Chapter 6 Neurologic Assessment Mosby items and derived

Learning Objectives After reading this chapter you will be able to: Define key terms related to neurologic assessment Describe functional anatomy of the nervous system Explain the cortical function of different lobes of the brain Describe common techniques used to assess the mental status Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 2

Learning Objectives (cont’d) Describe functions of the brainstem, the cerebellum, and 12 pairs of cranial nerves Identify the parameters necessary to obtain a Glasgow Coma Scale and be able to interpret the results Describe common techniques to assess the cranial nerves, the sensory system, the motor system, coordination, and gait Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 3

Learning Objectives (cont’d) Describe the importance of assessing sedation and delirium in the ICU Describe techniques used to assess deep, superficial, and brainstem reflexes Explain the relationship between vital signs and neurologic status Identify the importance of ICP monitoring and the value of assessing cerebral perfusion pressure Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 4

Overview Injuries of the nervous system Ø Ø May affect respiratory system May affect patient cooperation with respiratory procedures History may indicate nature of dysfunction Exam localizes and quantifies severity of dysfunction Initial interaction with patient is first step in neurologic assessment Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 5

Overview (cont’d) Neurologic assessment evaluates: Ø Ø Ø Mental status Cranial nerve function Motor system Coordination Sensory system Reflexes Meaningful neurologic assessment requires adequate stimulation Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 6

Functional Neuroanatomy Neurologic system Central nervous system • Brain: cerebrum, brainstem, cerebellum • Spinal cord Ø Peripheral nervous system • Cranial nerves • Spinal nerves Ø Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 7

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Functional Neuroanatomy (cont’d) Functional division Ø Ø Sensory system (afferent) Motor system (efferent) Cerebrum Ø Functions: movement, LOC, ability to speak and write, emotions, memory Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 9

Functional Neuroanatomy (cont’d) Brainstem Ø Ø Ø Consists of midbrain, pons, medulla oblongata Most cranial nerves originate in brainstem Regulation of heart rate, blood pressure, and breathing Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 10

Functional Neuroanatomy (cont’d) Cerebellum Posterior part of the brain Responsible for equilibrium, muscle tone, and coordination Ø Cerebellar lesions cause: • Loss of coordination (ataxia) • Tremors • Disturbances in gait and balance Ø Ø Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 11

Functional Neuroanatomy (cont’d) Spinal cord From base of the brain down to L 1 (45 cm) Connects brain to the body for motor and sensory function Ø 31 spinal nerves • C 1 -C 8, T 1 -T 12, L 1 -L 5, S 1 -S 5, one coccygeal • Posterior (dorsal) roots = sensory • Anterior (ventral) roots = motor Ø Ø Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 15

Functional Neuroanatomy (cont’d) Spinal cord Herniated vertebral disk is the most common spinal nerve root pathology Ø Involvement of multiple nerve roots • Guillain-Barré Ø Phrenic nerves arise from spinal roots C 3 to C 5 • Damage can result in diaphragmatic paralysis Ø Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 17

Mental Status and LOC and mentation: most important parts of the neurologic exam Changes due to CNS dysfunction Initial goal of exam is to determine patient’s awareness Ø Starts with patient encounter Compromise of LOC may be due to: Ø Ø Generalized dysfunction (e. g. , overdose) Abnormality in specific area Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 20

Glasgow Coma Scale (GCS) Most widely used instrument to quantify neurologic impairment Test Ø Ø Motor response Verbal response • Poorly suited for patients with impaired verbal response (e. g. , aphasia, hearing loss, tracheal intubation) Ø Eye opening Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 26

Glasgow Coma Scale (cont’d) Scale goes from 3 (deep coma) to 15 (fully awake) GCS of 12 -15 = non-ICU observation GCS of 9 -12 = significant insult GCS <9 = severe coma = requires endotracheal intubation Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 28

Mini-Mental State Examination MMSE or Folstein test 30 -point questionnaire to assess cognition Samples various functions • Arithmetic, memory, orientation Ø Score interpretation • >27/30 = normal • 20 -26 = mild dementia • 10 -19 = moderate dementia • <10 = severe dementia Ø Ø Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 29

Sedation and Delirium in the ICU Delirium occurs in 60% to 80% of mechanically ventilated patients Associated with: Ø Ø Ø Longer hospital stay Higher mortality Poor long-term cognitive function Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 30

Sedation and Delirium in the ICU (cont’d) Richmond Agitation Sedation Scale (RASS) Ø Titrate sedation Confusion Assessment Method for the ICU (CAM-ICU) Ø Evaluates delirium Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 31

Cranial Nerve Exam 12 cranial nerves = sensory and motor function Ø Ø Ø Midbrain (CN III, IV) Pons (CN VIII) Medulla (CN IX to XII) Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 33

Cranial Nerve Exam (cont’d) Ipsilateral findings except on CN V Ø Ø Acoustic problem (CN VII, VIII) Pupillary response (CN II, III) Corneal reflex (CN V, VII) Gag reflex (CN IX, X) Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 34

Sensory Exam Somatosensory pathways Ø Ø Spinothalamic (ST) = pain, temperature Dorsal column-medial lemniscus (DCML) = vibration, position sense (proprioception) Evaluates ability to perceive sensations with eyes closed Assessment of light touch, pinprick, and temperature Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 39

Motor Exam Patient’s ability to move on command Motor strength and range of motion Scale from 0 (no movement) to +5 (full range of motion and full strength) If unconscious = response to pain Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 40

Motor Exam (cont’d) Upper motor neuron (UMN) Ø Ø Babinski’s sign, hyperreflexia, clasp-knife Decorticate and decerebrate posture Lower motor neuron (LMN) Ø Loss of strength, tone and reflexes, muscle waste and fasciculations Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 41

Deep Tendon Reflexes Evaluate spinal nerves Triceps, brachioradialis, patellar, Achilles tendon Ø Westphal’s sign = absence of patellar reflex Ø Scale from 0 (no reflex), +2 (normal), +5 (hyperreflexia) Myasthenia gravis and botulism have abnormal deep tendon reflexes Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 44

Superficial Reflexes Plantar reflex Tested when suspected L 4 -L 5 or S 1 -S 2 injury Babinski’s sign Dorsiflexion of the great toe with fanning of remaining toes Ø Normal in children 12 to 18 months of age Ø Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 47

Brainstem Reflexes Gag reflex (CN IX, X) Ø Its absence may increase risk for

Brainstem Reflexes (cont’d) Pupillary reflex (CN II, III) Ø PERRLA • Pupils equal round reactive to light and accommodation Ø Ø Anisocoria Myosis = pontine hemorrhage, narcotics Mydriasis = brain injury, anticholinergics Mid-position fixed pupils = severe cerebral damage Corneal reflex (CN V, VII) Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 50

Coordination, Balance, and Gait Assessment of cerebellar function Patient should be able to follow commands during exam Dysmetria = under- and overshooting of goaldirected movements Ø Romberg test = balance Ø Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 53

Vital Signs and Neurologic System Brainstem = breathing Lesions from cerebrum to cervical cord cause changes of breathing patterns Cheyne-Stokes respiration Ø Intracranial cause, hypoxemia, cardiac failure Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 54

Vital Signs and Neurologic System (cont’d) Ataxic breathing: marker of brainstem dysfunction Increased ICP = Cushing’s triad Ø Hypertension, widening pulse pressure, bradycardia, bradypnea Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 55

Intracranial Pressure Monitoring Indications Monitor patients at risk for life-threatening intracranial hypertension Ø Monitor evidence of infection Ø Assess effects of therapy for reducing ICP Ø Although hyperventilation decreases ICP, cerebral perfusion pressure (CPP) is the most critical element to monitor Mosby items and derived items © 2010 by Mosby, Inc. , an affiliate of Elsevier Inc. 57