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Causes - Disorders

Brain Injury Classification

The term "Acquired Brain Injury" or ABI, is used to describe a brain injury that was not present at birth. Two categories of ABI are TRAUMATIC and NON-TRAUMATIC brain injuries.

However, there is also a distinction between FOCAL and DIFFUSE brain injury.


1. TRAUMATIC BRAIN INJURIES are the result of an accident or of violent causes, such as:
Contusion of the brain - Contusio cerebri
Concussion of the brain - Commotio cerebri

Epidural Hematoma

Subdural Hematoma

Shaken baby syndrome, SBS

2. NON-TRAUMATIC BRAIN INJURIES are the result of non-violent events. Some of the more common causes of non-traumatic brain injuries are:

-Stroke: Also known as a CerebroVascular Accident (CVA), a "stroke" or "brain attack", occurs as a result of a disruption of blood flow to the brain.

-Cerebral hemorrhage/ hemorrhagic stroke

-Ischemic stroke

-Transient Ischemic Attack (TIA)

-Brain Aneurysm: (also known as a cerebral or intracranial aneurysm) is described as an abnormal bulging of one or more arteries in the brain. If the aneurysm ruptures, brain damage will will likely occur.

-Brain Tumors: Damage to the brain may be caused by a tumor or be a consequence of treating the tumor through chemotherapy or radiation.

-Primary Brain Tumor: A tumor originating from within the brain cells themselves.

-Brain metastases : Clusters of malignant or cancerous cells that have spread from another part of the body to the brain.

-Cerebral Ischemia or brain ischemia: a condition in which there is insufficient blood flow to the brain to meet metabolic demand.:

-Hypoxia: A reduction or inadequate flow of oxygen to the brain. Causes of hypoxia may include heart attack, near drowning, choking or lack of oxygen from exposure to high altitude conditions without adequate pressurization.

-Anoxia: A total lack of oxygen to the brain. Causes may include heart attack, near drowning, choking or lack of oxygen from exposure to high altitude conditions without adequate pressurization.

- Infection - Bacterial or viral infections;
- Encephalitis – inflammation or swelling of the brain;
- Meningitis – inflammation or swelling of the membrane covering the brain and spinal cord.

-Toxic or Metabolic Injury: Injury resulting from exposure to toxic substances such as chemicals or high doses of lead.

Kidney failure can also cause a buildup of harmful toxins in the brain.

- Alcohol and Drug Abuse




Many websites do not classify degenerative brain diseases as ABIs because their treatment differs from that of other ABIs. However, they are mentioned below because the cognitive symptoms and other non-apparent consequences resulting from degenerative brain diseases are similar to those of other ABIs.

-Multiple sclerosis

-Huntington's disease

-Alzheimer's disease

-Parkinson's disease

-PSP Progressive Supranuclear Palsy


Distinction between FOCAL or DIFFUSE INJURY 

Focal injury usually occurs after a direct blow to the head, causing a skull fracture. There is often a bruise in the brains under the skull fracture. Focal injury leaves scars that can clearly be seen on MRI or CT scans.


Diffuse injury often occurs after a car accident or fall where the brains are shaken. It causes damage to the connections between nerve cells. This is called "diffuse axonal injury". It can also be caused by lack of oxygen. This type of damage is often spread over a larger part of the brains than a focal injury. Due to the fact that a larger part of the brains is damaged, it means that there may be more problems. This lesion is at the microscopic level, and it is therefore difficult to detect or even not visible on scans.


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