Neuro Nugget: Stroke. Free Additional Board Exam Preparation Resources

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1 Neur Nugget: Strke Free Additinal Bard Exam Preparatin Resurces

2 Neur Nugget: Strke By Jack Krasuski, MD cpyright American Physician Institute fr Advanced Prfessinal Studies Strke: Definitins & Backgrund Strke is als called Cerebrvascular Accident (CVA) Strke is the clinical designatin fr a rapidly develping lss f brain functin due t an interruptin in the bld supply t all r part f the brain. WHO defines a strke as a neurlgical deficit f cerebrvascular cause that persists beynd 24 hurs r is interrupted by death within 24 hurs If < 24 hrs then it is a Transient Ischemic Attack (TIA) If > 24 hrs f deficits and they reslve, called a Reversible Neurlgical Ischemic Deficit (RIND) Prir t 24 hrs when it is unknwn if strke r TIA, treat as strke TIA was develped fr research purpses. Strke, TIA and RIND are the same disease prcess 1/3 f pts with TIA will have a strke within 5 years In sme med centers strke-in-prgress is called a brain attack analgus t a heart attack. They have Brain Attack Teams wrking ut f Neurlgy Dept. Strkes are Medical Emergency - intervene early: Time is Brain refers t the increasing lss f brain tissue the lnger the delay in treatment. Strke is the third mst cmmn cause f death in US and industrialized West. Strke Types are divided int: Ischemic Strkes 80% f all strkes Hemrrhagic Strkes 20% f strkes Strke: Risk Factrs Mdifiable risk factrs High bld pressure Cigarette smking Transient ischemic attacks Heart disease Diabetes mellitus Hypercagulpathy Cartid stensis Ccaine -dubles strke risk Nn-mdifiable risk factrs Age Gender Race Prir strke Heredity Strkes: Ischemic Ischemic Strke Categries Thrmbtic (artery narrwed by thrmbus frmatin) Emblic (cclusin f artery, partial r cmplete, by a traveling clt r plaque) Systemic hypperfusin leads t watershed (r Brderzne) strkes Ischemic strkes have three surces f pathlgy Cardiac (pump) f 9

3 Vascular (vessel) Hematlgic (fluid) The Ischemic Cascade: This is hw the brain dies during ischemia Ischemic neurn deplarizes and calcium flds the cell Calcium leads t release f neurtransmitters, including excitatry nes. This leads t further deplarizatin f surrunding neurns Destructive enzymes are released leading t cell membrane destructin and death f cell Within hurs, certain genes are activated in the cells in the ischemic penumbra, which frm cytkines. This leads t an inflammatry respnse that cmprmises the micrcirculatin f these surrunding regins Thus, the cells in this penumbra begin t die. Thus, the penumbra jins the infracted cre. The gal f treatment is t abrt this cascade and save the penumbra, thus minimizing the brain damage. Belw are descriptins f the specific types f strkes. Strkes: Thrmbtic Thrmbtic clts usually frm at site f pre-existing arterisclertic plaque They cut ff bld supply t distal brain tissue, depriving f glucse (brain fd) and xygen Onset: Since thrmbus frmatin is ften gradual, thrmbtic strke symptm nset may be gradual Nte that thrmbus can break ff, leading t emblic strke distal t thrmbus Thrmbtic strkes divided int tw types: Large Vessel Disease: These ccur in the internal cartid and the large vessels ff the circle f Willis. The fllwing disease states (incmplete list) cause frmatin f thrmbi Athersclersis (chrnic inflammatry respnse due t depsitin f lipprteins; three parts: atherma macrphages, chlesterl crystals, calcificatins) Vascnstrictin (internal respnse r triggered by substances ccaine) Dissectin (tearing f artery wall caused by HTN r cnnective tissue disease) Takayasu Arteritis (inflammatry, cause unknwn, in Asian females ages 15-30, signs: wreath-like frmatin f new bld vessels in retina; symptms: night sweats, fever, weight lss, fatigue Giant Cell Arteritis r Tempral Arteritis: (Inflammatry disease with giant cells fund n bx, effecting medium and large arteries f the head, mstly tempral artery) Myamya Syndrme (rare except in Japan, cause unknwn, prgressive stenses f Circle f Willis; leads t strkes, migraine-like HA s) Fibrmuscular Displasia Small Vessel Disease Liphyalinsis (lipid hyaline build-up secndary t HTN and aging) and fibrinid degeneratin (depsits f acidphilic fibrin-like material leading t small strkes knwn as lacunar infarcts) Micrathermas (athermas that extend frm larger arteries int the smaller arteries) Strke: Emblic Strke Embli surces: brken ff bld clts, athersclertic plaques, bacterial embli (endcarditis), cancerus embli, fat r bne marrw embli (fllwing injury) Onset: Since an emblus ldges quickly, emblic strke nset is sudden and maximal at nset f 9

4 Embli frm the anterir circulatin mst ften cclude the Middle Cerebral Arteries, since 85% f anterir circulatin bld flw ges there. Treatment Apprach Treat emblism Identify surce f emblus and treat surce Categries: emblic strkes may be divided int 4 categries based n clinical presumptin f surce Cardiac Surce: Atrial fib, rheumatic mitral r artic valve disease, mechanical valve disease, atrial r ventricular thrmbus, sick-sinus syndrme, recent MI, CABG, infective endcarditis, nnbacterial endcarditis such as frm adencarcinma leading t valvular vegetatins Ptential Cardiac r Artic Surce: patent framen vale Arterial Surce: artic dissectin Unknwn Surce Strke: Watershed Strke Caused by systemic hypperfusin: Cardiac arrest, arrhythmia, MI, CHF, bdily injury, surgery Brderzne brain areas are the areas that are mst distal, in between the arterial territries. Strke: Hemrrhagic Strkes Intracerebral Hemrrhage Arterial bleed Causes symptms by cmpressing surrunding brain tissue, causing ischemia, and by direct destructin f tissue. S/S: severe headache, decreased LOC, deficits d nt fllw arterial distributin Subarachnid Hemrrhage Arterial bleed Causes effects thrugh 1. elevating intracranial pressure and 2. txic effects f the subarachnid bld n the brain tissue, and 3. secndary vasspasm leading t ischemia S/S: usually presents with headache rather than fcal neurlgical deficits Subdural & Epidural Hemrrhages Venus bleed Causes a mass lesin that cmpresses brain Often cause is head trauma S/S: present with headaches, altered LOC, including cma, r if nt acute, with neurpsychiatric symptms f 9

5 Illustratin f Dura, Arachnid, and Venus Sinuses Strke: Lcalizatin Arterial Supply Structures Supplied Clinical Strke Syndrme Anterir Circulatin 1. Anterir Chridal Hippcampus, glbus pallidus, lwer internal capsule 1. hemiplegia, 2. hemianesthesia, 3. hmnymus hemianpia 2. Anterir Cerebral Medial frntal & parietal crtex, anterir crpus callsum 1. Cntralateral leg 2. bladder center 3. Middle Cerebral Lateral frntal, parietal, ccipital, tempral crtex 3a. Superir Divisin Mtr-sensry crtex & expressive language 1. Cntralateral face & arm 2. Cntralateral hemianesthesia N hmnymus hemianpia 3b. Inferir Divisin Visual Radiatins, macular visual crtex, receptive language 3c. Lenticulstriates Caudate nucleus, putamen, internal capsule, deep white matter Brca s aphasia (dminant) 1. Wernicke s aphasia (dminant), 2. Gerstmann Syndrme f dminant parietal lbe (agraphia, acalculia, right-left cnfusin, finger agnsia, idemtr apraxia), 3. Hmnymus hemianpia 1. Cntralateral face, arm, & leg 2. Extrapyramidal mv t s/s f 9

6 Cmbined MCA Occlusins: Occlusin at MCA Bifurcatin (cmbined superir and inferir divisin syndrmes); Occlusin at stem f MCA (cmbined superir and inferir divisin and lenticulstriate syndrmes) Psterir Circulatin 1. Basilar Psterir ccipital and medial tempral lbes, thalamus, brain stem, cerebellum 1a. Psterir Cerebral Medial ccipital & tempral crtex, pst. crpus callsum Tp f the Basilar Syndrme: 1. paralysis f all mv t except lateral eye gaze and eyelid pening, 2. intact sensatin, 3, intact cnsciusness Antn Syndrme: bilateral lesins: 1. Crtical blindness (pupils still react t light) 2. denial f blindness Weber Syndrme: 1. Cntra arm & leg weakness, 2. Ipsi CN III (lateral gaze) palsy Thalamperfrates Thalamus Dejerine-Russy r Thalamic Pain Syndrme: 1. hemisensry lss in all mdalities, 2. hemibdy pain Thalamgeniculates Thalamus Thalamic Syndrmes 1b. Superir Cerebellar Midbrain, pns, cerebellum 1c. Anterir Inferir Cerebellar 2. Vertebral 2a. Psterir Inferir Cerebellar Pns, cerebellum Medulla, cerebellum Marie-Fix Syndrme: 1. Ipsi arm & leg ataxia, 2. Cntra arm & leg weakness, 3. Cntra hemisensry lss Wallenberg syndrme: 1. dysarthria, 2. dysphagia, 3. harseness 4. cntra pain/ temperature frm bdy, 5. Ipsi pain/temperature frm face; 5. Ipsi Hrner s, 6. vestibular signs vertig, nystagmus, nausea 2b. Vertebral branches Medial Medulla Dejerine Syndrme: 1. Cntra arm & leg weakness, 2. Cntra hemisensry lss psitin and vibratin, 3. tngue weakness (CNXII) Strkes NOT Assciated with majr cerebral artery distributins Lacunar strkes Ipsi = ipsilateral, Cntra = cntralateral Small vessels supplying deep brain and white matter; f 9

7 Strke: Bld Supply Nte: Crssed Strke Syndrmes Crssed strke syndrmes ccur with brain stem strkes (psterir circulatin). This is due t the Cerebrspinal that cntrls mvement f the cntralateral side f the bdy, crssing at the decussatin f the pyramids at the level f the medulla (see belw) f 9

8 Strke: Evaluatin & Treatment Strke is a medical emergency. Therefre reducing time t treatment is crucial. Experts at an NIH recmmended the fllwing apprach t Strke Evaluatin and Treatment Detectin: Dispatch: Delivery: Dr: Data: Decisin: Drug: Early recgnitin Early EMS activatin Transprt & management ED triage ED evaluatin & management Specific therapies Thrmblytic & future agents EMS Evaluatin and Transprt Cnduct ABC s Recgnize Strke Establish time f strke nset Perfrm neurlgical evaluatin Check glucse Ntify hspital early Transprt rapidly Strke-Team Strke Evaluatin & Treatment Prtect ABC s Maintain apprpriate bld pressure f 9

9 Cntrl glucse (hyperglycemia is assciated with pr utcme Cntrl fever Mnitr fr seizures Mnitr fr cerebral edema and treat with hyperventilatin and mannitl Wrk-UP Perfrm Physical Exam Perfrm extracranial exam fr surce f strke and strke-mimics Perfrm head exam fr evidence f trauma, infectin, meningeal signs Perfrm fundiscpic exam Perfrm neur exam fr lcalizing signs (see table abve) Cmplete Strke Scale (example belw) Neurimaging CT CT results are a fundamental branch pint in strke eval either ischemic strke r hemrrhagic. Lk fr evidence f hemrrhage and distributin f strke Often n changes seen n nn-cntrast CT in early hurs pst-strke. It is used t rule-ut hemrrhages. Labs CBC (plycythemia, thrmbcytsis, thrmbpenia, leukemia) Chem panel (electrlyte abnlties) Cagulatin studies Cardiac enzymes EKG Other studies used under specific circumstances Transcranial Dppler t view intracranial large vessels Cartid Duplex scanning when cartid cclusin suspected Echcardigram when cardiac surce f embli suspected Angigraphy when ischemic distributin needs t be clearly defined Thrmblytic Agent (rt-pa) Treatment Decisin: The MAIN treatment decisin is whether r nt t give a thrmblytic agent (recmbinant tissue-type plasmingen activatr (rt-pa)). This decisin is based n whether there is enugh evidence that the strke is hemrrhagic. In such cases, rt-pa is cntraindicated because it wuld lead t a further bleed (see exclusins belw). rt-pa used fr strkes with measurable neurlgical deficit Evidence shws decrease in deficits in pts treated with tpa at 3 mnth interval fr all types f ischemic strke. Cnverts plasmingen->plasmin->hydrlyze fibrin, fibringen. Must give intravenusly within 3hrs f strke symptms. (6% risk f ICH) Intra arterial tpa can be given within 6hrs f strke symptms (higher risk f ICH-20%) Exclusins t Thrmblytic Therapy Strke r head trauma within 3 mnths Majr surgery within 14 days Systlic BP > 185 mm Hg f 9

10 Diastlic BP > 110 mm Hg Rapidly imprving r minr symptms Glucse < 50 r > 400 mg/dl Seizures at the nset f strke Evidence f Hemrrhages Any histry f intracranial hemrrhage Symptms suggestive f subarachnid hemrrhage GI hemrrhage within 21 days Urinary tract hemrrhage within 21 days Arterial puncture at nn-cmpressible site past 7 days Patients taking ral anticagulants Heparin within 48 hurs AND an elevated PTT PT >15 / INR >1.4 Platelet cunt <100 X 10/L Initial Neurlgic Examinatin - NIH Strke Scale As an example, here is a cmmnly used Strke Assessment Scale Item Descriptin Range 1a 1b 1c Level f Cnsciusness LOC Questins LOC Cmmands Best Gaze Best Visual Facial Palsy Mtr Arm Left Mtr Arm Right Mtr Leg Left Mtr Leg Right Limb Ataxia Sensry Neglect Dysarthria Best Language f 9