traumatic and occupational injuries Flashcards
1
Q
- A 35-year-old woman works as a keyboard operator and must type
for 6 h per day. She is especially susceptible to injury of the
a. Axillary nerve
b. Median nerve
c. Ulnar nerve
d. Radial nerve
e. Long thoracic nerve
A
- The answer is b. (Victor, pp 1433–1434.) Pressure on the volar
aspect of the wrist may produce recurrent injuries to the carpal tunnel
through which the median nerve runs. The injury characteristically produces
pain and paresthesias in the hand over the distribution of the sensory
component of the median nerve. This sensory distribution extends over the
palmar surface of the thumb and first four digits, with the fourth digit supplied
on one side by the median nerve and on the other side by the ulnar
nerve. Median nerve injuries are consequently said to split the fourth digit
on sensory examinations. With carpal tunnel compression of the median
nerve, the sensory disturbance may be incapacitating. Subsequently, weakness
and atrophy may develop in the muscles that are innervated by the
median nerve. The abductor pollicis brevis may be severely involved late in
the progression of the disorder.
2
Q
- A 28-year-old police officer sustains a gunshot wound to the upper
arm. This type of trauma may cause partial damage to the median nerve
that may leave the patient with
a. Easily provoked pain in the hand
b. Weakness on wrist extension
c. Atrophy in the first dorsal interosseous muscle
d. Numbness over the fifth digit
e. Radial deviation of the hand
A
- The answer is a. (Victor, pp 1438–1439.) Trauma to nerves in the
extremities may give rise to causalgia, a disturbance in sensory perception
characterized by hypesthesia, dysesthesia, and allodynia. Hypesthesia is a
decrease in the accurate perception of stimuli. Dysesthesia is persistent discomfort,
which in the situation described is likely to be an unremitting
burning pain. Allodynia is the perception of pain with the application of
nonpainful stimuli. Bullets and other high-velocity missiles need not hit the
nerve to cause damage. Enough energy is transmitted as the missile passes
through adjacent tissues to produce substantial damage to the nerve.
3
Q
- A 19-year-old man is involved in a street fight in which he is
viciously attacked with a lead pipe. A particularly forceful blow hits his left
elbow. Blunt trauma to the elbow may lead to the development of
a. Wristdrop
b. Weakness of the abductor pollicis brevis
c. Clawhand or benediction sign
d. Ulnar deviation of the hand
e. Poor pronation of the forearm
A
- The answer is c. (Victor, p 1434.) The ulnar nerve runs superficially
at the elbow in the ulnar groove. It continues forward under the aponeurosis
of the flexor carpi ulnaris in the cubital tunnel. Damage to the nerve at
this site may produce weakness in the interosseous and ulnar lumbrical
muscles of the hand. With lumbrical weakness, the extensor sheaths of the
digits are not properly positioned and a claw deformity with impaired extension of the ulnar two digits develops when the patient tries to
straighten his or her fingers.
4
Q
- A 21-year-old right-handed woman works at an airport as a luggage
handler. She is usually on the tarmac working in an environment in which
loud noises are routine. Ear protection must be worn to protect against loss
of hearing and the development of
a. Vertigo
b. Tinnitus
c. Ataxia
d. Diplopia
e. Oscillopsia
A
- The answer is b. ( Rowland, p 26.) Acoustic trauma may produce
severe tinnitus in persons who have relatively little hearing loss. Although the
initial injury with acoustic trauma is sustained by the cochlear sensory cells,
tinnitus may persist even after the acoustic nerve is cut. Tinnitus may take
any one of several forms, ranging from a hissing sound to a high-pitched
screaming noise.
5
Q
- A young man fractures his humerus in an automobile accident. As
the pain from the injury subsides, he notices weakness on attempted flexion
at the elbow. He develops paresthesias over the radial and volar aspects
of the forearm. During the accident, he probably injured his
a. Suprascapular nerve
b. Long thoracic nerve
c. Musculocutaneous nerve
d. Radial nerve
e. Median nerve
A
- The answer is c. (Victor, p 1432.) The musculocutaneous nerve is
often damaged with fractures of the humerus. This nerve supplies the biceps
brachii, brachialis, and coracobrachialis muscles and carries sensory information
from the lateral cutaneous nerve of the forearm. Flexion at the elbow
with damage to this nerve is most impaired with the forearm supinated.
6
Q
111. A 37-year-old alcoholic man awakes with clumsiness of his right hand. Neurologic examination reveals poor extension of the hand at the wrist. He most likely has injured his a. Median nerve b. Brachioradialis nerve c. Musculocutaneous nerve d. Radial nerve e. Ulnar nerve
A
- The answer is d. (Victor, p 1432–1433.) Radial nerve injuries are
fairly common in alcoholic persons who may have lost consciousness in
awkward positions. These are sometimes referred to as Saturday night
palsies. The injury is usually a pressure palsy and produces a wristdrop.
The nerve is injured as it courses near the spiral groove of the humerus.
7
Q
- A 72-year-old man slipped and fell in the bathroom 1 week ago. He
hit the right side of his head, but did not think it was necessary to seek
medical attention. He finally goes to his doctor because his son thinks his
balance was off. Computed tomography (CT) of the brain may fail to reveal
a small subdural hematoma in this patient because
a. The lesion is subacute
b. The hematoma extends into the brain from the subdural space
c. The resolution of the CT machine is greater than 2 mm
d. The subdural hematoma is less than 4 h old
e. The patient has extensive cerebral atrophy
A
- The answer is a. (Osborn, pp 207–208.) Within a few days of formation,
the contents of a subdural hematoma are degraded into less dense fluid.
This fluid is transiently similar in density to the cerebral cortex. If the fluid
collection is too small to produce substantial deformation of the underlying
hemisphere, identification of the subdural collection may be difficult. Angiogram
will reveal displacement of the cerebrocortical vessels, but more
rapid and less invasive assessment of the patient is feasible with MRI.
8
Q
A 16-year-old boy is struck on the side of the head by a bottle thrown
by a friend involved in a prank. He appears dazed for about 30 s, but is
apparently lucid for several minutes before he abruptly becomes stuporous.
His limbs on the side opposite the site of the blow are more flaccid
than those on the same side as the injury. On arrival in the emergency room
25 min after the accident, he is unresponsive to painful stimuli. His pulse
is 40/min, with an ECG revealing no arrhythmias. His blood pressure in
both arms is 170/110 mmHg. Although papilledema is not evident in his
fundi, he has venous distention and absent pulsations of the retinal vasculature.
- The best explanation for this young man’s evolving clinical signs is
a. A seizure disorder
b. A cardiac conduction defect
c. Increased intracranial pressure
d. Sick sinus syndrome
e. Communicating hydrocephalus
A
- The answer is c. (Victor, p 948–950.) Something has abruptly
caused increasing intracranial pressure in this young man after his head
trauma. Consequently, he is at risk for herniation of the brain transfalcially
(across the falx cerebri) or transtentorially (across the tentorium cerebelli).
The head trauma produced an intracranial lesion, which is expanding very
rapidly. The slowing of his pulse and increase in his blood pressure are due
to the Cushing effect of a rapidly expanding intracranial mass.
9
Q
A 16-year-old boy is struck on the side of the head by a bottle thrown
by a friend involved in a prank. He appears dazed for about 30 s, but is
apparently lucid for several minutes before he abruptly becomes stuporous.
His limbs on the side opposite the site of the blow are more flaccid
than those on the same side as the injury. On arrival in the emergency room
25 min after the accident, he is unresponsive to painful stimuli. His pulse
is 40/min, with an ECG revealing no arrhythmias. His blood pressure in
both arms is 170/110 mmHg. Although papilledema is not evident in his
fundi, he has venous distention and absent pulsations of the retinal vasculature.
- The wisest management over the next 4 h for this patient is
a. Craniotomy
b. Antihypertensive medication
c. Transvenous pacemaker placement
d. Ventriculoperitoneal shunt
e. Antiepileptic medication
A
- The answer is a. (Victor, p 948–950.) Without emergency surgery,
the patient will die. His blood pressure and pulse abnormalities will correct
themselves when the intracranial mass is removed. His loss of consciousness
will not correct itself with antiepileptics. Shunt placement will not
prevent brain herniation and may in fact accelerate it. The hematoma must
be evacuated, and the bleeding giving rise to the hematoma must be
stopped.
10
Q
A 16-year-old boy is struck on the side of the head by a bottle thrown
by a friend involved in a prank. He appears dazed for about 30 s, but is
apparently lucid for several minutes before he abruptly becomes stuporous.
His limbs on the side opposite the site of the blow are more flaccid
than those on the same side as the injury. On arrival in the emergency room
25 min after the accident, he is unresponsive to painful stimuli. His pulse
is 40/min, with an ECG revealing no arrhythmias. His blood pressure in
both arms is 170/110 mmHg. Although papilledema is not evident in his
fundi, he has venous distention and absent pulsations of the retinal vasculature
115. Magnetic resonance imaging (MRI) of the patient’s head within the first few hours of injury should reveal a. A normal brain b. Intracerebral hematoma c. Temporal lobe contusion d. Subarachnoid hemorrhage e. Epidural hematoma
A
- The answer is e. (Victor, p 937–938.) Damage to the middle
meningeal artery allows blood at arterial pressures to dissect in the potential
space that exists between the dura mater and the periosteum of the
skull. Subarachnoid hemorrhage may have occurred along with the
epidural bleeding, but the small amount of blood present in the CSF would
be difficult to identify on MRI. With MRI, the epidural hematoma should
be evident soon after the injury and will certainly be evident by the time
the patient is symptomatic.
11
Q
A 16-year-old boy is struck on the side of the head by a bottle thrown
by a friend involved in a prank. He appears dazed for about 30 s, but is
apparently lucid for several minutes before he abruptly becomes stuporous.
His limbs on the side opposite the site of the blow are more flaccid
than those on the same side as the injury. On arrival in the emergency room
25 min after the accident, he is unresponsive to painful stimuli. His pulse
is 40/min, with an ECG revealing no arrhythmias. His blood pressure in
both arms is 170/110 mmHg. Although papilledema is not evident in his
fundi, he has venous distention and absent pulsations of the retinal vasculature.
- Computed tomography scanning of the patient’s head within 2 h of
the injury should reveal
a. A normal brain
b. A lens-shaped density over the frontal lobe
c. Increased CSF density with a fluid-fluid level
d. Multifocal attenuation of cortical tissue
e. Bilateral sickle-shaped densities over the hemispheres
A
- The answer is b. (Victor, p 937–938.) The typical shape of an
epidural hematoma is that of a biconvex mass that displaces normal brain
tissue. Parts of the ventricular system may be dilated as obstructive hydrocephalus
develops in parts of the system. Transfalcial herniation with displacement
of frontal lobe tissue across the midline and under the falx
cerebri is likely with an epidural hematoma on one side of the head. Although
subdural hematomas are often bilateral, epidural hematomas are
invariably unilateral.
12
Q
- The elderly person who suffers relatively mild head trauma, but subsequently
develops a progressive dementia over the course of several weeks,
is most likely to have sustained which of the following?
a. An acute subdural hematoma
b. An acute epidural hematoma
c. A chronic subdural hematoma
d. An intracerebral hematoma
e. An intracerebellar hematoma
A
- The answer is c. (Victor, p 452.) Chronic subdural hematoma is relatively
common in the elderly and in patients receiving renal dialysis. The
subdural fluid becomes isodense with the brain after several days or weeks
and may be overlooked on CT scanning. Magnetic resonance imaging will
identify the lesion, even if it is present bilaterally and produces no shift of
brain structures from the midline
13
Q
- A 42-year-old woman is involved in a head-on collision with a lamppost
at 50 mph. Her head hits the windshield. She is highly likely to have
an intracranial hemorrhage in which one of the following structures?
a. Occipital lobe
b. Thalamus
c. Putamen
d. Parietal lobe
e. Temporal lobe
A
- The answer is e. ( Rowland, pp 402–403.) The temporal lobes and
inferior frontal lobes are frequently involved in traumatic brain injuries.
The continued forward movement of the brain within the bony cranial
vault, which has suddenly decelerated at impact, leads to these anterior
brain structures striking the inside of the skull with great force, creating contusions in these areas. The rough surfaces of the cribriform plate and
the middle cranial fossa also lead to injury in these locations. These injuries
are referred to as the coup injuries, because they reflect the direct blow to
the brain. So-called contrecoup injury may also occur at the diametrically
opposed region of the brain (generally, the occipital lobes) when there is
rebound movement into the overlying skull there. Damage to the temporal
lobe may produce symptoms and signs by virtue of compression of adjacent
brain structures. As a hematoma expands, uncal herniation may crush
the brainstem. Less progressive injuries may disturb memory or even language
comprehension. Wernicke’s area, which is important in language
comprehension, is sufficiently posterior on the temporal lobe to escape
injury in most cases of frontal head trauma.
14
Q
- A 57-year-old woman is involved in a motor vehicle accident in
which she strikes the windshield and is briefly unconscious. She makes a
full recovery, except that 3 months later she complains she cannot taste the
food she is eating. Her complaint is most likely due to
a. Medullary infarction
b. Temporal lobe contusion
c. Sphenoid sinus hemorrhage
d. Phenytoin use to prevent seizures
e. Avulsion of olfactory rootlets
A
- The answer is e. (Victor, pp 927–928.) Anosmia is one of the more
common long-term cranial nerve deficits after head injury, though it is
present in only 6% in one series. It is often associated with ageusia (loss of
taste). It can be very disabling and discouraging to patients. Approximately
one-third of patients recover. It is caused by avulsion of olfactory nerve
rootlets due to acceleration-deceleration injury at the cribriform plate.
Damage may be unilateral or bilateral.
15
Q
- An 18-year-old boy is brought into the emergency room after a diving
accident. He is awake and alert, has intact cranial nerves, and is able to
move his shoulders, but he cannot move his arms or legs. He is flaccid and
has a sensory level at C5. Appropriate management includes
a. Naloxone hydrochloride
b. Intravenous methylprednisolone
c. Oral dexamethasone
d. Phenytoin 100 mg tid
e. Hyperbaric oxygen therapy
A
- The answer is b. (Victor, pp 1300–1301.) High-dose intravenous
methylprednisolone [30-mg/kg intravenous bolus followed by 5.4 mg/(kgh)
for 23 h] has been shown to have a statistically significant, if clinically modest,
benefit on the outcome after spinal cord injury when given within 8 h of
the injury. Naloxone hydrochloride and other agents, such as GM1 ganglioside,
have not been shown to be of benefit. The role of surgical decompression,
removal of hemorrhage, and correction of bone displacement is
controversial. Most American neurosurgeons do not advocate surgery, and
instead propose external spinal fixation.
