The High Yield Neurologic Examination John Engstrom, M.D. Sadly, - PDF document

Disclosures The High Yield Neurologic Examination John Engstrom, M.D. Sadly, I have no conflicts to disclose April 2019 Medical Chart Quotes Medical Chart Quotes “Exam of the genitalia reveals that he is circus sized.” “While in the ER, She was examined, X- rated and sent home.” 1

Overview – The Neurologic Medical Chart Quotes Examination • Mental status-brief review • Cranial nerves – common/urgent patterns “Both breasts are equal and reactive • Motor exam – common patterns to light and accommodation” • Sensory exam – common patterns • What is wrong with my walking? • Demonstrate the 15 minute exam • Other questions/demonstrations? Screening Mental Status Screening for Visual Field Deficits • Orientation-time, place, person • Visual field screen if you suspect a brain problem • Allows you to test function of broad areas of brain • Attention-Digit span forward (nl > 6-7) – Lobes-occipital, temporal, parietal • Language-repetition, naming, comprehen – Optic nerves, chiasm, optic tracts, and thalamus • Memory-Recall of 3 common objects at 5 • Clinical Importance minutes; if misses an answer give a prompt – “An anatomic sedimentation rate of the brain” • Abstractions-Similarities and differences – Detect abnormalities that require brain imaging (e.g.-apple vs. orange; lake vs. river) – Localize the deficit (right vs. left brain) 2

Screening for Visual Field Deficits- Ambulatory, Cooperative Patient • Imagine visual field cut in four equal pieces • Move examiner finger in the center of each quadrant with patient gaze fixed • Test each eye by covering the opposite eye, present stimulus in center of all 4 quadrants • Describe the deficit in terms of the portion of the visual field affected Assessment of Vision and Pupils • Measure acuity with glasses on/contacts in • Let the patient hold the vision card and read the lines back to you • Abnl pupils-indicate abnl CNs or brainstem – Afferent-retina, optic nerve/tract, midbrain – Efferent-midbrain, third nerve, ciliary muscle – Pupils always react in cortical blindness 3

Cranial Nerve Exam-Pupils Common Pupillary Exam Patterns • Anatomic pathways-afferent CN II, • Context matters-Does the history or exam midbrain, efferent bilat parasymp in CN III suggest an active intracranial process? – Best tested in dim light • When genuinely abnl without explanation- – Estimate size before and after light stimulus get a brain MRI – Assess baseline symmetry of shape and size • Common False Positives – Assess direct and consensual response – Inadequacy of light stimulus (use bright light – No other part of the nervous system affected! against a dim background) – Nl less than or equal to one mm asymmetry – Mydriatic drugs (unilateral if topical); child • Abnormalities may be in CN II or III – Post surgical-cataracts, prosthetic eye Outpatient Pupillary Exam Patterns Outpatient Pupillary Exam Patterns • Afferent pupillary defect • Efferent pupillary defect – Light stimulus in affected eye doesn’t reach – Accompanied by CN III palsy (eye down/out) brainstem due to diseased CN II – Light in affected eye-contralateral pupil – Both pupils dilated despite const light stimulus constricts but ipsilateral pupil does not react – Light in unaffected eye-both pupils react – Light in unaffected eye-ipsilateral pupil constricts and contralateral pupil is unreactive – Consider urgent brain MRI or head CT 4

What Cranial Nerves Have in Common • Brainstem portion-many other brainstem findings present (e.g.-MS, tumor) • Subarachnoid space -CN and nerve roots pass through the CSF after exit cord – Often multiple CN involved – Example-infectious/carcinomatous meningitis, • Skull base -inside/outside skull to target tissue innervated (e.g.-motor/sensory) Cranial Nerves III, IV, and VI CN VII-Examination • Movements-eye out is VI, eye down and in • Upper 1/3-furrowing brow, symmetry is IV, everything else is III • Middle 1/3-degree eye closure, symmetry – Move finger in horizontal and vertical planes – Power testing-force eyelids open using thumbs- – Move finger in and down bilaterally-IVth one each at upper and lower orbit • Binocular diplopia – With effort, globe rotates upward-see sclera – Pt cover one eye; is only one image remaining? – Lack of effort, globe motionless-see iris + pupil – Strongly consider ordering brain MRI to assess • Lower 1/3-excursion of smile, symmetry the brainstem, skull base, and orbit 5

CN VII-Utility of Testing CN V, VIII, X • Lower 2/3 face-MRI of brain • CN V-test face with pin and light touch • Entire face-Bell’s palsy • CN VIII-finger rub next to each ear; – LMN VII only finding audiogram if questionable – Acute onset; stabilize/improve over days-weeks • CN X-uvula elevation in the midline • Apparent Bell’s but CNS location (e.g.-MS, brain tumor) – Other neurol symptoms/signs – Coincident medical illness (e.g.-meningitis) CN XII-Tongue • Two muscles fused midline; separate CNs • Bulk-smooth lateral contour, symmetry • Power screen-tongue protrusion midline nl • Grading power-tongue-in-cheek vs. resist • Tongue fasciculations-all nl tongues twitch • Dysarthria-slurred speech due to weakness – Lips (labial dysarthria) – Tongue (lingual dysarthria) – Palate (nasal dysarthria) 6

The Symptom of Weakness Motor Exam • Bulk-place the contour of the muscle on a • Patients mean a functional limitation of perpendicular to your line of vision motor activity • Tone-move limb passively across a joint • Confused with: slowly and rapidly – fatigue • Power-grade 1-5 on the MRC scale – depression (“neurasthenia”) – decreased sensation • Reflexes-grade 0-4 – decreased force moving a painful limb • Gaits-Demonstration at the end of talk The Weak Patient: Pertinent History Examination Signs of True Weakness Temporal sequence • Reduced but constant resistance when Functional activities testing the power a muscle on clinical SOB examination Ambulation-independent vs. cane vs. walker • There are only two types of true weakness: vs. wheelchair – Central: brain, brainstem, cord Stand up/reach overhead-proximal muscles – Peripheral: anterior horn cell, root, plexus, Stand on toes; use pen/spoon-distal muscles nerve, neuromuscular junction, muscle Complete motor exam-not power alone 7

Breakaway Weakness is Not Weak Patient: History and Examination True Weakness • DEFINITION: Variable resistance by the NEUROLOGIC NON-NEUROLOGIC patient during muscle power testing • ASSOCIATED WITH PAIN: Cannot be sure UPPER MOTOR LOWER MOTOR FATIGUE BREAKAWAY NEURON NEURON if some underlying weakness present POOR EFFORT • UNASSOCIATED WITH PAIN: Poor effort PAIN OR ATTENTION or attention Weak Patient: Central Weakness II Weak Patient: Central Weakness I Power - ¯ distal > proximal in limbs Spasticity-velocity-dependent increase in tone ¯ extensors > flexors in arms to passive stretch of a limb that is greatest in the flexors of the arms and extensors of the legs ¯ dorsiflexors > plantar flexors in legs -Fast finger movts/foot taps -Rapid, repetitive ¯ lower 2/3 of face (if from brain injury) movements are slow in the fingers and feet; Bulk - Normal dominant side normally faster Tone - spastic; Babinski sign(s) present -Pronator drift-hand pronation essential finding; Reflexes - ­ may also flex the fingers and drop the arm 8

Motor Exam-Grading Power Motor Exam-The Challenge of Grading Power SCORE RESPONSE • Most weakness is between 4 and 5 5 Full power 4+/5- Minimal weakness • Inter-examiner variability 4 Mild weakness • What do you do with the weight-lifter? 4- Moderate weakness • Qualitative scale: mild, moderate, severe? 3 Severely weak; able to move vs. gravity • Pattern of weakness usu more informative 2 Moves, but not against gravity than attempt to exactly quantify weakness 1 Flicker of contraction 0 No muscle contraction Grading Reflexes-Asymmetry Impt Motor Examination-Common Traps • Focal atrophy from disuse SCORE RESPONSE 4 Clonus • Focal atrophy from pain w/ use-switch sides-another form of disuse 3 Hyperactive 2 Normoactive • Apparent increased tone from patient inability to relax during the exam-often 1 Hypoactive labeled as paratonia Trace Present with reinforcement only • Breakaway weakness 0 Absent 9