Muscle strength

Active movement, with gravity eliminated Active movement against gravity and resistance From Medical Research Council Aids to the Examination of the Peripheral Nervous System Memorandum No. 45. London, Crown Publishing, l976 discover whether there is a particular pattern of weakness that can be used to localize the lesion. Is it a hemiparesis, suggesting a hemispheric lesion, a paraparesis, which is consistent with a spinal cord lesion, or a proximal pattern of weakness compatible with a...

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...

Special Autonomic Function Testing

Many laboratory tests are used to diagnose autonomic disorders, quantify autonomic function, and evaluate the efficacy of treatment. Disorders for which autonomic testing provides useful information include those involving generalized autonomic failure such as the Shy-Drager syndrome, Parkinson's disease, and pure autonomic failure, suspected distal small-fiber and other peripheral neuropathies, orthostatic intolerance of uncertain etiology, syncope, localized autonomic disorders, unexplained...

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...

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...

Upper Motor Neuron Pool

There are many neurons in the cerebral cortex and brain stem that initiate and modify movement through their connections with the lower motor neurons in the anterior spinal gray. These projections also synapse on the internuncial pool of interneurons. which in turn make contact with the alpha and gamma motor neurons. These are known as the upper motor neurons. These supraspinal motor neurons in the cerebral cortex and brain stem are interconnected with each other and participate to various...

Amphetamine Analogs

The pathophysiological basis for the complications associated with amphetamine use are not well understood. Amphetamine-induced cerebral vasculitides cause occlusive as well as hemorrhagic strokes. Methamphetamine use can cause necrotizing angiitis. Also, cerebral arteritis with multiple occlusions of arterioles was reported in young abusers of intravenous methamphetamine who were hospitalized because of coma or stroke. y Angiographic studies in such patients...

Degenerative and Compressive Structural Disorders

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

Isaacs Disease

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

Directed Neurological Examination Cranial Nerve Xi

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

Clinical History

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

Progressive Aphasia

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

Other Positive Visual Phenomena

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

Dorsal Root Radiculopathy

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

REM Sleep

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

References

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

Unknown Inheritance Patterns

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

Abnormal Findings and Clinical Uses of the Blink Reflex

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

Etiology Percent

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

Measles

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

Other Peripheral Nerve Tumors

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

Associated Neurological Findings

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

History And Definitions

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

Evaluation Guidelines Table156

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

Neurological Applications in Diagnosis and Treatment

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

Anatomy of Arousal

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

Discriminative Touch Vibration and Conscious Sense of Joint Muscle Movement

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

Gastrointestinal Dysmotility

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

Reviews And Selected Updates

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

Neuropathy Ataxia Retinitis Pigmentosa Syndrome

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

Abnormal Findings and Clinical Uses of the SEP

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

Spinal Cord Tumors

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

Demyelinating Disorders of the Central Nervous System

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

Epstein Barr Virus

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

Comments

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

Normal and Pathological Findings see Tables262 263 and 264

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

Calcium Disorders

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

Limbic System

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

Spinal Cord Strokes

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

Metachromatic Leukodystrophies

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

Spinocerebellar Ataxia Type

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

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...

The Suprachiasmatic Nucleus

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

Pelizaeus Merzbacher Syndrome

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

Third Order Neuron

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

Clinical Environment

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

T2Wl

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

Syndromes of Overactivation

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

Exirapulmonary Causes

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

Fabrys Disease

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

Extracranial Steal Syndromes from Disease of the Aortic Branches

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

Anatomy of Cranial Nerves Iii Iv and VI

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

Reviews and Selected Updates References

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

Excessive Daytime Somnolence

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

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...

Clinical Uses of Nerve Conduction Studies

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

Basic Principles and Technique

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

Alexias And Agraphias Languagerelated Disorders

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

Visual Hallucinations

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

Partially Characterized Syndromes

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

Sympathetic Innervation of the Pupil

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

Directed Neurological Examination

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

Plexopathy

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

Selected Nonatherosclerotic Occlusive Diseases

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

Category C Severely Symptomatic

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

Table 162 Ototoxic Medications

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

Growth Hormone Hypersecretion Museuloskeletal Increas

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

Tetanus

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

Varicella Zoster Virus

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

Conjugate Gaze Palsy Syndromes

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

Associated Neurological Findings see Xable155

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

Druginduced

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

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...

Diffuse Autonomic Failure Pandysautonomia

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

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...

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...

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...

Stance and Gait Ataxia Presence of Rombergs Sign

Damage to the anterior lobe (spinocerebellum or paleocerebellum) result in ataxia of stance and gait. Patients with this disorder develop a severe disturbance of standing and walking with relatively preserved fine coordinated movements of the upper limbs. Lesions of the spinocerebellar part of the anterior lobe are mainly observed in chronic alcoholics and lead to anteroposterior body sway with a frequency of about 3 Hz. Visual stabilization of posture is preserved and the tremor is provoked by...

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...

Demyelinating Disorders

Multiple sclerosis (rare) Devic's disease Guillain-Barre syndrome (with dysautonomia) Autoimmune cerebritis including giant cell arterits, primary CNS artentis, and hypersensitivity arteritis and autoimmune induced dysautonomic states irom penpheral nervous system involvement including polyartentis and Wegener's granulomatosis. Systemic lupus erythematosus can affect either central or peripheral systems Cortical contusion, epidural hematomas, subdural hematomas Traumatic hematomas,...

Supranuclear Lesions

Interruption of the corticobulbar tracts providing innervation of cranial nerve motor nuclei from the cerebral precentral motor cortex produces disturbances of speech, swallowing, chewing, and occasionally breathing known as pseudobulbar palsy. Patients with this disorder may also have emotional lability with exaggerated crying or laughter in response to minimal provocation. Because the ninth and tenth cranial nerve nuclei receive bilateral innervation, a unilateral lesion may be silent or may...

History And Overview

First described in humans in the 1920s, spongiform encephalopathy is now known to encompass a group of noninflammatory degenerative disorders characterized neuropathologically by a diffuse spongiosis and amyloid protein deposition in the brain. These disorders include kuru, Creutzfeldt-Jakob disease (CJD), Gerstmann-Straussler- Scheinker syndrome (GSS), and fatal familial insomnia (FFI). The report in 1966 that kuru, an epidemic ataxic illness limited to the eastern highlands of Papua New...

Arenavirus Lymphocytic Choriomeningitis Virus

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

Vestibular System

The peripheral vestibular system consists of a set of three-dimensional angular velocity transducers, the semicircular canals, and a set of three-dimensional linear acceleration transducers, the otoliths (utricle and saccule) (see Fig. 12-1 (Figure Not Available) ). y These transducers are suspended by an assembly of membranes and connective tissue, the membranous labyrinth, within channels in the temporal bone, the bony labyrinth. Three important spatial arrangements characterize the...

Evaluation Guidelines Table82

Most patients with suspected optic neuropathies should undergo neuroimaging to exclude a compressive RDERS OF CRANIAL NERVE II AND AFFERENT VISUAL PATHWAYS MRA carotid occlusion, stenosis, or dissection electroretinogram if photoreceptors are affected Elevated ESR in giant cell arteritis Vascular occlusion or leakage on fluorescein angiography Thromboembolic source on cardiac echography or carotid ultrasound MRI with gadolinium and fat saturation, coronal views optic nerve...

Malignant Migraine

Various oxidative phosphorylation defects occur in the brain, although how they relate to the production of migraine is speculative. Migraine affects as much as 25 percent of the population and is frequently seen in maternal relatives of patients with diseases of oxidative phosphorylation. Malignant migraine refers to three situations migraine patients who turn out to have MELAS migraine patients who are maternal relatives of patients with oxidative phosphorylation diseases and who are...

Alcoholic Myopathy

There are two forms of alcoholic muscle disease (1) an acute, painful myopathy associated with weakness, cramps, swollen and tender muscles, high creatine kinase, and rhabdomyolysis with or without myoglobinuria and (2) a chronic myopathy that is painless and often unnoticed by the patient, causing proximal weakness and type II fiber atrophy on nerve biopsy. In addition to skeletal muscle involvement, patients may have an associated cardiomyopathy. 'sal Proposed mechanisms of alcoholic injury...

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...

Evaluation Guidelines j Table163

Many of the primary neurodegenerative movement disorders, whether hypokinetic or hyperkinetic, show no abnormalities on magnetic resonance imaging (MRI) or computed tomography (CT) scans other than mild to moderate cerebral atrophy. However, in N THE EVALUATION OF HYPOKINESIA AND HYPERKINESIA SYN In Parkinson's disease, MR and CT are normal. PET scans of F-dopa can show decreased uptake Usually not used. Can study tremor with tremorometer In multiple system atrophy putamen can...

Evaluation Guidelines Table95

Lesions of cranial nerves III, IV, and VI may occur anywhere along the course of the nerves, from the nuclei in the brain stem to the orbits. The possibility of focal neoplastic or inflammatory lesions requires evaluation with neuroimaging. Magnetic resonance imaging is more reliable than computed tomography for detecting brain stem, subarachnoid space, or cavernous sinus lesions. Magnetic resonance imaging is also the best procedure for imaging the orbits when fat suppression...

Evaluation Guidelines Table173

Immediate computerized tomography (CT) scanning or magnetic resonance imaging (MRI) has to be performed in the setting of acute and subacute cerebellar ataxia. Posterior fossa lesions (hemorrhage, ischemia, hydrocephalus, neoplasms, abscess, or parasitic infections) carry the risk of increased intracranial pressure and death because of the cerebellar tonsils moving downward and compressing the brain stem within the foramen magnum. Angiography of the vertebrobasilar vascular system...

Medulloblastoma

Almost two thirds of these tumors are located in the midline cerebellum, and over 90 percent are located in the vermis with encroachment on the cisterna magna. Laterally placed tumors are more common in adults. Ihe macroscopic appearance is that of a soft friable tumor with central necrosis. In children, these tumors are moderately demarcated, but in adults they are highly demarcated. Microscopically, neuropathological analysis has attempted to define these...

Neurological Examination

The neurological examination focuses on the general state of alertness. Patients may appear sleepy or even nod off during the examination if EDS is severe. Cognitive and psychological functioning is assessed for evidence of dementia or depression, both of which are associated with sleep pattern disruption. Excessive anxiety, fears, and concerns are frequent causes for insomnia, and clues to these problems may reveal themselves during cerebral assessments of memory, concentration, and...

Psychotic Syndromes

Antipsychotics (neuroleptics) can be used in patients with acute psychoses while a specific etiology is being sought ( .Jable.3-4 ). Although some of these drugs are sedating, they have more specific effects on the thought and mood disorder. Many different agents are available including the phenothiazines, thioxanthenes, dibenzoxazepines, and butyrophenones. The acutely psychotic patient who is a danger to himself or others may be treated parenterally with intramuscular haloperidol (5 mg every...

Speech Related Disorders

Miscellaneous speech-related disturbances not classified as dysarthrias or dysphonias include phonic tics, vocalizations, coprolalia, and reiterative speech disorders. PHONIC TICS AND VOCALIZATIONS Phonic tics are either simple or complex vocal tics. Simple vocal tics are similar in character to motor tics and are expressed as inarticulate noises and sounds (throat clearing, grunts, coughs, shouts, snorts, word accentuation). Complex vocal tics include articulate words, phrases, or sentences...

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...

Postgastroplasty Polyneuropathy

Some patients undergoing bariatric, or weight reduction, surgery develop a syndrome of acute or subacute sensory loss, weakness, and areflexia in the limbs, usually following a period of dramatic weight loss and repeated bouts of protracted vomiting. y A few patients have also developed a type of encephalopathy that is clinically and pathologically identical to WKS, with or without an associated polyneuropathy. y Indeed, Wernicke and Korsakoff each described young women with intractable...

Stroke Incidence and Prevalence

Stroke is a major public health problem, ranking among the top three causes of death in most countries. It affects the brains of almost a half million people every year, causing 150,000 deaths, and there are now approximately 3 million stroke survivors in the United States. Overall, ageadjusted incidence rates range between 100 and 300 per 100,000 population per year. Stroke is the major cause of serious disability in adults and is responsible for 20 billion in annual costs per year in lost...

Thiamine

The discovery and isolation of vitamins began with the study of beriberi in the 19th century. Although beriberi has been recognized for centuries, it was not until the Industrial Revolution that the disease reached epidemic proportions. Grain mills began producing polished rice, which was mechanically stripped of the nutrient-rich husk. Epidemics of painful polyneuropathy and heart failure rapidly developed in regions where rice was the major source of carbohydrate, particularly in Asia. In...

Rocky Mountain Spotted Fever

Rocky Mountain spotted fever is a rickettsial disease caused by Rickettsia rickettsi, a small intracellular parasite. Infection is acquired by a tick bite. The majority of infections are acquired in the south Atlantic coastal and the western and southern central states with the highest incidence in Virginia, North Carolina, South Carolina, Oklahoma, and Tennessee. The disease typically occurs during spring and summer. Fever, rash, and a history of exposure to ticks is the classic triad of Rocky...