CNRN Exam 2 Part 5

The definitive treatment for a high-flow spinal arteriovenous fistula is:

• Steroids only

• Endovascular embolization or surgical ligation of feeding arteries

• Chronic anticoagulation

• Physical therapy alone

Answer explanation

The definitive treatment for a high-flow spinal arteriovenous fistula is endovascular embolization or surgical ligation of feeding arteries, as these methods directly address the abnormal blood flow and vascular connections.

Low-back pain referrals should include all EXCEPT:

• Weight-bearing X-rays if red-flag signs are present

• Early MRI for any chronic pain > 2 weeks

• Discogram only for surgical planning

• Conservative management for most acute pain

Answer explanation

Early MRI for chronic pain > 2 weeks is not routinely recommended unless red flags are present, as it may lead to unnecessary interventions. Other options are appropriate for managing low-back pain.

Which is a primary brain injury?

• Cerebral edema from hypoxia

• Subdural hematoma from torn bridging veins at impact

• Ischemia from hypotension hours later

• Neurotoxicity from free radicals

Answer explanation

A primary brain injury occurs at the moment of impact. A subdural hematoma from torn bridging veins is a direct result of trauma, making it a primary injury, unlike the other options which are secondary effects.

A GCS of 7 after resuscitation indicates:

• Mild TBI

• Moderate TBI

• Severe TBI

• Concussion only

Answer explanation

A GCS (Glasgow Coma Scale) score of 7 indicates a severe traumatic brain injury (TBI). Scores of 3-8 are classified as severe, while higher scores indicate mild to moderate injuries.

The leading cause of TBI in people over 65 in the U.S. is:

• Motor vehicle crashes

• Falls

• Sports injuries

• Assault

Answer explanation

Falls are the leading cause of traumatic brain injury (TBI) in individuals over 65 in the U.S., significantly outpacing other causes like motor vehicle crashes, sports injuries, and assaults.

Coup-contrecoup contusions result from:

• Rotational forces only

• Direct impact and rebound-impact injuries

• Penetrating trauma

• Post-traumatic seizures

Answer explanation

Coup-contrecoup contusions occur due to a direct impact to the head, causing the brain to move and hit the opposite side of the skull, resulting in rebound injuries. Thus, the correct answer is direct impact and rebound-impact injuries.

An epidural hematoma typically arises from:

• Tearing of bridging veins

• Rupture of the middle meningeal artery

• Cavernoma bleed

• Dural venous sinus tear

Answer explanation

An epidural hematoma typically arises from the rupture of the middle meningeal artery, often due to head trauma, leading to blood accumulation between the skull and the dura mater.

The classic “talk-and-die” lucid interval occurs in:

• Acute SDH

• EDH

• SAH

• Contusion

Answer explanation

The classic 'talk-and-die' lucid interval is characteristic of epidural hematoma (EDH), where patients may initially be conscious after injury but then rapidly deteriorate as the hematoma expands.

Diffuse axonal injury is best detected by:

• Noncontrast CT

• Conventional MRI

• Diffusion-tensor MRI

• Angiography

Answer explanation

Diffuse axonal injury is best detected by diffusion-tensor MRI, as it can visualize microstructural changes in white matter that are not seen on noncontrast CT or conventional MRI.

Initial management in severe TBI includes maintaining PaO₂ > 100 mmHg and PaCO₂:

• < 25 mmHg

• 25–35 mmHg

• 35–45 mmHg

• 45 mmHg