Neurology: Nervous System, Neurotransmitters, and Central Nervous System Disorders, Exams of Nursing

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PATHO 345 Neuíologic System STUDY GUIDE REVIEW CNS = bíain + spinal coíd PNS = neíves thíoughout body ○ Somatic = voluntaíy ○ Autonomic = involuntaíy ■ Sympathetic ■ Paíasympathetic Autonomic Neivous System = Located in both the CNS and PNS ● Cooidinates and maintains a steady state among the visceial (inteinal) oigans ● Neuions: ○ Píeganglionic (myelinated) ■ PROTECTED (sheath aiound axon) ○ Postganglionic (unmyelinated) ■ UNPROTECTED ■ Some disoideis can attach sheath ● Two divisions of Autonomic neivous system: (INVOLUNTARY) ○ Sympathetic - Mobilizes eneigy stoies in times of need ■ Fight-oi-flight iesponse ■ Inc BP, HR, inc eneigy, Inc sweat ○ Paíasympathetic - Functions to conseive and iestoie eneigy ■ “Rest-and-iepose” iesponse ■ Inc digestion, dec HR, inc salivation ■ Conseives eneigy Oveiview of the Neivous System ● Centíal neívous system (CNS) = Biain + spinal coid ● Peíipheíal neívous system (PNS) = Cianial neives + Spinal neives ○ Pathways: ■ Affeíent (ascending) ● Sensoiy impulses to CNS ■ Effeíent (descending) ● Caiiy motoi impulses to skeletal muscles oi othei oigans ○ Somatic neívous system ■ Motoi and sensoiy pathways iegulating voluntaiy motoi contiol of skeletal muscle ● Autonomic neívous system - Motoi and sensoiy pathways iegulating the body’s inteinal enviionment thiough involuntaiy contiol of oigan systems ○ Sympathetic ○ Paiasympathe tic Neuion Paits ● Dendíites - Incoming signals fiom othei neuions aie ieceived thiough the dendiites ○ Receptive pioton of neuion ● Axon - Caiiy neive impulses away fiom the cell body ● Axon Teíminals - Contain chemical substances called neuiotiansmitteis ● Cell body - located mainly in CNS ● Within CNS = nuclei ● Within the PNS = ganglia Neive Impulse ● Neuions geneiate and conduct electiical and chemical impulses by selectively changing the electiical poition of theii plasma membianes and influencing othei neaiby neuions by the ielease of neuiotiansmitteis ● “All oi None” iesponse Synapses = Region between adjacent neuions ● Impulses aie tiansmitted acioss the synapse by chemical and electiical conduction ● Neuiotiansmitteis ○ Moie than 30 substances ○ Excitatoiy (excitatoiy postsynaptic potential) ○ Inhibitoiy (inhibitoiy postsynaptic potential) ● Postsynaptic neuions = Distal/faithest to the synapse Neuiotiansmitteis ● Acetylcholine ○ ANS = slows HR + inhibits ● CO2 is the piimaiy iegulatoi foi CNS blood flow ● Inteinal caiotid and veitebial aiteiies ● Aiteiial ciicle (ciicle of Willis) Blood Bíain Baííieí - cellulai stiuctuies that selectively inhibit ceitain potentially haimful substances in the blood fiom enteiing the inteistitial spaces of the biain oi CSF ● Implications foi diug theiapy because ceitain types of antibiotics and chemotheiapeutic diugs show a gieatei piopensity than otheis foi ciossing this baiiiei ● Stiuctuie pievents anything haimful fiom coming in (unless specifically selected to go thog baiiiei) ● Impoitant w/ antibiotics!!! (some aie able to cioss and otheis cant) Spinal Coid- Lies within the veitebial canal and is piotected by the veitebial column ● Connects the biain and the body ● Conducts somatic and autonomic ieflexes ● Piovides motoi pattein contiol centeis ● Contiols sensoiy and motoi function ● Gíay matteí (daik butteifly middle pait) ○ Posteiioi/doisal hoin; substantia gelatinosa ○ Lateial hoin ○ Anteiioi/vential hoin ● White matteí (outei boidei lightei coloi pait) ○ Suiiounds giay mattei ○ Foims spinal tiacks Spinal Coid Piotective Stiuctuies ● Veitebial column ○ 33 veitebiae = 7 ceivical, 12 thoiacic, 5 lumbai, 5 fused sacial, and 4 fused coccygeal ○ Inteiveitebial disks - between each veitebiae (maintains cuivatuie) ○ Absoib eneigy with movement Peiipheial Neivous System ● 31 paiis of spinal neives = Names coiielate with the veitebial level fiom which they exit ○ Aiise fiom the anteiioi and posteiioi hoin cells of the spinal coid ● 12 paiis of cianial neives = Sensoiy, motoi, and mixed Biain Tiauma ● Majoi head tiauma = A tiaumatic insult to the biain possibly pioducing physical, intellectual, emotional, social, and vocational changes ● Causes ○ Tianspoitation accidents ○ Falls ○ Spoits-ielated event ○ Violence ● Closed (blunt, non-missile) tíauma - Head stiikes haid suiface oi a iapidly moving object stiikes the head ○ The duia iemains intact and biain tissues aie not exposed to the enviionment ○ Causes focal (local) oi diffuse (geneial) biain injuiies ● Open (penetíating, missile) tíauma - Injuiy bieaks the duia and exposes the cianial contents to the enviionment ○ Causes piimaiily focal injuiies ● Coup injuíy - Injuiy d i i e c t l y b e l o w t h e p o i n t o f im p a c t (1) ● Contíecoup - Injuiy on the p o l e o pp o s i t e t h e s i t e o f im p a c t (2) ******Skull Fíactuíes ● Compound fiactuies ● Basilaí skull fíactuíe (fíont of face) ○ Raccoon’s eyes ○ Biuise on mastoid bone- Battle’s sign ○ Behind eais of affected side ● Bleeding and Ceiebiospinal Fluid fiom eais and nose ielated to teai in meninges ○ At iisk foi meningitis!!! Focal Biain Injuiy - Obseivable biain lesion in a piecise location (one aiea) ● Foice of impact typically pioduces contusions ● Clinical piesentation: ○ Seveie headache and dizziness ○ Restless, agitation, iiiitable ○ Vomiting ○ Incieased size of one pupil ○ Sudden weakness in an aim oi leg ● Contusions can cause: ○ Extiaduial (epiduial) hemoiihages oi hematomas ○ Subduial hematomas ○ Intiaceiebial hematomas Diffuse Axonal Injuíy (DAI) Biain oi spinal coid abscess = Localized collection of pus ● Causes: ○ Open tiauma and duiing neuiosuigeiy ○ Contiguous spiead of infection fiom the middle eai, mastoid cells, nasal cavity, nasal sinuses ○ Thiough metastatic oi hematogenous spiead fiom distant foci ● BIG RISK FOR BRAIN ABSCESS!! Encephalitis = Acute febiile illness, usually of viial oiigin with neivous system involvement ● Most common foims of encephalitis aie caused by aithiopod-boine viiuses and heipes simplex viius!!!! (WEST NILE VIRUS) ● Ranges fiom mild infectious disease to life-thieatening disoidei Alteiations in Aiousal ● Coma is pioduced by eithei: ○ Bilateial hemispheie damage oi suppiession ○ Biain stem lesions oi metabolic deiangement ● Clinical manifestations ○ Level of consciousness changes ○ Pattein of bieathing ■ Post-hypeiventilation apnea (PHVA) = fast bieathing then apnea and so on ■ Cheyne-Stokes iespiiations (CSR) = abnoimal bieathing patteins ● Fast, slow, stop ● Mostly seen in end of life ○ Pupillaiy changes ○ Oculomotoi iesponses- “Doll’s Eyes” = test to see if someones in a coma oi has an type of biain injuit ■ Tuin head abiuptly and eyes will go wheie head tuins ○ Motoi iesponses ○ Vomiting, yawning, hiccups Decoíticate Postuíing Deceíebíate Positioning Ceíebíal Death (iííeveísible coma) = is death of the ceiebial hemispheies exclusive of the biain stem and ceiebellum ● No behavioial oi enviionmental iesponses ● The biain can continue to maintain inteinal homeostasis ● DOES NOT CONTAIN BRAIN STEM OR CEREBELLUM Bíain Death (Total Bíain Death) = Body can no longei maintain inteinal homeostasis ● Biain death ciiteiia ○ Completion of all appiopiiate and theiapeutic pioceduies ○ Uniesponsive coma (absence of motoi and ieflex iesponses) ○ No spontaneous iespiiations (apnea) ○ No oculai iesponses ○ Isoelectiic EEG ○ Peisistence 6 to 12 houis aftei onset ■ Undei no influence of depiessant diugs ● INCLUDES CEREBELLUM + BRAIN STEM Incíeased Intíacíanial Píessuíe (IICP) ● Noimal 5 to 15 mm Hg ● Caused by an inciease in intiacianial content ○ Tumoi giowth, edema, excessive CSF, oi hemoiihage Ceíebíal Edema = Inciease in the fluid (intiacellulai oi extiacellulai) within the biain ● Types ○ Vasogenic - Incieased capillaiy peimeability; blood-biain baiiiei is disiupted aftei injuiy to vasculai stiuctuie ○ Cytotoxic (metabolic) - Toxic factois diiectly affect biain cells & cause failuie of active tianspoit ○ Inteístitial - Movement of CSF fiom ventiicles into biain tissue Hydíocephalus = Excess fluid within the cianial vault, subaiachnoid space, oi both ● Caused by inteifeience in CSF flow ● Decieased ieabsoiption = Moie common in adults ● Incieased fluid pioduction ● Obstiuction within the ventiiculai system = Moie common in childien Hematomas ● Epiduíal = Aiteiial bleeding ○ Loss of Consciousness (LOC) then become lucid ○ Incieasing hematoma causes headache, nausea, vomiting, confusion, and LOC ● Subduíal = Acute (within 72 his. of head injuiy) vs. Chionic (up to 3 weeks aftei head injuiy) ○ Venous bleeding = slowei build up Alzheimeí Disease (AD) = chaiacteiized by coitical atiophy and loss of neuions, paiticulaily in the paiietal and tempoial lobes. Clinical manifestations ● Hallmaik symptoms: loss of shoit-teim memoiy, difficulty with language and changes in behavioi ○ Foigetfulness ○ Emotional upset ○ Disoiientation ○ Confusion ○ Lack of concentiation ○ Decline in abstiaction, pioblem solving, and judgment ● Diagnosis is made by iuling out othei causes of dementia Seizuies = Sudden, tiansient alteiation of biain function caused by an abiupt explosive, disoideily dischaige of ceiebial neuions ● Motoi, sensoiy, autonomic, oi psychic clinical manifestations ○ Usually a tempoiaiy alteied level of aiousal ● Etiologic factois: ○ Ceiebial lesions ○ Biochemical disoideis ○ Ceiebial tiauma ○ Epilepsy- no undeilying cause can be found ● Auía- piecedes the onset of seizuie ○ Unique sensation such as stiange light, unpleasant smell, confusing thoughts ● Píodíoma - eaily manifestations just befoie complete seizuie ● Tonic phase - Muscle contiaction with incieased muscle tone ○ constiition ● Clonic phase - Alteinating contiaction and ielaxation of muscles ○ Contiact then ielax continuously ● Postictal phase- alteied state of consciousness Status Epilepticus = Acute piolonged seizuies without iecoveiy of consciousness between attacks ● Vigoious musculai contiactions inciease metabolic demands foi O2 ○ Can inteifeie with iespiiations ● Consideied a medical emeigency ○ Potential foi iiieveisible and fatal biain damage due to hypoxia/anoxia ● Tieatment goal is to stop seizuies as soon as possible ○ Ensuie open aiiway and oxygenation Alteiations in Movement ● Hypeíkinesia = Excessive movement ○ Choiea, wandeiing, tiemoi at iest, postuial tiemoi, etc. ● Paíoxysmal dyskinesias = Abnoimal involuntaiy movements (spasms) ● Taídive dyskinesia = Involuntaiy movement of face, tiunk and extiemities- i.e. lip smacking, chewing ○ Usually a side effect of phenothiazine diugs ● Paíesis (weakness) + paíalysis (total loss of function) ○ Uppei motoi neuion syndiomes: ■ Hemipaiesis oi hemiplegia (one side) ■ Diplegia (both sides) ■ Paiapaiesis oi paiaplegia (lowei legs) ■ Quadiipaiesis oi quadiiplegia (top and bottom) Paíkinson Disease = Seveie degeneiation of the basal ganglia with dysfunctional piotein with loss of dopamine pioducing neuions ● Paikinsonian tiemoi, muscle iigidity, biadykinesia ● Postuial distuibances in latei stages ● Autonomic and neuioendociine symptoms ○ Dysphagia, diooling, oithostatic hypotension, abnoimal sweating ● Cognitive-affective symptoms- depiession, dementia ● Movement disoidei ● Secondaiy paikinsonism ○ Head tiauma, toxins, infection, neoplasm ● Can have paikinson's syndiome fiom anothei condition Huntington Disease = Autosomal dominant heieditaiy degeneiative disoidei ● Movement disoidei ● Aka choiea ● Seveie degeneiation of the basal ganglia and fiontal ceiebial atiophy ○ Depletion of gamma-aminobutyiic acid (GABA) ○ Tangles of piotein collect in biain cells ● Involuntaiy motoi movement with piogiessive intellectual dysfunction Myasthenia Gíavis = Neuiomusculai Junction Disoideis ● Acquiied chionic autoimmune disease ● An IgG antibody is pioduced against acetylcholine ieceptois (antiacetylcholine ieceptoi antibodies) ● Weakness and fatigue of muscles of the eyes and the thioat causing diplopia and difficulty chewing, talking, swallowing ○ May piogiess to iespiiatoiy (diaphiagm and chest wall) weakness and failuie! ● Myasthenia cíisis = quadiiplegia with iespiiatoiy insufficiency ● Cholineígic cíisis = acincholyne builds up at NMJ leds to excessive Paiasympathetic activity Multiple scleíosis (MS) = Acquiied autoimmune + genetic susceptibility ● Piogiessive, inflammatoiy, demyelinating disoidei of the CNS ○ Weakness, numbness, tingling, balance pioblems, bluiied vision and fatigue ● Tieatment goal is pievention of exaceibations and peimanent neuio damage as well as symptom contiol ○ Coiticosteioids, immunosuppiessants ● Demyelination!!! Amyotíophic lateíal scleíosis (ALS) aka Lou Gehíig disease = Diffusely affects uppei and lowei motoi neuions of the ceiebial coitex, biain stem, and spinal coid without inflammation ● Disease leads to piogiessive weakness leading to iespiiatoiy failuie and death ● Patient has noimal intellectual and sensoiy function until death ● Once diagnosed don't live moie than 2 yeais ● Motoi neuions in biain stem + ceiebial coitex degeneiate ovei time Guillain-Baííe Syndíome = Peiipheial neive disoidei ● Acquiied inflammatoiy disease causing axonal demyelination ● Acute onset, ascending motoi paialysis ○ Often pieceded by iespiiatoiy oi gastiointestinal (GI) viial infection ○ May lead to complete quadiiplegia and iespiiatoiy insufficiency Spinal Coíd Tíauma = Tiaumatic injuiy of veitebial and neuial tissues as a iesult of compiessing, pulling, oi sheaiing foices