John W. Engstrom, MD October 16, 2015

Neurologic Examination

1

Neurologic Examination

John W. Engstrom, M.D.

Dept. of Neurology

University of California, San Francisco

October 16, 2015

Overview – The Neurologic Examination

• Mental status – description/questions

• Cranial nerves – demonstration/questions

• Motor exam – demonstration/questions

• Sensory exam – demonstration and questions

• “Top Ten Suggestions for a Better Neurologic Examination”

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination

1. If the patient can give a completely coherent history, then the mental status examination is probably normal

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination

1. If the patient can give a completely coherent history, then the mental status examination is probably normal

2. The neurologist says the encephalopathy is metabolic… and is almost always correct

Delirium/Encephalopathy- Common Causes and Evaluation

Metabolic Causes Laboratory Studies

Hyponatremia, hypernatremia Na

Renal failure BUN, Cr

Hypoxia, ischemia PO2

Hypoglycemia, hyperglycemia Glucose

Hypothyroidism, hyperthyroidism Thyroid function tests

Recreational drugs Toxicology screen

Alcohol intoxication / withdrawal Alcohol level, osmolarity

Pharmaceutical drugs Review medications

Hypercalcemia, hypermagnesia Calcium, magnesium

Hyperphosphatemia Phosphate

Delirium/Encephalopathy –Common Causes and Evaluation

Infectious Causes Laboratory Studies

Sepsis Cultures, CBC, Chest X-Ray, UA

Meningitis Lumbar puncture (LP), Cultures, CBC

Neurologic Causes

Subarachnoid hemorrhage Brain CT, LP

Cerebral infarction Brain CT or MRI

Seizures, post-ictal state Consider brain CT/MRI, EEG

HIV infection, encephalitis HIV testing, MRI

John W. Engstrom, MD October 16, 2015

Neurologic Examination

2

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination

1. If patient gives completely coherent history, then mental status exam is probably normal

2. The neurologist says the encephalopathy is metabolic… and is almost always correct

3. Dementia-preserved attention (Normal digit span early); no disturbance of consciousness

4. Delirium-poor attention/digit span; fluctuating level of consciousness

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination

5. After establishing new-onset coma, the pupillary examination is the most important initial neurologic examination test

“Fixed” Pupils and Coma

Dilated (7-9 mm) – Early brain herniation

Mid-position (3-5 mm) – Late herniation

False positives

-Drug effect (Mydriacyl, barbs)

-Adequacy of light stimulus

-Prosthetic eye

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination

4. After establishing new-onset coma, the pupillary examination is the most important initial neurologic examination test

5. Visual field testing is highly informative and underutilized by the non-neurologist

Screening for Visual Field Deficits

• Cooperative patient-Move examiner finger in the center of each quadrant with patient gaze fixed– Test each eye by covering the opposite eye, present

stimulus in all 4 quadrants

• Uncooperative patient-Use a single digit to suddenly approach each half of the visual fields; normally elicits a blink– Avoid using entire hand-wind elicits corneal reflex

– Report as “Does/Does not blink to threat”

John W. Engstrom, MD October 16, 2015

Neurologic Examination

3

Assessment of Vision

• Measure acuity with glasses on/contacts in

• Establishing a visual field cut establishes a structural lesion (eye vs. brain)

• The pupils always react in cortical blindness– Afferent-retina, optic nerve/tract, brainstem

– Efferent-midbrain, third nerve, ciliary muscle

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination

4. After establishing new-onset coma, the pupillary examination is the most important initial neurologic examination test

5. Visual field testing is highly informative and underutilized by the non-neurologist

6. There are only two types of headaches, old and new

Old Headaches vs. New Headaches

• Severity or location of headaches rarely helpful with diagnosis

• Historical risk factors:– New-onset – elderly, immunosuppressed– Focal neurologic signs– Postural – supine or standing– Fever, rash, stiff neck– Sudden onset over 1-2 seconds

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination

4. After establishing new-onset coma, the pupillary examination is the most important initial neurologic examination test

5. There are only two kinds of headaches-old headaches and new headaches.

6. Visual field testing is highly informative and underutilized by the non-neurologist

7. Weakness is either neurologic or non-neurologic

John W. Engstrom, MD October 16, 2015

Neurologic Examination

4

The Weak Patient:Breakaway Weakness

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

• ASSOCIATED WITH PAIN: Cannot determine if underlying weakness present

• UNASSOCIATED WITH PAIN: Poor effort

The Weak Patient: History and Examination

NEUROLOGIC NON-NEUROLOGIC

UPPER MOTORNEURON

LOWER MOTORNEURON

BREAKAWAYFATIGUE

POOR EFFORTPAINANTERIOR

HORNCELL

NERVEROOT NERVE-

AxonalORDemyelination

NMJ MUSCLE

“Aids to the Examination of the Peripheral Nervous System”

Neuro Exam in New Neuromuscular Respiratory Failure

Disease Weakness Sensory Reflexes

GBS Global Nl or decr Absent

MG CN/Prox Normal Normal

Botulism CN/Prox Normal Nl or Decr

Prog Myop Prox Normal Normal

Order a CPK + inpatient EMG to clarify

The Weak Patient: Central Weakness I

Power - distal > proximal

extensors > flexors in arms

dorsiflexors > plantar flexors in legs

Bulk - Normal

Tone - spastic; Babinski signs present

Reflexes - Sensation - Normal or

John W. Engstrom, MD October 16, 2015

Neurologic Examination

5

The Weak Patient: Central Weakness II

Spasticity-velocity-dependent increase in tone

to passive stretch of a limb

Rapid, repetitive movements are slow-fingers and feet

Pronator drift

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination

8. The presence of diminished sensation is more helpful in defining a neurologic deficit than positive sensory phenomena (i.e.-paresthesias or pain).

Basic Rules of the Sensory Exam

• A patch of reduced sensation in a limb is a PNS lesion

• Circumferential reduced sensation in a limb is almost always a CNS lesion

• Circumferential reduced sensation in both legs-PNS (polyneurop) or CNS (cord/brain)

8. The presence of diminished sensation is more helpful in defining a neurologic deficit than positive sensory phenomena (i.e.-paresthesias or pain).

9. Use the history to determine which parts of the neurologic examination need to be performed in detail.

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination

10. Symmetry, or lack thereof, is a powerful diagnostic observation on the cranial nerve, motor, sensory, coordination, and reflex examinations.

8. The presence of diminished sensation is more helpful in defining a neurologic deficit than positive sensory phenomena (i.e.-paresthesias or pain).

9. Use the history to determine which parts of the neurologic examination need to be performed in detail.

The “High-Yield” Neurologic Examination: Top Ten Suggestions for a Better Neurologic Examination Conclusions

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

• Additional neurologic exam will be dictated by the history and initial examination findings

• The pattern of neurologic findings is the most helpful, rather than a single finding