Focal and diffuse brain injury

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Focal and diffuse brain injury
Epidural hematoma.png
Epidural hematoma, an example of a focal injury

Focal and diffuse brain injury are ways to classify brain injury: focal injury occurs in a specific location, while diffuse injury occurs over a more widespread area. It is common for both focal and diffuse damage to occur as a result of the same event; many traumatic brain injuries have aspects of both focal and diffuse injury. [1] Focal injuries are commonly associated with an injury in which the head strikes or is struck by an object; diffuse injuries are more often found in acceleration/deceleration injuries, in which the head does not necessarily contact anything, but brain tissue is damaged because tissue types with varying densities accelerate at different rates. [2] In addition to physical trauma, other types of brain injury, such as stroke, can also produce focal and diffuse injuries. [1] There may be primary and secondary brain injury processes.

Contents

Focal

A focal traumatic injury results from direct mechanical forces (such as occur when the head strikes a windshield in a vehicle accident) and is usually associated with brain tissue damage visible to the naked eye. [3] A common cause of focal injury is penetrating head injury, in which the skull is perforated, as frequently occurs in auto accidents, blows, and gunshot wounds. [3] Focal injuries typically have symptoms that are related to the damaged area of the brain. [3] Stroke can produce focal damage that is associated with signs and symptoms that correspond to the part of the brain that was damaged. [1] For example, if a speech center of the brain such as Broca's area is damaged, problems with speech are common.[ citation needed ]

Focal injuries include the following:

Diffuse

Diffuse injuries, also called multifocal injuries, include brain injury due to hypoxia, meningitis, and damage to blood vessels. [2] Unlike focal injuries, which are usually easy to detect using imaging, diffuse injuries may be difficult to detect and define; often, much of the damage is microscopic. [4] Diffuse injuries can result from acceleration/deceleration injuries. [2] Rotational forces are a common cause of diffuse injuries; [5] these forces are common in diffuse injuries such as concussion and diffuse axonal injury. The term "diffuse" has been called a misnomer, since injury is often actually multifocal, with multiple locations of injury. [2]

Diffuse injuries include the following:

See also

Related Research Articles

Head injury Serious trauma to the cranium

A head injury is any injury that results in trauma to the skull or brain. The terms traumatic brain injury and head injury are often used interchangeably in the medical literature. Because head injuries cover such a broad scope of injuries, there are many causes—including accidents, falls, physical assault, or traffic accidents—that can cause head injuries.

Bleeding Loss of blood escaping from the circulatory system

Bleeding, also known as a hemorrhage, haemorrhage, or simply blood loss, is blood escaping from the circulatory system from damaged blood vessels. Bleeding can occur internally, or externally either through a natural opening such as the mouth, nose, ear, urethra, vagina or anus, or through a wound in the skin. Hypovolemia is a massive decrease in blood volume, and death by excessive loss of blood is referred to as exsanguination. Typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious medical difficulties. The stopping or controlling of bleeding is called hemostasis and is an important part of both first aid and surgery. The use of cyanoacrylate glue to prevent bleeding and seal battle wounds was designed and first used in the Vietnam War. Today many medical treatments use a medical version of "super glue" instead of using traditional stitches used for small wounds that need to be closed at the skin level.

Brain damage Destruction or degeneration of brain cells

Neurotrauma, brain damage or brain injury (BI) is the destruction or degeneration of brain cells. Brain injuries occur due to a wide range of internal and external factors. In general, brain damage refers to significant, undiscriminating trauma-induced damage.

Shaken baby syndrome Medical condition

Shaken baby syndrome (SBS), also known as abusive head trauma (AHT), is claimed by some to be the leading cause of fatal head injuries in children younger than 2 years. Diagnosing the syndrome has continuously proved both challenging and contentious for medical professionals, in that they often require objective witnesses to the initial trauma, or rely on uncorroborated recounts. This is said to be particularly problematic when the trauma is deemed 'non-accidental'. Some medical professionals propose that SBS is the result of respiratory abnormalities leading to hypoxia and swelling of the brain However, the courtroom has become a forum for conflicting theories that generally accepted medical literature has not been reconciled with. Often there are no visible signs of trauma. Complications include seizures, visual impairment, cerebral palsy, cognitive impairment and death.

Bruise Type of localized bleeding in tissues outside blood vessels

A bruise, also known as a contusion, is a type of hematoma of tissue, the most common cause being capillaries damaged by trauma, causing localized bleeding that extravasates into the surrounding interstitial tissues. Most bruises are not very deep under the skin so that the bleeding causes a visible discoloration. The bruise then remains visible until the blood is either absorbed by tissues or cleared by immune system action. Bruises which do not blanch under pressure can involve capillaries at the level of skin, subcutaneous tissue, muscle, or bone. Bruises are not to be confused with other similar-looking lesions. (Such lesions include petechia, purpura, and ecchymosis.

Subdural hematoma Hematoma usually associated with traumatic brain injury

A subdural hematoma (SDH) is a type of bleeding in which a collection of blood—usually but not always associated with a traumatic brain injury—gathers between the inner layer of the dura mater and the arachnoid mater of the meninges surrounding the brain. It usually results from tears in bridging veins that cross the subdural space.

Intracranial hemorrhage Hemorrhage, or bleeding, within the skull

Intracranial hemorrhage (ICH), also known as intracranial bleed, is bleeding within the skull. Subtypes are intracerebral bleeds, subarachnoid bleeds, epidural bleeds, and subdural bleeds. More often than not it ends in a lethal outcome.

Epidural hematoma Build-up of blood between the dura mater and skull

Epidural hematoma is when bleeding occurs between the tough outer membrane covering the brain and the skull. Often there is loss of consciousness following a head injury, a brief regaining of consciousness, and then loss of consciousness again. Other symptoms may include headache, confusion, vomiting, and an inability to move parts of the body. Complications may include seizures.

Traumatic brain injury Injury of the brain from an external source

A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity, mechanism, or other features. Head injury is a broader category that may involve damage to other structures such as the scalp and skull. TBI can result in physical, cognitive, social, emotional and behavioral symptoms, and outcomes can range from complete recovery to permanent disability or death.

Closed-head injury is a type of traumatic brain injury in which the skull and dura mater remain intact. Closed-head injuries are the leading cause of death in children under 4 years old and the most common cause of physical disability and cognitive impairment in young people. Overall, closed-head injuries and other forms of mild traumatic brain injury account for about 75% of the estimated 1.7 million brain injuries that occur annually in the United States. Brain injuries such as closed-head injuries may result in lifelong physical, cognitive, or psychological impairment and, thus, are of utmost concern with regards to public health.

Penetrating head injury Medical condition

A penetrating head injury, or open head injury, is a head injury in which the dura mater, the outer layer of the meninges, is breached. Penetrating injury can be caused by high-velocity projectiles or objects of lower velocity such as knives, or bone fragments from a skull fracture that are driven into the brain. Head injuries caused by penetrating trauma are serious medical emergencies and may cause permanent disability or death.

Diffuse axonal injury Medical condition

Diffuse axonal injury (DAI) is a brain injury in which scattered lesions occur over a widespread area in white matter tracts as well as grey matter. DAI is one of the most common and devastating types of traumatic brain injury and is a major cause of unconsciousness and persistent vegetative state after severe head trauma. It occurs in about half of all cases of severe head trauma and may be the primary damage that occurs in concussion. The outcome is frequently coma, with over 90% of patients with severe DAI never regaining consciousness. Those who do wake up often remain significantly impaired.

Intracerebral hemorrhage Type of intracranial bleeding that occurs within the brain tissue itself

Intracerebral hemorrhage (ICH), also known as cerebral bleed, intraparenchymal bleed, and hemorrhagic stroke, or haemorrhagic stroke, is a sudden bleeding into the tissues of the brain, into its ventricles, or into both. It is one kind of bleeding within the skull and one kind of stroke. Symptoms can include headache, one-sided weakness, vomiting, seizures, decreased level of consciousness, and neck stiffness. Often, symptoms get worse over time. Fever is also common.

Cerebral contusion Medical condition

Cerebral contusion, Latin contusio cerebri, a form of traumatic brain injury, is a bruise of the brain tissue. Like bruises in other tissues, cerebral contusion can be associated with multiple microhemorrhages, small blood vessel leaks into brain tissue. Contusion occurs in 20–30% of severe head injuries. A cerebral laceration is a similar injury except that, according to their respective definitions, the pia-arachnoid membranes are torn over the site of injury in laceration and are not torn in contusion. The injury can cause a decline in mental function in the long term and in the emergency setting may result in brain herniation, a life-threatening condition in which parts of the brain are squeezed past parts of the skull. Thus treatment aims to prevent dangerous rises in intracranial pressure, the pressure within the skull.

Blunt trauma Physical trauma caused to a body part, either by impact, injury or physical attack

Blunt trauma, also known as blunt force trauma or non-penetrating trauma, is physical trauma or impactful force to a body part, often occurring with road traffic collisions, direct blows, assaults, injuries during sports, and particularly in the elderly who fall. It is contrasted with penetrating trauma which occurs when an object pierces the skin and enters a tissue of the body, creating an open wound and bruise.

Coup contrecoup injury Type of head injury

In head injury, a coup injury occurs under the site of impact with an object, and a contrecoup injury occurs on the side opposite the area that was hit. Coup and contrecoup injuries are associated with cerebral contusions, a type of traumatic brain injury in which the brain is bruised. Coup and contrecoup injuries can occur individually or together. When a moving object impacts the stationary head, coup injuries are typical, while contrecoup injuries are produced when the moving head strikes a stationary object.

A cerebral laceration is a type of traumatic brain injury that occurs when the tissue of the brain is mechanically cut or torn. The injury is similar to a cerebral contusion; however, according to their respective definitions, the pia-arachnoid membranes are torn over the site of injury in laceration and are not torn in contusion. Lacerations require greater physical force to cause than contusions, but the two types of injury are grouped together in the ICD-9 and ICD-10 classification systems.

Primary and secondary brain injury are ways to classify the injury processes that occur in brain injury. In traumatic brain injury (TBI), primary brain injury occurs during the initial insult, and results from displacement of the physical structures of the brain. Secondary brain injury occurs gradually and may involve an array of cellular processes. Secondary injury, which is not caused by mechanical damage, can result from the primary injury or be independent of it. The fact that people sometimes deteriorate after brain injury was originally taken to mean that secondary injury was occurring. It is not well understood how much of a contribution primary and secondary injuries respectively have to the clinical manifestations of TBI.

Traumatic brain injury can cause a variety of complications, health effects that are not TBI themselves but that result from it. The risk of complications increases with the severity of the trauma; however even mild traumatic brain injury can result in disabilities that interfere with social interactions, employment, and everyday living. TBI can cause a variety of problems including physical, cognitive, emotional, and behavioral complications.

A sports-related traumatic brain injury is a serious accident which may lead to significant morbidity or mortality. Traumatic brain injury (TBI) in sports are usually a result of physical contact with another person or stationary object, These sports may include boxing, gridiron football, field/ice hockey, lacrosse, martial arts, rugby, soccer, wrestling, auto racing, cycling, equestrian, rollerblading, skateboarding, skiing or snowboarding.

References

  1. 1 2 3 Lovell MK, Franzen MD (1994). "Neuropsychological assessment". In Silver JM, Yudofsky SC, Hales RE (eds.). Neuropsychiatry of Traumatic Brain Injury. Washington, DC: American Psychiatric Press. pp. 152–3. ISBN   0-88048-538-8 . Retrieved 2008-06-17. Although brain injuries are often described as diffuse or focal in nature, in reality many traumatic brain injuries have both focal and diffuse components.
  2. 1 2 3 4 Gennarelli GA, Graham DI (2005). "Neuropathology". In Silver JM, McAllister TW, Yudofsky SC (eds.). Textbook Of Traumatic Brain Injury. Washington, DC: American Psychiatric Association. pp. 27–34. ISBN   1-58562-105-6 . Retrieved 2008-06-10.
  3. 1 2 3 LaPlaca MC, Simon CM, Prado GR, Cullen DR (27 July 2007). "CNS injury biomechanics and experimental models". In Weber JT (ed.). Neurotrauma: New Insights Into Pathology and Treatment. p. 16. ISBN   978-0-444-53017-2 . Retrieved 2008-06-10.
  4. 1 2 3 4 5 6 7 8 9 10 11 12 13 Granacher RP (2007). Traumatic Brain Injury: Methods for Clinical & Forensic Neuropsychiatric Assessment, Second Edition. Boca Raton: CRC. pp. 26–33. ISBN   978-0-8493-8138-6 . Retrieved 2008-07-06.
  5. ↑ Hammeke TA, Gennarelli TA (2003). "Traumatic brain injury". In Schiffer RB, Rao SM, Fogel BS (eds.). Neuropsychiatry. Hagerstown, MD: Lippincott Williams & Wilkins. p. 1150. ISBN   0-7817-2655-7 . Retrieved 2008-06-16.
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