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 )....

Preganglionic Syndromes

Trigeminal nerve compression can occur in the area between the brain stem nuclei and the gasserian ganglion, specifically within the brain stem itself or in the cerebellopontine angle. Patients can present with reduced facial sensation in association with poor hearing, nystagmus, limb ataxia, facial weakness, and a diminished corneal reflex. Common lesions in this area include tumorsy such as acoustic or trigeminal neuromas,y meningiomas, metastatic cancers, carcinomatous meningitis, and...

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...

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...

Abnormal EEG Activity

The pathophysiology of abnormal EEG activity is multifactorial and difficult to clarify. Increased excitability of the cerebral cortex probably accounts for cortical spike activity. More generalized spike-wave bursts probably depend on thalamocortical projections. The delta activity recorded under certain pathological circumstances probably reflects lesions involving predominantly the cerebral white matter. When subcortical nuclei are involved, either alone or in association with pathology...

Abnormal EMG Activity

Insertion activity is increased in neuropathic and certain myopathic or myotonic disorders and in myositis. Abnormal Figure 24-17 Motor unit action potentials , Normal potential.fi, Long-duration polyphasic potential (shown twiceC, Short-duration, low-amplitude, polyphasic potentisfFrom Aminoff MJ Electromyography in Clinical Practice, 3rd ed. New York, Churchill Livingstone, 1998.) spontaneous activity is present in various neuromuscular diseases. Fibrillation potentials (. Fig, 24-1.8 ) are...

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...

Abnormal Findings and Clinical Uses of the BAEP

The BAEP is an important means of evaluating function of the eighth cranial nerve and the central auditory pathways in the brain stem. In infants, young children, and adults who are unable to cooperate for behavioral testing, BAEPs can be used to evaluate hearing. y The wave V component of the response is generated by auditory stimuli that are too weak to generate other components. As a screening test of hearing, then, the electrophysiological threshold for eliciting wave V is determined. An...

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...

Abnormal Findings and Clinical Uses of the VEP

Visual evoked potentials are useful in evaluating the function of the anterior visual pathways. They are not useful in evaluating lesions posterior to the optic chiasm. In patients with an acute optic or retrobulbar neuritis, the P100 response is initially lost with time, it recovers and is then found to have a markedly prolonged latency that generally persists indefinitely (see Fig 24-12 ),y , y even if apparently complete clinical recovery occurs. The VEP is therefore an important means of...

Acute Head Injury

Head injury (HI) accounts for a disproportionate share of morbidity and mortality in traumatized patients. The past two decades have witnessed a significant decline, however, in overall HI mortality from the mid-30 percent range in the 1970s to less than 20 percent in the 1990s. This improvement has paralleled an understanding of the secondary injury process and an appreciation that all neurological damage does not occur at the moment of insult but evolves over...

Acute Inflammatory Demyelinating Polyradiculoneuropathy Guillainbarre Syndrome

Until approximately a decade ago, GBS was considered to be a single clinical entity, a rapidly evolving sensorimotor polyradiculoneuropathy resulting from widespread demyelination in the PNS and due to inflammation. Consequently, GBS was viewed as synonymous with AIDP. However, it is now obvious that demyelination is only one of the causes for the combination of clinical features labeled GBS different pathological processes can lead to the same clinical presentation (,TabJ,e,49z1). 13' , 14 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...

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...

Adolescence

Leber's hereditary optic neuropathy (II) Kearns-Sayre syndrome (III) Chronic progressive external ophthalmoplegia (III) Others Leber's hereditary optic neuropathy plus multiple system degeneration (II) Inherited exertional myoglobinuria (I) ADULTHOOD Malignant migraine (III) Neuropathy, ataxia, retinitis pigmentosa syndrome (II) Hypertrophic cardiomyopathy and myopathy (II) Mitochondrial myopathy (II, IV) *Diseases are listed by order of most likely age presentation The molecular genetics class...

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...

Alexias and Agraphias

Alexia without agraphia was first described by Dejerine in 1892 in a patient who suddenly lost the ability to read but had no other language disturbance. The only neurological finding of significance was a right homonymous hemianopia. Although the patient was unable to read except for some individual letters, he could write adequately. In patients with this syndrome, the patient can write but cannot read his or her own written output. If the letters of a word are read aloud, the patient can...

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,...

Altered Sexuality Syndromes

Brain MRI CT Epilepsy, Huntington's disease, CNS neoplasm, trauma, stroke, encephalitis Brain MRI CT Epilepsy, CNS neoplasms, stroke, trauma, carbon monoxide poisoning, hydrocephalus, encephalitis, Wernicke-Korsakoff syndrome Brain MRI CT CNS neoplasms, stroke, trauma Brain MRI CT Post-trauma, stroke, encephalitis, multiple sclerosis Brain MRI CT Degenerative disorders, CNS tumors, trauma, encephalitis Brain MRI CT Encephalitis, CNS tumors, hypothalamic lesions, trauma EEG Psychosis associated...

Amebic Infections

Naegleria and Acanthamoeba are free-living amebae that infect the CNS. Naegleria fowleri causes an acute fulminant meningoencephalitis, known as primary amebic meningoencephalitis (PAM), and is acquired by swimming or waterskiing in small, shallow freshwater lakes as a result of direct contamination through the nasal cavity. Infection with this organism has also been acquired from swimming in chlorinated pools presumably, the organism gets into the pool through cracks in the pool. In Africa,...

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...

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...

Anaplastic Astrocytoma and Glioblastoma Multiforme

Malignant tumors are thought to evolve from lower grade tumors, although they can evolve spontaneously, perhaps as the result of abnormalities of gene function. Alteration of one gene may lead to transformation to a low-grade glioma, and subsequent cell division leads to the accumulation of multiple genetic alterations that ultimately result in a tumor with the histological characteristics of a glioblastoma multiforme. Alternatively, a putative glioblastoma...

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...

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 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...

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 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 the Pursuit System

In contrast to the saccadic control, the conjugate pursuit system of each hemisphere controls binocular eye movements Figure 9-6 (Figure Not Available) Hypothetical cortical pathways involved in saccade control. The cortical relays of saccade pathways are represented by arrowheads. FEF, frontal eye field H, hippocampal formation OC, occipital cortex PEF, parietal eye field PFC, prefrontal cortex (i.e., area 46 of Brodmann) PPC, posterior parietal cortex SC and RF, superior colliculus and...

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...

Anosmia and Hyposmia

Loss or decreased olfactory function is estimated to be present in approximately 1 percent of the American population under the age of 60 and in more than half of the population over that age.y The causes of loss or decreased olfactory function are variable, and simply establishing the presence of olfactory loss per se provides little insight into the cause. Nearly two thirds of patients with chronic anosmia or hyposmia (i.e., those that are presumably permanent) are due to prior upper...

Antibacterial Agents

PENICILLINS, CEPHALOSPORINS, AND IMIPENEM Historically, radiculitis, paraplegia, hemiplegia, and convulsions occurred after penicillin was administered into the CSF, but because this route of administration has been abandoned, such reactions are exceedingly rare. The neurotoxic clinical manifestations of penicillins, cephalosporins, and imipenem include myoclonus, seizures, confusion, hallucinations, encephalopathy, nystagmus, and agitation. Imipenem, cefazolin, and benzyl penicillin are the...

Antifungal Drugs

Encephalopathy, occasionally with parkinsonian features, can be associated with intravenous administration of amphotericin B. Autopsy examination of afflicted patients discloses diffuse noninflammatory degeneration of the white matter, characterized by demyelination and infiltration by foamy macrophages. The leukotoxic effect of amphotericin B is related to its binding to myelin and an increase in membrane permeability, resulting in leakage of intracellular components. y Clinically, the...

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...

Arenavirus Lymphocytic Choriomeningitis Virus

The natural reservoir for the lymphocytic choriomeningitis virus (LCMV) is the common house mouse. Hamsters and laboratory animals can also be infected with this virus. Most human infections result from contact with house mice. y , y Four clinical syndromes due to infection with LCMV have been described (1) subclinical asymptomatic infection, (2) nonmeningeal influenza-like illness, (3) aseptic meningitis, and (4) meningoencephalomyelitis. y The LCMV was the first...

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...

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 Diseases

NEUROFIBROMATOSIS (VON RECKLINGHAUSEN'S DISEASE) Pathogenesis and Pathophysiology. Neurofibromatosis y is no longer considered a single clinical entity and has been divided into at least two distinct forms. y The common form, once known as peripheral neurofibromatosis (NF), is called NF-1, and the rare form, once termed central NF, is NF-2. Both are inherited as autosomal dominant traits, and the gene locus responsible for NF-1 is on chromosome 17 (17q11.2), whereas that for NF-2 is on...

Bacterial

Cytomegalovirus Herpes simplex viruses 1 and 2 Varicella zoster virus JC virus Toxoplasma gondii Trypanosoma cruzi Acanthamoeba Modified from Marra CM Opportunistic infections in AIDS, Infections of the Nervous System II. Minneapolis, MN, American Academy of Neurology, 1997, pp 234-259 TABLE 44-14 -- CORRELATION BETWEEN CENTRAL NERVOUS SYSTEM DISEASE SUSCEPTIBILITY AND PERIPHERAL BLOOD CD4 COUNT TABLE 44-14 -- CORRELATION BETWEEN CENTRAL NERVOUS SYSTEM DISEASE SUSCEPTIBILITY AND PERIPHERAL...

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...

Basic Principles and Technique

Disorders of sleep are common and often respond well to treatment. Polysomnography is important in diagnosing and characterizing such disorders. It involves recording the EEG on two or a few channels to characterize the stage of sleep while recordings are also made of eye movements, mentalis muscle activity (chin EMG), electrocardiogram, respiration, and oxygen saturation. Respiratory movements are recorded by measurement of air flow through the nasal passages and the mouth using thermistors...

Basic Principles and Techniques

Ultrasonography depends on the presence of sonographic windows, which allow sound wave propagation and detection of echo signals. These signals form the basic sonographic units for image generation. Therefore, as a general rule, US is indicated when visualization of the target object is not blocked by intervening bone or air, such as calvarium or bowel gas. This limitation does not completely negate the use of US in the evaluation of adult brain disorders, as discussed later. The usefulness of...

Blastomyces dermatitidis

As discussed previously, infection with Blastomyces dermatitidis is primarily associated with outdoor activities including occupational exposure such as construction work, mining, and recreational activities. The AIDS epidemic has not affected the epidemiology of blastomycosis. 115 Initial infection with this fungus is essentially a pulmonary disease. The chest radiograph demonstrates nonspecific infiltrates predominantly at the bases. 115 Dissemination to the CNS presents as single or multiple...

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...

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),...

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...

Carnitine Transport Defect Primary Generalized Carnitine Deficiency

Carnitine fails to be taken up in muscle, heart, and kidney but not liver, leading to insufficient carnitine to support fatty acid oxidation. Ihe kidney fails to conserve carnitine by reabsorption, resulting in very low plasma carnitine levels, which then causes decreased passive diffusion into liver, impairing ketogenesis. Accumulating acyl-CoA compounds become substrates for peroxisomal beta- oxidation, which produces medium-chain fatty acids and dicarboxylic acids, which do not require...

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...

Central Connections

The olfactory tract, which contains both afferent and efferent fibers, is relatively flat posteriorly and becomes the olfactory trigone just rostral to the anterior perforated substance (so named because of the many small holes for blood vessels found throughout this region). At the edges of the trigone, the tract divides into the medial and lateral olfactory striae. The axons of the mitral and tufted cells arise from the caudolateral part of the olfactory bulb and form the olfactory tract at...

Cerebral Venous Thrombosis

Intracranial venous occlusive disease is significantly less common than arterial disease. The symptoms can be nonspecific. The symptoms that are present depend upon the venous structure that is affected, the extent and rapidity of thrombosis, and the extent of venous collaterals. Common symptoms include headache, nausea, vomiting, altered consciousness, and seizures. Examination may show papilledema, meningismus, and subtle focal neurological deficits (see Tabie. 22-2.). Possible findings on CT...

Channelopathies Myotonias and Periodic Paralysis

The channelopathies are disorders of ion channels that result in altered excitability of cellular membranes. At present, more is known about muscle and peripheral nerve than central nervous system channelopathies. Most of the well-characterized channelopathies are disorders of muscle membrane ion channels. A disturbance of ion channel function may result in muscle membrane hyperexcitability leading to myotonia as the dominant feature, or, alternatively, it may result in muscle membrane...

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...

Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome

Belman Thomas Preston Maria Milazzo Human Immunodeficiency Virus Biology and General Medical Overview of Seroconversion and Early Infection HIV-Related Central Nervous System Disorders HIV-Associated Cognitive Impairment--Adults HIV-Associated Central Nervous System Disorders-Children HIV-Related Peripheral Nervous System Disorders Primary Central Nervous System Lymphoma

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

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...

Chickpea Lathyrism

Lathyrism is related to a neurotoxin acting through the glutaminergic system. Spastic paraplegia has been observed in Europe and India following consumption of different varieties of chickpea. Development of human lathyrism is associated with two potent neurotoxins found in the peas alpha-amino beta oxalylaminopropionic acid and alpha-amino gamma oxalylaminobutyric acid.'39' Toxic neurological signs are seen when 30 percent or more of the diet consists of chickpeas. Men tend to be affected more...

Cholesterol Lowering Agents Clofibrate

Clofibrate, an aromatic monocarboxylic acid, is capable of inducing myotonia in humans and experimental animals and is clinically significant because it is widely used to reduce serum triglyceride levels. The mechanism by which it induces myotonia is believed to be through a decrease in chloride conductance. Lovastatin and pravastatin are HMG-CoA reductase inhibitors that are effective cholesterol-lowering agents used in the treatment of hypercholesterolemia. They can induce myotonia by...

Chordoma

Chordomas are often considered benign tumors that are amenable to surgical resection alone. However, they can be invasive and can metastasize, and, without complete resection, they can produce local regrowth. They are considered embryonal tumors and are remnants of the notochord. The primary histological feature is the presence of large mucin-containing physaliferous cells. Areas of hemorrhage and calcification may also be seen. Chordomas may degenerate to a more malignant histological...

Chronic Falsepositive Vdrl Test Lasting Longer Than 6 Months

Systemic lupus erythematosus and other connective tissue disorders Reproduced with pemmission from Roos KL Syphilitic meningitis. In Roos KL (ed) Meningitis 100 Maxims in Neurology London, Amold, 1997, pp 171-181. with neurosyphilis have a positive VDRL test. A CSF examination should be performed in patients with a reactive MHA-TP or FTA-ABS. The diagnosis of neurosyphilis is made in the presence of a reactive serological test with either neurological manifestations consistent with...

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

Clinical Syndromes Table115

The sensory examination aims to establish the sensory modality involved, the intensity of involvement, and the anatomical distribution of the sensory change. In combination, these patterns isolate the likely neurological location of disease and later suggest etiology. In lesions of the peripheral nervous system the sensory loss tends to be intense, with fixed, clearly defined zones. With central nervous system sensory deficits the boundaries are vague and the deficit is more mild as compared...

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...

Coccidioides immitis

Coccidioides immitis is a dimorphic fungus that is endemic to the desert areas of the Southwest, specifically California, Arizona, New Mexico, and Texas. C. immitis grows as a mycelia that releases air-borne arthroconidia, which when inhaled and in the alveoli transform into spherules containing endospores. Infection is most often either asymptomatic or a limited pneumonitis with fever and cough. Dissemination occurs in less than 1 percent of patients, and CNS disease is primarily a meningitis....

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...

Colloid Cysts

Colloid cysts are benign tumors that are amenable to curative neurosurgical resection. They must be diagnosed promptly before symptoms develop that can lead to acute conditions and sudden death. They are rare tumors but, with the advent of neuroradiological imaging, can be identified incidentally when imaging is performed for other reasons. They typically present in midlife, although pediatric diagnoses are known. They are located most frequently in the third ventricle and can cause variable...

Congenital Myasthenias

The onset of myasthenic symptoms at birth or in patients with a family history of this disease has always made congenital forms of myasthenia a diagnostic possibility. With the advent of the acetylcholine receptor (AChR) and the calcium channel antibody test as markers for myasthenia gravis and Lambert Eaton myasthenia, it has become apparent that congenital myasthenia, like the congenital myopathies, may present later in life and, in some cases, without a family history. Pathogenesis and...

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...

Cranial Nerve XII

The hypoglossal nerve is classified as a general somatic efferent (GSE) nerve because it innervates striated muscle that arises embryologically from the somites. i , y The nucleus of CN XII is located in the medulla, ventral to the floor of the fourth ventricle. The hypoglossal triangle or trigonum hypoglossi, in the floor of the fourth ventricle, serves as an external landmark for the rostral portion of the hypoglossal nucleus. y As with some of the other pure motor cranial nerves, the nucleus...

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...

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...

Critical Illness Polyneuropathy

The occurrence of muscle weakness in patients with sepsis and multiple organ failure managed in the intensive care unit has been recognized with increasing frequency in the last 15 years. This weakness is due to an axonal polyneuropathy, otherwise called critical illness polyneuropathy. It must be differentiated from myopathy or disturbance of the neuromuscular junction that can also occur in the intensive care setting. y Neither the cause nor the exact mechanism of critical illness...

Cryptococcus neoformans

Cryptococcus neoformans is an encapsulated yeastlike fungus. Infection is acquired through direct exposure to bird droppings. The infection is initially characterized by a localized pneumonitis, but when dissemination occurs the CNS is a preferential site for disease presumably because the CSF is a good culture media for cryptococci. 115 The most common symptoms of cryptococcal meningitis are headache, fever, and malaise. Cryptococcal skin lesions may precede the development of meningitis, and...

Cyclosporine

Neurotoxicity is a well-recognized sequela of cyclosporine, and the most common complications are tremor and altered mental status. Cyclosporine neurotoxicity can occur in one in 10 patients after liver transplantation. Behavioral signs include acute psychosis, restlessness, wide mood swings with inappropriate crying and laughing, cortical blindness, visual hallucinations, stupor, and akinetic mutism. Additionally, seizures, extrapyramidal symptoms, action myoclonus, and quadriparesis have been...

Death by Brain Criteria

The ability to transplant organs successfully led to the need of criteria for brain death, and national and international definitions have been developed. Many now argue that current criteria are restrictive and should be expanded to include patients who have no reasonable chance of regaining consciousness. y If this change is to be made, a substantial shift in societal thinking about life and death may need to precede it. However, in North America, death by brain criteria is still considered...

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...

Diencephalic Dysfunction

Disorders of the diencephalon may affect consciousness either directly, by interfering with reticular system function, or indirectly, by producing endocrine disorders. These conditions may develop slowly, as with anterior pituitary syndromes resulting in hypothyroidism or cortisol deficiency, or rapidly, as with osmoregulatory disorders. The lesions producing these problems may also affect the cerebral cortex, as in the case of neoplasms, and produce seizures or other focal neurological...

Diffuse Autonomic Failure Pandysautonomia

Preganglionic autonomic failure central neurodegenerative diseases Multiple system atrophy (Shy-Drager syndrome) Parkinson's disease with autonomic failure Ganglionic and postganglionic disorders-peripheral neurodegeneranve disorders Pure autonomic failure Peripheral neuropathies and neuronopathies with autonomic failure Acute and subacute (preganglionic and postganglionic) Chronic small-fiber (postganglionic) neuropathies ) Hereditary (familial dysautonomia, Fabry's disease Subacute or chronic...

Diffuse Autonomic Failure Pandysautonomia Central Preganglionic Disorders

Multiple system atrophy (MSA, Shy-Drager syndrome) is a degenerative disorder of the CNS that affects the extrapyramidal, cerebellar, and autonomic neurons (see Chaptei 34,). Autonomic dysfunction in patients with MSA is due to the loss of preganglionic neurons in the brain stem and spinal cord. Patients with MSA typically present with diffuse autonomic failure and parkinsonian, cerebellar, or pyramidal deficits in different combinations. y Autonomic features include...

Directed General Examination

The general medical examination provides useful diagnostic information in patients with hypokinesia and hyperkinesia. The skin examination in patients with Parkinson's disease shows seborrhea, scaly skin, and often patches of excessive dryness. Increased salivation and drooling are typical. The eyes should be examined in patients with movement disorders to detect the presence of Kayser-Fleischer rings or copper deposits in the cornea (Wilson's disease), and proptosis and lid-lag suggests...