ENA Head Trauma

In a patient with a diffuse axonal injury in a prolonged coma, autonomic dysfunction causes which finding? A. Excessive sweating B. Hypothermia C. Hypotension D. Abnormal posturing

A Rationale: Autonomic dysfunction causes excessive sweating, hyperthermia, and hypertension. Abnormal flexion or extensor posturing is not a sign of autonomic dysfunction. Posturing may occur during the coma but quickly improves.

Injury to the hypothalamus can cause which effect? A. Hyperthermia B. Decreased metabolic rate C. Inadequate respiratory rate D. Increased cerebral blood flow

A Rationale: Because the hypothalamus controls temperature, hyperthermia can occur with hypothalamic injury. Hyperthermia is associated with an increased metabolic rate. An inadequate respiratory rate and increased cerebral blood flow result from a brainstem injury. When the respiratory rate and effort is inadequate, the body retains carbon dioxide. This potent vasodilator causes increased cerebral blood flow.

Testing the corneal reflex assesses which cranial nerve? A. Cranial nerve III (oculomotor nerve) B. Cranial nerve V (trigeminal nerve) C. Cranial nerve IX (glossopharyngeal nerve) D. Cranial nerve X (vagus nerve)

A Rationale: Corneal reflex testing assesses cranial nerve V (trigeminal nerve) and is an important indicator of brainstem function in an unconscious patient. Pupillary response testing evaluates cranial nerve III. Gag reflex testing assesses cranial nerves IX and X.

In a patient who is unconscious after sustaining a head injury, which cranial nerve should you test first? A. Cranial nerve IV (trochlear nerve) B. Cranial nerve VII (facial nerve) C. Cranial nerve I (olfactory nerve) D. Cranial nerve XI (spinal accessory nerve)

A Rationale: Head injury can cause dysfunction of any cranial nerve. In an unconscious patient, however, you should first test cranial nerves III (oculomotor nerve), IV (trochlear nerve), IX (glossopharyngeal nerve), and X (vagus nerve). These nerves have involuntary responses that do not require the patient's participation. Testing them provides information about brainstem function.

Which drug decreases cerebral metabolism and oxygen consumption in a patient with a head injury? A. Propofol (Diprivan) B. Ketamine (Ketalar) C. Mannitol (Osmitrol) D. Norepinephrine (Levophed)

A Rationale: Propofol decreases cerebral metabolism and oxygen consumption. Ketamine increases intracranial pressure in a patient with a head injury. Mannitol may result in massive diuresis, hypotension, and electrolyte disturbances. Norepinephrine (Levophed) is a vasopressor used to reduce intracranial pressure and raise the mean arterial pressure.

A finding of doubled vision suggests a deficit in which cranial nerve? A. Cranial nerve III (oculomotor nerve) B. Cranial nerve II (optic nerve) C. Cranial nerve IV (trochlear nerve) D. Cranial nerve VI (abducens nerve)

B Rationale: Double vision, blurred vision, or visual field cuts indicate a deficit in cranial nerve II (optic nerve). Deficits in cranial nerve III include an irregular, unequal, dilated, or constricted pupil; the inability to lift one or both eyelids; and the inability of eyes to track in the same direction at the same time (which also reflects cranial nerves IV and VI). Deficits in cranial nerve IV include the inability to move the eye down and in. Deficits in cranial nerve VI involve lateral eye movement.

For a patient receiving mannitol (Osmitrol), which intervention should you perform? A. Monitor the hemoglobin level and hematocrit. B. Insert an indwelling urinary catheter. C. Insert a gastric tube. D. Assist with induced hypothermia.

B Rationale: Mannitol creates a gradient that draws fluid from the tissues into the interstitial space and vascular compartment and inhibits the reabsorption of water and solutes in the renal tubules, producing diuresis. Insert an indwelling urinary catheter to accurately assess the diuretic response, which can be rapid and large and may cause hypotension and electrolyte imbalances. The other interventions may be appropriate but are not specifically indicated for mannitol administration.

A woman, age 46, is brought to the emergency department after being hit by a car. Her Glasgow Coma Scale score is 5. What is the priority intervention for this patient? A. Hyperventilate the patient. B. Prepare the patient for intubation. C. Initiate two large-bore intravenous catheters. D. Prepare to insert an intracranial pressure monitoring device.

B Rationale: Your first priority is to prepare the patient for intubation. The Brain Trauma Foundation's Guidelines for Management of Severe Traumatic Brain Injury state that an airway should be established for patients who score less than 9 on the Glasgow Coma Scale and cannot maintain an adequate airway. The guidelines do not recommend prophylactic hyperventilation. Because you do not have enough information to determine whether the patient may have an impending herniation, hyperventilation would not be your first priority. Initiating intravenous access is appropriate to do after the airway is secured. Inserting an intracranial pressure monitoring device is appropriate to do after addressing the patient's airway, breathing, and circulation.

Which injury is common in patients with chronic alcoholism? A. Epidural hematoma B. Diffuse axonal injury C. Subdural hematoma D. Basilar skull fracture

C Rationale: Although the risky behavior of patients with chronic alcoholism can lead to all of these injuries, chronic subdural hematoma is the most likely to occur because these patients may have brain atrophy and coagulopathies related to alcohol use.

Which injury is characterized by a brief loss of consciousness followed by a lucid period? A. Contusion B. Subdural hematoma C. Epidural hematoma D. Diffuse axonal injury

C Rationale: Classic signs of an epidural hematoma include a brief loss of consciousness followed by a lucid period and then rapid neurologic deterioration. Signs and symptoms of a contusion depend on the location but can include a decreased level of consciousness and signs of increasing intracranial pressure. A subdural hematoma may cause a decreased level of consciousness initially or days later, but does not usually cause a loss of consciousness followed by a lucid period. A diffuse axonal injury produces immediate loss of consciousness, which can last for hours, days, or longer.

Your patient has these findings: heart rate of 62 beats per minute; respiratory rate of 18 breaths per minute and regular, oxygen saturation of 99% on 100% fraction of inspired oxygen (FiO2) on a ventilator; mean arterial pressure of 70; and an intracranial pressure of 16 mm Hg. What is this patient's cerebral perfusion pressure? A. 70 mm HG B. 62 mm HG C. 54 mm HG D. 16 mm HG

C Rationale: The cerebral perfusion pressure for this patient is 54 mm Hg. Cerebral perfusion pressure (CPP) equals mean arterial pressure (MAP) minus intracranial pressure (ICP), or CPP = MAP - ICP. For this patient, 70 - 16 = 54.

Which cranial nerve is responsible for the gag reflex? A. Cranial nerve V (trigeminal nerve) B. Cranial nerve VII (facial nerve) C. Cranial nerve X (vagus nerve) D. Cranial nerve XII (hypoglossal nerve)

C Rationale: The gag reflex is the function of cranial nerves IX (glossopharyngeal nerve) and X (vagus nerve). Cranial nerve V is responsible for chewing, jaw clench, lateral jaw movement, corneal reflexes, and facial sensation. Cranial nerve VII is responsible for facial movements, salivation, lacrimation, and taste. Cranial nerve XII is responsible for the tongue movements involved in speech and swallowing.

A man, age 63, falls off a ladder while cleaning his gutters. On arrival in the emergency department, he is moaning but not using any comprehensible words. He opens his eyes when you call his name and reaches to push your hand away when you perform a sternal rub. What is this patient's Glasgow Coma Scale score? A. 6 B.8 C. 10 D. 12

C Rationale: The patient's Glasgow Coma Scale score is 10. He receives a 3 for eye opening because he opens his eyes to verbal stimuli. He receives a 2 for verbal response because he is moaning and using incomprehensible words. He receives a 5 for motor response because he localizes to painful stimuli. The total of these scores is 10.

Which finding requires treatment first? A. Dilated right pupil B. Bradypnea C. Bleeding from a mouth wound D. Abnormal motor posturing

C Rationale: The priority for any patient in the emergency department is assessment and stabilization of the ABCs: airway, breathing, and circulation. Clear and secure the airway first because mouth wounds can bleed profusely, interfering with the airway. Then focus on breathing (bradypnea), circulation, and disability (dilated right pupil and abnormal posturing).

Which injury is most likely to become more pronounced 12 to 24 hours after the event? A. Scalp laceration B. Linear skull fracture C. Mild traumatic brain injury D. Contusion

D Rationale: A contusion (bruise on the surface of the brain) results from movement of the brain tissue in the skull. Contusions typically blossom in 12 to 24 hours, increasing in size and developing surrounding cerebral edema. Linear skull fractures, mild traumatic brain injury, and scalp lacerations do not typically worsen 12 to 24 hours after the event.

A side-to-side and twisting movement of brain tissue causes which injury? A. Skull fracture B. Coup-countercoup injury C. Epidural hematoma D. Diffuse axonal injury

D Rationale: A diffuse axonal injury occurs when the axons are disrupted, sheared, or destroyed by a rotational force, as in a side-to-side and twisting movement of brain tissue. A skull fracture can result from acceleration, deceleration, and deformation forces. A coup-countercoup injury results from acceleration-deceleration forces. An epidural hematoma is caused by a laceration of the middle meningeal artery from a temporal or parietal skull fracture.

Which finding is a late sign of increased intracranial pressure? A. Sluggish pupillary response B. Speech or visual disturbances C. Behavior changes, such as agitation D. Irregular respiratory pattern

D Rationale: An irregular respiratory pattern is a late sign of increased intracranial pressure. Sluggish pupillary response, speech or visual disturbances, and behavior changes occur earlier. Early recognition of increased intracranial pressure promotes prompt treatment before irreversible neurologic deterioration occurs.

Which sign indicates impending herniation? A. Agitation B. Narrowed pulse pressure C. Tachycardia D. Asymmetric pupillary response

D Rationale: Asymmetric pupillary response, unilateral or bilateral pupillary dilation, and abnormal motor posturing are signs of impending herniation from an uncontrolled increase in intracranial pressure. Agitation is an early sign of increased intracranial pressure. The body tries to compensate for uncontrolled intracranial pressure by increasing the systolic blood pressure, leading to a widened pulse pressure. Pressure on the pons and medulla results in cardiac deceleration and asystole but not tachycardia.

Which problem is a type of diffuse head injury? A. Intracerebral hematoma B. Linear skull fracture C. Postconcussion syndrome D. Epidural hematoma

D Rationale: Postconcussion syndrome, concussion, mild traumatic brain injury, and diffuse axonal injury are examples of diffuse head injuries. Linear skull fracture, intracerebral hematoma, and epidural hematoma are examples of focal head injuries.

Which mechanism of injury is most likely to cause more than one contusion to the brain? A. A pediatric patient who hit his head on a cabinet B. An adolescent who was hit on the head by a baseball bat C. An older adult patient who fell backward onto concrete D. A driver of a motor vehicle that hit a tree at high speed

D Rationale: The driver of the motor vehicle is most likely to sustain an acceleration-deceleration injury. Rapid changes in the velocity of the brain commonly lead to two contusions: a coup injury (at the site of initial energy transfer) and a contrecoup injury (on the opposite side of the brain). The other mechanisms of injury would cause one contusion. Hitting the head on a cabinet causes a deceleration injury. Being hit on the head by a baseball bat produces an acceleration injury. Falling backward on concrete leads to a deceleration injury.