Книги по МРТ КТ на английском языке / Neurosurgery Fundamentals Agarval 1 ed 2019

limb is moved quickly, the tone increases and more force is required to move the limb further. This is often tested with passive foot dorsiflexion. In contrast, increased tone in rigidity does not depend on how fast the muscle is moved. Cogwheel rigidity is characterized by rhythmic, jerky increased tone during passive motion, whereas lead-pipe rigidity is characterized by continuous increased tone during passive motion.

each movement is performed with the relevant joint stabilized, such that muscles and the nerves that innervate them are tested in isolation ( Table 3.5). If a patient is unable to overcome any resistance, the examiner should have the patient perform the movements without resistance both against gravity and in a plane that eliminates the effect of gravity in order to appropriate grade strength ( Table 3.6).

3.4.3  Strength

When testing muscle movements, the examiner should have the patient resist the examiner as he or she attempts to move a certain limb. It is important that

Subtle Weakness

Drift

In clinical practice, drift can refer to either simple extremity drift or pronator drift. Extremity drift refers to an extremity

Lower extremities

Table 3.6  Strength grading scale

gradually drifting downward after 5–10 seconds when voluntarily raised against gravity. Pronator­ drift is assessed by having the patient fully extend the arms at shoulder level with the palms facing upwards. The patient should then close the eyes and shake

the head for approximately 10 seconds. Arm pronating and downward drift are signs of an upper motor neuron lesion.

Satelliting

Satelliting is another sign of subtle weakness and is assessed by having the patient rotate the arms around each other. If one arm becomes more stationary after several seconds with the other arm “satelliting” around it, this suggests some degree of weakness in the stationary arm.

3.4.4  Involuntary

There are several involuntary motor movements that the examiner should also note should they be present ( Table 3.7).

3.5  Reflex Examination

3.5.1  Reflex Grading

There are several deep tendon reflexes that the examiner should assess ( Table 3.8). Deep tendon reflexes are graded on a scale from 0 to 4, where 0 is absent, 1 is reduced, 2 is normal, 3 is increased, and 4 is defined

Table 3.7  Involuntary movements

as myoclonus. As this scale is relatively subjective, comparing right-sided and leftsided reflexes is often more valuable than the grading itself.

3.5.2  Babinski’s Sign

Babinski’s sign is a primitive reflex that occurs in infants and normally disappears by 12 months of age. The examiner assesses for Babinski’s sign by stroking the sole of the patient’s foot with a blunt instrument along the lateral aspect starting at the heel and then moving in a curve just below the toes. In adults, the normal response is a flexor plantar response (i.e., down-going big toe), whereas the abnormal Babinski’s sign is an extensor plantar response (i.e. up-going big toe).

Hoffman’s sign

Hoffman’s sign is not a true primitive reflex and can be present in normal adults. The examiner assesses for Hoffman’s sign by flicking distal aspect of the middle finger and observing for any flexion of the thumb. The presence of Babinski’s and/or Hoffman’s sign can suggest an upper motor neuron (UMN) lesion.

A careful motor and reflex examination can often distinguish between UMN and

Table 3.9  Features of upper motor neuron versus lower motor neuron dysfunction

lower motor neuron (LMN) lesions, as both will present with weakness, but UMN lesions lack inhibitory modulation via descending pathways ( Table 3.9).

3.6  Sensory Examination

3.6.1 Light Touch

To assess light touch, the examiner should ask the patient to close the eyes and indicate whether he or she feels touch in various regions of all extremities and the trunk. It is reasonable to begin more distally and then progress proximally.

3.6.2  Pain and Temperature

Pain is assessed in a similar manner to light touch, but with a sharp pin and asking the patient if it feels sharp or dull while the eyes are closed. Temperature sense is carried by the same afferent small fibers as pain, and can be assessed with a cold object (e.g., tuning fork).

the examiner can feel the tuning fork vibrating after the patient can no longer feel vibration, vibration sense may be partially impaired.

3.6.4  Proprioception

Proprioception refers to a sense of body position in space and can be assessed by having the patient close the eyes and state the direction of movement as the examiner moves a body part. Second, the examiner can perform the Romberg test, in which the patient stands up with the eyes closed and the examiner observes whether the patient loses balance without visual sensory information.

3.6.5  Sensory Localization

Findings from the sensory examination can be used for localization of lesions given the presence of dermatomes, which correspond to areas of sensory innervation arising from a single spinal nerve ganglion ( Fig. 3.1). It is worth remembering that the median nerve transmits sensation from the thumb, index finger, middle finger, and half of the fourth finger, while the ulnar nerve transmits sensation from the fifth finger and the other half of the fourth finger. In the leg, the common peroneal nerve transmits sensation from the lateral aspect of the lower leg and dorsum of the foot, while the tibial nerve transmits sensation from the posterior aspect of the lower leg and sole of the foot.

3.6.3  Vibration

Vibration is assessed by placing a vibrating 128 Hz tuning fork against the patient’s joints while the eyes are closed and asking if the patient feels vibration. If

3.7  Gait and Coordination

Gait and coordination are critical aspects of the neurological examination because they can inform the examiner about the presence of a lesion in the cerebellum.

3.7.1  Gait

The examiner should begin by observing the patient’s spontaneous gait. Following this, the examiner should have the patient walk on the heels and tiptoes. The examiner should also instruct the patient to perform tandem gait, where one foot is placed in front of the other for each step.

3.7.2  Coordination

The simplest coordination test is finger tapping, in which the patient taps the thumb to the index finger repeatedly as fast as possible. The examiner can also have the patient tap the thumb to each of the other fingers sequentially as fast as possible. Speed, accuracy, and rhythm should be assessed.

Rapid alternating movements can be tested by having the patient flip one hand back and forth as fast as possible against a flat surface or the other hand. Dysdiadochokinesis describes abnormal rapid alternating movements.

Finger-to-nose is performed by having the patient alternate touching the index finger to the examiner’s index finger and then patient’s own nose as the examiner moves his or her index finger to various positions. Heel-to-shin is performed by having the patient place the heel on the contralateral knee and move the heel down the shin. An abnormality in

accuracy with either of these tests is termed dysmetria.

3.8  Special Tests

3.8.1  Straight Leg Raise

The straight leg raise can be used to determine whether a patient may be suffering from lumbar radiculopathy, particularly of the L5 nerve root. The test is performed by having the patient lie supine and passively lifting the patient’s straight leg. The examiner asks the patient whether this maneuver reproduces radiating sciatic pain down the leg ( Fig. 3.2).

3.8.2  FABER/FADIR Tests

The FABER (Flexion, ABduction, and External Rotation) test is used to evaluate hip and sacroiliac joint (SI) pathology, which may be important to distinguish from spinal pathology in evaluating a complaint of low back pain. The patient’s leg is flexed, and the thigh is then abducted and externally rotated ( Fig. 3.3). A related test if the FADIR (Flexion, ADduction, and Internal Rotation) test where the patient’s leg is flexed, and the thigh is then adducted and internally rotated. Each specific pain response guides decision-making regarding a corresponding pathology. Other tests to evaluate for sacroiliac joint pathology include distraction, compression, thigh trust, sacral trust, and Gaenslen’s test.

3.8.3  Spurling Test

The Spurling test can be used to determine whether a patient may be suffering from cervical radiculopathy. The examiner performs the test by passively rotating the patient’s head to the side while simultaneously applying downward and extending force on top of the patient’s head. The examiner asks the patient whether this maneuver reproduces radiating pain from the neck on the same side of head rotation ( Fig. 3.4).

3.8.4  Lhermitte’s Sign

Lhermitte’s sign suggests an upper cervical spinal cord lesion and is often described as an electrical shock sensation that passes down the neck and back and into the extremities. The examiner assesses for this sign by flexing the neck (i.e., bending the neck forward).

3.8.5  Tinel’s Sign

Tinel’s sign suggests irritated or damaged nerves and is performed by tapping directly over the nerve, resulting in paresthesias (i.e., tingling) within the sensory distribution of the nerve. Tinel’s sign is commonly checked when evaluating for carpal tunnel syndrome from median nerve entrapment.

Phalen’s maneuver

Phalen’s maneuver is specific to carpal tunnel syndrome and is performed by having the patient fully flex both wrists and then push the dorsal surfaces of the hands together for 60 seconds. Paresthesias within the sensory distribution of the median nerve during this maneuver suggests the presence of carpal tunnel syndrome.

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3.8.6  Bulbocavernosus

The bulbocavernosus reflex involves S2–S4, and is a useful test for spinal shock or spinal cord injuries. The test is performed by monitoring internal or external anal sphincter contraction in response to squeezing the penis or clitoris, or tugging on an indwelling Foley’s catheter ( Fig. 3.5).

Pearls

•Use the neurological examination to corroborate pathology identified by other diagnostic modalities.

•Use the neurological examination to assess daily clinical status in the inpatient setting.

•Tailor the neurological examination to your own unique style as well as each patient and clinical situation.

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3.9  Top Hits

3.9.1  Questions

1.A 26-year-old man with no relevant past medical history is brought into the ED following a motor vehicle collision. The patient’s eyes are open and he was conversing with you appropriately. CT spine shows complete transection of cervical spinal cord. Patient is not moving any extremities. What is the GCS for this patient?

a) 9 b) 15 c) 14 d) 8

2.You ask a patient to name items in your white coat such as “pen” and “stethoscope”, but the patient is unable

to do so. The patient is also unable to follow simple commands such as “stick out your tongue”. Otherwise, the patient speaks fluently, but the content is nonsensical. Where is the lesion?

a) Broca’s area b) Arcuate fasciculus

c) Transcortical motor area d) Wernicke’s area

3.You are called to evaluate a patient with a newfound facial droop. On examination, the corner of the patient’s left mouth is drooping, there is nasolabial fold flattening, and the patient cannot close the left eye tightly. Where does the lesion localize? a) Right-sided central CN VII b) Right-sided peripheral CN VII c) Left-sided central CN VII d) Left-sided peripheral CN VII

4.On visual field examination, you ask the patient to cover up the right eye. The patient exclaims “Doc! The right side of your face is missing!” Intrigued, you ask the patient to cover up the left eye. The patient exclaims “Doc! Now the left side of your face is

Fig. 3.5  Illustration of eliciting the bulbocavernosus reflex (S2–S4) to evaluate for spinal shock after spinal cord injury. (Reproduced from Albert T, Vaccaro A, Physical Examination of the Spine, 2nd edition, ©2016, Thieme Publishers, New York.)

missing!” Where does the lesion localize?

a) Left optic nerve b) Bilateral occipital lobes c) Right thalamus d) Optic chiasm

5.A patient presents to the clinic with chief complaint of frequent tripping. When you ask the patient to walk up and down the hallway, the gait appears normal. When you ask the patient to walk on tippy-toes, you notice that the right heel barely lifts above the floor. To which spinal cord root does this motor deficit localize? a) S1-S2

b) C8-T1 c) L4-L5 d) L2-L3

6.On a patient’s MRI, you notice a lesion in the cortical region anterior to the central sulcus. What motor findings might you expect to see on neurological examination?

a) Pronator drift b) Fasciculations c) Diplopia

d) Positive Romberg sign

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7.A 21-year-old college student was brought to ER for acute alcohol intoxication on Sunday morning after a night of festivities. On reflex examination, you notice that the biceps and brachioradialis reflexes are intact but the triceps reflex is diminished. To which spinal cord root does this deficit localize?

a) C5 b) C6 c) C7 d) C8

8.A patient comes into the clinic complaining of back pain with radiation down the lateral aspect of the thigh and anterior aspect of the leg to the dorsum of the foot. On sensory examination, you also notice diminished pinprick sensation in the web space between the big toe and second toe. To which spinal cord root does this sensory deficit localize?

a) L3 b) L4 c) L5 d) S1

9.A patient presents with a long history of pain in the right hand and wrist. On careful examination, you elicit tingling of the thumb, index, and middle finger by tapping the anterior aspect of the distal forearm. What other physical examination finding might you observe? a) Tingling in fifth finger

b) Atrophy of the thenar eminence c) Weakness on wrist flexion d) Positive Hoffman’s sign

10.An 80-year-old patient presents to the clinic with a chief complain of low back pain that gets worse after walking for 5 minutes and radiates along the lateral aspect of the right hip and thigh. On neurological examination, lower extremity strength is 5/5, reflexes are normal and symmetric, and

straight leg test is negative. What ­additional test would be helpful to ­localize the lesion?

a) Bulbocavernosus reflex b) Babinski’s sign c) Tandem gait d) FABER/FADIR

3.9.2  Answers

1.b. The patient has spontaneous eye opening (eye opening = 4) and oriented spontaneous speech (verbal = 5). Although he cannot move lower extremities, he is speaking appropriately which is indicative of full motor movement with his tongue (motor = 6).

2.d. The patient has deficits in comprehension, as manifested by impaired naming and an inability to follow commands. However, the patient speaks fluently though the content is nonsensical, which fits with a fluent aphasia from a lesion in Wernicke’s area.

3.d. Central CN VII lesions result in contralateral facial weakness that spares the forehead, whereas peripheral CN VII lesions result in ipsilateral facial weakness that includes the forehead.

4.d. The clinical vignette describes bitemporal hemianopia, meaning loss of temporal visual fields in both eyes. This usually results from compression of the optic chiasm, which contains crossing nasal retinal fibers.

5.c. The clinical vignette describes a case of foot drop, which is due to weakness in ankle dorsiflexion. This localizes to the L4–L5 spinal cord root, which contributes to the peroneal nerve and innervates the tibialis anterior muscle.