The Neurological Exam


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The Neurological Exam

  1. 1. John W. Engstrom, M.D. October 24, 2008 The Neurological Exam Mental Status Examination Before beginning the mental status examination, assess education level and native language of the patient. The results of the exam must be interpreted in the context of these factors. 1. Orientation – Ask for the patient's name, the date (as day, month, year), and where the patient is located now. You will have an excellent index of orientation simply by interviewing the patient. “Learning effect” – a patient repeatedly asked the same orientation question on successive days will “learn” the answers. Ask about other items (i.e. – seasons, holidays close to the current date). 2. Attention span – One simple test of attention span is the instantaneous recall of a particular order of numbers, such as a telephone number. Normally a patient should be able to recall 7-8 digits forward and 4 - 5 digits backward. An alternative is to ask the patient to spell “world” forward and backward. The likelihood of normal recent recall at 5 minutes is low if attention span is impaired. 3. Recent recall – Ask the patient to remember 3 items and repeat them back to you after 5 minutes. This test is best performed if the objects to be remembered are familiar to the patient. For example, one might ask a carpenter to remember a hammer, a board, and a house. In addition, you should always ask the patient to repeat all 3 items immediately back to you to make sure the patient understands each item. 4. Aphasia – Aphasia can be detected by the ability of the patient to repeat, to name, and to comprehend. A sentence can be repeated such as, “Today is a sunny day”. Naming can be performed with common objects such as a pencil, tie, shoe, or belt. Objects should be easily identifiable and appropriate to the cultural background and educational level of the patient. Comprehension is tested throughout the examination history and by the ability of the patient to follow directions and answer questions. 5. Calculations (optional) – Calculations can be difficult to assess depending on the educational level of the patient and cultural background, but can be useful under certain circumstances. For example, it would be abnormal for an accountant to be unable to perform simple subtraction (i.e. – serial 7s). 6. Abstractions – Abstractions are complex, difficult tasks for a cognitively impaired patient to perform. Examples of testing simple abstractions are, “What is the difference between a cat and a dog?” “How would you distinguish between a lake and a river?” or “How are a lake and river alike?” The answers will be abnormal in patients with either delerium or dementia. 7. Speech – One can easily argue that the evaluation of language is a part of the mental status examination (i.e. – the aphasia screen). Speech is often placed under the mental status examination as well. Abnormalities of speech (dysarthria) can be related to cranial Page 1
  2. 2. nerve abnormalities including VII (labial dysarthria), X (palatal dysarthria), or XII (lingual dysarthria). For simplicity, one can include speech under the mental status examination when a specific etiology for the speech difficulty is not clear. 8. The above guidelines are for a screening mental status examination only. There are many different forms of the mental status examination that can be adapted to specific circumstances. Cranial Nerve Examination If in doubt about whether or not a cranial nerve finding is abnormal, check for symmetry between the two sides. I – Smell (optional) – Testing smell is not part of a routine screening examination. Coffee, floral scents, or cloves are all adequate. Avoid using noxious odors (i.e. – ammonia, alcohol). Smell testing is particularly useful when a subjective lack of taste or smell is a primary symptom. Two most common causes – prior head trauma and smoking. II – Vision – Screen corrected (i.e.- with glasses) visual acuity with a vision card. Allow the patient to hold the card. Screen for major visual field deficits by having the patient cover one eye and identify an object (often a finger) in the center of each visual quadrant of each eye. II, III – Pupillary examination – Normal size in moderate light for adults is 3-4 mm. Larger in children and smaller in the elderly (senile miosis). Acceptable asymmetry is ≤ 1 mm. Check both direct and consensual reactions. For patients with a dark pigmented iris, try using a second flashlight held from below or above the face to illuminate the pupils without causing constriction. III, IV, VI – Extraocular movements. Check horizontal, vertical, and inferonasal (down and in) eye movements. Can the patient move the eyes from side-to-side fully so as to eliminate the sclera from view? Nystagmus is a rapid, beating movement of the eyes – (usually in a horizontal plane) that is triggered by eye movement. Remember that VI controls abduction and IV controls inferonasal movement. III controls the other eye movements. Ask the patient to follow your finger with his/her eyes as you elicit the eye movements. V – Corneal response, facial sensation, and pterygoid power. Use a wisp of cotton and lightly touch the cotton to the surface of each cornea. Note if both the direct and consensual corneal responses are present. Check pin and light touch sensation on each cheek. Check pterygoid muscle power by having the patient keep the jaw open against resistance provided by the examiner’s hand. If the pterygoid muscles are weak, then the jaw will deviate toward the side of the weakness. VII – Facial expression – Test the muscles of facial expression by having the patient raise the eyebrows, close the eyes tightly, and smile. Note any asymmetry in the extent of facial movement and speed of movement on the two sides of the face. VIII – Hearing – Rub the fingers together by each ear so that the fingers can normally be heard, but no movement of the fingers or arms seen by the patient. Vestibular function is screened Page 2
  3. 3. during testing of the extraocular movements by noting the presence or absence of nystagmus. A few beats of nystagmus at the extremes of horizontal eye movement is normal. The direction of the nystagmus (by convention) is named for the fast component of the beating eye movements. IX, X – Soft palate function – Gag reflex, nasal voice, elevation of the palate. Elevation of the palate is the best screening test. The uvula will normally elevate in the midline when the patient says 'Ahhhhhhhl" A nasal voice is an indication of soft palate dysfunction. The gag reflex is helpful when asymmetric, but it is uncomfortable for patients and may be bilaterally absent in normal patients. XI – Sternomastoid (SM) – Many muscles turn the head from side-to-side. The SM turns the head toward the opposite side. As a practical matter, compare the bulk of the SM muscles on the two sides. It is very difficult to convincingly demonstrate weakness limited to this muscle. XII – Tongue – Note the bulk of the two sides of the tongue when protruded. If the tongue is weak from a XIIth nerve lesion, it will protrude toward the side of the lesion. Strength can be tested by having the patient push the tongue against the inside of each cheek. In the presence of facial weakness, one can be misled into thinking the tongue protrudes to one side. Be careful to line up the position of the tongue with the tip of the nose and the middle of the chin to determine if the tongue has protruded to one side or another. The Motor Examination 1. If in doubt about whether or not a finding (bulk, power, reflexes) is abnormal, check for symmetry between the two limbs. 2. A screening examination will include sampling of the proximal and distal muscles of the arms and legs. In otherwise healthy patients, the ability to perform a deep-knee bend is a good screen of proximal leg power. 3. You cannot perform an adequate muscle examination unless you can see the muscles! The patient must be positioned and dressed appropriately. 4. You will not remember the innervation and action of all the muscles. You may want to get a portable book with diagrams that can serve as an instant resource (i.e.-Aids to the Examination of the Peripheral Nervous System). Bulk – Check the bulk of the deltoid, abductor pollicis brevis (APB), quadriceps, and the extensor digitorum brevis (EDB) muscles. Visually compare the same muscles on the right with the left arm. Repeat inspection in the legs. Tone – Move the limbs slowly and quickly through their range of motion with the patient relaxed and supine. Increased tone consists of resistance to passive movement of the limbs, despite adequate relaxation and the absence of pain during the movement. Spasticity is a velocity- dependant increase in resistance that is greatest in the flexors of the arms and extensors of the legs. Page 3
  4. 4. Power – Check one proximal and one distal arm muscle: biceps and first dorsal interosseus muscle are good choices in the arms. Check one proximal and one distal leg muscle: iliopsoas and tibialis anterior are good choices. Alternatively, screen the proximal muscles of the legs by having the patient perform a deep-knee bend. Coordination – Check finger-to-nose and heel-knee-shin on both sides. Check tandem gait by having the patient walk while placing the toe of one foot to the heel of the opposite foot repetitively. The patient can use laterally outstretched arms for balance while walking and should keep their eyes open. Tandem gait is not a speed test! Correct results for patient age; tandem gait normally begins to deteriorate over age 60. Check for fast finger movements by having the patient tap the first finger and thumb in a rhythmic and rapid fashion. Asymmetric, slow, but rhythmic fast finger movements or foot tapping is a sensitive test for an upper motor neuron lesion. Check for pronator drift by having the patient extend outstretched arms fully forward with the palms up and close the eyes. The patient is instructed to hold the arms steady. The hand of a weak arm in an upper motor neuron lesion (i.e. – a stroke) will pronate, flex, and tend to drift downward. Gait – Many neurologic problems may be subtle until a patient attempts to walk. Walking can be difficult for the hospitalized patient due to pain, instrumentation, or extreme fatigue. Can the patient independently bear weight on both legs? Can the patient independently maintain balance while standing? Do the legs move symmetrically when walking? These questions can be answered when a patient stands and takes just a few steps at the bedside. Specific gait disorders (i.e. – spastic, parkinsonian, steppage, and elaboration) for inpatents able to ambulate will be demonstrated. Reflexes – The limbs to be tested should be relaxed and in a comparable position bilaterally if interpretation of the results is to be valid. Always check for symmetry. The most common cause of an unobtainable ankle reflex is improper positioning of the leg! Your reflex screen should include the biceps, triceps, finger flexors, quadriceps, and ankle reflexes. For the neuroanatomy of each reflex, consult your handout. Check for a Babinski response by lightly stroking the lateral aspect and ball of the foot from back to front with a key. You can use a more vigorous stimulus if a response is initially absent. A normal response is plantar flexion of the toes. A Babinski response consists of dorsiflexion of the great toe. The Sensory Examination “The sensory examination almost kept me out of the field of neurology” – Robert A. Fishman, MD, former Professor and Chairman, UCSF Neurology. The sensory examination should ideally include small fiber modalities (pain or temperature) and large fiber (light touch, vibration, position) modalities because disease may selectively involve one or the other. Light touch – Use a cotton swab or fingertip to check for asymmetry of touch sensation or a proximal-to-distal gradient below the knees. If the patient has a subjective complaint of diminished sensation, compare sensation on the affected patch of skin with an analogous patch of Page 4
  5. 5. skin on the opposite limb. Define normal touch as 10 (on a scale of 0-10) and complete absence of touch as 0. Ask the patient to assign a number to the “amount of touch” always beginning with demonstration of normal sensation as 10. Reduction of touch sensation below 7 strongly suggests decreased sensation. Pin – Use a safety pin and lightly touch the patient asking if a sharp sensation can be felt. Check one spot on each hand and foot. Check from proximal-to-distal below the knees to see if perception of the sharpness declines. An increase in sensitivity from proximal to distal can be normal, but a decrease is abnormal. Romberg – The patient stands with the feet together as closely as possible and the eyes open. First verify that balance is maintained, then ask the patient to close the eyes. The most common cause of a “false positive” test is failure to perform this first step. If the patient cannot maintain balance when the eyes are closed, then a Romberg sign is present. The Romberg sign is a sensory test of large fiber sensation, not a cerebellar test of coordination. Cold (optional) – Check (as with pin) for asymmetry of cold sensation and proximal-to-distal gradient below the knees. Be careful if the hands and feet are already cold, the cold object will feel warmer distally than proximally. The patient detects both the difference in temperature between the test object and skin as well as the absolute temperature of the test object. For this reason, cold can be a difficult screening test for sensation. Position (optional) – The patient must relax the hands and feet for this test to be successful and should be in a supine position. Place your thumb and index finger on the sides of the great toe and flex or extend the DIP joint of the toe with your other hand. Ask the patient to state if the perceived movement is up (toward the patient) or down (toward the examiner). Vibration (optional) – Check for vibration by placing the 128 Hz tuning fork dorsally on the IP joint of the great toe and your index finger DIP joint ventrally under the patient's joint. Ask the patient to say immediately when the vibration stops. Can you still feel the vibration in your finger? Repeat the same test on the other foot and the index fingers of both hands. Direction sense (optional) – Use a cotton swab and check the feet and hands (in areas without hair). Lightly touch and move the swab up (toward the patient) or down (toward the examiner) or to the patient's left or right side. The patient should have the eyes closed to avoid visual cues regarding the direction of the movement. Ask the patient (with each movement) about the direction of the movement. This test is a sensitive measure of large sensory fiber function in peripheral nerves and dorsal columns of the spinal cord. Page 5
  6. 6. Helpful Tables Table 1 – COMMON DRUGS CAUSING DELIRIUM Barbiturates Benzodiazepines Anticholinergics Clonidine Antihistamines Digitalis Dopamine agonists Levodopa Antipsychotics Lithium Tricyclic antidepressants Glucocorticoids Anticholinergics Opiate analgesics Table 2 – COMMON CAUSES OF DRUG-INDUCED HEADACHE Nifedipine Isosorbide dinitrite Cimetidine Estrogen Indomethacin Cyclosporin Atenolol Nytroglycerin Ranitidine Oral Contraceptives Trimethoprim-sulfamethoxazole Table 3 – CAUSES OF HORNER'S SYNDROME Brainstem/cervical cord (diminished sweating ipsilateral body) Wallenberg's syndrome (brainstem infarction) Multiple sclerosis Tumor Syringomyelia Cord/C8-T1 root/Sympathetic chain (diminished sweating ipsilateral face) Pancoast tumor (carcinoma of lung apex) Aortic aneurysm Neck surgery Superior cervical ganglion/Carotid artery/Orbit (no anhydrosis) Tumors Carotid artery dissection Cluster headache Page 6
  7. 7. Table 4 – SOME NEUROLOGIC CAUSES OF DIPLOPIA NEUROANATOMIC SITE CLINICAL EXAMPLE Brainstem pathways (MLF lesion) Multiple sclerosis Lower motor neuron (III, IV, VI) Cranial nerve nuclei/nerves: Brainstem stroke Subarachnoid Space Basilar meningitis (tuberculosis) Nerve trunks IIIrd nerve compression (aneurysm), Diabetes Neuromuscular junction Myasthenia gravis Muscle Thyrotoxicosis, oculopharyngeal dystrophy Retina Congenital retinal anomaly Table 5 – SELECTED CAUSES OF VERTIGO PNS CNS Vestibular neuronitis Vertebrobasilar ischemia Benign positional vertigo (BPV) Temporal lobe disease (rare) Meniere's syndrome Brainstem/cerebellar glioma or AVM Cerebellopontine angle tumor Demyelinating disease (MS) Drug-induced Posterior fossa mass lesions Post-traumatic Hereditary spinocerebellar degeneration Systemic-infection, hypotension Table 6 – NEUROLOGIC CAUSES OF DYSPHAGIA Oropharyngeal Esophageal Amyotrophic lateral sclerosis (ALS) Achalasia Brainstem stroke or tumor Vagus nerve injury Multiple Sclerosis Scleroderma Myasthenia Gravis Dysautonomia Tardive Dyskinesia Esophageal spasm Myopathy Amyloidosis Syrinx Myopathy Spinocerebellar degeneration Arnold-Chiari malformation Parkinson’s disease Tardive dyskinesia (drug-related) Page 7
  8. 8. Table 7 – SCORING SYSTEM FOR REFLEXES Score Observation 0 Absent (areflexia) Trace Present with reinforcement only 1 Hypoactive (hyporeflexia) 2 Normal 3 Brisk (hyperreflexia) 4 Clonus Table 8 – COMMONLY TESTED REFLEXES Reflex Peripheral Nerve Root/Segmental Level Jaw jerk Trigeminal Pons Biceps Musculocutaneous C5/C6 Triceps Radial C7 Finger flexors Median/Ulnar C8 Knee (quadriceps) Femoral L4 Ankle Tibial S1 Anal sphincter Pudendal S3/S4 Table 9 – CAUSES OF FOOT DROP L5 root compression Peroneal neuropathy Sciatic nerve palsy Motor neuron disease Polyneuropathy (bilateral) Anterior cerebral artery stroke Table 10 – URINARY INCONTINENCE AND DRUGS Class/Medication Effect on Urination Diuretics, Alcohol, Caffeine Polyuria Tricyclic ats Retention, Overflow Opiates Retention, Overflow Anticholinergies Retention, Overflow Calcium channel blockers Retention Page 8
  9. 9. Table 11 – SOME NEUROLOGIC CAUSES OF URINARY INCONTINENCE Multiple sclerosis Anterior spinal artery syndrome Spinal cord compression (abscess, tumor, disk) Cauda equina syndrome Spinal stenosis Intrinsic spinal cord tumors (glioma) Diabetes mellitus Table 12 – CSF FINDINGS IN MENINGITIS Pressure [mm White cells Protein Glucose water] [cells/mm3] [mg/dl] [mg/dl] Normal 50-200 Not > 5 white blood 15 - 50 60-80% of cells blood glucose Acute bacterial Usually elevated 100s-1000s; 100-500 5-40 meningitis Polymorphs Acute viral Normal or 5-100 ; Normal or Normal meningitis moderate Lymphocytes <100 elevation Tuberculous Usually elevated 25-100; Usually 100- Reduced meningitis Lymphocytes 200 Cryptococcal Usually elevated Lymphocytes 20-500 Reduced; meningitis Average 30 Carcinomatous Normal or 0-300 mononuclear Elevated to Normal/reduced meningitis elevated cells, malignant cells very high Subarachnoid Normal or raised Red and White cells Raised Normal or hemorrhage if acute reduced May be higher in obesity Always abnormal if < 40 mg/dl Rarely > 1000 cells/mm{sup2(3)} Page 9
  10. 10. Table 13 – CAUSES OF INCREASED CSF PRESSURE DESPITE A NORMAL OR NONDIAGNOSTIC CT/MR BRAIN SCAN Elevated central venous pressure Meningitis and encephalitis Respiratory failure Postanoxic encephalopathy Fulminant hepatic encephalopathy Reye’s syndrome Lead encephalopathy Water intoxication/hyponatremia Dural venous sinus occlusion Psuedotumor cerebri Spinal cord tumors Acute polyneuritis (Guillian-Barre syndrome) Table 14 – CAUSES OF PIGMENTED CSF Subarachnoid blood Bilirubin > 10-15 mg/dl in serum Carotenemia Protein > 150 mg/dl Chromatins of old age Rifampin, pyridium, INH Table 15 – MRC MUSCLE STRENGTH TESTING SCORE SCORE RESPONSE 5 Full power 4+/5- Minimal weakness 4 Mild weakness 4- Moderate weakness 3 Severe weakness with slight movement vs. gravity 2 Moves, but not against gravity 1 Flicker of contraction 0 No muscle contraction Page 10
  11. 11. Table 16 - CAUSES OF AN ISOLATED THIRD NERVE PALSY LOCATION LESION Brainstem (nucleus or Stroke, Mass lesion fascicle) Subarachnoid space Posterior communicating aneurysm, Meningitis(infectious, neoplastic), Uncal herniation with raised ICP. Cavernous sinus Fistula, tumor, aneurysm Orbit/superior orbital fissure Trauma (fracture), mass lesions, ??MG Not localized clearly Diabetic infarction, GBS, Migraine Table 17 – CAUSES OF STIFF NECK Menigeal Mechanical/Other Infectious meningitis Cervical Spondylosis Parameningeal infection (mastoiditis) Musculoskeletal neck injury Subarachnoid hemorrhage Retropharyngeal abscess Neoplastic invasion of the meninges Paraspinal muscle spasm Axial rigidity (Parkinsonian syndromes) Page 11
  12. 12. 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 3. Dementia – the lights are on but nobody is home; Delerium – the lights are flickering on and off. 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 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. Page 12
  13. 13. References 1. Victor M, Ropper AH. Principles of Neurology, 7th ed. New York: McGraw Hill, 2001. 2. Brown WF, Bolton CF, Aminoff MJ et al. Neuromuscular Function and Disease. Philadelphia: WB Saunders, 2002. 3. Wijdicks EFM. The Clinical Practice of Critical Care Neurology, 2nd ed. New York: Oxofrd University Press, 2003. 4. Brazis PW, Masdeu JC, Biller J. Localization in Clinical Neurology, 4th ed. Philadelphia: Lippincott Williams and Wilkins, 2001. 5. Lin VW, Cardenas DD, Cutter NC et al. Spinal Cord Medicine. New York: Demos, 2003. 6. Bradley WG, Daroff RB, Fenichel GM, Jankovic J. Neurology in Clinical Practice. Philadelphia: Butterworth Heinemann, 2004. 7. Stewart JD. Focal Peripheral Neuropathies, 3rd ed. Philadelphia: Lippincott Williams and Wilkins, 2000. 8. Glaser JS. Neuro-ophthalmology, 3rd ed. Philadelphia: Lippincott Williams and Wilkins, 1999. 9. Brain. Aids to the Examination of the Peripheral Nervous System, 4th ed. Philadelphia: WB Saunders, 2000. 10. Silberstein SD, Lipton RB, Goadsby PJ. Headache in Clinical Practice, 2nd ed. XXX: Taylor and Francis Group, 2002. 11. Jankovic JJ, Tolosa E. Parkinson’s Disease and Movement Disorders, 4th ed. Philadelphia: Lippincott Williams and Wilkins, 2002. 12. Hauser, SL, Josephson SA, English JD, Engstrom JW. Harrison’s Neurology in Clinical Medicine. New York: McGraw-Hill, 2006. Page 13