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 )....

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...

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...

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...

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...

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...

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 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 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...

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 Medical Findings

Because one of the most common causes of orbital infiltration is thyroid disease, patients with orbital signs such as proptosis, chemosis and conjunctival injection together with abnormal ocular motility should be examined for goiter, pretibial myxedema, smooth moist skin, and loss of lateral eyebrows. y In thyroid disease, the extraocular muscles can develop edema, lymphocytic infiltration, and fibrosis, resulting in loss of elasticity more than loss of contractile strength. The diplopia that...

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...

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...

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...

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...

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...

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...

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...

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...

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...

Experimental Allergic Encephalomyelitis

As mentioned earlier, there is no spontaneous animal model that closely resembles MS. EAE is the most widely studied animal model of this disease. EAE is an antigen-specific, T-cell-mediated autoimmune disease that can be induced in many species, although rat and mice models predominate in the literature. Acute EAE is a monophasic illness that more closely resembles ADEM. Chronic-relapsing EAE closely mimics the clinical course of MS with repeated clinical relapses from which the animal makes...

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...

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...

Gasserian Ganglion Syndromes

Numerous pathological processes occurring within the middle cranial fossa can result in trigeminal dysfunction by affecting the gasserian ganglion. In children, osteitis of the petrous apex following suppurative otitis media or mastoiditis, which leads to inflammation and infection affecting the trigeminal ganglion, may result in Gradenigo's syndrome. The syndrome is characterized by facial pain, headache, or sensory loss and a sixth cranial nerve palsy, facial palsy (due to seventh nerve...

General Management Goals

The performance of learned motor tasks involves the ability to complete many of the activities of daily living including personal hygiene and meal preparation. As a result, the presence of apraxic deficits can result in the loss of independence for many patients. While physical rehabilitation may improve other associated neurological deficits following head trauma or stroke, the presence of apraxia can make occupational rehabilitation difficult because the patient will have difficulty in...

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...

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...

Historical Background

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

HIV1Related Myopathies

Muscle disorders related to HIV-1 infection include HIV-1-associated polymyositis, ZDV toxic myopathy, pyomyositis or infectious myopathy, cardiomyopathy, and the so-called wasting syndrome myopathy. Of these conditions, HIV-1-associated polymyositis and toxic myopathy related to ZDV are the most common. Distinguishing between these two forms of myopathy at times may be difficult. Pathogenesis and Pathophysiology. The pathophysiological mechanisms underlying HIV-related myopathy are uncertain....

Human Immunodeficiency Virus Biology And General Medical Overview Of Seroconversion And Early Infection

HIV-1, the etiological agent of AIDS, is a non-oncovirus ribonucleic acid (RNA) retrovirus that belongs to the lentivirinae genus of the Retroviridae family. Lentiviruses are species specific, having long periods of clinical latency and mechanisms to evade immune clearance. They target specific organs and cause persistent infection and multisystem disease in their natural hosts. Lentiviruses characteristically cause neurological disease. HIV-1, as other human...

Huntingtons Disease

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

Hypocapnia

Hyperventilation is defined as breathing in excess of metabolic demands and, therefore, is purely a respiratory disturbance. It produces hypocapnia, respiratory alkalosis, cerebral vasoconstriction (which, in turn, reduces the CBF), a reduction in the availability of O 2 peripherally (through shifts of the O 2 dissociation curve), a reduction in the level of ionized serum Ca, and when sustained, significant hypophosphatemia. y Thus, neurological features are frequent, and patients with...

Iatrogenic Disease

Iatrogenic disease poses no difficulty in regard to pathogenesis when the infectious agent is accidentally introduced into the body, whether directly into the nervous system or by peripheral routes, the seed is sown for its replication and spread, and the disease eventually appears when infectivity and neuropathology have reached a high enough level. The length of the incubation period between the infecting event and the onset of symptomatic disease ranges from...

Impulse Dyscontrol and Aggression Syndromes

The impulse dyscontrol and aggression syndrome consists of an inability to resist an impulse to perform a harmful act the impulse is accompanied by a buildup of tension needing to be released, and is followed by a feeling of satisfaction or relief when the act is committed. This in turn is followed by either relief, remorse, or a sense of justification for the act. Impulse dyscontrol and aggression can occur in neurologically normal individuals, but this behavior becomes pathological when...

Inclusion Body Myositis

The specific hallmarks of inclusion body myositis (IBM) are inflammation, vacuolated muscle fibers, intracellular amyloid deposits, and 15 to 18 nm tubulofilamentous inclusions. Although there are familial forms of this disease, either autosomal dominant or recessive, inflammation is only rarely seen in those cases, Wi and, therefore, the familial forms are best referred to as inclusion body myopathies. The inflammatory cells that are present in affected muscle...

Intellectual Abilities

Intelligence is considered to be the culmination of cognitive abilities. The testing of intelligence involves assessments of attention, reasoning, memory, language, perception, and construction. Intelligence tests should provide an overview of cognitive function integrity. Most tests of intelligence do not adequately assess all cognitive abilities, however. These tests are the current gold standard in intelligence testing and include the Wechsler Adult Intelligence Scale- Revised (WAIS-R),...

Intracranial Arterial System Circle of Willis

INTERNAL CAROTID ARTERY AND BRANCHES (OPHTHALMIC AND ANTERIOR CHOROIDAL) The internal carotid artery (ICA) can be conceptually divided into three main segments cervical, petrosal, and intracranial. The cervical portion extends from the carotid bifurcation to the base of the skull. This segment has no branches. The petrosal segment begins after the artery enters the base of the skull and travels through the carotid canal in the petrous portion of the temporal bone. The artery then crosses the...

Isaacs Disease

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

Lesch Nyhan Disease Hypoxanthine Guanine Phosphoribosyltransferase Deficiency

Lesch-Nyhan disease is an X-linked recessive disease involving abnormal purine metabolism. The disorder is due to complete deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT), an enzyme necessary for the recycling of free purine bases and reconversion into their nucleotide forms, after nucleotides are metabolized during DNA or RNA synthesis or after serving as coenzymes. Specifically, if HPRT is deficient, hypoxanthine, a free purine base, cannot be reconverted back to inosine 5...

Local Anesthetics

When they are applied locally, local anesthetics reversibly block the action potentials responsible for nerve conduction. The most commonly used local anesthetics are cocaine, lidocaine, bupivacaine, chloroprocaine, etidocaine, mepivacaine, prilocaine, ropivacaine, procaine, and tetracaine. Local anesthetics entering the systemic circulation produce adverse effects primarily on the CNS. Usually, when they are administered locally, they cannot reach sufficient systemic concentrations to...

Malignant Hyperthermia

Malignant hyperthermia is a hereditary skeletal muscle disease characterized by a hypercatabolic reaction of muscle to anesthetic agents or to physical or emotional stress. Pathogenesis and Pathophysiology. The central event in malignant hyperthermia appears to be an increase in the calcium concentration, which results in continuous activation of the actin-myosin contraction apparatus and sustained muscle contraction. This increase in calcium level is due to an increased release of calcium from...

Memory See Chapters5 and

The ability to record, retain, and reproduce information constitutes memory functioning. Memory is not a unitary phenomenon, however. There are different forms of memory ( .Table.2Z 2. ) including memory requiring awareness (explicit memory) as well as memory that occurs in the absence of awareness (implicit memory) (see Chapters ). All standard clinical assessments of memory test explicit memory. Even within explicit memory there are different forms. Semantic memory represents the ability to...

Memory Related Chemical Changes

The specific roles of different neurotransmitters in memory are just beginning to be appreciated. The cholinergic system appears to be critical for the acquisition of long-term declarative memories. In healthy subjects, cholinergic antagonists such as scopolamine impair declarative memory performance, whereas agonists such as physostigmine facilitate such performance. y Some nondeclarative forms of memory, however, are not affected by scopolamine. Cholinergic function decreases somewhat with...

Methylphenyltetrahydropyridine

The first case of methyl-phenyl-tetrahydropyridine (MPTP)-induced parkinsonism was reported in 1979. y The subject later died of a drug overdose. At autopsy, destruction of the substantia nigra zona compacta was evident other areas usually involved in Parkinson's disease such as the locus coeruleus were not affected. This article lay dormant until parkinsonism began appearing in the San Francisco Bay area among users of MPTP sold as synthetic heroin. The responsible chemical was identified as a...

Mitochondrial Encephalopathy Lactic Acidosis and Strokelike Episodes

About 80 percent of MELAS patients exhibit a heteroplasmic A to G point mutation in the dihydrouridine loop of the tRNA Leu(UUR) gene at mt3243.y Two other mutations in the same gene, at mt3250 and mt3271, have been identified in the remaining cases. The MELAS3243 mutation alters the dihydrouridine loop of the tRNALeu(UUR) gene and changes a nucleotide at the binding site for a nuclear DNA encoded transcription termination factor. It is hypothesized that the mutation reduces the binding...

Mitochondrial Enzyme Defects

Mitochondrial DNA (mtDNA) was first discovered in 1963, and in the following 20 years the basic principles of mitochondrial genetics were established. y These are maternal inheritance, replicative segregation, threshold expression, high mtDNA mutation rate (compared with nuclear DNA genes), and accumulation of somatic mutations with aging. The mtDNA of the mother is transmitted to all of her children through the egg cytoplasm, containing 200,000 to 300,000 mtDNAs. The number of mitochondria...

Monoclonal Gammopathies Of Undetermined Significance

A heterogenous group of peripheral neuropathies has been associated with the presence of an MGUS. However, the precise relationship of the monoclonal (M-) protein to the peripheral nerve disorder remains unclear. By definition, MGUS indicates the presence of an M-protein of less than 3 g dl in concentration, with less than 5 percent plasma cells in bone marrow, none or only a very small amount of M-protein in the urine, and the absence of other abnormalities,...

Muscle Biopsy

The decision to proceed with a muscle biopsy is made after a thorough medical and neurological history, examination, laboratory evaluation, and electromyogram study, thereby permitting the formulation of a preliminary diagnosis and, hence, dictating the studies required of the muscle biopsy specimen. The history characterizes the weakness (e.g., its rate of onset, distribution, time course, precipitants e.g., exercise-induced , associated symptoms, and family pedigree). The clinical examination...

Myoclonic Epilepsy and Ragged Red Fibers Syndrome

The majority of cases of MERRF syndrome have a heteroplasmic G to A point mutation at bp8344 in the tRNALys gene.y This results in protein synthesis defects involving primarily complexes I and IV, which have the greatest number of mtDNA coded subunits. Any quantitative measure of energy metabolism-- y P-NMR, anerobic threshold determination, or biochemical analysis of skeletal muscle--shows decreased ATP-generating capacity. When mutant mtDNAs exceed 85 percent in a tissue, the patient becomes...

Myopathic Syndromes

In general, diseases of muscle (myopathies) are recognized by the characteristic pattern of proximal shoulder and hip girdle weakness with relative preservation of distal strength (see Table 15-2 ). Myopathic syndromes also differ from symmetrical polyneuropathies in their effect on reflexes. In contrast to polyneuropathies, in which the distal reflexes are lost early, in myopathies the reflexes are reduced in proportion to the degree of weakness only with severe weakness in the end stages of a...

Neurological Applications in Diagnosis and Treatment

CT is useful in detecting structural abnormalities causing multifocal, focal, or subcortical cerebral dysfunction. Evaluation of the brain stem is generally limited to the midbrain and upper pons. CT has limited usefulness in the evaluation of the spinal cord and nerve roots. CT is not useful in the evaluation of neuromuscular disease. Intra-axial Disorders. CT can often identify lesions responsible for cerebral dysfunction and is ordered in the acutely ill neurological patient with a history...

Neuromuscular Junction and Muscle Disorders

In Lambert-Eaton myasthenic syndrome (LEMS), autoantibodies disrupt the function of neuronal voltage-gated calcium channels, leading to a reduction in the release of acetylcholine at the neuromuscular junction and at synapses of autonomic nerves. Changes in membrane voltage and depolarization of the neuronal membrane by influx of potassium ions leads to the opening of calcium channels. Calcium ions flow into the nerve terminal, and neurotransmitter vesicles fuse with the neuronal membrane,...

Neuropsychological Tests

California Verbal Learning, Wechsler Memory Scale, Controlled Oral Word Fluency, Beck Depression Inventory, Hamilton Depression Rating Scale, Geriatric Depression Rating Scale Minnesota Multiphasic Personality Inventory-2 (MMPI-2) Brief psychiatric rating scale scale for assessment of positive symptoms scale for assessment of negative symptoms State train anxiety inventory anxiety disorders interview schedule Yale-Brown Obsessive-Compulsive Scale Luria Complex Motor Tasks (go no go) Wisconsin...

Normal Findings

A normal unenhanced head CT scan shows midline position of the third and fourth ventricles and the septum pellucidum fornix positioned between the lateral ventricles. The bodies of the lateral ventricles need not be symmetrical. Mild differences in the sizes of the frontal, temporal, and occipital horns are common. There should be density discrimination between the white matter (centrum semiovale, corona radiata, internal capsule, and brachium pontis) and gray matter. No focal white matter low...

Normal Pressure Hydrocephalus

NPH is the result of an imbalance between production and resorption of the CSF, usually around the brain convexities. Whereas there is full communication between the ventricles and the subarachnoid space (communicating hydrocephalus), the communication between the subarachnoid space and the arachnoid villi and granulations is not intact, so fluid is not transferred efficiently to the superior sagittal sinus. Subarachnoid hemorrhage, meningitis, head trauma, and...

Oculomotor Nerve Cranial Nerve III

The third cranial nerve innervates the medial rectus, superior rectus, inferior rectus, and inferior oblique muscles, along with the pupillary sphincter and the levator palpebrae that elevates the upper eyelid. The third nerve originates in a rostrocaudally elongated group of subnuclei clustered in the midbrain, just rostral to the level of the fourth cranial nerve nucleus. The architecture of this nuclear group has been the subject of intensive study over the years. The most widely accepted...

Orientation Attention and Vigilance

Impairments in orientation, attention, and vigilance are common sequelae to brain damage, and regardless of the localization of brain pathology, these abilities are often compromised. When a patient is disoriented and unable to attend to ongoing events, there is usually severe pathology. In addition, inability to attend to ongoing stimuli makes the interpretation of neuropsychological tests of higher cognitive functions, such as intelligence or memory, difficult. Therefore, the assessment of...

Other Forms of Chorea

Senile chorea (essential chorea) begins after age 60 and is unaccompanied by any particular neurobehavioral symptoms or a family history of chorea. Whereas some patients have caudate atrophy similar to that seen in HD, others have predominant putaminal degeneration. In occasional cases, genetic detection studies in these patients reveal that the correct diagnosis is actually HD. Treatment of the chorea is similar to that used for HD. Paroxysmal dyskinesia is a chronic condition that becomes...

Other Segmentation And Cleavage Disorders

Septo-optic dysplasia is pathologically defined as absence of the septum pellucidum and hypoplastic optic nerves. This clinical constellation of symptoms and signs has also been referred to as de Morsier's syndrome. Other abnormalities are variably reported, suggesting considerable heterogeneity underlying this phenotype. Clinically, there are optic nerve hypoplasia resulting in visual impairment, endocrine abnormalities resulting from hypothalamic-pituitary insufficiency, and frequently...

Parasomnias

The term parasomnia refers to a group of disorders of arousal, partial arousal, and sleep-stage transition. A feature of many of the parasomnias is the occurrence of abnormal muscle activation behaviors occur during sleep. These behaviors may be associated with REM or NREM sleep. Behaviors occurring predominantly during the first third of the night are likely to be related to Stages 3 and 4 sleep because this is the time of night when SWS predominates and are largely considered disorders of...

Potassium Disorders

The total body content of potassium (K) is about 3500 mEq,y and roughly 98 percent is intracellular, two thirds of which is intramuscular. 9 Because cell membranes are more permeable to K than to Na and Cl, K is primarily responsible for the resting transmembrane potential and is therefore critical to the function of excitable tissue. Hypokalemia, the most frequent electrolyte disorder encountered by the clinician, is defined as a plasma K concentration below the normal range (3.5 to 5.5 mEq...

Principles of Antiepileptic Drug Treatment

The selection of an AED is based on efficacy against specific seizure types and the potential for producing adverse effects ( Ta.ble.52. 6. ). First-line agents against TCS include phenytoin, carbamazepine, and valproic acid. Ethosuximide and valproic acid are effective against AS. Valproic acid is the only primary drug effective against tonic-clonic, absence, and myoclonic seizures, making it the drug of choice for JME. Myoclonic seizures are responsive to valproic acid and benzodiazepines....

Proteinenergy Malnutrition

In acute starvation, the nervous system sustains itself first on glucose derived from alanine, then on ketone bodies from the breakdown of fats. This process continues until fat is depleted, and then catabolism returns to visceral proteins. Death results from cardiac muscle resorption and eventual cardiac failure. In chronic PEM, the nervous system adapts poorly, and a retarded rate of brain growth, hypomyelination, and slowed conduction velocities of peripheral nerves results. Chronic PEM has...

Pure Cholinergic or Adrenergic Disorders

Associated with neuromuseular transmission defect Botulism (acute) Lambert-Eaton myasthenic syndrome (chronic) Not associated with neuromuscular transmission defect Dopamine-beta-hydroxylase deficiency children. Its clinical features include insensitivity to pain and temperature, absence of tears, hypoactive corneal and tendon reflexes, and absence of fungiform papillae of the tongue. Patients with familial dysautonomia have poor suck and feeding responses, esophageal reflux with vomiting and...

Receptors

Sensation begins most distally with the transduction of mechanical stimulation by mechanoreceptors in the dermis, epidermis, muscles, and joints. To stimulate the axon associated with a mechanoreceptor, the stimulus must first pass through intervening tissues. This process is referred to as stimulus accession. This is followed by stimulus transduction, in which the stimulus energy is transformed into electrical energy by depolarization of the axon terminal in proportion to the amount of...