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...

DNA viruses

Adapted from Bale JF Viral encephalitis Med Clin North Am 1993 77 2542. may enter the host through the mucosal surfaces of the gastrointestinal or respiratory tract. Enteroviruses are acquired most commonly by fecal-oral contamination and, less commonly, via aerosolized respiratory droplets. Enteroviruses

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...

Anatomy Of Mood Emotion And Thought

The neuroanatomic structures related to human mood, emotion, and thought function are complex, and research in this area is still under development. The association of various brain regions with particular functions is based primarily on studies of lesions and, more recently, on functional neuroimaging. Although generalizations based on these isolated cases are somewhat precarious, extended observations based on series of cases are somewhat more reliable. Additionally, although the findings of...

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...

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...

Reviews And Selected Updates

Chaves-Carballo E Detection of inherited metabolic disorders. Pediatr Clin North Am 1992 39 801-820. Chinnery PF, Johnson MA, Taylor RW A novel mitochondrial tRNA isoleucine gene mutation causing chronic progressive external ophthalmoplegia. Neurology 1997 49 1166-1168. DiDonato S, Parini R, Uziel G Metabolic Encephalopathies, Therapy and Prognosis. London, John Libbey & Co, 1995. Lindoz NM, Karnes PS Initial assessment of infants and children with suspected inborn errors of metabolism. Mayo...

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...

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...

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),...

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...

Reasoning and Problem Solving Through Concept Formation

Reasoning and problem solving are highly related to intellectual functioning. Similar to intellectual function, these abilities tend to be impaired following damage to the CNS. Specific location of injury appears to be less important to reasoning impairments, as does the presence of CNS disturbance. Impairments in reasoning and problem solving result in difficulties in all areas of daily functioning. Patients may be not be able to form generalizations from a given situation and interpret events...

Distal Myopathies

The distal myopathies are a rare heterogeneous group of disorders characterized by progressive muscular weakness and atrophy beginning in the hands or feet ( . Table.36-7,). Several types of distal myopathies have been differentiated clinically, distinguished either by site of onset or mode of inheritance or by differences seen on muscle biopsy. The late adult-onset distal autosomal dominant myopathy that first appears in the hands, also called Welander distal myopathy or Swedish-type distal...

Disorders of Memory

A disorder of declarative memory is defined as amnesia. A pure amnesia refers to a relatively circumscribed disorder of declarative memory that cannot be accounted for by nonmnemonic deficits such as attention, perception, language, or motivation. Anterograde amnesia refers to the inability to acquire new declarative memories. Retrograde amnesia refers to the loss of memories acquired prior to the onset of the amnesia. Retrograde amnesias are described as flat when they extend back uniformly...

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...

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...

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,...

Primary Small Brain Size

Nongenetic insults (prenatal, perinatal, postnatal) Infectious Vascular disruption, hypoxic-ischemic insult Irradiation Trauma (including shaken baby syndrome) Metabolic and degenerative conditions with onset before completion of brain growth Infantile neuronal ceroid lipofuscinosis Chromosomal instability and premature aging disorders Nijmegen chromosome breakage syndrome Monogenic or sporadic syndromic disorders Cornelia de Lange's syndrome Meckel's syndrome Rubinstein-Taybi syndrome Also

Organic Mercury

Organic mercury readily crosses the blood-brain barrier, and its turnover in the brain is slow. In cases of chronic exposure, approximately 10 percent of the body burden localizes in the brain. Less than 3 percent is degraded into inorganic mercury. In a single case study, histological changes and high mercurial content were noted in the corpus callosum. Excretion occurs primarily through the gastrointestinal tract, mostly through biliary secretion, and the...

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...

Clinical History

A patient's description of the nature and onset of the chemosensory problem is an essential element of the clinical history, as is an historical assessment of the patient's general health, including endocrinological state, hospital admissions, surgical interventions, radiological treatments, and medications received for other conditions. The use of thyroid agents and drugs that affect cell turnover (e.g., chemotherapeutic drugs) may be of etiological significance. Retarded or delayed puberty in...

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 Praxis

Much of what we know about the anatomical basis of praxis (the ability to perform voluntary skilled movements) comes from the observations of patients with discrete cerebral lesions who have lost these abilities. To perform learned skilled movements, several types of knowledge are required. One must know how to move the limb through space (spatial trajectory) and how fast to move it. To successfully interact with the environment, a conceptual knowledge of praxis is also needed, such as what...

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...

Dermoid Epidermoid and Teratoma

These rare embryonic remnant tumors may present anywhere in the CNS but most commonly occur in the posterior fossa and the cauda equina. They are congenital tumors and may be seen at any age however, they are more likely to occur in children or young adults of either sex. They are slow growing and present with symptomatology specific for compressive syndromes at their location within the central nervous system. These symptoms can be insidious, and blockage of cerebrospinal flow occurs rarely....

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...

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...

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...

History And Definitions

The afferent visual pathways encompass structures responsible for perceiving, relaying, and processing visual information the eyes, optic nerves (cranial nerve II), chiasm, tracts, lateral geniculate nuclei, optic radiations, and striate cortex. In general, the visual abnormalities caused by lesions anterior to and including the chiasm cause acuity (clarity) loss, color deficits, and visual field defects (abnormal central or peripheral vision). From a neuro-ophthalmical standpoint, patients...

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....

Syndromes Of Parenchymal Overgrowth Neurocutaneous Syndromes

Neurofibromatosis 1 Tuberous sclerosis Proteus syndrome Klippel-Trenaunay-Weber syndrome Riley-Smith syrdrome Shapiro-Shelman syndrome Linear sebaceous nevus syndrome Generalized Overgrowth Syndromes Sotos' syndrome Ruvalcaba-Myhre-Smith syndrome Beekwith-Wiedemann syndrome Weaver's syndrome Bannayan-Zonana syndrome METABOLIC DISORDERS Alexander's disease Canavan's disease (N-acetyl aspartoacylase deficiency)

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...

Abnormal Findings and Clinical Uses of FResponse and HReflex Studies

F-response and H-reflex studies are sometimes useful in the evaluation of patients with peripheral neuropathies, Figure 24-23 Diagrammatic representation of the relationship between the direct (M) response, F response, and H reflex, and the intensity of the eliciting stimulus. With low-intensity stimulation of the tibial nerve, an H reflex is elicited from the soleus muscle. As the intensity of stimulation increases, the H reflex declines and a small M wave is seen. With a higher stimulus...

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...

Pontine Lesions

A unilateral lesion in the brain stem (e.g., stroke, multiple sclerosis, abscess, tumor) may produce dissociated weakness, with ipsilateral weakness of the SCM and contralateral weakness of the trapezius. y In addition, the supranuclear fibers for the SCM muscle probably decussate twice. A lesion in the right side of the pons may result in left-sided weakness (i.e., involvement of the corticospinal tract fibers before their decussation in the medulla) and possible deviation of the head to the...

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,...

Visual Association Areas

Extrastriate areas V2 and V3 surround V1 above and below the calcarine sulcus. Isolated and clinically apparent lesions of V2 and V3 are unusual, but a combined lesion of V2 and V3 restricted to upper or lower bank typically causes a homonymous quadrantic visual field defect. y Higher cortical processing of visual information occurs in visual association areas, which are divided anatomically and functionally into ventral and dorsal pathways. In general, the ventral stream (occipitotemporal) is...

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...

Abnormal Findings and Clinical Uses of Repetitive Nerve Stimulation

Repetitive nerve stimulation is a useful technique for evaluating neuromuscular transmission. In diseases in which such transmission is impaired, the muscle response to repetitive nerve stimulation may show abnormal alterations in size or area. In myasthenia gravis, a progressive decrement in the response may occur with repetitive stimulation (especially at 2 to 3 Hz), or an initial decrement may be followed by a leveling off of the response at a reduced size. Abnormalities are more likely to...

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...

Cobalamin Vitamin B12

Vitamin B12 deficiency produces neurological and hematological effects by impairing the function of two enzyme systems (Fig. 40-5 (Figure Not Available) ). y , y Methylcobalamin is a co-factor of methionine synthase, a cytosolic enzyme that catalyzes the conversion of homocysteine and methyltetrahydrofolate to produce methionine and tetrahydrofolate. Methionine is further metabolized to S-adenosylmethionine, which is necessary for methylation of myelin sheath...

Subacute Necrotizing Encephalomyelopathy Leighs Disease

At the molecular level, Leigh's disease can be caused by both mendelian (autosomal recessive nuclear coded DNA) and mtDNA defects.y , y Areas affected are primarily the basal ganglia, brain stem, and cerebellum. The cerebral cortex and retinal pigment are less involved. Pathologically, there is spongy degeneration, demyelination, gliosis, necrosis, relative sparing of neurons, and capillary proliferation. Several enzyme complexes involved in mitochondrial...

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...

Neuronal Ceroidlipofuscinoses

Neuronal ceroid-lipofuscinoses (NCLs) are a group of diseases characterized by neurological symptoms and the accumulation of autofluorescent waxy lipopigments within the lysosomes of neurons and other cells. The disorders are linked to a number of celebrated names in neurological history, including Batten, Jansky, Bielschowsky, Santavuori, and Kuf, each of whom described clinical variants of these multidimensional disorders. The conglomerate term neuronal ceroid-lipofuscinoses was coined by...

Spinal Cord Myelopathy

Generally with transverse lesions of the spinal cord there is a demonstrable sensory level with bilateral loss of all modalities of sensation below a definite level. With involvement of the dorsal columns there is loss of proprioception, discriminative modalities, and vibration within a couple of levels caudad to the lesion site. With smaller lesions it is possible to selectively involve certain dorsal column modalities owing to the topographical distribution of the various modalities fibers...

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...

Carnitine Transport Defect Primary Generalized Carnitine Deficiency

Carnitine fails to be taken up in muscle, heart, and kidney but not liver, leading to insufficient carnitine to support fatty acid oxidation. 70 The kidney fails to conserve carnitine by reabsorption, resulting in very low plasma carnitine levels, which then causes decreased passive diffusion into liver, impairing ketogenesis. Accumulating acyl-CoA compounds become substrates for peroxisomal beta- oxidation, which produces medium-chain fatty acids and dicarboxylic acids, which do not require...

Brain Stem

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

Peripheral Neuropathies

Approximately 5 percent of cancer patients have clinical neuropathy, 12 percent have abnormalities on quantitative sensory testing, and 40 percent have electrophysiological abnormalities. y Typically, women with small cell lung or breast carcinoma present with asymmetrical upper limb pain, paresthesia, and sensory loss preceding the diagnosis of cancer. When proprioception is lost, pseudoathetosis occurs. Subacute sensory neuronopathy results from inflammation and degeneration of the dorsal...

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...

Heart Studies

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

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...

Coccidioides immitis

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

Meningiomas

Many classification schemes are used for meningiomas, usually based on the histological appearance (see Ja.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,...

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...

Affective Disorder Syndromes

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

Abducens Nerve Cranial Nerve VI

The abducens nucleus is medial and dorsal at the pontomedullary junction, separated from the floor of the fourth ventricle by the genu of the facial nerve. Within the abducens nucleus, lateral rectus motor neurons intermix with internuclear neurons, sending their axons across to the opposite MLF and then to the contralateral third cranial nerve. Axons of the sixth cranial nerve course almost directly ventral and exit from the pons near the midline. The axons emerge in the horizontal sulcus...

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...

Extracranial Arterial System

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

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...