Head Trauma

Head trauma occurs when external forces are directed to the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull and brain structures, resulting in damage to the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull, brain, and intracranial structures. Head injuries can be classified as open (penetrating) or closed (blunt), and primary (from the initial trauma) or secondary (indirect brain injury), and range from mild to severe and life-threatening. The majority of cases are mild, but presentation can vary from a mild concussion to a comatose state depending on the severity of the insult. Management ranges from observation to intensive care monitoring and neurosurgical interventions. Prognosis is good for mild injuries, but severe trauma can result in death or permanent damage.

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Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

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Overview

Definition

Head trauma is an injury to the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull, brain, and/or intracranial structures.

Epidemiology

  • 2.8 million people suffer head injuries each year in the United States.
  • 75% of cases are considered mild.
  • The most common injury resulting in death
  • Bimodal age distribution, with children, young adults, and the elderly having a higher incidence
  • More common in men than women

Etiology

  • Falls (most common cause in the elderly)
  • Motor vehicle accidents
  • Occupational accidents
  • Sports 
  • Physical assault

Classification of Severity

Glasgow Coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma Scale (GCS)

  • The GCS exam addresses the level of consciousness after a head injury.
  • Patients receive a score for the best response in each area.
  • Scores in each area are combined to reach a total score of 3–15.
  • ↑ the number → the better the prognosis
  • Score ≤ 9:
    • Indicates coma
    • Patient needs endotracheal intubation for airway protection
Table: Glasgow Coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma Scale
Feature Response Score
Eye opening Open spontaneously 4
Open to verbal command 3
Open to pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain 2
No eye opening 1
Verbal response Oriented and appropriate 5
Disoriented but conversant 4
Nonsensical words 3
Moaning 2
Silent 1
Motor response Follows commands 6
Localizes pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain 5
Withdraws from pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain 4
Flexor posturing 3
Extensor posturing 2
Flaccid 1

Traumatic brain injury (TBI) severity scale

  • Mild TBI:
    • GCS of 13–15
    • Non-severe mechanism
    • 0–30-minute loss of consciousness
    • Amnesia brief, < 24 hours
  • Moderate TBI:
    • GCS of 9–12
    • Loss of consciousness for > 30 minutes and < 24 hours
    • Headache
    • Vomiting
    • Amnesia > 24 hours and < 7 days
    • Alteration in mental status at the time of injury
  • Severe TBI:
    • GCS < 9
    • Prolonged loss of consciousness (> 24 hours)
    • Neurologic deficits
    • Amnesia > 7 days 
Table: Classification of TBI severity
Criteria Mild Moderate Severe
Structural imaging Normal Normal or abnormal Normal or abnormal
LOC 0–30 minutes > 30 minutes and < 24 hours > 24 hours
AOC For a moment, up to 24 hours > 24 hours severity based on other criteria
PTA 0–1 day > 1 and < 7 days > 7 days
GCS 13–15 9–12 < 9
LOC: loss of consciousness
AOC: alteration of consciousness/mental state
PTA: post-traumatic amnesia
GSC: Glasgow Coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma Scale (best available score in the first 24 hours)

Pathophysiology

Timing

  • Primary:
    • Occurs at the moment of injury
    • Coup (on the side of impact) and contrecoup (on opposite side) injuries
    • Acceleration-deceleration injuries (abrupt brain movement and deformation within cranial cavity; common in motor vehicle collisions)
  • Secondary: 
    • Injuries that occur hours/days/weeks after trauma
    • Result from the body’s response to the original trauma
    • Molecular injury mechanisms ( inflammation Inflammation Inflammation is a complex set of responses to infection and injury involving leukocytes as the principal cellular mediators in the body's defense against pathogenic organisms. Inflammation is also seen as a response to tissue injury in the process of wound healing. The 5 cardinal signs of inflammation are pain, heat, redness, swelling, and loss of function. Inflammation, apoptosis, secondary ischemia)
    • Can result in local or diffuse brain edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema, hemorrhage or ↑ intracranial pressure ( ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP)), electrolyte disturbance
    • May eventually lead to coma and death

Types

  • Open (penetrating):
    • Injury that involves penetration of the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull, dura mater, and fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures of the calvarium
    • Brain tissue is directly injured by fragments of bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones or other objects such as bullets, knives, etc.
  • Closed:
    • More common than open injuries
    • Intact cranium and dura mater
    • Brain is damaged due to acceleration-deceleration.
    • Can be focal or diffuse
Coup and contrecoup head injury

Coup and contrecoup head injury

Image: “Contrecoup” by Patrick J. Lynch. License: CC BY 2.5

Types of Injuries

Skull fractures

  • Occur when mechanical force exceeds the integrity of calvarium
  • Often associated with intra- and extracranial injuries
  • Parietal bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones is most commonly fractured.

Linear fractures:

  • Most common skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull fractures
  • Patient presents with swelling overlying the fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures site.
  • Neurologic symptoms or intracranial hemorrhage are rare.
  • Usually, no intervention is needed.

Comminuted fractures:

  • Complex, with multiple bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones fragments
  • Associated with a significant force of impact
  • Often become depressed fractures

Depressed fractures:

  • Significant force results in inward displacement of a portion of the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull.
  • May be closed or open (with skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull laceration)
  • May be seen on exam as obvious depressed area
  • Can lacerate dura mater, create a point of entry into the cerebrospinal fluid, and introduce infection
  • Clinical presentation depends on underlying brain injury.

Elevated fractures:

  • Elevation of a bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones fragment above calvarium
  • Rare, usually involve frontal bones
  • Associated with tangential impact
  • Usually have significant underlying brain injury

Basilar skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull fractures:

  • Include fractures of:
    • Cribriform plate of the ethmoid bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones
    • Orbital plate of the frontal bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones
    • Temporal bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones
    • Sphenoid bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones
    • Occipital bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones
  • Most common through a temporal bone Bone Bone is a compact type of hardened connective tissue composed of bone cells, membranes, an extracellular mineralized matrix, and central bone marrow. The 2 primary types of bone are compact and spongy. Structure of Bones
  • Epidural hematomas common (injury to middle meningeal artery and vein)
  • Presentation depends on the degree of brain, cranial nerves Cranial nerves There are 12 pairs of cranial nerves (CNs), which run from the brain to various parts of the head, neck, and trunk. The CNs can be sensory or motor or both. The CNs are named and numbered in Roman numerals according to their location, from the front to the back of the brain. Overview of the Cranial Nerves, and vessels injury:
    • Rhinorrhea or otorrhea (cerebrospinal fluid (CSF) leak)
    • Hemotympanum (blood behind tympanic membrane)
    • Raccoon eyes (periorbital ecchymosis)
    • Battle sign (retroauricular or mastoid ecchymosis)
    • Subconjunctival hemorrhage
    • Nausea and vomiting
    • Cranial nerve palsies 

Intracranial bleeding

Focal cerebral contusions:

  • Most common hemorrhagic lesions
  • Usually in basal frontal and temporal regions
  • Disruption of intraparenchymal vessels may lead to larger intracerebral hematomas.

Extra-axial hemorrhage:

  • Epidural hematoma:
    • Results from rupture of the middle meningeal artery
    • Life-threatening condition 
    • Rapidly expanding blood collection in the potential space between the skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull and dura mater 
    • Initial loss of consciousness marked by lucid interval (temporary neurological recovery)
    • Computed tomography (CT) scan shows biconvex, hyperdense blood collection that does not cross the suture lines.
    • Usually requires emergent surgery
  • Subdural hematoma:
    • Blood collection between the dura and the arachnoid membrane due to rupture of bridging veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins
    • CT scan shows crescent-shaped blood collection that crosses the suture lines.
  • Subarachnoid hemorrhage:
    • Results from tear of small pial vessels
    • Usually in sylvian fissures and interpeduncular cisterns
    • Can extend into intraventricular hemorrhage

Diffuse axonal injury (DAI)

  • Associated with acceleration-deceleration injury with unrestricted head movement 
  • Rotational forces affect the brain areas with different density (gray-white matter junction).
  • Symptoms can be mild, but typically are severe. 
  • Severe DAI patients have loss of consciousness, which persists to a vegetative state (90% of cases).
  • CT scan or magnetic resonance imaging (MRI) shows numerous minute punctate hemorrhages with blurring of grey-white interface.
  • Most significant cause of morbidity in patients with TBIs as it results in vegetative state 

Concussion

  • Mild TBI
  • GCS score 13–15
  • Usually no visible abnormalities on CT scan
  • Believed to be a functional rather than anatomic disturbance
  • Results from mild cortical contusions on coup or contrecoup sides
  • Mild axonal injury
  • Early symptoms of concussion include:
    • Headache
    • Dizziness 
    • Disorientation
    • Amnesia for the traumatic event
    • Nausea and vomiting
  • Post-concussion syndrome:
    • Symptoms persist weeks to months after injury.
    • Headache, dizziness, cognitive impairment, and psychological symptoms
    • May be a result of secondary injury:
      • Release of excitatory neurotransmitters
      • Generation of free radicals

Diagnosis

History and physical exam

  • Reported loss of consciousness and for how long
  • Mental status (GCS evaluation)
  • Scalp lacerations, palpable fractures
  • Signs of basilar skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull fractures:
    • Oto-/rhinorrhea
    • Ecchymosis (periorbital, periauricular)
    • Conjunctival hemorrhage, blood behind tympanic membranes
  • Neurologic exam

Canadian CT Head Rule (CCHR)

The CCHR is used to determine the need for CT in adult emergency department patients with minor head injuries. Its sensitivity is close to 100% for identifying clinically significant brain trauma (i.e., trauma that requires neurosurgical intervention).

Requirements:

  • None of the exclusion criteria are met.
  • At least 1 of the inclusion criteria is present.

Inclusion criteria:

  • Loss of consciousness
  • Amnesia to the head injury event
  • Witnessed disorientation
  • GCS 13–15

Exclusion criteria:

  • Age < 16 years
  • Blood thinners
  • Seizure after injury

High-risk factors:

  • GCS < 15 2 hours post-injury
  • Suspected open skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures
  • Sign of base of skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures
  • Vomiting more than twice
  • Age > 65 years

​Medium risk factors:

  • Amnesia post-event > 30 minutes
  • Dangerous mechanism of injury
  • Pedestrian struck by motor vehicle
  • Occupant ejected from motor vehicle
  • Fall from > 3 feet (1 meter) or down 5 stairs

Interpretation:

  • If no risk factors, CT of the head is unnecessary.
  • If any of the above risk factors are identified, a CT of the head should be obtained.

Imaging

  • CT scan without contrast (1st line):
    • Skull fractures
    • Dura mater injury
    • Midline shift 
    • Bleeding (epidural, subdural, subarachnoid, intracerebral)
    • Diffuse axonal injury (DAI) 
  • CT angiography: if vascular injury is suspected
  • MRI: 
    • For late diagnosis (> 48 hours after trauma) 
    • Can evaluate for contusion and concussion better than CT 

Management

Initial management

  • Airway protection: intubation usually required for GCS < 9
  • Fluid resuscitation, oxygenation
  • Assessment and management of associated injuries
  • Antifibrinolytic therapy:
    • For moderate TBI (GCS 8–13)
    • Within 3 hours of injury
    • Reduces mortality

Concussion (mild TBI)

  • No specific treatment
  • Observation for 4–6 hours or CT scan without contrast
  • Avoid narcotics or anything that could alter the patient’s mental status.
  • Control pain Pain Pain has accompanied humans since they first existed, first lamented as the curse of existence and later understood as an adaptive mechanism that ensures survival. Pain is the most common symptomatic complaint and the main reason why people seek medical care. Physiology of Pain with over-the-counter medicines such as acetaminophen Acetaminophen Acetaminophen is an over-the-counter nonopioid analgesic and antipyretic medication and the most commonly used analgesic worldwide. Despite the widespread use of acetaminophen, its mechanism of action is not entirely understood. Acetaminophen or ibuprofen.
  • Athletes should abstain from contact sports until cleared by a medical provider.

Moderate or severe TBI

Intensive care management (typically required):

  • Maintain euvolemia (isotonic intravenous fluids Intravenous Fluids Intravenous fluids are one of the most common interventions administered in medicine to approximate physiologic bodily fluids. Intravenous fluids are divided into 2 categories: crystalloid and colloid solutions. Intravenous fluids have a wide variety of indications, including intravascular volume expansion, electrolyte manipulation, and maintenance fluids. Intravenous Fluids).
  • Maintain cerebral perfusion pressure:
    • Avoid hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension.
    • Monitor ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) (if GCS < 9 or evidence of hemorrhage).
  • Mechanical ventilation
  • Correct coagulopathy
  • Maintain optimal body temperature and glucose levels
  • Seizure prophylaxis

Control of ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP):

  • Head elevation
  • Hyperventilation
  • Sedation and analgesia
  • CSF drainage: through ventriculostomy
  • Osmotic therapy:
    • Hypertonic saline
    • Mannitol

Surgery:

  • Decompressive craniectomy for refractory ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) elevation
  • Evacuation of hematoma:
    • Epidural: if > 30 cc of blood
    • Subdural: if > 10 mm or > 5 mm midline shift on CT
    • Intracerebral: if significant mass effect
  • Closure of dura, debridement, elevation:
    • For depressed skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull fractures
    • For penetrating injuries

References

  1. Ian Stiell. Canadian CT Head Injury/Trauma Rule. Retrieved January 12, 2021, from https://www.mdcalc.com/canadian-ct-head-injury-trauma-rule
  2. Evans, R. (2018). Postconcussion syndrome. UpToDate. Retrieved January 12, 2021, from https://www.uptodate.com/contents/postconcussion-syndrome
  3. Evans R.W., Whitlow C.T. (2019). Acute mild traumatic brain injury (concussion) in adults. UpToDate. Retrieved January 12, 2021, from https://www.uptodate.com/contents/acute-mild-traumatic-brain-injury-concussion-in-adults
  4. Healy, Ellen & Walter, Kristen & Chard, Kathleen. (2015). Effectiveness of Cognitive Processing Therapy for PTSD Across Various Populations, Traumatic Events, and Co-occurring Conditions. https://doi.org/10.1007/978-3-319-08613-2_114-1 
  5. Heegard W. (2019). Skull fractures in adults. UpToDate. Retrieved January 12, 2021, from https://www.uptodate.com/contents/skull-fractures-in-adults
  6. Rajajee, V. (2019). Management of acute moderate and severe traumatic brain injury. UpToDate. Retrieved January 12, 2021, from https://www.uptodate.com/contents/management-of-acute-moderate-and-severe-traumatic-brain-injury
  7. Rajajee, V. (2020). Traumatic brain injury: Epidemiology, classification, and pathophysiology. UpToDate. Retrieved December 24, 2020, from https://www.uptodate.com/contents/traumatic-brain-injury-epidemiology-classification-and-pathophysiology#H4 

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