Prehospital Academy Lesson 33.1
Trauma: Head Injuries
This lesson discusses the prehospital assessment and management of common head injuries for EMTs. Head injuries are a critical concern in emergency medicine due to their potential for severe, life-threatening complications and long-term disability. A solid understanding of the central nervous system's anatomy, physiology, and pathophysiology is crucial for effective patient care.
Anatomy and Physiology of the Central Nervous System (CNS)
The CNS, consisting of the brain and spinal cord, is the command center of the body.
Brain: Housed within the rigid skull, it controls all voluntary and involuntary functions, thought, emotion, and sensation. It requires a constant supply of oxygen and glucose.
Spinal Cord: Extends from the brainstem through the vertebral column, transmitting signals between the brain and the rest of the body.
Cerebrospinal Fluid (CSF): Surrounds the brain and spinal cord, providing protection, nourishment, and waste removal.
Meninges: Three layers of membranes (dura mater, arachnoid mater, pia mater) that enclose the brain and spinal cord.
The skull and CSF offer protection, but the enclosed nature of the brain means that any swelling or bleeding within the skull can rapidly increase intracranial pressure (ICP), leading to brain compression and herniation.
Common Traumatic Head Injuries
Head injuries are classified based on the mechanism, anatomical location, and severity.
Types of Head Injuries:
Concussion (Mild Traumatic Brain Injury - mTBI): A temporary alteration in brain function caused by a sudden impact to the head or whiplash-type forces.
Signs/Symptoms: Brief loss of consciousness, confusion, disorientation, headache, dizziness, nausea, memory problems.
Contusion: A bruise of the brain tissue, often associated with a coup-contrecoup injury (injury at the site of impact and on the opposite side).
Skull Fractures: Breaks in the bony protection of the skull. Can be linear (most common), depressed (bone fragments pushed inward), or basilar (fracture at the base of the skull).
Signs/Symptoms (Basilar): "Raccoon eyes" (periorbital ecchymosis), Battle's sign (mastoid ecchymosis), CSF leakage from nose/ears.
Intracranial Hemorrhages: Bleeding within the skull, which can rapidly increase ICP.
Epidural Hematoma: Bleeding between the dura mater and the skull, typically arterial. Often associated with a brief loss of consciousness, a lucid interval, then rapid deterioration.
Subdural Hematoma: Bleeding between the dura mater and the arachnoid mater, typically venous. Can be acute, subacute, or chronic, with symptoms developing over hours to weeks.
Intracerebral Hemorrhage: Bleeding within the brain tissue itself.
Signs of Increased Intracranial Pressure (ICP)
Increased ICP is a critical concern in head injuries and can lead to herniation and irreversible brain damage.
Altered Mental Status: Progressive decrease in level of consciousness.
Pupil Changes: Unequal pupils (anisocoria), sluggish or non-reactive pupils.
Motor Dysfunction: Weakness, paralysis, posturing (decorticate or decerebrate).
Cushing's Triad (Late Sign):
Increased Systolic Blood Pressure (widening pulse pressure).
Decreased Heart Rate (bradycardia).
Irregular Respirations (Cheyne-Stokes or ataxic breathing).
Headache, nausea, vomiting (especially projectile).
Prehospital Care for Traumatic Head Injuries
The primary goals are to prevent secondary brain injury (hypoxia, hypotension, hyper/hypocapnia) and ensure rapid transport.
C-Spine Immobilization: Assume concomitant spinal injury until proven otherwise. Maintain in-line spinal immobilization.
ABCs:
Airway: Ensure a patent airway. Be prepared to manage secretions or vomitus. Consider adjuncts.
Breathing: Administer high-flow oxygen to maintain SpO2 ≥ 94%. Assist ventilations as needed, avoiding hyperventilation unless signs of herniation are present (per local protocol).
Circulation: Control external bleeding. Maintain adequate perfusion; treat hypotension with fluid boluses (advanced providers) as per protocol.
Neurological Assessment: Perform frequent neurological assessments (GCS, pupil response, motor function).
Temperature Management: Prevent hyperthermia or hypothermia.
Rapid Transport: Transport to the nearest appropriate trauma center.
Critical Thinking Questions
You are assessing a patient with a head injury who initially had a brief loss of consciousness, then was alert and talking, but is now rapidly becoming unresponsive. What type of intracranial hemorrhage is most likely, and what is the urgency of this situation?
A patient with a suspected basilar skull fracture presents with "raccoon eyes." What other physical signs would you look for to confirm your suspicion?
Why is preventing hypoxia and hypotension critical in managing a patient with a head injury? Explain the concept of "secondary brain injury."
You observe a patient with a head injury exhibiting Cushing's Triad. What does this indicate, and what immediate management strategy should you consider (if within your scope of practice)?
Discuss the importance of strict C-spine immobilization in all patients with suspected head injuries, even in the absence of obvious neck pain.