Neurologic Examination

Transcription

1 John W. Engstrom, MD October 16, 2015 Neurologic Examination Overview The Neurologic Examination Neurologic Examination John W. Engstrom, M.D. Dept. of Neurology University of California, San Francisco October 16, 2015 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 1. If the patient can give a completely coherent history, then the mental status examination is probably normal 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 Delirium/Encephalopathy Common Causes and Evaluation Metabolic Causes Hyponatremia, hypernatremia Renal failure Hypoxia, ischemia Hypoglycemia, hyperglycemia Hypothyroidism, hyperthyroidism Recreational drugs Alcohol intoxication / withdrawal Laboratory Studies Na BUN, Cr PO2 Glucose Thyroid function tests Toxicology screen Alcohol level, osmolarity Infectious Causes Sepsis Meningitis Neurologic Causes Subarachnoid hemorrhage Laboratory Studies Cultures, CBC, Chest X-Ray, UA Lumbar puncture (LP), Cultures, CBC Brain CT, LP Pharmaceutical drugs Hypercalcemia, hypermagnesia Hyperphosphatemia Review medications Calcium, magnesium Phosphate Cerebral infarction Seizures, post-ictal state Brain CT or MRI Consider brain CT/MRI, EEG HIV infection, encephalitis HIV testing, MRI 1

2 John W. Engstrom, MD October 16, 2015 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 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 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 2

3 John W. Engstrom, MD October 16, 2015 Neurologic Examination 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 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 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 3

4 John W. Engstrom, MD October 16, 2015 Neurologic Examination The Weak Patient: Breakaway Weakness The Weak Patient: History and Examination DEFINITION: Variable resistance by the patient during muscle power testing NEUROLOGIC NON-NEUROLOGIC ASSOCIATED WITH PAIN: Cannot determine if underlying weakness present UNASSOCIATED WITH PAIN: Poor effort UPPER MOTOR NEURON ANTERIOR HORN NERVE CELL ROOT LOWER MOTOR NEURON NERVE- NMJ Axonal OR Demyelination FATIGUE MUSCLE PAIN BREAKAWAY POOR EFFORT 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 4

5 John W. Engstrom, MD October 16, 2015 Neurologic Examination The Weak Patient: Central Weakness II Spasticity-velocity-dependent increase in tone to passive stretch of a limb 8. The presence of diminished sensation is more helpful in defining a neurologic deficit than positive sensory phenomena (i.e.-paresthesias or pain). Rapid, repetitive movements are slow-fingers and feet Pronator drift 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. 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. 10. Symmetry, or lack thereof, is a powerful diagnostic observation on the cranial nerve, motor, sensory, coordination, and reflex examinations. Conclusions A good screening neurologic exam can be performed in 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 5

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