Disclosures The High Yield Neurologic Examination Sadly, I still have nothing new to disclose since Tuesday John Engstrom, M.D. August 2018 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 – Localize the deficit (right vs. left brain) (e.g.-apple vs. orange; lake vs. river) 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 cover • Lower 1/3-excursion of smile, symmetry 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, nerve, neuromuscular junction, muscle Stand on toes; use pen/spoon-distal muscles 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 • Focal atrophy from pain w/ use-switch 4 Clonus 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
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