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ICD-10 | S062, S063 | |
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OMIM | [1] | |
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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 the 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.
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.
Focal injuries include the following:
- Cerebral contusion is a bruise of brain tissue that commonly results from contact of the brain with the inside of the skull.[4]
- Cerebral laceration is a brain injury in which the pia-arachnoid is torn.[4]
- Epidural hemorrhage is bleeding between the dura mater and the skull.[4] It is commonly associated with damage to the middle meningeal artery, often resulting from a skull fracture.
- Subdural hemorrhage is bleeding between the dura mater and the arachnoid.[4]
- Intracerebral hemorrhage is bleeding within the brain tissue itself.[4]
- Intraventricular hemorrhage is bleeding within the ventricles of the brain.[4]
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:
- Diffuse axonal injury is widespread damage to the white matter of the brain that usually results from acceleration/deceleration types of injury.[4]
- Ischemic brain injury resulting from an insufficient blood supply to the brain, is one of the leading causes of secondary brain damage after head trauma.[4]
- Vascular injury usually causes death shortly after an injury.[4] Although it is diffuse type of brain injury itself, diffuse vascular injury is generally more likely to be caused by focal than diffuse injury.[4]
- Swelling, commonly seen after TBI, can lead to dangerous increases in intracranial pressure.[4] Though swelling itself is a diffuse type of injury, it can result from either focal or diffuse injury.[4]
See also[]
- Focal neurologic deficit
References[]
- ↑ 1.0 1.1 1.2 Lovell MK, Franzen MD (1994). "Neuropsychological assessment" Silver JM, Yudofsky SC, Hales RE Neuropsychiatry of Traumatic Brain Injury, 152–3, Washington, DC: American Psychiatric Press. URL accessed 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."
- ↑ 2.0 2.1 2.2 2.3 Gennarelli GA, Graham DI (2005). "Neuropathology" Silver JM, McAllister TW, Yudofsky SC Textbook Of Traumatic Brain Injury, 27–34, Washington, DC: American Psychiatric Association. URL accessed 2008-06-10.
- ↑ 3.0 3.1 3.2 LaPlaca MC, Simon CM, Prado GR, Cullen DR. "CNS injury biomechanics and experimental models" Weber JT Neurotrauma: New Insights Into Pathology and Treatment, 16. URL accessed 2008-06-10.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 Granacher RP (2007). Traumatic Brain Injury: Methods for Clinical & Forensic Neuropsychiatric Assessment, Second Edition, 26–33, Boca Raton: CRC. URL accessed 2008-07-06.
- ↑ Hammeke TA, Gennarelli TA (2003). "Traumatic brain injury" Schiffer RB, Rao SM, Fogel BS Neuropsychiatry, 1150, Hagerstown, MD: Lippincott Williams & Wilkins. URL accessed 2008-06-16.