Disorders of the Central and Peripheral Nervous Systems and the Neuromuscular Junction Chapter 17...

Disorders of the Central and Disorders of the Central and Peripheral Nervous Systems and the Peripheral Nervous Systems and the

Neuromuscular JunctionNeuromuscular Junction

Chapter 17Chapter 17

Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.

2Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.Mosby items and derived items © 2010, 2006 by Mosby, Inc., an affiliate of Elsevier Inc.

Brain TraumaBrain Trauma Traumatic brain injuryTraumatic brain injury

A traumatic insult to the brain possibly producing A traumatic insult to the brain possibly producing physical, intellectual, emotional, social, and physical, intellectual, emotional, social, and vocational changesvocational changes


At-Risk IndividualsAt-Risk Individuals Infants 6 months to 2 yearsInfants 6 months to 2 years School-age childrenSchool-age children Adolescents and young adults 15 to 35 years Adolescents and young adults 15 to 35 years

of ageof age People more than 70 years of age People more than 70 years of age Men 1.5 times as likely to sustain a TBIMen 1.5 times as likely to sustain a TBI Persons living in high-crime areasPersons living in high-crime areas


Brain TraumaBrain Trauma Blunt (closed, nonmissile) traumaBlunt (closed, nonmissile) trauma

Head strikes hard surface or a rapidly moving Head strikes hard surface or a rapidly moving object strikes the headobject strikes the head

The dura remains intact; brain tissues not exposed The dura remains intact; brain tissues not exposed to the environment to the environment

Causes focal (local) or diffuse (general) brain Causes focal (local) or diffuse (general) brain injuriesinjuries

Open (penetrating, missile) traumaOpen (penetrating, missile) trauma Injury breaks the dura and exposes the cranial Injury breaks the dura and exposes the cranial

contents to the environmentcontents to the environment Causes primarily focal injuriesCauses primarily focal injuries


Brain TraumaBrain Trauma Compound fracturesCompound fractures Basilar skull fractureBasilar skull fracture


Brain TraumaBrain Trauma


Causes of Brain InjuryCauses of Brain Injury Falls 28% Falls 28% Motor vehicle crashes 20% Motor vehicle crashes 20% Moving objects or moving against stationary Moving objects or moving against stationary

objects 19% objects 19% Assault 11% Assault 11% Sports-related events Sports-related events Blasts (military active duty personnel)Blasts (military active duty personnel)


Severity of Brain InjurySeverity of Brain Injury

75% to 90% of head injuries not severe 75% to 90% of head injuries not severe Focal brain injury and diffuse axonal injury (DAI) Focal brain injury and diffuse axonal injury (DAI)

each account for half of all injuries each account for half of all injuries Focal brain injury accounts for more than two Focal brain injury accounts for more than two

thirds of head injury thirds of head injury deaths; deaths; DAI less than one DAI less than one third of deathsthird of deaths DAI accounts for the greatest number of severely DAI accounts for the greatest number of severely

disabled survivorsdisabled survivors


Severity of Brain InjurySeverity of Brain Injury

Hallmark of severe brain injuryHallmark of severe brain injury Loss of consciousness for six or more hoursLoss of consciousness for six or more hours


Focal Brain InjuryFocal Brain Injury Observable brain lesionObservable brain lesion Cerebral edemaCerebral edema Coup injuryCoup injury

Injury directly below the point of impactInjury directly below the point of impact ContrecoupContrecoup

Injury on the pole opposite the site of impactInjury on the pole opposite the site of impact


Focal Brain InjuryFocal Brain Injury Force of impact typically produces contusionsForce of impact typically produces contusions Contusions can cause: Contusions can cause:

Extradural (epidural) hemorrhage or hematomaExtradural (epidural) hemorrhage or hematoma Subdural hematomaSubdural hematoma Intracerebral hematoma Intracerebral hematoma Clinical manifestations of contusionClinical manifestations of contusion


Extradural HematomaExtradural Hematoma 85% arterial bleeding85% arterial bleeding 15% meningeal vein or dural sinus injury15% meningeal vein or dural sinus injury 90% have a skull fracture 90% have a skull fracture The temporal fossa is the most common site The temporal fossa is the most common site

of extradural hematoma caused by injury to of extradural hematoma caused by injury to the middle meningeal artery or vein the middle meningeal artery or vein

Clinical manifestations of hematomaClinical manifestations of hematoma


Subdural HematomaSubdural Hematoma 10% to 20% of persons with traumatic brain 10% to 20% of persons with traumatic brain

injury injury MVAs are the most common cause MVAs are the most common cause 50% of subdural hematomas associated with 50% of subdural hematomas associated with

skull fracturesskull fractures Falls (older adults, substance abuse)Falls (older adults, substance abuse)


Subdural HematomaSubdural Hematoma AcuteAcute

Develops within 48 hoursDevelops within 48 hours Often located at the top of the skullOften located at the top of the skull

ChronicChronic Develops over weeks to monthsDevelops over weeks to months

• Older adultsOlder adults

• Alcohol abuseAlcohol abuse

• 80% complain of chronic headaches and have tenderness at 80% complain of chronic headaches and have tenderness at site of injurysite of injury


Intracerebral HemorrhageIntracerebral Hemorrhage Associated with MVA and fallsAssociated with MVA and falls Intracerebral hemorrhage and resultant Intracerebral hemorrhage and resultant

hematoma acts as an expanding masshematoma acts as an expanding mass Increased ICP and compression of brain tissues Increased ICP and compression of brain tissues

with resultant edema with resultant edema


Diffuse Brain InjuryDiffuse Brain Injury DAIDAI

Shaking, inertial effectShaking, inertial effect Acceleration/decelerationAcceleration/deceleration Axonal damageAxonal damage

• Shearing, tearing, or stretching of nerve fibersShearing, tearing, or stretching of nerve fibers

Severity corresponds to the amount of shearing Severity corresponds to the amount of shearing force applied to the brain and brainstem (mild, force applied to the brain and brainstem (mild, moderate, severe)moderate, severe)


Diffuse Brain Injury Diffuse Brain Injury ConcussionsConcussions

Mild concussionMild concussion Classical concussionClassical concussion


Mild ConcussionMild Concussion Temporary Temporary axonal disturbancesaxonal disturbances causing causing

attention and memory deficits but no loss of attention and memory deficits but no loss of consciousnessconsciousness I—confusion, disorientation, and momentary I—confusion, disorientation, and momentary

amnesiaamnesia II—momentary confusion and retrograde amnesiaII—momentary confusion and retrograde amnesia III—confusion with retrograde and anterograde III—confusion with retrograde and anterograde

amnesiaamnesia


Classic Cerebral ConcussionClassic Cerebral Concussion Grade IVGrade IV

Disconnection of cerebral systems from the Disconnection of cerebral systems from the brainstem and reticular activating systembrainstem and reticular activating system

Physiologic and neurologic dysfunction without Physiologic and neurologic dysfunction without substantial anatomic disruption substantial anatomic disruption

Loss of consciousness (<6 hours)Loss of consciousness (<6 hours) Anterograde and retrograde amnesiaAnterograde and retrograde amnesia Uncomplicated (no focal injury) Uncomplicated (no focal injury) Complicated (focal injury)Complicated (focal injury)


Postconcussive SyndromePostconcussive Syndrome Headache, cognitive impairments, Headache, cognitive impairments,

psychologic and somatic complaints, cranial psychologic and somatic complaints, cranial nerve signs and symptomsnerve signs and symptoms

Treatment Treatment Reassurance and symptomatic reliefReassurance and symptomatic relief Close observation for 24 hours by a reliable Close observation for 24 hours by a reliable

individual so immediate intervention can be individual so immediate intervention can be obtained if delayed effects become severeobtained if delayed effects become severe


Spinal Cord Trauma Spinal Cord Trauma

Commonly occurs from vertebral injuriesCommonly occurs from vertebral injuries Simple fracture, compressed fracture, and Simple fracture, compressed fracture, and

comminuted fracturecomminuted fracture Traumatic injury of vertebral and neural tissues Traumatic injury of vertebral and neural tissues

due to compressing, pulling, or shearing forcesdue to compressing, pulling, or shearing forces Most common locations: cervical (1, 2, 4-7), Most common locations: cervical (1, 2, 4-7),

and T1-L2 lumbar vertebraeand T1-L2 lumbar vertebrae Locations reflect most mobile portions of vertebral Locations reflect most mobile portions of vertebral

column and the locations where the spinal cord column and the locations where the spinal cord occupies most of the vertebral canaloccupies most of the vertebral canal

Primary vs. secondary injuryPrimary vs. secondary injury






Spinal Cord Trauma Spinal Cord Trauma Spinal shockSpinal shock

Normal activity of the spinal cord ceases at and Normal activity of the spinal cord ceases at and below the level of injury; sites lack continuous below the level of injury; sites lack continuous nervous discharges from the brainnervous discharges from the brain

Complete loss of reflex function (skeletal, bladder, Complete loss of reflex function (skeletal, bladder, bowel, sexual; thermal control; autonomic control)bowel, sexual; thermal control; autonomic control)


Spinal Cord Trauma Spinal Cord Trauma Neurogenic shockNeurogenic shock

Loss of sympathetic outflowLoss of sympathetic outflow• VasodilationVasodilation

• HypotensionHypotension

• BradycardiaBradycardia

• HypothermiaHypothermia


Spinal Cord Trauma Spinal Cord Trauma ParaplegiaParaplegia QuadriplegiaQuadriplegia Autonomic hyperreflexia (dysreflexia)Autonomic hyperreflexia (dysreflexia)

Massive, uncompensated cardiovascular response Massive, uncompensated cardiovascular response to stimulation of the sympathetic nervous systemto stimulation of the sympathetic nervous system

Stimulation of the sensory receptors below the Stimulation of the sensory receptors below the level of the cord lesionlevel of the cord lesion


Spinal Cord TraumaSpinal Cord Trauma Chemical and metabolic changes in tissues Chemical and metabolic changes in tissues

Release of toxic excitatory amino acids, accumulation Release of toxic excitatory amino acids, accumulation of endogenous opiates, lipid hydrolysis with of endogenous opiates, lipid hydrolysis with production of active metabolites, and local free radical production of active metabolites, and local free radical release release

Produce further ischemia, vascular damage, and Produce further ischemia, vascular damage, and necrosis of tissues necrosis of tissues

Necrosis consumes 40% of cross-sectional cord Necrosis consumes 40% of cross-sectional cord within 4 hours of trauma and 70% within 24 hours within 4 hours of trauma and 70% within 24 hours

Cord swelling increases degree of dysfunction Cord swelling increases degree of dysfunction • Distinguishing functions to be lost permanently from those Distinguishing functions to be lost permanently from those

that are impaired temporarily becomes difficult that are impaired temporarily becomes difficult • In the cervical region, cord swelling may be life threateningIn the cervical region, cord swelling may be life threatening


Autonomic Hyperreflexia Autonomic Hyperreflexia


Degenerative Disorders of the Degenerative Disorders of the SpineSpine

Degenerative disk disease (DDD)Degenerative disk disease (DDD) SpondylolysisSpondylolysis SpondylolisthesisSpondylolisthesis Spinal stenosisSpinal stenosis

Low back painLow back pain Herniated intervertebral diskHerniated intervertebral disk


Cerebrovascular DisordersCerebrovascular Disorders Cerebrovascular accidents (CVAs) Cerebrovascular accidents (CVAs)

Thrombotic strokeThrombotic stroke• Arterial occlusions caused by thrombi formed in arteries Arterial occlusions caused by thrombi formed in arteries

supplying the brain or in intracranial vesselssupplying the brain or in intracranial vessels

• Transient ischemic attacksTransient ischemic attacks

Embolic strokeEmbolic stroke• Fragments that break from a thrombus formed outside Fragments that break from a thrombus formed outside

the brain the brain


Cerebrovascular DisordersCerebrovascular Disorders Hemorrhagic stroke (ICH)Hemorrhagic stroke (ICH) Lacunar strokeLacunar stroke Cerebral infarctionCerebral infarction Cerebral hemorrhageCerebral hemorrhage


Cerebrovascular DisordersCerebrovascular Disorders Intracranial aneurysmIntracranial aneurysm

Saccular (berry) aneurysmsSaccular (berry) aneurysms Fusiform (giant) aneurysmsFusiform (giant) aneurysms Mycotic aneurysmsMycotic aneurysms Traumatic aneurysmsTraumatic aneurysms

• Dissecting aneurysmsDissecting aneurysms


Intracranial AneurysmIntracranial Aneurysm


Cerebrovascular DisordersCerebrovascular Disorders Vascular malformationsVascular malformations

Cavernous angiomasCavernous angiomas Capillary telangiectasisCapillary telangiectasis Venous angiomaVenous angioma Arteriovenous malformationArteriovenous malformation


Cerebrovascular DisordersCerebrovascular Disorders Subarachnoid hemorrhageSubarachnoid hemorrhage

Blood escapes from defective or injured Blood escapes from defective or injured vasculature into the subarachnoid spacevasculature into the subarachnoid space

ManifestationsManifestations Kernig signKernig sign Brudzinski signBrudzinski sign

Risk factorsRisk factors


HeadacheHeadache Migraine headacheMigraine headache

Trigger factorsTrigger factors AuraAura

Cluster headacheCluster headache Several attacks can occur during the day for days Several attacks can occur during the day for days

followed by a long period of spontaneous followed by a long period of spontaneous remissionremission


HeadacheHeadache Chronic paroxysmal hemicraniaChronic paroxysmal hemicrania

Cluster-type headache that occurs with more daily Cluster-type headache that occurs with more daily frequency but with shorter durationfrequency but with shorter duration

Tension-type headacheTension-type headache Mild to moderate bilateral headache with a Mild to moderate bilateral headache with a

sensation of a tight band or pressure around the sensation of a tight band or pressure around the headhead


Central Nervous System TumorsCentral Nervous System Tumors Cranial tumorsCranial tumors

Primary intracerebral tumors (gliomas)Primary intracerebral tumors (gliomas)• AstrocytomaAstrocytoma

• OligodendrogliomaOligodendroglioma

• EpendymomaEpendymoma

Primary extracerebral tumorsPrimary extracerebral tumors• MeningiomaMeningioma

• Nerve sheath tumorsNerve sheath tumors

• Metastatic carcinomaMetastatic carcinoma


Central Nervous System TumorsCentral Nervous System Tumors Spinal cord tumorsSpinal cord tumors

Intramedullary tumorsIntramedullary tumors Extramedullary tumorsExtramedullary tumors

• Intradural Intradural • Extradural Extradural

ManifestationsManifestations• Compressive syndromeCompressive syndrome• Irritative syndromeIrritative syndrome• Syringomyelic syndromeSyringomyelic syndrome


Spinal Cord TumorsSpinal Cord Tumors


Infection and Infection and Inflammation of the CNSInflammation of the CNS

MeningitisMeningitis Bacterial meningitisBacterial meningitis Aseptic (viral, nonpurulent, lymphocytic) meningitisAseptic (viral, nonpurulent, lymphocytic) meningitis Fungal meningitisFungal meningitis Tubercular (TB) meningitisTubercular (TB) meningitis



Suppurative cerebral massesSuppurative cerebral masses Cerebral abscessCerebral abscess Spinal cord abscessSpinal cord abscess

• Intramedullary spinal cord abscessIntramedullary spinal cord abscess



EncephalitisEncephalitis Acute febrile illness, usually of viral origin with Acute febrile illness, usually of viral origin with

nervous system involvementnervous system involvement Most common forms of encephalitis are caused by Most common forms of encephalitis are caused by

arthropod-borne viruses and herpes simplex virusarthropod-borne viruses and herpes simplex virus


Neurologic Complications of Neurologic Complications of AIDSAIDS

HIV-associated cognitive dysfunctionHIV-associated cognitive dysfunction HIV myelopathyHIV myelopathy HIV neuropathyHIV neuropathy Aseptic viral meningitisAseptic viral meningitis Opportunistic infectionsOpportunistic infections Cytomegalovirus infectionsCytomegalovirus infections Parasitic infectionParasitic infection CNS neoplasmsCNS neoplasms


HIV DementiaHIV Dementia

Affects adults and childrenAffects adults and children Insidious and unpredictable courseInsidious and unpredictable course Impaired concentration, short-term memory, Impaired concentration, short-term memory,

retrieval retrieval Generalized cognitive system deficits Generalized cognitive system deficits

Occur later Occur later Psychomotor slowing Psychomotor slowing Decreased speech spontaneity and fluency Decreased speech spontaneity and fluency Progressive loss of balance, ataxia, spastic paraparesis Progressive loss of balance, ataxia, spastic paraparesis

or paralysis, and generalized hyperreflexia or paralysis, and generalized hyperreflexia


Lyme DiseaseLyme Disease Tick-borne spirochete bacterial infectionTick-borne spirochete bacterial infection Borrelia burgdorferiBorrelia burgdorferi ProgressionProgression

Introduced by tick biteIntroduced by tick bite Incubates 3 to 32 daysIncubates 3 to 32 days Migrates to skin, lymph nodes, and other body Migrates to skin, lymph nodes, and other body

systemssystems


Lyme DiseaseLyme Disease StagesStages

1 Bull's eye rash1 Bull's eye rash 2 Cardiac and neurological manifestations2 Cardiac and neurological manifestations 3 MS, enhanced neurological manifestations3 MS, enhanced neurological manifestations


Demyelinating DisordersDemyelinating Disorders Multiple sclerosis (MS)Multiple sclerosis (MS)

Progressive, inflammatory, demyelinating, Progressive, inflammatory, demyelinating, autoimmune disorder of the CNSautoimmune disorder of the CNS

Degeneration of the myelin sheath in CNS Degeneration of the myelin sheath in CNS neuronsneurons

TypesTypes• Mixed (general)Mixed (general)

• SpinalSpinal

• CerebellarCerebellar


Neurodegenerative DisordersNeurodegenerative Disorders Amyotrophic lateral sclerosis (ALS)Amyotrophic lateral sclerosis (ALS)

Classic ALS—Lou Gehrig’s diseaseClassic ALS—Lou Gehrig’s disease Diffusely affects upper and lower Diffusely affects upper and lower motormotor neurons of neurons of

the cerebral cortex, brainstem, and spinal cord the cerebral cortex, brainstem, and spinal cord (corticospinal tracts and anterior roots)(corticospinal tracts and anterior roots)

Progressive weakness leading to respiratory Progressive weakness leading to respiratory failure and deathfailure and death

Person has normal intellectual and sensory Person has normal intellectual and sensory function until deathfunction until death


Peripheral Nervous System Peripheral Nervous System DisordersDisorders

NeuropathiesNeuropathies Generalized symmetric polyneuropathiesGeneralized symmetric polyneuropathies

• Distal axonal polyneuropathyDistal axonal polyneuropathy

• Demyelinating polyneuropathyDemyelinating polyneuropathy

Generalized neuropathiesGeneralized neuropathies• Sensory neuropathiesSensory neuropathies

Focal or multifocal neuropathiesFocal or multifocal neuropathies



Guillain-BarrGuillain-Barréé syndrome syndrome Acquired inflammatory disease causing Acquired inflammatory disease causing

demyelination of the peripheral nerves with demyelination of the peripheral nerves with relative sparing of axonsrelative sparing of axons

Acute onset, ascending motor paralysisAcute onset, ascending motor paralysis Humoral and cellular immunologic reactionHumoral and cellular immunologic reaction



RadiculopathiesRadiculopathies RadiculitisRadiculitis

• Inflammation of the spinal nerve rootsInflammation of the spinal nerve roots

Radicular pain Radicular pain Plexus injuresPlexus injures

Involves the nerve plexus distal to the spinal roots Involves the nerve plexus distal to the spinal roots but proximal to the formation of the peripheral but proximal to the formation of the peripheral nervesnerves


Neuromuscular Junction Neuromuscular Junction DisordersDisorders

Myasthenia gravisMyasthenia gravis Chronic autoimmune disease Chronic autoimmune disease IgG antibody produced against acetylcholine IgG antibody produced against acetylcholine

receptors (antiacetylcholine receptor antibodies)receptors (antiacetylcholine receptor antibodies) Weakness and fatigue of muscles of the eyes and Weakness and fatigue of muscles of the eyes and

the throat, causing diplopia, difficulty chewing, the throat, causing diplopia, difficulty chewing, talking, swallowingtalking, swallowing


Neuromuscular Junction Neuromuscular Junction DisordersDisorders

Myasthenia gravisMyasthenia gravis ClassificationClassification

• Neonatal myastheniaNeonatal myasthenia• Congenital myastheniaCongenital myasthenia• Juvenile myastheniaJuvenile myasthenia• Ocular myastheniaOcular myasthenia• Generalized autoimmune myastheniaGeneralized autoimmune myasthenia

Myasthenia crisisMyasthenia crisis Cholinergic crisisCholinergic crisis

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Disorders of the Central and Peripheral Nervous Systems and the Neuromuscular Junction Chapter 17...

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