Renal Failure

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

Medical Findings

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

Rheumatoid Arthritis

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

Pyridoxine Vitamin B6

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

History And Definitions

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

Evaluation Guidelines

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

Associated Medical Findings

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

Evaluation Guidelines Table132

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

Evaluation Guidelines Table142

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

Clinical History

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

Preferential Atrophy

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

Specific Indications

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

Laboratory Test

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

Types of Detectable Abnormalities

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

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...

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...

Alkylating Agents

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

Amyotrophic Lateral Sclerosis

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

Anatomy 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...

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...

Antituberculous Drugs

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

Associated Neurological Findings

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

Associated Neurological Findings see IabJe155

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

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...

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 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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

Druginduced And Iatrogenic Neurological Disorders

ADCA, autosomal dominant cerebellar ataxia CNS, central ataxia. Alcoholic cerebellar degeneration (thiamine deficiency) 40 Chronic panencephalitis of congenital rubella 41 Varicella, measles, rubella, echo, coxsackie A B, polio, Epstein-Barr, herpes simplex Postinfectious disseminated encephalomyelitis Mumps, cytomegalic Mycoplasma pneumoniae Toxoplasmosis Lyme disease Plasmodium falciparum Cysticercosis Tuberculosis Cerebellopontine angle tumors (acoustic neurinoma, meningioma) Metastases lung...

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...

Executive Function and Motor Performance

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

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...

Familial Disease

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

Familial Spastic Paraplegias

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

Far Distal Peripheral Lesions

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

Fetal Alcohol Syndrome

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

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

Patients with dysfunction of either CN XI or CN XII may exhibit a number of problems with communication, swallowing, and well as difficulty resulting from weakness of the neck or trapezius muscle. Difficulty with swallowing may be amenable to swallowing therapy, including oral excercises and methods of postural facilitation. A soft mechanical diet with thickened liquids may decrease the likelihood of tracheal aspiration however, a nasogastric tube or even a percutaneous gastrostomy device may...

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...

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...

Hereditary Sensory and Motor Neuropathies

In general, the hereditary sensory and motor neuropathies are peripheral neuropathies that affect either autonomic nerves, sensory nerves, motor fibers, or a combination thereof. The molecular genetics of these disorders is being ardently pursued and the mechanisms underlying them are rapidly being unraveled. However, to date there is overlapping terminology used when they are described (i Ta.bie 36z8 ). This discussion is organized according to the classification that is emerging based on...

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...

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...

Adverse Effects

Nausea, lethargy, tremor, weight gain, hair loss rarely abnormal liver function, pancreatitis Nausea, paresthesia, intermittent claudication, ergotism Weakness, nausea, thirst, tremor, lethargy, slurred speech, blurred vision Muscle cramps, nausea, diarrhea, abdominal discomfort Insomnia, restlessness, taper over 1-2 personality changes, weeks hyponatremia, edema, hyperglycemia, osteoporosis, myopathy, gastric ulcers, hip necrosis Constipation, edema, dizziness, nausea, hypotension, fatigue

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...

Integration with Neurological Examination

Neuropsychological assessments are ancillary to the typical neurological examination, and establish better precision of the type and extent of cognitive and behavioral deficits found on bedside testing. To accomplish this goal, neuropsychological tests need to be standardized, valid and reliable, and need to make meaningful comparisons of patient- derived data to normative performance. Standardization of neuropsychological testing procedures allows for the comparison of performance across time...

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...

Lightning And Electrical Injuries

Although incompletely understood, the two major causes of tissue damage are thermal injury and electroporation, which is the production and expansion of transient aqueous pores in the lipid bilayer component of the cell membrane. y Epidemiology and Risk Factors. About 100 lightning and 1500 technical electricity-related deaths per year occur in the United States. The following routes can produce lightning injury. A direct strike is the most damaging, which is...

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...

Management and Prognosis of Paraneoplastic Syndromes as a Group

Paraneoplastic syndromes may be separated into those that are responsive and those that are unresponsive to therapy. Frequently, the syndromes responsive to therapy are characterized by antibodies directed against neurotransmitters or physiological processes stiff-person syndrome with antibodies to glutamic acid dehydrogenase and Lambert-Eaton myasthenic syndrome with antibodies to gated sodium channels. More than one half of these patients with neurophysiological or neurochemical disorders of...

Meningiomas

Many classification schemes are used for meningiomas, usually based on the histological appearance (see Ta.ble,,46-6. ). Meningiomas have a firm off-white appearance, and because they are extra-axial, they are usually well demarcated from the surrounding brain. Microscopically, they display a characteristic TABLE 46-6 -- CLASSIFICATIONS OF MENINGIOMAS TABLE 46-6 -- CLASSIFICATIONS OF MENINGIOMAS Narrow, long cells in sheets less commonly, Meningothelial cells,...

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...

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,...

Motor Neuron Diseases

An illness similar to motor neuron disease manifested as spinal cord or anterior horn cell disease has been linked with cancer. Motor neuronopathy with loss of anterior horn cells can occur as part of a paraneoplastic syndrome. In addition, a motor neuronopathy with multifocal conduction blocks can be seen. Patients with predominant motor neuron involvement may have the anti-Hu antibody, and patients with motor neuron disease and cancer may have resolution of their neurological symptoms...

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...

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...

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...

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...

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...

Partially Characterized Syndromes

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

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...

Primary Central Nervous System Lymphoma

PCNSL (see Cha.pter46 ) develops in approximately 5 percent of patients with AIDS and is found at autopsy in up to 10 percent of cases. It is the initial AIDS-defining illness in 0.6 percent of adults. Primary CNS lymphoma develops in patients with advanced HIV-1 disease who are severely immunosuppressed. The incidence of PCNSL in the AIDS population may be increasing as longevity is extended by medical management and antiretroviral agents. Lymphomas are usually of the diffuse immunoblastic, or...

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...

Purposes of Neuropsychological Examination

With the advent of modern structural imaging techniques such as computed axial tomographic imaging (CAT), and magnetic resonance imaging (MRI), and even newer functional imaging techniques such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI), the use of neuropsychological assessments to identify the location and type of CNS lesion has waned. y M y However, because they identify and quantify both cognitive strengths and deficits, neuropsychological...

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...

References

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

Reviews And Selected Updates

Bassetti C, Bogousslavsky J, Mattle H Medial medullary syndrome. Neurology 1997 48 882-890. Chen J, Simon R Ischemic tolerance in the brain. Neurology 1997 48 306. Hornig CR, Bauer T, Carmen S, et al Hemorrhagic transformation in cardioembolic cerebral infarction. Stroke 1993 24(3) 465. Tatu L, Moulin T, Bogousslavsky J Arterial territories of human brain. Neurology 1996 47 1125-1135. 1. Bell BA Early study of cerebral circulation and measurement of cerebral blood flow. In Wood JH (ed) Cerebral...

Segmentation Cleavage And Midline Defects

These disorders are believed to arise from a defect in midline development. The result is a failure of midline structures, like the corpus callosum, to form. Included are also abnormalities in the separation of the neural tube into two hemispheres. This later defect is believed to result in holoprosencephaly and related disorders. Pathogenesis and Pathophysiology. Completion of neural tube closure is followed by segmentation in the anteroposterior axis. Although these segments were originally...

Sensory Receptors and Primary Neurons

Cranial nerve I is the collection of approximately 6 million bipolar receptor cells whose cell bodies, dendrites, and initial axon segments are located within the olfactory neuroepithelium and whose axons project through the cribriform plate of the ethmoid bone to the anterior cranial fossa (Fig. 7-1 (Figure Not Available) ). '4 The olfactory neuroepithelium is a pseudostratified columnar epithelium supported by a highly vascularized lamina propria and is situated on the cribriform plate as...

Spinal Cord Strokes

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