Retina

Retina-related visual loss is usually painless and, in the acute setting, is almost always associated with some abnormality TABLE 8-3 -- SELECTED ETIOLOGIES ASSOCIATED WITH DISORDERS OF CRANIAL NERVE II AND AFFERENT VISUAL PATHWAYS TABLE 8-3 -- SELECTED ETIOLOGIES ASSOCIATED WITH DISORDERS OF CRANIAL NERVE II AND AFFERENT VISUAL PATHWAYS Storage diseases lipidoses, glycogen disorders, and leukoencephalopatbies Adrenoleukodystrophy, Niemann-Pick disease, Amino organic acidopathies, mitochondrial...

Organophosphate Insecticides

Organophosphates inhibit acetylcholinesterase and pseudocholinesterase. Insecticides that are cholinesterase inhibitors include chlorpyrifos (Dursban), diazinon, malathion, ethyl and methyl parathion, and trichlorofon. y The neurotoxicity of these compounds is related to their ability to inhibit acetylcholinesterase, which occurs in the brain, spinal cord, myoneural junctions, pre- and postganglionic parasympathetic synapses, and preganglionic and some...

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...

Disease and Enzymes

Maple symp urine disease branched-chain alpha-keto acid dehydrogenase (E1, E2, and E3 subunits) E1alpha l9ql3 1-ql3 2 E* 6p21-p22 E2 Propionicacidemia propionyl-CoA carboxylase Methylmalonicacidemia methylmalonyl-CoA mutase, hydroxycobalamin reductases, adenosyl transferase and Urea cycle disorders carbamoylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), argininosuccinic acid Classic PKU phenyllalanine hydroxylase Biopterin-dependent PKU GTP cyclohydrolase, 6-pyruvoyl...

Monosodium Glutamate

In 1968, Kowk, a Chinese physician, described a transient neurological syndrome that occurred when he ate at American-Chinese restaurants. He suggested that monosodium glutamate could be the provoking agent because this product is used widely in Chinese restaurants to enhance the flavor of food. The pathophysiology of the syndrome has been suggested to relate to glutamate. As an excitatory agent, glutamate may alter synaptic transmission. Some authors suggest that the symptoms of monosodium...

References

Rotbart HA, Sawyer MH, Fast S, Lewinski C Diagnosis of enteroviral meningitis by using PCR with a colorimetric microwell detection assay. j Clin Micro 1994 32 2590-2592 2. Rotbart HA Enteroviral infections of the central nervous system. Clin Infect Dis 1995 20 971-981 3. Morrison LA, Fields BN Parallel mechanisms in neuropathogenesis of enteric virus infections. j Virol 1991 65 2767-2772 4. McKinney RE, Katz SL, Wilfert CM Chronic enteroviral meningoencephalitis in agammaglobulinemic patients....

Renal Failure

The kidney is one of the principle homeostatic organs of the body and is involved in the regulation of water, electrolyte, and acid-base balance the excretion of metabolic waste products and the synthesis of erythropoietin, renin, and 1,25-DHCC. This section focuses on the neurological manifestations of RF, both acute (ARF) and chronic (CRF), and the neurological complications of its treatment. Pathogenesis and Pathophysiology. UE regularly occurs when the glomerular filtration rate falls below...

Medical Findings

Ipsilatral weakness of the sternocleidomastoid and trapezius muscles, and atrophy and weakness of the ipsilateral tongue Ipsilateral weakness of the sternoeleidomastoid and trapezius muscles Atrophy and weakness of the ipsilateral tongue Ipsilateral paralysis of the Sternoeleidomastoid and trapezius muscles Ipsilateral weakness of the sternoeleidomastoid and trapezius muscles, and atrophy and weakness of the ipsilateral tongue Ipsilateral weakness of the sternocleidomastoid and trapezills...

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an immune complex disease. The most important autoantibody in RA is the rheumatoid factor, an antibody, usually of the IgM or IgG class, which reacts with immunoglobulins. The original triggering mechanism may be exposure to a microbial antigen. Autoantibodies to other cellular antigens such as histones, single-stranded DNA, filaments, collagen, and nuclear antigens have been described. Immune complexes composed of IgG combined with...

Pyridoxine Vitamin B6

Pyridoxal phosphate is the active biochemical form of pyridoxine. It is a coenzyme of amino acid metabolism, particularly tryptophan and methionine. By inhibiting methionine metabolism, excessive S-adenosylmethionine accumulates, which inhibits nerve lipid and myelin synthesis. y Because tryptophan is required in the production of niacin, pyridoxine deficiency can produce a secondary niacin deficiency indistinguishable from primary pellagra. Pyridoxine is also involved in lipid and...

History And Definitions

In an attempt to distinguish the class of motor disturbances resulting from lesions of the basal ganglia, Kinnier Wilson coined the term extrapyramidal in his famous 1912 articled describing hepatolenticular degeneration, now known as Wilson's disease. This term was widely adopted thereafter and continues to be used today. The extrapyramidal system refers to the basal ganglia with their anatomical connections, and extrapyramidal disorders are hypokinetic and hyperkinetic states that ensue from...

Evaluation Guidelines

In virtually every patient who presents with overt or subtle manifestations of trigeminal nerve dysfunction, some form of laboratory evaluation is indicated ( Table 10-2 ). Careful and directed neurological examination dictates the most important tests to obtain. Neuroimaging. Once a lesion has been reasonably localized to the cortex, white matter pathways, thalamus, or brain stem, neuroimaging is essential to support a definitive clinical diagnosis (for complete text, see reference 'i )....

Associated Medical Findings

The skin should be checked for rashes, lesions, or evidence of insect bites. The head and neck should be examined for masses, signs of trauma, or postoperative scars. The auricle and ear canal should be examined thoroughly for vesicles, ulcers, or other lesions. The tympanic membrane should be checked for perforation, drainage, or cholesteatoma. Infections, neoplasms, and evidence of prior otological surgery should be sought while examining the middle ear. The oral cavity and pharynx should be...

Evaluation Guidelines Table132

Lesions of the medulla such as infarction or neoplasm, or extramedullary, intracranial lesions, are better visualized by magnetic resonance imaging (MRI) than by computer-assisted tomography (CT). Some lesions that involve bone, especially the skull base, may be detected by CT or radiographs, the latter usually requiring the neurologist to request special views of the base of the skull. Imaging should be employed to assist in defining lesion type when the clinical examination...

Evaluation Guidelines Table142

The following tests may aid in the diagnosis of problems affecting the eleventh and twelfth cranial nerves. Neuroimaging. Various neuroimaging studies may be useful. y y Plain films of the skull may provide diagnostic information in platybasia (flattening of the base of the skull so that the angle formed by an imaginary line connecting the anterior margin of the foramen magnum, the tuberculum sella, and the nasion is greater than 143 degrees), Paget's disease (areas of increased and decreased...

Clinical History

Because cranial nerves III, IV, and VI innervate the extraocular muscles that move the eyes, the striated muscles that elevate the upper eyelids, and the iris sphincters that constrict the pupils, several symptoms develop when damage occurs. In general, dysfunction of these nerves causes different combinations of binocular double vision from misalignment of the visual axes. Damage to cranial nerve III causes ptosis from weakness of the levator palpebrae muscle, as well as pupil mydriasis or...

Preferential Atrophy

Type 1 fibers Myotonic dystrophy (prominent), nemaline myopathy, centronuclear myopathy, congenital fiber type disproportion Type 2 (especially 2B) fibers Disuse, corticosteroid excess (exogenous, endogenous)* CYTOARCHITECTURAL ABNORMALITIES Type 1 fibers Target fibers, central cores (central core disease), rod bodies (nemaline myopathy), motichondrial abnormalities Type 2 fibers Tubular aggregates *Type fiber atrophy, especially if limited to type 2B fibers, is a nonspecific finding most...

Specific Indications

Categories of CNS disease amenable to diagnosis by brain biopsy or mimicking types of disease normally presenting as neurosurgical conditions are summarized in Table 25-8 . This disorder can be grouped into conditions that present with mass lesions, focal or multifocal nonmass TABLE 25-8 -- BRAIN AND MENINGEAL BIOPSY DIAGNOSES TABLE 25-8 -- BRAIN AND MENINGEAL BIOPSY DIAGNOSES Gliomas, metastatic tumors, CNS lymphoma HIV encephalitis, opportunistic infections (toxoplasma, cytomegalovirus,...

Laboratory Test

Morning ACTH Fasting am cortisol 24-hour urine free cortisol Dexamethasone suppression test a Test results may be altered by pharmacological agents.b Tests should be performed and related to normal values for timing of menstrual cycle. infectious causes of problems, including sarcoidosis, histiocytosis X, bacterial meningitis, tuberculosis, or abscess, are typically resolved by the presence of other findings of these diseases. Lymphocytic hypophysitis and Sheehan's syndrome often occur in the...

Types of Detectable Abnormalities

The use of water-soluble intrathecal contrast medium has markedly decreased over the past 10 to 15 years with the introduction of CT and, more recently, MRI. Before these more advanced imaging tools, water-soluble myelography was the gold standard in evaluating patients with back pain and had the ability to evaluate spinal stenosis, disc bulges and herniations, other extradural impressions on the thecal sac, spinal cord enlargement, and various inflammatory conditions. However, intrathecal...

Basic Principles and Techniques

Diagnostic neuroangiography is the study of the central nervous blood vessels and related cervicocerebral vasculature using radiographs during the injection of intravascular contrast media. Cerebral angiography was first introduced by Moniz in 1927 and remains a vital tool in the neuroradiological evaluation of cerebrovascular diseases. Although neuroangiography had been historically used to evaluate many types of central nervous system diseases, CT and MRI have largely supplanted diagnostic...

Abetalipoproteinemia Bassen Kornzweig Syndrome

This autosomal recessive lipid disorder develops clinically in the first decade of life with steatorrhea, distal sensorimotor neuropathy, and retinitis pigmentosa. Ataxia, dysarthria, areflexia, and ophthalmoparesis may also develop. y Serum cholesterol levels are low, betalipoproteins are low or absent, and erythrocytes take on the appearance of acanthocytes. Ihe primary metabolic defect relates to the inability to synthesize betalipoprotein, the major protein of chylomicrons and very low...

Additional Brain Stem Cortical Loops

A series of anatomical loops have been identified that are involved in the genesis of myoclonus, presumably through transmission of aberrant electrical discharges. A cortical loop has been proposed involving diffuse areas of the cortex, but predominantly the sensorimotor area, the pyramidal tract, medial lemniscus, and thalamus, with return fibers to the cortex. Complementing and interacting with the cortical loop is the spino-bulbar-spinal reflex, which primarily involves the brain stem...

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...

Affective Disorder Syndromes

When secondary causes have been sufficiently evaluated, treatment of depression can be initiated. Treatment may include psychological therapies (supportive psychotherapy and behavior therapy) as well as pharmacological agents. Nearly 80 percent of patients with major and most chronic minor depressions respond to drug therapy, including tricyclic antidepressants, specific serotonin reuptake inhibitors, and MAO inhibitors. Electroconvulsive therapy may be necessary if medications fail or their...

Afferent Autonomic Pathways

Visceral afferents transmit conscious sensations (e.g., gut distention, cardiac ischemia) and unconscious visceral sensations (e.g., blood pressure, chemical composition of the blood). Their most important function is to initiate autonomic reflexes at the local, ganglion, spinal, and supraspinal levels. y Visceral receptors are innervated by small myelinated and unmyelinated fibers that have cell bodies in the dorsal root ganglia of the spinal or cranial nerves. Spinal visceral afferents are...

Alkylating Agents

Nitrogen mustard (NM) administered intravenously in a dose of 0.4 mg kg is not usually associated with neurotoxicity. Hemiplegia, coma, chills, and fever, with increased intracranial pressure and CSF pleocytosis, however, were reported in one patient 7 days after each of two standard intravenous doses of NM (0.4 mg kg). y On both occasions the signs and symptoms subsided after therapeutic measures to decrease intracranial pressure. When the patient died four years later, from unrelated reasons,...

Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS), which is also called motor neuron disease, Charcot's disease, or Lou Gehrig's disease, is an age-dependent fatal paralytic disorder caused by the degeneration of motor neurons in the motor cortex, brain stem, and spinal cord. About 10 percent of cases are familial (FALS) and the rest are sporadic (SALS). Pathogenesis and Pathophysiology. ALS is a combined gray and white matter disease, affecting motor cells and motor fiber tracts. The hallmark of ALS is...

Anatomy

The choroid plexus produces the majority of the CSF in addition to smaller amounts secreted by the ependyma and the perivascular spaces. The choroid plexus is derived embryologically from the neural epithelium and is composed of two layers including a specialized ependymal cell layer composed of the epithelial lining of the ventricular system and a highly vascularized pia mater layer. This bilayered structure, known as the choroidal epithelium, is folded into microvilli and forms a brush border...

Anatomy of Declarative Memory

A broad convergence of human and animal research indicates that declarative memory depends on an interaction between domain-specific neocortical regions and domain-independent medial-temporal, diencephalic, and basal forebrain regions. Long-term memories are thought to be stored in the neocortex, the neocortical location reflecting the content of the memory. Thus, knowledge about the visual appearance of a tool may be stored separately, TABLE 5-1 -- CLINICO-ANATOMICAL CORRELATIONS OF MEMORY...

Anatomy Of Gait And BalancedabJe181

Normal gait and posture depend on the normal function of various structures along the entire neuroaxis. This includes the cortical, subcortical, and spinal cord regions as well as the final common pathway of motor neurons, the neuromuscular junctions and the muscles they innervate. The anatomy and neurological examination of the motor, sensory, cerebellar, and basal gangliar components of normal gait and posture are addressed in specific chapters. This chapter integrates the function of those...

Anatomy of Nondeclarative Memory

Whereas declarative memory depends on the integrity of a limited number of brain regions, nondeclarative memory encompasses all other forms of memory mediated by all other brain regions. In this sense, nondeclarative memory may be described as more diffuse in its neural representation. Each specific form of nondeclarative memory, however, is closely linked to specific brain structures and regions. Immediate memory stores appear to be located in posterior neocortical regions, the location...

Anatomy Of The Autonomic Nervous System

The term autonomic (autonomous, self-governing) nervous system was introduced to describe the system of nerves which controls the unstriated tissue, the cardiac muscle and the glandular tissue of mammals. 2 Originally, the term applied only to neurons with axons outside the central nervous system (CNS). More recently, the discovery that discrete neuronal groups in the brain stem, diencephalon, and cerebral cortex are involved in the control of autonomic function has broadened the definition of...

Anatomy of the Saccade System

Three important cortical areas are involved with saccade generation and include the frontal eye fields (FEF), the supplementary eye fields (SEF), and the parietal eye fields (PEF). Other zones of the association cortex that play a secondary, but important role in saccade generation are the prefrontal cortex (PFC) and posterior parietal cortex. The interrelationships of these structures are complex and are summarized with a clinical emphasis (Fig. 9-6 (Figure Not Available) ). y The FEF is...

Antimetabolites

Methotrexate is a competitive inhibitor of dihydrofolate reductase, acting primarily during DNA synthesis (S-phase) as an antifolate antineoplastic drug. It prevents two primary reactions, the conversion of folic acid to tetrahydrofolic acid and the conversion of tetrahydrofolic acid to folinic acid, therefore blocking DNA, RNA, and protein synthesis by limiting the availability of reduced folates. 1 , y , y As an oral or intravenous drug in the usual prescribed doses, methotrexate is a...

Antituberculous Drugs

Isoniazid inhibits the phosphorylation of pyridoxine and chelates whatever pyridoxal phosphate remains. Because pyridoxal phosphate is a co-factor that is important to the GABA system, it has been hypothesized that the centrally diminished GABA activity may relate to the pathophysiology of isoniazid-induced seizures. In chronic toxicity, isoniazid predominantly inhibits the phosphorylation of pyridoxine to induce a peripheral neuropathy. ' ' The incidence of pyridoxine-associated polyneuropathy...

Associated Neurological Findings

With regard to CN XI or XII, bihemispherical lesions may result in significant weakness of the SCM, trapezeii, or extrinsic tongue muscles. Other features that confirm the presence of bihemispherical lesions are urinary incontinence, gait apraxia, pseudobulbar palsy (i.e., dysarthria, dysphagia, and emotional incontinence), cognitive deficits, and alterations in personality. Cranial Nerves. Dysfunction of neck or tongue musculature may be the result of lesions in the brain stem...

Associated Neurological Findings see IabJe155

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...

Asymmetrical Cortical Degeneration Syndromes

This is a heterogeneous group of disorders that produce distinctive cortical syndromes including aphasia, apraxia, and agnosia but that have a more focal appearance than Alzheimer's dementia. They can be roughly localized by the more focal features, though only a small subset are truly focal. There are four primary categories, each with several subtypes, including progressive aphasia, progressive frontal lobe frontotemporal syndromes, progressive perceptual-motor syndromes, and progressive...

Autonomic Innervation of Specific Organs

The heart receives parasympathetic and sympathetic innervation. The cell bodies of the parasympathetic preganglionic neurons innervating the heart are located in the medulla (nucleus ambiguous and dorsal motor nucleus of the vagus). The axons of these neurons, which are part of the vagus nerve, join the cardiac neural plexus after entering the thorax to synapse with neurons in the intracardiac ganglia. y From these ganglia, short postganglionic parasympathetic neurons emerge to innervate the...

Autosomal Dominant Inheritance

Bilateral asymmetrical areas of hypopigmented whorls (marbling) central nervous system, eye, tooth, skin, nail, and bone anomalies Mukiple angiomas of skin and mucous membranes that are dilations of capillaries and venules bleeding from any site nose, gastrointestinal, pulmonary, and urinary systems Frontal patch of white hair, heterochromia iridis, lateral displacement of inner canthus, and at times, cochlear deafness Clinical findings are similar to type I without the lateral displacement of...

Basic Mechanisms Of Epileptogenesis

To understand the mechanisms related to the development of epilepsy, some basic principles of normal neurophysiology must be reviewed. Electrical signals in neurons take two forms the action potential, which propagates down the axon of the neuron from the soma to the axon terminal translocating information within a neuron and transmission of information between neurons, which is accomplished primarily by chemical synapses. A complex series of events underlie these electrical signals. Central to...

Botulism

Botulism is the most potent poison known to man. It is produced by the spores of Clostridium botulinum. Three distinct varieties of the disease exist. Foodborne botulism results primarily from the ingestion of contaminated home-canned fruits and vegetables. Since this type of botulinum toxin is produced by spores that are already formed and ingested, toxic signs appear rapidly, usually between 8 and 36 hours after ingestion, and an incubation period is not...

Brain Embolism

There are three major types of embolism--cardiogenic, intra-arterial, and paradoxical (.Fig, 45.-7.). Emboli from any source tend to be arrested in a recipient artery, depending on the location of branch points and the size of the embolic material. Once lodged, embolic matter often migrates distally within 48 hours, allowing reperfusion of the previously ischemic zone. This reperfusion frequently causes extravasation of blood through the disintegrated...

Brain Stem

The brain stem has three important functions in balance and locomotion (1) setting the activity of the spinal central pattern generators to determine the initiation and speed of locomotion (2) setting postural tone and (3) modulating the force generated by the muscles activated by the central pattern generators. Control of the spinal cord central pattern generators is exerted by the subthalamic and midbrain locomotor regions and relayed to the spinal cord by the reticulospinal tracts. The...

Carnitine Palmitoyl Transferase II Deficiency

In CPI II deficiency, long-chain acylcarnitines are transported across the inner mitochondrial membrane but cannot be converted to their corresponding long-chain acyl- CoAs. They accumulate in the mitochondrial matrix and are transported out into plasma. Ihese elevated levels may produce cardiac arrhythmias. Dicarboxylicaciduria is absent, because of the same explanation given for carnitine transport defect. Ihe exact incidence is unknown, but the adult form is more common than the infantile...

Cat Scratch Disease

Cat-scratch disease is caused by the bacterium Bartonella henselae and begins with a cutaneous papule or pustule at the site of inoculation, usually a kitten scratch or bite, within a week of the injury. A regional adenopathy involving the head, neck, and upper extremity follows in 1 to 7 weeks. Fever and malaise occurs in approximately one third of patients. The diagnosis is made by demonstrating pleomorphic bacilli by Warthin-Starry silver stain of a lymph node biopsy or by polymerase chain...

Central Autonomic Network

The ANS, like the somatic nervous system, is organized in segmental levels. Neurons in the cerebral cortex, basal forebrain, hypothalamus, midbrain, pons, and medulla participate in autonomic control. Autonomic neurons are reciprocally interconnected by neurochemically complex pathways and constitute a functional unit referred to as the central autonomic network (CAN).y , 4 The CAN integrates visceral, humoral, and environmental information to produce coordinated autonomic, neuroendocrine, and...

Cerebellar Afferents

The cerebellar cortex receives afferent input from most parts of the peripheral (proprioceptive, cutaneous, vestibular, and visual, except olfactory) and central nervous system. The afferent fibers consist of mossy fibers, the climbing fibers, and monoaminergic fibers. The two most important types of excitatory cerebellar afferents, mossy and climbing fibers, have been defined based on the morphology of their terminal fibers. Mossy * The term interposed nucleus refers to the cerebellum in the...

Cerebellar Efferents

The cerebellar nuclei are the principal source of cerebellar efferent fibers. The efferent fibers from the cerebellum are distributed to several parts of the central nervous system (see Fig 17-3 ). Cerebellar output is essentially ipsilateral. Most of the efferents leave the cerebellum via the superior cerebellar peduncle and a few via the inferior cerebellar peduncle. Efferent cerebellar pathways descend to the brain stem and spinal cord, and ascend to the cerebral cortex. Efferents from the...

Proprioception Touch and Vibratory Sensation

History and Definitions Clinical History Anatomy of Proprioception, Touch, and Vibratory Senses Receptors First-Order Neuron Second-Order Neuron Third-Order Neuron Spinocerebellar Pathways Discriminative Touch, Vibration, Conscious Sense of Joint Muscle Movement Light Touch and Pressure Examination of the Position, Touch, and Vibratory Sensory Systems Directed Neurological Examination Associated Neurological Findings Associated Medical Findings Evaluation Guidelines Clinical Syndromes...

Pain and Temperature

Cea Mario Campero Jose L. Castillo History and Definitions Clinical History Anatomy of Pain and Temperature Sensation Receptors First-Order Neurons Second-Order Neurons Third-Order Neurons Pain Control Mechanisms in the Central Nervous System Gate Control Theory Examination of Pain and Temperature Sensory Systems Sensitization of C-Polymodal Nociceptors Central Spinal Cord Syndrome Syringomyelia Cauda Equina Versus Conus Medullaris Syndrome Combined Radicular and...

Cerebrospinal Fluid and Intracranial Pressure

Cerebrospinal Fluid and the Ventricular System Normal and Pathological Findings Intracranial Pressure Treatment of Increased Intracranial Pressure Reviews and Selected Updates References The cerebrospinal fluid (CSF) has served as an aid to the diagnosis and treatment of a variety of central nervous system (CNS) disorders for more than 100 years. In 1891, Quinke first developed the technique of spinal puncture and introduced it into clinical practice. i He was the first to use a needle with a...

Traumatic Disorders

Acute Head Injury Postconcussion Syndrome Cranial Neuropathies Post-traumatic Epilepsy Post-traumatic Movement Disorders Spinal Cord Injury Whiplash Injuries Brachial and Lumbosacral Plexopathies Reflex Sympathetic Dystrophy and Causalgia Disorders due to head, spine, and peripheral nerve injuries are among the most commonly seen by neurologists. The impact of these injuries can be devastating for individuals and society, because injuries occurring in a fraction of time can result in death or...

Clinical Syndromes

Syndrome of Diffuse Excitation of Internuncial Pool Progressive Spinal Muscular Atrophy Syndromes Peripheral Neuropathy and Mononeuropathy Syndromes Combined Upper and Lower Motor Neuron Syndromes Motor Neuron Syndromes Myelopathic Syndromes Neuromuscular Junction Syndromes Myasthenia Gravis Myasthenic Syndrome (Eaton-Lambert Syndrome) Other Disorders of the Neuromuscular Junction Myopathic Syndromes Syndrome of Acute Generalized Weakness

Clinical Uses of the EEG

The EEG is useful in the evaluation of patients with several types of neurological disorders, including seizures, encephalopathy, and focal cerebral abnormalities. It also provides an ancillary aid to the diagnosis of brain death and may suggest certain specific neurological diagnoses when characteristic EEG findings are recorded in patients with clinical disorders of uncertain nature. The EEG is important in the evaluation of patients with known or suspected epilepsy. The interictal occurrence...

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...

Cognition and Memory

Cognition refers to the mental processes of knowing, including high-level perception, language, and reasoning. Cognitive processes may be dichotomized as crystallized or fluid. y Crystallized processes involve the application of well-established knowledge and well-practiced routines, such as vocabulary knowledge. Fluid processes are invoked when a problem must be solved with a novel, flexible strategy, such as reasoning. Fluid processes are far more dependent on working memory capacity than...

Comments

Facial weakness rarely seen as sole finding. Spasticity and hyperreflexia are found The lesion is below the facial decussation and above the corticospinal decussation. If congenital, may see anomalies of the ear or jaw CN VlII is usually involved, and its symptoms are usually the chief complaint, especially unilateral hearing loss. As lesions enlarge, other structures are involved Signs and symptoms from CN Vll and CN Vlll only When the facial canal is involved, the cochlea and or the...

Conceptual Apraxia

Whereas patients with ideomotor apraxia make production errors (e.g., spatial and temporal errors), patients with conceptual apraxia make content and tool selection errors. These patients may not recall the type of actions associated with specific tools, utensils, or objects (tool-object action knowledge) and therefore make content errors.y , y For example, when asked to demonstrate the use of a screwdriver, either pantomiming or using the tool, the patient who has lost tool-object action...

Congenital Myopathies

The initial definition of the so-called congenital myopathies implied the onset at birth of a nonprogressive primary myopathy, that could not be explained on the basis of a dystrophic or metabolic abnormality. However, in some morphologically and genetically identical cases, no symptoms are not present at birth and instead occur later. Furthermore, some cases of congenital myopathies such as nemaline myopathy and centronuclear myopathy are characterized by progressive weakness with a fatal...

Coronary Artery Bypass Graft Surgery

Coronary artery bypass graft (CABG) surgery is the most frequently performed cardiac surgery in North America, with nearly 400,000 procedures performed annually in the United States and Canada. '751 Early retrospective studies of open heart surgery found that stroke and anoxic encephalopathy were common postoperative neurological complications occurring in more than 20 percent of patients. Improvement in surgery and extracorporeal circulation may have initially reduced the frequency of...

Craniopharyngioma

Craniopharyngiomas are thought to be congenitally derived and to arise from remnants of Rathke's pouch. Embryonic collections of epithelial cells remain after absorption of the hypophysealpharyngeal duct, from which the infundibulum tuber cinereum is derived ( Fig , 4.6. 8 ). The squamous cells are found to be metaplastic and may be present for a significant period before transformation occurs. Alternative proposals suggest that these tumors are derived from a...

Deficiency Amblyopia

This disorder is most likely related to the depletion of one or more B vitamins, although none has been specifically implicated. Deficiency amblyopia occurs only after severe and prolonged nutritional deprivation. The strict dietary deficiencies required to produce amblyopia are known to occur mainly in mistreated prisoners of war and alcoholics. Smoking tobacco was once considered another risk factor (hence, the alias tobacco-alcohol amblyopia), but this is no longer believed to be true....

Definitions

Sleep occupies approximately one third of the adult life. Although the function of sleep is not understood, the inherent necessity for sleep is widely recognized and is present in almost all mammals. The notion that sleep is a time of rest and brain inactivity persisted until the 20th century when electrophysiological techniques were applied to the study of sleep. Thereafter sleep was found to be a dynamic process, with the cyclical recurrence of different stages. The discovery of rapid eye...

Degenerative Muscular Disorders

The muscular dystrophies are hereditary, degenerative dystrophinopathies and disorders of dystrophin-associated proteins. In 1987, with the identification of a defect in the dystrophin gene as the cause of Duchenne muscular dystrophy (DMD), Monaco and Kunkel opened the door TABLE 36-4 -- FAMILIAL SPASTIC PARAPLEGIA (SPG), GE AR, Autosomal recessive AD, autosomal dominant, LICAM, L1 cell adhesion molecule. for research into its role in muscle function and maintenance. Dystrophin is controlled by...

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....

Diagnostie Criteria for Neurofibromatosis

Six or more cafe au lait macules over 5 mm in greatest diameter in prepubertal individuals and over 15 mm in greatest diameter in postpubertal individuals Two or more neurofibromas of any type or one plexiform neuroma Freckling in the axillary or inguinal region Optic glioma Two or more Lisch nodules (iris hamartomas) Distinctive osseous lesion such as sphenoidal dysplasia or thinning of long bone cortex with or without pseudoarthrosis First-degree relative (parent, sibling, or offspring) with...

Diffuse Hypoperfusion Syndromes Cerebral and Spinal Cord

As discussed in the section on arterial anatomy, the midthoracic spinal cord is a border zone or watershed area that is susceptible to ischemia due to the unequal blood supply in this region. In situations of systemic hypoperfusion, there can be a spinal cord infarction. Conditions such as an aortic dissection can also cause a global decrease in spinal cord perfusion that results in gray matter infarction with relative sparing of the white matter tracts. There can be border zone or watershed...

Directed Neurological Examination Assessment Of Muscle Bulk

The patient should be in a state of sufficient undress for the physician to be able to appreciate his or her general bodily habitus and especially the muscle bulk of the extremities. Before actual testing of muscle strength begins, simple observation may disclose asymmetries in muscle bulk of the extremities or more focal atrophy of specific muscles or muscle groups. The upper extremities should be inspected in both the pronated and supinated positions, which is especially important to...

Directed Neurological Examination

Essential components of the directed physical examination include a neurological evaluation emphasizing the cranial nerves and orbital contents (to direct attention to lesions of the skull base) as well as a general evaluation of the ears, upper respiratory tract, and head and neck. Although much can be gained by evaluating the nose using anterior rhinoscopy, nasal endoscopy allows a more thorough assessment. With this procedure, the rhinologist can often directly visualize the olfactory...

Directed Neurological Examination Cranial Nerve Ix

The functions of the glossopharyngeal nerve overlap with those of other cranial nerves, making it difficult to test in isolation. Motor. The sole skeletal muscle innervation of cranial nerve IX is the stylopharyngeus, which aids in elevation of the pharynx. The oral cavity should be inspected visually at rest to ascertain whether asymmetrical lowering of the pharynx is present. The pharynx is elevated also by the palatopharyngeus and salpingopharyngeus muscles, both of which derive their nerve...

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...

Directed Neurological Examination MOTOR

First, the clinician should observe the patient at rest for symmetry and the presence of any involuntary movements (e.g., fasciculations, tics). Signs of facial weakness include flattening of the nasolabial groove, slower blinking, and loss of facial wrinkles. Next, clinicians should check the amount of voluntary motion in each of the five peripheral branches by having the patient perform the following (1) temporal--raise the eyebrows, wrinkle the brow (2) zygomatic--close the eyes gently, and...

Directed Neurological Examination Overview

The examination of the patient with altered consciousness begins by ensuring that the patient's vital signs and basic biochemistry are adequate to support brain function. It is essential to ensure that blood pressure, respiration, and oxygen saturation are adequate and that the patient is not hypoglycemic or thiamine deficient before proceeding with the examination outlined later. In many situations (e.g., emergency departments), naloxone is also administered at this point to reverse any...

Directed Neurological Examination Sensory Function Of Cranial Nerve V

When assessing the trigeminal system, it is important to perform a directed and assiduous neurological examination because subtle alterations in function may provide clues to detect potentially serious neurological disease. Sensory and motor components should be tested separately, comparing right and left sides, and light touch, pin, and temperature sensation should be tested individually in V1 to V3. The cornea and sclera should be inspected for evidence of keratitis, which may be suggestive...

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...

Disorders of Later Infancy with Recurrent Metabolic Crises

Late-onset disease has been described in patients with CPS, OTC, ASA synthetase, AS lyase, and arginase deficiencies. They will appear from the first year of life to adulthood with abrupt episodes of acute hyperammonemia. Initial crisis will occur usually when the infant is weaned from breast milk or from low-protein formulas to cow's milk formulas. Decompensation can also occur when the patient ingests a high protein load or experiences increased catabolism...

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...

Dysarthria

Dysarthria is the inability to form or produce understandable speech due to lack of motor control over peripheral -- USEFUL STUDIES IN THE EVALUA riON OF SPEECH AND LANGUAGE DISORDERS Mass lesion compressing the tenth cranial nerve, or on the vocal cords Abnormal decrement of CMAP with repetitive stimulation in myasthenia gravis. Single-fiber EMG showing jitter in NMJ defects Carcinoma of the vocal cords, carcinomatous meningitis Normal language and cognitive function Vocal cord pathology...

Dysosmia

Dysosmia (disordered smell perception) presents as either a distortion in the perceived quality of an odor ( parosmia, cacosmia) or as the presence of a strange odor in the absence of actual odor stimulation (phantosmia or olfactory hallucinations). Most dysosmias reflect dynamic elements associated with degeneration (or, more rarely, regeneration) of the olfactory epithelium and remit over time. However, it is common for patients with anosmia to report that prior to the onset of anosmia they...

Dyssynergy Synergy Syndromes

Although locomotor synergies, the basic patterns of muscle contraction and relaxation that produce coordinated rhythmic stepping, exist in the spinal cord, dyssynergies resulting from discrete spinal lesions are not recognized clinically. This is partly because spinal lesions that would disrupt the central pattern generators would probably affect TABLE 18-2 -- USEFUL STUDIES IN THE EVALUATION OF DISORDERS OF GAIT AND

Emery Dreifuss Muscular Dystrophy

ED MD, which is characterized by early contractures and cardiomyopathy, was first identified as a distinct form of muscular dystrophy in a large Virginia family in 1966.y Generally it is X-linked recessive, although there is an autosomal dominant form, sometimes called Hauptmann-Tannhauser muscular dystrophy. y The incidence of the X-linked type is estimated to be about 1 in 100,000, with the autosomal dominant form being even more rare. One of 10 new X-linked cases may be a new mutation.y In...

Emotionalpersonality Functions

Symptom Checklist 90-Revised Millon Clinical Mulhaxial Inventory Minnesota Multiphasic Personality Inventory-Second Edition (MMPI-2) disease processes may present with a similar neurocognitive picture. Consideration of this issue is particularly important because HIV-infected individuals quite often present with histories that include other problems (e.g., alcohol drug abuse, depression and other psychiatric disorders, learning disabilities, head injury). In addition, concurrent CNS processes...

Examination of the Neurovascular System

Directed Neurological Examination Associated Neurological Findings Evaluation Guidelines Clinical Syndromes Diffuse Hypoperfusion Syndromes (Cerebral and Spinal Cord) Extracranial Steal Syndromes from Disease of the Aortic Branches Posterior Inferior Cerebellar Artery Syndrome Anterior Inferior Cerebellar Artery Syndrome Midline Basilar Artery Syndromes Midbrain Midline Vertebrobasilar Syndromes Pons Lateral and Combined Vertebrobasilar Syndromes Midline Vertebrobasilar Syndrome Medulla...

Executive Function and Motor Performance

Traditionally, executive functions have been ascribed to the frontal lobes. They involve the ability to assess ongoing stimuli for relevance to specific goals, the formation of goals, planning action to achieve goals, ability to evaluate plans for efficacy, and executing plans. According to this description, executive functions involve many processes associated with reasoning and intellectual performance. Indeed, the Digit Symbol subtest of the WAIS-R (discussed in the section on Tests of...

Extracranial Arterial System

HEART, AORTA, COMMON CAROTID, SUBCLAVIAN, INNOMINATE ARTERIES The ascending aorta arises from the left ventricle. The aortic arch gives rise to several important branches. The first branch of the aorta is normally the innominate artery, which is also referred to as the brachiocephalic trunk. Shortly after its origin, the innominate artery divides into the right subclavian and right common carotid arteries. The right vertebral artery arises from the right subclavian artery, courses...

Fabrys Disease

This X-linked lipidosis is characterized biochemically by the accumulation of two glycosphingolipids, globotriaosylceramide and galabiosylceramide. Ihe enzymatic deficiency is alpha-galactosidase A. Ihe 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. Ihe majority of the glycosphingolipids are synthesized in...

Facioscapulohumeral Muscular Dystrophy

Facioscapulohumeral muscular dystrophy (FSH MD), or Landouzy-Dejerine muscular dystrophy, is slowly progressive degenerative myopathy that affects particular facial, torso, and extremity muscles. There are at least two loci for FSH MD. Most large families thus far are linked to 4q35, in which no gene has been found. About 15 percent of other clinically indistinguishable families remain unlinked. y Although isolated cases have been identified, generally TABLE 36-6 -- DIFFERENTIAL DIAGNOSES IN...

Familial Disease

The molecular genetic basis for inherited disease remains to be defined. It seems probable that mutation-induced alterations in the primary amino acid structure of PrP facilitate its transition from an alpha helix to a beta-pleated sheet configuration. If the magnitude of facilitation were a million-fold, the one per million occurrence of sporadic disease would assume the appearance of a fully penetrant inherited disease linked to the mutation. y This...

Familial Spastic Paraplegias

The FSPs, also known as Strumpell-Lorrain syndrome and hereditary spastic paraplegias, are a broad group of TABLE 36-3 -- SELECTED DIFFERENTIAL DIAGNOSIS OF MOTOR NEURON DISEASES OF CHILDREN ACCORDING TO SOME PRESENTING SYMPTOMS Hereditary motor and sensory neuropathies Subacute inflammatory polyradieuloneuropathy Congenital myopathies with distinguishing structural abnormalities genetically and clinically diverse disorders characterized by lower extremity spasticity and weakness. Generally,...

Far Distal Peripheral Lesions

Isolated lesions of either the glossopharyngeal or vagus nerves are unusual. As noted earlier, glossopharyngeal nerve abnormalities may be clinically undetectable unless adjacent structures are also involved. Perhaps the most common vagus nerve lesion is that involving the recurrent laryngeal nerve, resulting in ipsilateral vocal cord paresis and hoarseness of voice. The left nerve has a longer course, with its looped recurrence in the chest rather than in the neck, as on the right. The nerve...

Fetal Alcohol Syndrome

The mechanism by which the abnormalities of the fetal alcohol syndrome are produced is unknown, but it is thought to be due to a direct teratogenic effect. There is no general agreement regarding the limits of vulnerability of the fetus in terms of gestational age. To date, this syndrome has been described only in children of mothers who drank alcohol frequently during their pregnancy. Fetal alcohol syndrome results in low birth weight and small head circumference. Cranial and joint deformities...

General Management Goals

Rapid diagnosis of stroke and initiation of treatment are important to maximize recovery and to prevent recurrence of stroke (see Chapter.45 ). Patients with an acute stroke should be admitted to the hospital for emergency evaluation and treatment, preferably in a stroke unit or intensive care unit where close medical and nursing observation is available. A multidisciplinary approach with referral to specialists with expertise in stroke is beneficial. Care should focus not only on the treatment...

Glucocorticosteroids

Neurological side effects of glucocorticosteroids are well described and may be as serious as the diseases being treated. Neuropsychiatric disorders and myopathy are common. Most of the neurological sequelae are often related to dosage and duration of therapy and may be reversible by modification of the drug regimen. y Glucocorticosteroid use can be associated with a broad spectrum of neuropsychiatric disorders, ranging from emotional lability and anxiety to confusion, mood disorders, and...

Gross Examination

Cerebral atrophy of variable degrees Ventricular enlargement Widening of sulci Attenuation of deep cerebral white matter MICROSCOPIC EXAMINATION Perivascular foci of inflammatory cells, microglia, macrophages, MGC involving the basal ganglia and subcortical white matter predominantly HIV-1 leukoencephalopathy Diffuse myelin pallor and white matter damage, reactive astrogliosis, macrophages Calcific vasculopathy Small vessel mineralization of basal ganglia, frontal white matter (children >...

Heart Studies

Echocardiography transthoracic, transesophageal 24-hour ambulatory cardiac monitoring Cardiac nuclear scanning Blood Tests Coagulation and platelet function tests Vascular imaging can be divided into noninvasive and invasive studies. Four commonly used noninvasive tests are Duplex scans (B-mode and Doppler combined), transcranial Doppler ultrasonography (TCD), MRA, and CTA. Duplex scans show an accurate image of the extracranial carotid and subclavian arteries. TCD is useful for the evaluation...

Hemifacial Spasm

Hemifacial spasm (HFS) is characterized by intermittent twitching of the muscles supplied by one facial nerve. It is thought to result from compression of the facial nerve at its junction with the brain stem by an aberrant or ectopic posterior fossa artery. Whereas many cases are idiopathic in origin, a review of 539 cases of HFS for which the cause was specified showed that compression by vascular structures was responsible in 94 percent of cases, tumor in 4 percent, and bony or other...

Hereditary Sensory and Autonomic Neuropathies

The hereditary sensory and autonomic neuropathies (HSANs) are conditions in which primary sensory and autonomic neurons either fail to develop or undergo system atrophy and degeneration. Dyck proposes the comprehensive subdivision seen in T.ab e 36.-10 . These disorders have been called by a large variety of names because their symptoms were described by various investigators. Types I, II, and III are discussed here. Within this classification there are two large divisions HSAN I is a...

Hereditodegenerative Disorders

Corticobasal ganglionic degeneration Metastatic neoplasms and paraneoplastic syndromes of movements involved in gestures, including emblems and pantomimes. Two forms of ideomotor apraxia can be identified. A posterior form can be induced by left parietal cortex (angular or supramarginal gyrus) lesions, while an anterior form can occur following lesions anterior to the supramarginal gyrus that disconnect the visual kinesthetic motor engrams from the premotor and motor areas. Patients with...