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A taxia in the S troke P atient. Kelli Kulpa BSN, RN Alverno College MSN Student Neurosciences Department Froedtert Hospital. Objectives. Describe pathophysiology of cerebellum as it relates to smooth muscle movements Describe how ischemia to cerebellum causes ataxia in stroke patient
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Ataxiain the Stroke Patient Kelli Kulpa BSN, RN Alverno College MSN Student Neurosciences Department Froedtert Hospital
Objectives Describe pathophysiology of cerebellum as it relates to smooth muscle movements Describe how ischemia to cerebellum causes ataxia in stroke patient Identify presence of ataxia in stroke patient Identify appropriate nursing interventions and outcomes
TOPICS TO REVIEW STROKE CEREBELLUM ATAXIA NIH STROKE SCALE CARE OF THE PATIENT WITH ATAXIA
Stroke (Porth, 2005) “Syndrome of acute focal neurologic deficit from a vascular disorder that injures brain tissue” Porth (2005, p. 1245) US leading cause of mortality & morbidity About 700,000 Americans afflicted with stroke Many survivors left with some degree of deficit Image from Microsoft Clipart
Risk Factors for Stroke • Controllable • Hypertension (HTN) • Atrial Fibrillation • High Cholesterol • Diabetes • Tobacco Use & Smoking • Alcohol Use • Physical Inactivity • Obesity • Uncontrollable • Age • Race • Gender • Family History • Previous Stroke or TIA • Fibromuscular Dysplasia • Patent Foramen Ovale (National Stoke Association, 2009) Image from Microsoft Clipart
Uncontrollable Risk Factor • AGE: • Risk of stroke increases with age • After age 55, risk doubles for every decade that passes • Increased prevalence of controllable risk factors as age increases • Hypertension • High Cholesterol • Diabetes • RACE: AFRICAN-AMERICAN • Most impacted race in US • Twice as likely to die from stroke than Caucasians • Occur earlier in life • Reasons not fully understood, but have a higher rate of risk factors • ex: 41% have HTN (National Stoke Association, 2009) Image from Microsoft Clipart
Uncontrollable Risk Factor (National Stoke Association, 2009) • GENDER: WOMEN • 55,000 more women than men experience stroke each year • Unique risk factors: • Oral Contraceptives • Pregnancy • Hormone replacement therapy • Post-menopausal with thick waist and high triglyceride levels • Suffer more migraines, increase risk 3-6 times Image from Microsoft Clipart
Uncontrollable Risk Factor (Morrison, Brown, Kardia, Turner, & Boerwinkle, 2003) (Humphries & Morgan, 2004) • FAMILY HISTORY • Evidence suggests genes influence vulnerability to HTN & stroke • A region on: • Chromosome 13 in Caucasians • Chromosome 19 in African-Americans • Carotid intimalmedial wall thickness (IMT) • Surrogate measure of subclinical atherosclerosis • Strong predictor of future ischemic strokes • Homozygous for 6A genotype • Genetically predisposed to produce less stromelysin 1 • High carotid artery wall thickness & greater risk of stroke Image from Microsoft Clipart
Controllable Risk Factor & Inflammation (Humphries & Morgan, 2004) • Inflammation can influence the development of atherosclerosis • Causes endothelial dysfunction • One of the earliest manifestations of atherosclerosis • Inflammatory markers associated: • Coronary disease development • Disease severity • Occurrence of coronary events • Progression of atherosclerosis may be associated with high concentrations of inflammatory markers
TEST YOUR KNOWLEDGE GOOD JOB! Hypertension SORRY! Cannot control if you have a history of stroke Previous Stroke OPPS! Cannot control age Age GREAT! Hyperlipidemia Select the controllable risk factors for stroke (Multiple answers)
TEST YOUR KNOWLEDGE Sorry! Women are at higher risk of stroke & also have increased mortality. TRUE Yes! Women are at higher risk of stroke & also have increased mortality. FALSE Men are at higher risk of stroke
Types of Stroke • ISCHEMIC • Interruption of blood flow in a cerebral vessel • Most common type • Account for 70-80% of strokes • HEMORRHAGIC • Bleeding into the brain tissue, from blood vessel rupture • Caused by: • HTN • Aneurysms • AVM • Head injury • Much higher fatality rate • 37-38% of occurrence results in death (American Heart Association, 2010) (Porth, 2005) Image from Microsoft Clipart
Cell Ischemia (Porth, 2005) • Reduced or absent blood flow deprives cell of needed nutrients • Effects occur quickly • No stored glucose in brain • Incapable of anaerobic metabolism
Neuronal Injury: Excitotoxicity (Porth, 2005) • Ischemia depletes neuronal energy stores causing energy dependent membrane ion pumps to fail • Results in increased extracellular glutamate concentration • Release of excitotoxic glutamate & aspartate open up calcium channels • Influx of calcium, sodium and chloride • Intracellular calcium responsible for activation of a series of destructive enzymes • Out flux of potassium • Resulting in irreversible neuronal damage • Results in release of cytokines and other mediators
Inflammation Following Ischemia (Porth, 2005) Image used with permission from http://images.wellcome.ac.uk/ Rapid production of inflammatory mediators White blood cell (WBC) recruitment to ischemic area as early as 30 minutes Capillary endothelium produces adhesive proteins causing WBCs to adhere to capillary lining WBCs move into injured tissue Phagocytize injured cells Extent of inflammation can be determined by C-reactive protein levels
TEST YOUR KNOWLEDGE Try again If the cell is not getting adequate blood flow, there is not enough energy available. Too much energy available to the cell GOOD JOB! No energy is getting to the cell. Energy dependent membrane ion pumps fail Try again Phosphorus is not directly related to this process Lack of phosphorus available Try again There are increased levels of glutamate. Decreased levels of glutamate Neural cell ischemia is caused from:
Cerebellum • Stores learned sequences of movements • Fine tuning & coordination of movement produced elsewhere in brain • Integrates all information to produce fluid movements (Dubuc, 2002) Image used with permission from http://thebrain.mcgill.ca/flash/i/i_06/i_06_cr/i_06_cr_mou/i_06_cr_mou.html#3
Movement • Motor cortex: • Sends signals to cerebellum • Communicates movement to make • Cerebellum: • Makes continuous adjustments • Final result: • Smooth movement, key with delicate maneuvers (Porth, 2005) Hover over the highlighted words for definition Cerebellum Image used with permission from http://thebrain.mcgill.ca/flash/i/i_06/i_06_cr/i_06_cr_mou/i_06_cr_mou.html
Cerebellum Involvement • Receives proprioceptor input from vestibular system • Feedback from muscles, tendons, & joints • Indirect signals from somesthetic, visual, & auditory systems to provide background info for ongoing movement (Porth, 2005) • Can continuously assess status of each body part • Position • Rate of movement • Forces, such as gravity, opposing it (McGill University, 2002)
Dampening Muscle Movement • All body movements are pendular • Intact cerebellum analyzes proprioceptive information to predict: • Future position of moving parts • Speed of movement • Projected time course of movement • As movement approaches target, Cerebellum will: • Inhibit agonist muscles • Excite antagonist muscles (Porth, 2005) (Porth, 2005) Image from Microsoft Clipart
Type of Movement “Require a burst of energy from an agonist muscle group; the movement is programmed from the start, so the movement proceeds from start to finish without modification” Simple Movement Self-terminating Movement: require smooth muscle sequence of coordinated agonist & antagonist movements programmed by higher brain centers to start, then are modified as the movement proceeds Complex Movement Click for Explanation Click for Explanation Porth (2005, p. 1194) Image from Microsoft Clipart
TEST YOUR KNOWLEDGE Try again; This is part of the somesthetic system. Meaningfulness of integrated sensory information from various sensory systems GOOD JOB! Any sensory nerve ending responding to stimuli from within body related to movement & spatial position OPPS! Vestibular apparatus, try again. The inner ear structures that are associated with balance and position sense Try again; This is part of the somesthetic system. Concerning perceptions of ‘where’ the stimulus is in space and in relation to body parts Proprioreceptor input is:
TEST YOUR KNOWLEDGE Yes! Movement is pendulous, so muscles have to be stopped. Inhibit agonist muscles & Excite antagonist muscles Opps! Think this through again. Movement is pendulous. Excite agonist muscles & Inhibit antagonist muscles As movement approaches a target, the cerebellum will:
Ataxia (National Institute Of Neurological Disorders And Stroke, 2010) • People with ataxia experience • Failure of muscle control in arms and legs • Results in: • Lack of balance & coordination • Disturbance in gait Image from Microsoft Clipart
Acquired (non-genetic) Ataxia (National Institute Of Neurological Disorders And Stroke, 2010) Image from Microsoft Clipart • Conditions that can cause acquired ataxia • Stroke • Multiple Sclerosis • Tumors • Alcoholism • Peripheral neuropathy • Metabolic disorders • Vitamin deficiencies
Ataxia after Stroke (Mayo Clinic Staff, 2009) • Right side of cerebellum controls coordination on right side of body, left side controls left • When nerve cells are lost or damaged: • Provide less control to muscles • Resulting in: loss of coordination • During a stroke: • Blood supply is interrupted or severely reduced • Deprivation of oxygen and nutrients to brain tissue • Brain cells begin to die Image from Microsoft Clipart
Recent Findings Image from Microsoft Clipart • 15% of all cerebral strokes involve the cerebellum (Timmann et al., 2009) • Anterior lobe of cerebellum is involved in motor control • Concluded from a study containing 34 patients with cerebellar infarcts (Schmahmann, Macmore, & Vangel, 2009)
Cerebellar Ataxia How does alcohol relate? Select the beer for the answer! • Decomposition of movement • Each component of the movement occurs separately instead of being blended into a smooth action (Porth, 2005) “Ethanol specifically affects cerebellar function, persons who are inebriated often walk with a staggering and unsteady gait” Porth (2005, p. 1213) (Porth, 2005) Image from Microsoft Clipart
Ataxia • Rapid alternating movements are performed slowly and jerky • Such as pronation-supination-pronation of hands • Touching a target: • Movements broken down into small steps • Each movement goes too far, then overcompensated • DYSMETRIA SELECT THE TARGET TO SEE AN ANIMATION OF DYSMETRIA (Porth, 2005) Image from Microsoft Clipart
Clinical Pearl Image from Microsoft Clipart Read the CT or MRI reports to identify where the infarct is located in the brain. If the cerebellum is involved, chances are ATAXIA will be exhibited in the patient
TEST YOUR KNOWLEDGE Try again Weakness GOOD JOB! Lack of coordination OPPS! Impaired speech Try again No need to pay taxes Ataxia is:
TEST YOUR KNOWLEDGE AWESOME! Cerebellum Motor Cortex Think again, motor cortex is involved in movement, but not directly related to ataxia. Try again; not related to movement Parietal Lobe Almost there… look closer at the options. Cerebrum What part of the brain was infarcted if the patient has ataxia?
TEST YOUR KNOWLEDGE Yes! Acquired ataxia is non-genetic. True Opps! Ataxia after a stroke is not a genetic cause of ataxia. Genetic ataxia is caused from mutations in genes. False Ataxia in stroke is acquired ataxia.
National Institute of Health Stroke Scale (NIHSS) (Jensen & Lyden, 2006) • Stroke scale functions: • Document and communicate • Baseline deficits • Changes over time • First used in 1989 • Administered in mean time of 6.6 minutes • Interrater and intrarater agreement is good Image from Microsoft Clipart
National Institute of Health Stroke Scale (NIHSS) (Duncan et al., 2005) • Strongly predicts the likelihood of recovery after stroke • Total score • > 16 high probability of death or severe disability • <6 predicts a good recovery Image from Microsoft Clipart
National Institute of Health Stroke Scale (NIHSS) • 15 Item Clinical Deficit Scale • Assess: • Level of Consciousness • Gaze • Vision • Facial Palsy • Arm & Leg Strength • Limb Ataxia • Neglect • Dysarthria • Aphasia REMEMBER: MUST BE ASSESSED IN ORDER LISTED (Jensen & Lyden, 2006) Image from Microsoft Clipart
NIHSSLimb Ataxia YOU’RE NOT THE ONLY ONE WHO MAY MAKE AN ERROR SCORING ATAXIA!!! “A few items consistently show poor agreement, notably ataxia, dysarthria, and facial weakness” Jensen & Lyden (2006, p. 2)
NIHSSLimb Ataxia Assesses evidence of a unilateral cerebellar lesion Assesses incoordination from weakness Test with eyes open, in intact visual field Test on bilateral extremities (NIH Stroke Scale International, 2001) (National Institute Of Neurological Disorders And Stroke, 2001)
Evaluating Limb Ataxia • Scored if present out of proportionto weakness • Two instances when ataxia would not be assessed • Absent in patients who do not understand or are paralyzed • Untestable (UN) if amputation or joint fusion present (NIH Stroke Scale International, 2001) (National Institute Of Neurological Disorders And Stroke, 2001)
Finger-Nose-Finger Test Click on picture of face to view example of finger-nose-finger test with ataxia present (NIH Stroke Scale International, 2001) Ask patient to touch your index finger with his index finger and then back to his nose Repeat enough times to fully assess for ataxia, moving your index finger each time to make a new target Then repeat using other extremity Image from Microsoft Clipart
Heel-Shin Test Click on picture to view example of heel-shin test with ataxia present (NIH Stroke Scale International, 2001) • Ask patient to move right heel up and down the left shin • Repeat enough times fully assess for ataxia • Then repeat using other extremity Image from Microsoft Clipart
Limb Ataxia (NIH Stroke Scale International, 2001) Video used with permission from NIHSS English Training Campus • SCALE DEFINITION • 0 Absent (Not present or paralyzed) • 1 Present in 1 limb (an arm or a leg) • 2 Present in 2 limbs (both arms, both legs, or arm and leg on same side of body) • UN Amputation or joint fusion (explain) • The link below will take you to the National Institute of Health Stroke Scale Training Video • Assessment #7 Limb Ataxia http://www.youtube.com/watch?v=8AXtl3QPH7Y&feature=related
TEST YOUR KNOWLEDGE False: Ataxia is incoordination, not weakness! True Great job! Ataxia is incoordination, not weakness! False Ataxia occurs because of muscle weakness after a stroke.
TEST YOUR KNOWLEDGE Think about the order of the exam. Ataxia is assessed after weakness! True Great job! Ataxia is assessed after weakness! False Ataxia needs to be assessed prior to weakness in the NIH Stroke Scale.
TEST YOUR KNOWLEDGE No, ataxia is not present because the patient is unable to perform the test. The score would be absent or 0 due to paralysis. Yes Great job! Ataxia is not present because the patient is unable to perform the test. The score would be absent due to paralysis. No If the patient has weakness in the right arm and is unable to lift the arm off the bed, would ataxia be present?
TEST YOUR KNOWLEDGE Try again! Ataxia is present in R arm. 0 GREAT JOB! 1 Try again! Ataxia is only present in the R arm. 2 Try again! Only score UN if amputation or joint fusion present. UN The patient exhibits some weakness in the right arm and is able to perform the finger-nose-finger test. The patient misses the assessors finger. The patient completes test on left arm without difficulty. What score would be given for the upper extremity test?
Treatment (National Institute Of Neurological Disorders And Stroke, 2010) • There is no current cure of ataxia following a cerebellar stroke • Physical & Occupational Therapy • Strengthen muscles • Assistive devices • Assist in walking and other activities of daily living (ADLs) Image from Microsoft Clipart
Nurse Sensitive Outcomes (Bader & Littlejohns, 2004) • Impaired Mobility • Mobilize early to prevent complications • Active & Passive range of motion (ROM) • Participate in self-care & activities frequently • Teach safe use of assistive devices • Educate & Facilitate adaptation of home/work environment for maximal independence • Teach safety precautions • Expected outcomes: • Optimal independence with ADLs & mobility • Maintain safety precautions
Nurse Sensitive Outcomes (Bader & Littlejohns, 2004) Self-Care Deficit • Evaluate ability to perform ADLs • Consult occupational therapy (OT) • Assess for risk of falls • Expected outcomes: • Functional abilities recognized & advanced
Nurse Sensitive Outcomes (Summers et al., 2009) Safety • Identify Fall Risk • Implement fall prevention strategies • Universal Fall Risk Interventions • Fall Precautions due to activity impairment • Expected outcome: • Effective in decreasing vulnerability to falls and related injury