and VI

Extraocular Muscles Oculomotor Nerve (Cranial Nerve III) Sympathetic Innervation of the Pupil Trochlear Nerve (Cranial Nerve IV) Abducens Nerve (Cranial Nerve VI) Supranuclear Control of Eye Movements Anatomy of the Saccade System Anatomy of the Pursuit System The Vestibulo-ocular System Internuclear Oculomotor Control The Final Common Pathway Examination of Cranial Nerves III, IV, and VI Directed Neurological Examination Examination of Cranial Nerve III and the Pupil Examination of Cranial...

Reviews and Selected Updates References

The diagnosis and therapy of central nervous system (CNS) viral infections is one of the most rapidly evolving and exciting areas in neurology. Viruses gain access to the CNS either through the bloodstream or through an intraneuronal route from the peripheral nerves. Viruses may cause acute CNS disease such as meningitis or encephalitis, a delayed complication of an acute infection such as postinfectious polyneuritis or autoimmune encephalomyelitis, latent infections with recurrence of disease...

Anatomy Of Praxis

Much of what we know about the anatomical basis of praxis (the ability to perform voluntary skilled movements) comes from the observations of patients with discrete cerebral lesions who have lost these abilities. To perform learned skilled movements, several types of knowledge are required. One must know how to move the limb through space (spatial trajectory) and how fast to move it. To successfully interact with the environment, a conceptual knowledge of praxis is also needed, such as what...

Anatomy of Language

Language processes are lateralized to the left hemisphere. This has been determined through anatomoclinical correlation in patients with language disturbances and associated brain pathology. It has also been demonstrated by electrical stimulation and seizure activity in the left hemisphere, as well as injection of sodium amytal in the left internal carotid, all causing language disturbances and speech arrest. Increased cerebral blood flow to the left hemisphere during language processing also...

Historical Background

During the seventeenth and eighteenth centuries, physicians and morphologists (Wepfer, Willis, Morgagni, Cheyne, and others) recognized that the brains of patients who died of apoplexy often contained hemorrhages and softenings and that brain damage could result from either bleeding or deprivation of the vital blood supply. 1 , y During the nineteenth and early twentieth centuries, physicians became interested in correlating the neurological symptoms and signs found in stroke patients during...

Excessive Daytime Somnolence

EDS indicates the occurrence of abnormal sleepiness during the normal waking hours. y EDS may be associated with inadequate nocturnal sleep and can arise secondary to insomnia. EDS can also occur independently of insomnia. y Primary sleep disorders, such as sleep apnea and PLMD, may disrupt nocturnal sleep, leading to sleep deprivation and EDS. Often, patients with these disorders have frequent arousals punctuating the night but are unaware of these events. During the day, they report a...

Dermoid Epidermoid and Teratoma

These rare embryonic remnant tumors may present anywhere in the CNS but most commonly occur in the posterior fossa and the cauda equina. They are congenital tumors and may be seen at any age however, they are more likely to occur in children or young adults of either sex. They are slow growing and present with symptomatology specific for compressive syndromes at their location within the central nervous system. These symptoms can be insidious, and blockage of cerebrospinal flow occurs rarely....

Strokes In The Young

Strokes in children younger 15 are often different from those found in adults. Brain infarcts tend to be limited more to the deeper regions of the cerebral hemispheres, especially the striatocapsular areas. Vascular occlusive lesions are more often intracranial and affect mostly the intracranial carotid and the middle cerebral and basilar arteries. Extracranial lesions are less common when they occur, they usually involve the pharyngeal portions of the carotid and vertebral arteries rather than...

Additional Neurological Findings

The presence of accompanying cortical signs other than memory loss helps to localize the anatomical basis of an amnestic syndrome. Accompanying dyspraxia, aphasia, or agnosia indicates that the cortex is involved in the pathological process. An assessment of affect is also important, since depression can produce a picture of seeming dementia (pseudodementia). Emotional lability or poor voluntary control over emotional expression (pseudobulbar affect) can occur in patients with...

Coagulation Disorders

Brain ischemia and hemorrhage often result from hematological disorders. Changes in the formed cellular constituents of the blood may be quantitative or qualitative. Polycythemia increases blood viscosity, decreases cerebral blood flow, and increases the risk of thrombosis. Sickle-cell disease and sickle-cell hemoglobin-C disease are examples of qualitative red blood cell abnormalities that affect blood flow. Sickle-cell disease causes occlusive changes in large intracranial arteries and small...

Clinical Uses of Nerve Conduction Studies

Motor conduction studies are helpful in indicating that weakness is due to pathology of the peripheral nerves rather than other parts of the motor unit. Sensory conduction studies may indicate that sensory symptoms are due to an impairment of peripheral nerve function or, when normal, to a lesion proximal to the dorsal root ganglia. Motor and sensory conduction studies are important in determining the presence and extent of a peripheral neuropathy, distinguishing between a polyneuropathy and...

Basic Principles and Technique

Needle electromyography is generally performed in conjunction with nerve conduction studies, which may be undertaken to determine the functional integrity of the peripheral nerves. For motor conduction studies, the nerve is stimulated at two or more points along its course while the electrical response is recorded of one of the muscles Figure 24-21 A myotonic discharge evoked by electrode movemenFrom Aminoff MJ Electromyography in Clinical Practice, 3rd ed. New York, Churchill Livingstone,...

Alexias And Agraphias Languagerelated Disorders

Psychiatric disorders Right hemisphere disorders Dementing diseases lips and impairs enunciation of labial consonants (B, M, P). Neurological examination may reveal atrophy and fasciculations of the tongue and weakness of the palate and the facial muscles. When a history of variable dysarthria or dysphonia, with prominent fatigability is elicited, a neuromuscular junction disorder such as myasthenia gravis may be present. Spastic dysarthria is also called upper motor neuron dysarthria. It is a...

Visual Hallucinations

These are visual images that the patient claims to see but that other observers do not. Visual hallucinations can be characterized as unformed (e.g., dots, flashes, zig-zags) or formed (actual objects or people). They may occur in patients with damage to the afferent visual pathways, sensory deprivation, migraine, seizures, brain stem lesions, drug toxicity or abuse, and psychiatric illnesses. y Patients with visual loss due to a lesion anywhere within the afferent visual pathways may complain...

Partially Characterized Syndromes

Congenital myasthenic syndrome resembling LEMS Congenital myasthenic syndrome with facial malformations Familial limb girdle myasthenia LEMS, Lambert-Eaton myasthenic syndrome ACh, acetylcholine AChR, acetyl-choline receptor AChE, acetylcholinesterase. upset and at times with no obvious reason. The physical examination is characterized by fatigable weakness. Fixed weakness is usually generalized, but very selective weakness is described. Delayed pupillary responses occur in some cases. Reflexes...

Sympathetic Innervation of the Pupil

In opposition to the pupillary constriction produced by cranial nerve III, the sympathetic system dilates the pupil. The dilator system functions by a reflex arc similar to the sphincter system. The afferent arm, however, is much less circumscribed than the light reflex. Afferent stimulation along pain and temperature pathways from the spinal cord generally causes pupillary dilatation that is abrupt in onset and lasts 20 to 60 seconds. More sustained dilatation often attends mental states...

Directed Neurological Examination

The examination should begin during the clinical history, when there is the opportunity to observe the patient's head, Figure 9-7 (Figure Not Available' , Semischematic diagram of the brain stem pathways and centers that serve horizontal conjugate gaze. Multisynaptic pathways from the right frontal cortex decussate in the midbrain and form synapses in the left pontine paramedian reticular formation (PPRF), which relays innervation to two cell populations within the sixth cranial nerve nucleus....

Syndromes Of Parenchymal Overgrowth Neurocutaneous Syndromes

Neurofibromatosis 1 Tuberous sclerosis Proteus syndrome Klippel-Trenaunay-Weber syndrome Riley-Smith syrdrome Shapiro-Shelman syndrome Linear sebaceous nevus syndrome Generalized Overgrowth Syndromes Sotos' syndrome Ruvalcaba-Myhre-Smith syndrome Beekwith-Wiedemann syndrome Weaver's syndrome Bannayan-Zonana syndrome METABOLIC DISORDERS Alexander's disease Canavan's disease (N-acetyl aspartoacylase deficiency)

Plexopathy

Sensory loss due to a lesion of the brachial plexus will appear in the distribution of two or more peripheral nerves if the lesion is infraclavicular and in the distribution of multiple cervical dermatomes if the lesion is supraclavicular. All sensory modalities may be involved. In radiation-induced plexopathy, 77 percent of patients have upper trunk involvement predominantly that generally occurs 3 months to 26 years after irradiation of the chest. It is quite characteristic to find myokymia...

Grade Description

I Subependymal hemorrhage into one or both germinal matrices II Germinal matrix hemorrhage with intraventricular extension, no hydrocephalus III Germinal matrix hemorrhage with intraventricular extension and hydrocephalus IV Germinal matrix hemorrhage with intraparenchymal extension infants are evaluated for neurological disorders secondary to prematurity. This coupled with primary neurological diseases has led to wide use of US as a leading diagnostic imaging tool in the neurological...

Abnormal Findings and Clinical Uses of FResponse and HReflex Studies

F-response and H-reflex studies are sometimes useful in the evaluation of patients with peripheral neuropathies, Figure 24-23 Diagrammatic representation of the relationship between the direct (M) response, F response, and H reflex, and the intensity of the eliciting stimulus. With low-intensity stimulation of the tibial nerve, an H reflex is elicited from the soleus muscle. As the intensity of stimulation increases, the H reflex declines and a small M wave is seen. With a higher stimulus...

Selected Nonatherosclerotic Occlusive Diseases

Fibromuscular dysplasia (FMD) is a rare condition that affects any or all of the three layers in the arterial walls of both extracranial and intracranial arteries, particularly those of the bilateral ICAs. FMD causes fibrous dysplastic tissue and proliferating smooth muscle cells in the media, presenting as constricting bands and a string-of-beads appearance on arteriography. '1 , y FMD is commonly found in middle-aged women and is most often asymptomatic. Because of its frequent association...

Conduction Apraxia

Patients with conduction apraxia show a greater impairment when imitating movements than when pantomiming to command. Because this constellation of signs was similar to those of the conduction aphasic who repeats poorly, Ochipa and colleagues termed this disorder conduction apraxia. y Patients with conduction apraxia can comprehend examiners' pantomimes and gestures but cannot perform the movements themselves. We, therefore, believe that patients' visual systems can access the movement...

General Management Goals

Beyond the initial stabilization of the patient and the detection of conditions that require immediate specific treatment, the management of patients with altered consciousness is primarily supportive. The responsibility to protect patients from harm runs the gamut from keeping the confused ambulator from wandering away to endotracheal intubation and mechanical ventilation. Making an etiological diagnosis as rapidly as possible may permit specific treatment ( .Table.l-B ).

Pontine Lesions

A unilateral lesion in the brain stem (e.g., stroke, multiple sclerosis, abscess, tumor) may produce dissociated weakness, with ipsilateral weakness of the SCM and contralateral weakness of the trapezius. y In addition, the supranuclear fibers for the SCM muscle probably decussate twice. A lesion in the right side of the pons may result in left-sided weakness (i.e., involvement of the corticospinal tract fibers before their decussation in the medulla) and possible deviation of the head to the...

Category C Severely Symptomatic

Children who have any condition listed in the 1987 surveillance ease definition for acquired immunodeficiency syndrome (with the exception of LIP) Candidiasis, esophageal or pulmonary Mycobacterium, other species or unidentified species Mycobacterium avium complex or M. kansasii Pneumocystis carinii pneumonia Progressive multifocal leukoencephalopathy Salmonella Toxoplasmosis of the brain with onset > 1 month of age Wasting syndrome Adapted from centers for Disease Control and Prevention...

Table 162 Ototoxic Medications

Aspirin and sodium salicylate (cochleotoxic, reversible) Chemotherapy (mainly mixed toxicity) including lack of normal gesturing and spontaneous movements. The face is hypomimetic, with lack of expression, and there is reduced rate of blinking. Rest tremor, if present, is elicited when the hands and feet are completely relaxed. In hyperkinesias, key information is obtained by observing the patient at rest in complete repose without talking. Relaxing these patients and finding the best rest...

Growth Hormone Hypersecretion Museuloskeletal Increas

Ng hat, glove, or shoe sizes prognathism prominent supraorbital ridges coarsening of facial features (e.g, large bulbous nose, thick lips, separated teeth) Endocrine Hyperhidrosis, fatigue, exercise intolerance, hoarseness, sleep apnea (peripheral and central) Cardiopulmonary Hypertension, hyperlipidemia, cholelithiasis, carbohydrate intolerance, overt diabetes, heart disease (e.g., arrhythmias, congestive heart failure, coronary artery disease) Other Arthralgias, slight kyphosis,...

Visual Association Areas

Extrastriate areas V2 and V3 surround V1 above and below the calcarine sulcus. Isolated and clinically apparent lesions of V2 and V3 are unusual, but a combined lesion of V2 and V3 restricted to upper or lower bank typically causes a homonymous quadrantic visual field defect. y Higher cortical processing of visual information occurs in visual association areas, which are divided anatomically and functionally into ventral and dorsal pathways. In general, the ventral stream (occipitotemporal) is...

Tetanus

Tetanus is caused by a powerful exotoxin, Clostridium tetani, which produces spores. The spores can remain dormant in the soil or in animal excrement for many years until they enter the body and produce a toxin. In patients with tetanus toxicity, both the CNS and the PNS as well as the musculature are involved. y The major CNS effect occurs through disinhibition on gray matter gangliosides and through presynaptic antagonism of GABA. At high concentrations,...

Varicella Zoster Virus

Varicella-zoster virus (VZV) is the etiological agent of chickenpox. Von Bokay was the first to observe that susceptible children might develop varicella after exposure to the herpes zoster virus. Joseph Garland, a long-term editor of the New England Journal of Medicine, was the first to suggest that zoster reflected activation of a latent varicella virus. a1 In 1954, Thomas Weller confirmed von Bokay's observation that children develop varicella following...

Conjugate Gaze Palsy Syndromes

Gaze palsies can be divided into disorders of vertical or horizontal gaze and further into nuclear or supranuclear lesions. Horizontal gaze palsies can be divided into impaired saccadic and pursuit eye movements. IMPAIRED CONJUGATE SACCADIC EYE MOVEMENTS The saccade system generates very high velocity ballistic movements called saccades used primarily to examine the elements of a stationary but large or extended visual scene. An adult scans a scene in a highly organized way, extracting data...

Associated Neurological Findings see Xable155

In addition to patterns of weakness and reflex changes, clinical findings in other neural systems will confirm or further help in localizing the source of the weakness. Cerebral. A command center for conjugate gaze is located in each frontal lobe. When one is damaged, the unopposed action of the other causes deviation of the eyes to the side of the lesion and away from the hemiplegia. The motor cortex is very close to Broca's area, and a nonfluent or Broca's aphasia often accompanies a right...

Abnormal Findings and Clinical Uses of Repetitive Nerve Stimulation

Repetitive nerve stimulation is a useful technique for evaluating neuromuscular transmission. In diseases in which such transmission is impaired, the muscle response to repetitive nerve stimulation may show abnormal alterations in size or area. In myasthenia gravis, a progressive decrement in the response may occur with repetitive stimulation (especially at 2 to 3 Hz), or an initial decrement may be followed by a leveling off of the response at a reduced size. Abnormalities are more likely to...

Druginduced

Tions in frequency and amplitude seen in patients with other myotonias. In phenotypically similar cases, in which the electrical activity closely resembles that noted in myotonia, the likely diagnosis is myotonia permanans.pl In all these conditions, muscle biopsy shows few abnormalities, although there may be variations in fiber size with fiber hypertrophy and increased central nuclei. In paramyotonia congenita with hyperkalemic periodic paralysis, vacuolated and necrotic fibers may occur. In...

Cobalamin Vitamin B12

Vitamin B12 deficiency produces neurological and hematological effects by impairing the function of two enzyme systems (Fig. 40-5 (Figure Not Available) ). y , y Methylcobalamin is a co-factor of methionine synthase, a cytosolic enzyme that catalyzes the conversion of homocysteine and methyltetrahydrofolate to produce methionine and tetrahydrofolate. Methionine is further metabolized to S-adenosylmethionine, which is necessary for methylation of myelin sheath...

Subacute Necrotizing Encephalomyelopathy Leighs Disease

At the molecular level, Leigh's disease can be caused by both mendelian (autosomal recessive nuclear coded DNA) and mtDNA defects.y , y Areas affected are primarily the basal ganglia, brain stem, and cerebellum. The cerebral cortex and retinal pigment are less involved. Pathologically, there is spongy degeneration, demyelination, gliosis, necrosis, relative sparing of neurons, and capillary proliferation. Several enzyme complexes involved in mitochondrial...

Huntingtons Disease

The cognitive impairment in HD, like other subcortical dementias, primarily reflects frontostriatal dysfunction, and there is pathological evidence of both subcortical and cortical pathology. Grossly, the cortical gyri appear normal to slightly atrophic. Coronal sections reveal striking caudate greater than putamen and pallidum atrophy. Neuronal loss and gliosis follow the same regional distribution. The medium-sized spiny type I striatal neurons are...

Neuronal Ceroidlipofuscinoses

Neuronal ceroid-lipofuscinoses (NCLs) are a group of diseases characterized by neurological symptoms and the accumulation of autofluorescent waxy lipopigments within the lysosomes of neurons and other cells. The disorders are linked to a number of celebrated names in neurological history, including Batten, Jansky, Bielschowsky, Santavuori, and Kuf, each of whom described clinical variants of these multidimensional disorders. The conglomerate term neuronal ceroid-lipofuscinoses was coined by...

Spinal Cord Myelopathy

Generally with transverse lesions of the spinal cord there is a demonstrable sensory level with bilateral loss of all modalities of sensation below a definite level. With involvement of the dorsal columns there is loss of proprioception, discriminative modalities, and vibration within a couple of levels caudad to the lesion site. With smaller lesions it is possible to selectively involve certain dorsal column modalities owing to the topographical distribution of the various modalities fibers...