Steven L.
Guide to the Neurologic Examination, 1st Edition
Wilkins
Neurologic Examination in Common Clinical Scenarios >Chapter 51 –
Examination of the Patient With a Suspected Spinal Cord Problem
Problem
examination, when a patient’s symptoms are likely to be due to spinal cord
dysfunction so that the appropriate investigations can be performed.
extrinsic to the spinal cord (e.g., tumor, abscess, or disc) or due to an
intrinsic lesion within the spinal cord (e.g., demyelination, inflammation, or
infarction). Dysfunction of the spinal cord due to any cause is referred to by
the generic term myelopathy. Acute dysfunction of the
spinal cord causing severe motor and sensory loss below the level of the lesion
is often called a transverse myelopathy. When spinal
cord dysfunction is thought to be due to an intrinsic demyelinative or
inflammatory process, it is called myelitis.
autonomic dysfunction below the level of the spinal cord lesion; however, the
symptoms of spinal cord disease vary, not only depending on the level of the
lesion (e.g., cervical or thoracic), but also the severity of the process and
the part of the cord that is being affected at that level (Table
51-1).
PROBLEM
When taking the history, use the combination of motor, sensory,
and any autonomic (bowel, bladder, sexual) symptoms to clue you in on the
possibility that your patient’s symptoms might be due to spinal cord
dysfunction. Be aware that cord lesions can present in several different ways
(Table 51-1).
Ask about bowel, bladder, and sexual function (patients may not
always volunteer this information); these can be affected by lesions at any
level of the spinal cord.
Patients with a lesion at the level of the cervical spinal cord
will most likely have symptoms of weakness and sensory loss in the arms and
legs; however, mild or moderate cervical spinal cord dysfunction might cause
primarily lower extremity symptoms. Patients with lesions at the level of the
thoracic cord can have weakness and sensory loss in the legs, trunk, or
abdomen below the dermatomal level of the lesion, but they would not have
symptoms in the arms.
Patients who have hemi-spinal cord dysfunction (i.e., dysfunction
affecting only the left or right side of the spinal cord at a particular
level) may specifically complain of weakness on one side of the body with
sensory loss to temperature sensation (such as when taking a shower or bath)
on
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the opposite side of the body, symptoms
characteristic of the Brown-Séquard syndrome (Table
51-1).
Some patients with a myelopathy have Lhermitte’s sign, an
uncomfortable feeling of electricity, vibration, or tingling radiating down
the neck, back, or extremities occurring on neck flexion. Lhermitte’s sign is
actually
P.176
a symptom, and not a sign tested for
during the examination. Although often primarily thought of as a symptom of
spinal cord dysfunction due to multiple sclerosis, Lhermitte’s sign can occur
due to any process affecting the cervical cord (whether intrinsic or
compressive), causing dysfunction of the posterior columns. Lhermitte’s sign
can be a helpful clue to a cervical spinal cord localization of pathology;
therefore, patients with a suspicion of spinal cord dysfunction should
specifically be asked about the presence or absence of this
symptom.
Most patients with spinal cord dysfunction do not have pain in
the neck or back. Neck or back pain may occur in some patients with spinal
cord disorders, however, particularly those with epidural spinal cord
compression from neoplasms or abscesses that are also affecting bone.
Radicular pain may occur in patients who have pathology causing simultaneous
root and cord dysfunction.
Like any neurologic process, the temporal course of symptom
development can provide clues to the most likely mechanism of the cord
dysfunction. Sudden dysfunction suggests acute compression or infarction,
whereas more gradually progressive symptoms suggest processes such as chronic
compression, inflammation, or demyelination.
TABLE 51-1 Signs and Symptoms of Common Spinal Cord Syndromes and the Cauda Equina Syndrome | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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The motor examination of patients with spinal cord disorders may
show weakness in muscles below the level of the cord lesion. Depending on the
severity of the process, the weakness may be mild or severe. The highest level
of major root innervation of the weak muscles (see Tables
25-1 and 26-1) represents the lowest possible
superior aspect of the spinal cord lesion. In other words, if there is
weakness in C6-innervated muscles and below, the spinal cord lesion must start
at or above C6.
The sensory examination of a patient with spinal cord dysfunction
may show bilateral sensory loss to any modality below the level of the lesion.
Sensory testing should particularly focus on looking for diminished pin
sensation below a dermatomal level, by marching the pin down from superior to
inferior dermatomes on each side of the body, asking the patient if there is
any decrease in the pin sensation as you go down. March the pin down the chest
and abdomen when assessing for a thoracic pin sensation level or between
dermatomes of the arm looking for a cervical pin level. If a sensory level is
found, the pin level represents the lowest possible superior aspect of the
spinal cord lesion. In other words, if there is diminished pin sensation from
the T4 level and down (i.e., normal above T4), the spinal cord lesion must
start at or somewhere above T4. Cervical cord lesions may, therefore,
sometimes cause a thoracic sensory level.
The sensory examination of patients with spinal cord disorders
usually also shows loss of vibration sensation (and, if severe, proprioceptive
loss) below the level of the lesion. These signs of posterior column
dysfunction are helpful in assessing the severity of a lesion (i.e., the more
severe the lesion, the worse the vibration or proprioceptive sensation loss
below the lesion) but are not as helpful in defining the possible level of the
lesion as pin sensation.
Patients with spinal cord dysfunction typically have upper motor
neuron signs (hyperreflexia) below the level of the lesion, as well as upgoing
toes (Babinski sign). Patients with chronic spinal cord disorders also
typically have increased tone (spasticity) below the level of the
lesion.
When a hemi-spinal cord (Brown-Séquard) syndrome is suspected, in
addition to assessing for asymmetric weakness, look for side-to-side
differences in vibration and proprioception, as well as side-to-side
differences in pin and temperature sensation below the level of the lesion. To
test temperature sensation, simply touch an area of skin on each side of the
patient’s body with the side of a (nonvibrating) tuning fork, because a metal
tuning fork usually feels cold against the skin. Ask the patient if he or she
feels the coldness the same on each side. A sensory level to temperature
sensation can also be tested in the Brown-Séquard syndrome (or in any
potential spinal cord syndrome) simply by marching the side of the tuning fork
from superior dermatomes down to inferior dermatomes.
Anal sphincter tone should be examined in patients when a
significant spinal cord disorder (particularly due to possible spinal cord
compression) is suspected. Sphincter tone can be assessed by performing a
digital lubricated rectal examination and feeling the resistance to insertion
of your finger during insertion and after asking the patient to squeeze down.
Any decrease you perceive in sphincter tone is potentially abnormal. Another
test of sphincter function that may be helpful in the assessment of severe
spinal cord disorders is the anal wink reflex. This consists of stroking the
perianal skin lightly with a wooden stick and looking for reflex contraction
of the anal sphincter; this reflex can be lost with severe spinal cord
disorders.
Table 51-1 summarizes the characteristic
signs and symptoms of various common spinal cord syndromes, as well as the
cauda equina syndrome (due to lesions affecting the lumbosacral roots below
the spinal cord).