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Disorders of Movement, Sensation, and Mental FunctionDr. Gary Mumaugh and Dr. Bruce SimatContext for Assessment of DysfunctionAutonomic Nervous System (ANS) regulates homeostatic, reactive, and sensory functionsEfferent nerves traveling out of CNS2 Divisions: ParasympatheticSympatheticBrain Stem regulates breathing and alertness and directs nerve connectionsMidbrain, Pons, and Medulla Cranial Nerves have sensory and motor functions12 nerves Motor Neurons control voluntary movementDisease Categories in NeurologyMyopathy – muscle diseasesMyelopathy – cord compression diseasesNeuropathy – nerve diseasesRadiculopathy – nerve root compressionPlexopathy – nerve plexus compressionEncephalopathy – brain diseasesDisorders of Neuromuscular JunctionMyasthenia Gravis (MG)Characterized by skeletal muscle weakness and malaiseCaused by an autoimmune disorderAntibodies are produced against acetylcholine (Ach) receptors. Antibodies bind to the receptor and are not easily released. Bound antibodies stimulate phagocytosis of endplate muscle membraneBound antibodies induce degradation of receptor channelsSymptoms include Myasthenic crisis – acute muscle weakness resulting in inability to swallow, clear secretions, or breathe well. Lambert-Eaton Myasthenic Syndrome (LEMS)Similar to MG, but weakness improves with exertionCaused by impaired release of AchSymptoms: Muscle weakness, dry mouth, decreased sweating, constipation60% of patients have lung carcinomas prior to diagnosisPeripheral Nerve DisordersDiffuse PolyneuropathiesGuillain-Barre SyndromeEntrapment SyndromesCharcot-Marie-Tooth Disease - (Peroneal Muscular Atrophy)Diffuse PolyneuropathiesCharacterized by peripheral nerve lesionsCaused by a variety of metabolic, toxic, and nutritional conditionsSymptoms include Glove-and-stocking anesthesia Characterized by loss of sensation in the hands and feet; loss of larger fibers leads to impaired proprioceptionNeuropathyAffects distal nerves in a glove like patternParesthesias, weakness, sensory lossCommon in diabetes, RA, alcoholic abuse and B12 deficiencyGuillain-Barre SyndromeCharacterized by immune-mediated attack on sheaths of well-myelinated fibersTypically occurs after an upper respiratory tract or flu viral infection. Idiopathic. Symptoms: Varying degrees of weakness and tingling sensation in the legs leads to complete paralysis. 85% make complete recovery within 4 - 6 monthsEntrapment SyndromesCharacterized by focal slowing and loss of intensity of motor and sensory signalsCauses of Peripheral nerve lesions: Local compression and trauma (Ex. Saturday night palsy or tardy ulnar palsy)Overuse, repetitive motion injury (Ex. Pronator terres syndrome)Combination of overuse and genetic predisposition (Ex. Carpal tunnel syndrome)Symptoms: Muscle wasting, eventually irreversible fibrosisCharcot-Marie-Tooth Disease - (Peroneal Muscular Atrophy)Heritable, autosomal dominantCharacterized by atrophy of peripheral motor and sensory neuronsCharacterized by onset in late adolescenceSymptoms: Weakness and atrophy in distal muscles of the legsDisorders of the Spinal CordSyringomyeliaSubacute Combined Degeneration of the Cord (Lichtheim’s disease)Amyotrophic Lateral Sclerosis (ALS)Spinal Muscular Atrophies of Infancy and ChildhoodFriedreick’s AtaxiaSyringomyeliaA rare condition that produces a syrinx (fluid filled cavity) in the central spinal cord. Syrinx caused by spinal cord traumaCause is idiopathic Symptoms include Shawl anesthesia - pain and temperature insensitivity in arms and upper trunkSubacute Combined Degeneration of the Cord (Lichtheim’s disease)Characterized by a generalized lesion of the posterior half of the spinal cordUsually caused by chronic alcohol abuseAmyotrophic Lateral Sclerosis (ALS) Also called Lou Gerhig’s disease and Motor Neuron diseaseCharacterized by lower motor neuron lesion and lateral scarring because of upper motor neuron lesionFatal; 80% of people die within 3 years of diagnosis; no effective treatmentsCaused by: Environmental toxins, slow virusesSymptom: Excitotoxicity (destructive response of neurons to excessive stimulation)Degenerative disease of UMN & LMN lesionsDiffusely affects upper and lower motor neurons of the cerebral cortex, brain stem, and spinal cord (corticospinal tracts and anterior roots)Disease leads to progressive weakness leading to respiratory failure and deathUnknown cause autoimmune disorderUsually fatal in 1-2 yearsS & SWeakness of hands, loss of grip, tripping, fallingDisease begins distally and works proximallyNo sensation loss, no pain, no mental lossDifficulty speaking and swallowing, droolingDeath in 1-3 years from respiratory failureDiagnosis - History and muscle biopsyPatient has normal intellectual and sensory function until deathSpinal Muscular Atrophies of Infancy and ChildhoodRare, heritable motor disorders that leave sensory capacities intactWerdnig-Hoffman disease (floppy baby syndome)Onset in infancy, rapidly progresses Symptoms: Motor degeneration, but normal intelligence and developmentFriedreick’s AtaxiaFatal motor-sensory disorderChronic, average course of 15-20 yearsHalf of patients diagnosed develop cardiomyopathiesCaused by autosomal recessive disorder affecting production of frataxin Results in mitochondrial dysfunction and free radical toxicitySymptoms: Spinal cord is small and nerve fibers are depletedDisorders Arising in the Basal GangliaParkinson’s DiseaseHuntington’s DiseaseParkinson DiseaseSevere degeneration of the basal ganglia (corpus striatum) involving the dopaminergic nigrostriatal pathwayParkinsonian tremorParkinsonian rigidityParkinsonian bradykinesiaPostural disturbancesAutonomic and neuroendocrine symptomsCognitive-affective symptomsSlow, degenerative CNS disorderCourse of disease lasts 10-20 yearsAffects twice as many men as womenCaused by damage to the substantia negraNormally provides outflow pathway from basal ganglia to the cortex and a feedback loop to the caudate and putamenImpairs flow of motor programs from the basal gangliaCauses bradykinesia (slow movement) and difficulty initiating movementLoss of feedback loop expresses itself as resting tremorGradual loss of dopamine-producing cellsTypically idiopathicKnown to result from lesion by toxinsSymptomsMuscle rigidity, bradykinesia, palsy (resting tremor), tiredness and weakness, poor balance, dementiaDegenerative disorder of the basal ganglia Usually in men over 50One million cases in USA3480435000Parkinson Disease S & SFour classic symptoms:Resting muscle tremorSlowness of voluntary movement – bradykinesiaImpaired postural reflexes – simian postureInability to maintain balance when being shoved or bumpedOther symptoms:Increased muscle tone or rigiditySmall “steppage” gaitsFrozen facial expression – “masked face”Handwriting changes – micrographiaDiagnosis - No classic diagnostic tests or lab studiesTreatmentDopamine is used for the first five yearsAnticholinergic drugs, MAO inhibitors, SymmetrylThe meds do not stop the progression, they only provide symptomatic reliefSurgical treatment is currently experimentalImplanting cadaver or fetal basal ganglion cellsHuntington’s DiseaseCharacterized by dominant genetic defect on chromosome 4Dementia consists of progressive loss of cognitive functionMassive cellular loss from caudate and putamenCourse of disease is about 15 yearsSymptoms: rapid, writhing contortions of hands, arms, face, trunk and profound dementiaAlso known as “chorea”Autosomal dominant hereditary-degenerative disorderSevere degeneration of the basal ganglia (caudate nucleus) and frontal cerebral atrophyDepletion of gamma-aminobutyric acid (GABA)Cerebral PalsyGeneral term that applies to disabilities that derive from perinatal brain injuryMovement problems, sensory and cognitive impairmentCP is commonly classified based on the area of the body most affectedQuadriplegic CP – all 4 limbs affectedDiplegic CP – lower limbs affected more than upperMonoplegic CP – only 1 limb affected268278491002680335508000Demyelinating DisordersMultiple sclerosis (MS)MS is a progressive, inflammatory, demyelinating disorder of the CNSTypesMixed (general)SpinalCerebellarMultiple Sclerosis (MS)Possibly caused by an interaction between a viral illness in teen years and a genetic predispositionArises through a single mechanism of lesionFocal, chronic, progressiveAreas of demyelination are called plaquesConfined to white matterOptic neuritis is often the first symptomChronic exacerbation and remissionTriggers: infection, medication, stress, fatigueAlzheimer’s DiseaseDementia is the loss of ordered neural functionMain characteristic of Alzheimer’s is a slow progression of dementia, 5 yearsInitially only short-term storage and retrieval is affectedGradually well-consolidated memories are affectedPatient experiences restlessness and wanderingEventually patient is mute and paralyzedDeath usually comes from infection of a weakened, dehydrated patientAtrophyPyramidal cells die along with axons → loss of white matter → Gyri shrink → ventricles expandSeverity and progression of disease due toNeurofibrillary tanglesNeurotic plaques - Senile plaquesMade up of Amyloid (starchlike) proteinsAmyloid beta proteinDirectly toxic to neural tissueTriggers inflammatory responseFamilial, early and late onsetNonhereditary (sporadic, late onset)Alzheimer’s DiseaseTheoriesMutation for encoding amyloid precursor proteinAlteration in apolipoprotein ELoss of neurotransmitter stimulation of choline acetyltransferaseClinical manifestationsForgetfulness, emotional upset, disorientation, confusion, lack of concentration, decline in abstraction, problem solving, and judgmentDiagnosis is made by ruling out other causes of dementia ................
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