Disclosures The High Yield Neurologic Examination...¯lower 2/3 of face (if from brain injury) Bulk -Normal Tone -spastic; Babinski sign(s) present Reflexes - Weak Patient: Central

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The High Yield Neurologic Examination

John Engstrom, M.D.April 2019

Disclosures

Sadly, I have no conflicts to disclose

“Exam of the genitalia reveals that he is circus sized.”

Medical Chart Quotes Medical Chart Quotes

“While in the ER, She was examined, X-rated and sent home.”

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Medical Chart Quotes

“Both breasts are equal and reactive

to light and accommodation”

Overview – The Neurologic Examination

• Mental status-brief review• Cranial nerves – common/urgent patterns• Motor exam – common patterns• Sensory exam – common patterns• What is wrong with my walking?• Demonstrate the 15 minute exam• Other questions/demonstrations?

Screening Mental Status

• Orientation-time, place, person• Attention-Digit span forward (nl > 6-7)• Language-repetition, naming, comprehen• Memory-Recall of 3 common objects at 5

minutes; if misses an answer give a prompt• Abstractions-Similarities and differences

(e.g.-apple vs. orange; lake vs. river)

Screening for Visual Field Deficits

• Visual field screen if you suspect a brain problem• Allows you to test function of broad areas of brain

– Lobes-occipital, temporal, parietal– Optic nerves, chiasm, optic tracts, and thalamus

• Clinical Importance– “An anatomic sedimentation rate of the brain”– Detect abnormalities that require brain imaging– Localize the deficit (right vs. left brain)

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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

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Cranial Nerve Exam-Pupils

• Anatomic pathways-afferent CN II, midbrain, efferent bilat parasymp in CN III– Best tested in dim light– Estimate size before and after light stimulus– Assess baseline symmetry of shape and size– Assess direct and consensual response– No other part of the nervous system affected!– Nl less than or equal to one mm asymmetry

• Abnormalities may be in CN II or III

Common Pupillary Exam Patterns

• Context matters-Does the history or exam suggest an active intracranial process?

• When genuinely abnl without explanation-get a brain MRI

• Common False Positives– Inadequacy of light stimulus (use bright light

against a dim background)– Mydriatic drugs (unilateral if topical); child– Post surgical-cataracts, prosthetic eye

Outpatient Pupillary Exam Patterns

• Afferent pupillary defect – Light stimulus in affected eye doesn’t reach

brainstem due to diseased CN II– Both pupils dilated despite const light stimulus– Light in unaffected eye-both pupils react

Outpatient Pupillary Exam Patterns

• Efferent pupillary defect – Accompanied by CN III palsy (eye down/out)– Light in affected eye-contralateral pupil

constricts but ipsilateral pupil does not react– Light in unaffected eye-ipsilateral pupil

constricts and contralateral pupil is unreactive– Consider urgent brain MRI or head CT

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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

• Movements-eye out is VI, eye down and in is IV, everything else is III– Move finger in horizontal and vertical planes– Move finger in and down bilaterally-IVth

• Binocular diplopia– Pt cover one eye; is only one image remaining?– Strongly consider ordering brain MRI to assess

the brainstem, skull base, and orbit

CN VII-Examination

• Upper 1/3-furrowing brow, symmetry• Middle 1/3-degree eye closure, symmetry

– Power testing-force eyelids open using thumbs-one each at upper and lower orbit

– With effort, globe rotates upward-see sclera – Lack of effort, globe motionless-see iris + pupil

• Lower 1/3-excursion of smile, symmetry

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CN VII-Utility of Testing

• Lower 2/3 face-MRI of brain• Entire face-Bell’s palsy

– LMN VII only finding– Acute onset; stabilize/improve over days-weeks

• Apparent Bell’s but CNS location (e.g.-MS, brain tumor)– Other neurol symptoms/signs– Coincident medical illness (e.g.-meningitis)

CN V, VIII, X

• CN V-test face with pin and light touch• CN VIII-finger rub next to each ear;

audiogram if questionable• CN X-uvula elevation in the midline

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)

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Motor Exam

• Bulk-place the contour of the muscle on a perpendicular to your line of vision

• Tone-move limb passively across a joint slowly and rapidly

• Power-grade 1-5 on the MRC scale• Reflexes-grade 0-4• Gaits-Demonstration at the end of talk

The Symptom of Weakness

• Patients mean a functional limitation of motor activity

• Confused with:– fatigue – depression (“neurasthenia”) – decreased sensation – decreased force moving a painful limb

The Weak Patient:Pertinent History

Temporal sequenceFunctional activities

SOBAmbulation-independent vs. cane vs. walker vs. wheelchair Stand up/reach overhead-proximal musclesStand on toes; use pen/spoon-distal muscles

Complete motor exam-not power alone

Examination Signs of True Weakness

• Reduced but constant resistance when testing the power a muscle on clinical examination

• There are only two types of true weakness:– Central: brain, brainstem, cord– Peripheral: anterior horn cell, root, plexus,

nerve, neuromuscular junction, muscle

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Weak Patient: History and Examination

NEUROLOGIC NON-NEUROLOGIC

UPPER MOTORNEURON

LOWER MOTORNEURON BREAKAWAYFATIGUE

POOR EFFORTOR ATTENTIONPAIN

Breakaway Weakness is Not True Weakness

• DEFINITION: Variable resistance by the patient during muscle power testing

• ASSOCIATED WITH PAIN: Cannot be sure if some underlying weakness present

• UNASSOCIATED WITH PAIN: Poor effort or attention

Weak Patient: Central Weakness I

Power - ¯ distal > proximal in limbs¯ extensors > flexors in arms¯ dorsiflexors > plantar flexors in legs¯ lower 2/3 of face (if from brain injury)

Bulk - NormalTone - spastic; Babinski sign(s) presentReflexes - ­

Weak Patient: Central Weakness II

Spasticity-velocity-dependent increase in tone to passive stretch of a limb that is greatest in the flexors of the arms and extensors of the legs-Fast finger movts/foot taps -Rapid, repetitive movements are slow in the fingers and feet; dominant side normally faster-Pronator drift-hand pronation essential finding; may also flex the fingers and drop the arm

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Motor Exam-Grading Power

SCORE RESPONSE5 Full power4+/5- Minimal weakness4 Mild weakness4- Moderate weakness3 Severely weak; able to move vs. gravity

2 Moves, but not against gravity1 Flicker of contraction0 No muscle contraction

Motor Exam-The Challenge of Grading Power

• Most weakness is between 4 and 5• Inter-examiner variability• What do you do with the weight-lifter?• Qualitative scale: mild, moderate, severe?• Pattern of weakness usu more informative

than attempt to exactly quantify weakness

Motor Examination-Common Traps

• Focal atrophy from disuse • Focal atrophy from pain w/ use-switch

sides-another form of disuse• Apparent increased tone from patient

inability to relax during the exam-often labeled as paratonia

• Breakaway weakness

Grading Reflexes-Asymmetry Impt

SCORE RESPONSE4 Clonus3 Hyperactive2 Normoactive1 HypoactiveTrace Present with reinforcement only

0 Absent

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The Weak Patient: Key Evaluation Features

Power Reflexes Sensation

Anterior Horn Cells (Spinal cord) Patchy ¯ or normal normal

Nerve Root (i.e. - Radiculopathy) ¯ or normal ¯* ¯ or normal

Nerve-Axonal (i.e. – DSPN) ¯ distal ¯ distal ¯ distal

Nerve - Demyelination (i.e. - GBS) ¯ diffuse ¯ diffuse ¯ patchy/ normal

NMJ (i.e. -Myasthenia) ¯ proximal normal normal

(+ bulbar)

Muscle(i.e. - Polymyositis) ¯ proximal normal normal

* - in distribution of affected root

Sensory Examination

• Light touch-tests primarily large diameter nerve fibers and CNS sensory pathways– Easy to test with finger or Q-tip– Can use over entire body– Can use VAS (0-10) for semi-quantitation– Change in quantity or quality of light touch?

• Pin sensation tests small diameter nerve fibers and CNS pain pathways-sharp or dull

CNS Sensory Loss (2 Cs) and PNS Sensory Loss (2 Ps)

• Central-Circumferential limb/trunk distrib.– Distribution belong to many nerves/nerve roots– Cord, brainstem, brain

• Peripheral-Patchy distribution over a limb– In nerve or root distribution– Distribution belongs to single nerve/nerve root

• Exception: stocking-glove sensory loss of a distal sensory polyneuropathy

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Gait Assessment-What is wrong with my walking?

• This is a visual engagement exercise-you need to know what the gait looks like

• All material you need is reproduced in the slides on your handout

Gait-Hemiparetic

• Affected leg is stiff from spasticity Leg circumducts during walking

• Affected arm may be partially flexed in a spastic posture

Gait-Parkinsonian

• Short small shuffling steps bilaterally• En-bloc turning-multiple steps to turn

around instead of the normal two steps• Reduced arm swing- “arms stiff like a

robot” when walking; unilateral or bilateral• Retropulsion-tendency to fall backwards

when standing still and given a minor push

Gait-Alcoholic Cerebellar Degeneration

• Affects the truncal balance center in the midline cerebellum

• Limb coordination-nl or minimally abnl • Gait is wide-based• Cannot tandem walk-no direction to falls• Very severe-truncal bobbing when sits• No leg sensory loss or weakness

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Gait-Steppage

• Due to foot drop of any cause• To avoid tripping over the toes during the

foot drop, the patient compensates by lifting the proximal leg high in the air

• High risk of falls• Socially embarrassing• Correctable with ankle-foot orthosis (brace)

Gait-Sensory Ataxia

• Lack of sensation in the feet; Romberg sign• Inability to tell position of feet in space

results in imbalance– Visual compensation is gone in darkness

(washing hair with eyes closed while standing)– Wide-based gait accompanied by sensory loss– Grab bars/shower chair; flashlight on key chain

or flashlight app on smart phone

Gait that Shall not be Named

• Patient reports severe imbalance• Despite imbalance, falls with injury rare• Trunk pitches in many directions while

patient is walking– Pt able to compensate for pitching– No falls

Demonstrate 15 Minute Exam

• Mental status-Orientation, attention, language, abstractions, speech

• Cranial nerves II-XII• Motor-Tone, tremor, power, coordination,

reflexes, gait• Sensory-light touch/pin in face, hands, feet

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Conclusions

• A good screening neurologic exam can be performed in 10-15 minutes

• Neurologic examination details will be dictated by the history and initial neurologic examination findings

• The disease context and pattern of neurologic findings is most helpful, not a single finding

Questions and Demonstrations

• What questions can I answer?• What would you like to see me

demonstrate?