Post on 26-Jul-2020
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
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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