From the Guidelines
Traumatic brain injuries (TBI) can be classified into several types based on the mechanism and severity of damage, including primary brain injuries such as concussions, contusions, diffuse axonal injuries, and intracranial hematomas, as well as secondary brain injuries like brain swelling, increased intracranial pressure, hypoxic brain injury, and infection, with severity categorized as mild, moderate, or severe based on the Glasgow Coma Scale, duration of consciousness loss, and post-traumatic amnesia 1.
Types of Brain Injuries
The types of brain injuries from trauma can be broadly categorized into:
- Primary brain injuries: occur at the moment of impact and include:
- Concussions: a mild type of TBI caused by a blow to the head or a violent shaking of the head and body 1
- Contusions: bruising of brain tissue
- Diffuse axonal injuries: widespread tearing of nerve fibers
- Intracranial hematomas: blood collections such as epidural, subdural, and intracerebral hemorrhages
- Secondary brain injuries: develop after the initial trauma and include:
- Brain swelling (cerebral edema)
- Increased intracranial pressure
- Hypoxic brain injury
- Infection
Severity of Brain Injuries
The severity of TBI is typically categorized as:
- Mild: characterized by a Glasgow Coma Scale score of 13-15, with symptoms such as headache, dizziness, and confusion, and often resolving within days or weeks with rest 1
- Moderate: characterized by a Glasgow Coma Scale score of 9-12, with symptoms such as loss of consciousness, memory loss, and difficulty with coordination and balance
- Severe: characterized by a Glasgow Coma Scale score of 3-8, with symptoms such as prolonged loss of consciousness, severe memory loss, and significant difficulty with coordination and balance
Importance of Prompt Treatment
Prompt treatment is essential for optimizing outcomes in TBI, as severe injuries can result in long-term or permanent cognitive, physical, and behavioral impairments 1. Prevention and prompt treatment can help reduce the risk of secondary brain injuries and improve overall outcomes.
From the Research
Types of Brain Injuries from Trauma
The types of brain injuries from trauma can be categorized based on their severity and characteristics. Some of the main types include:
- Mild Traumatic Brain Injury (mTBI): This is the most common type of brain injury, often referred to as a concussion 2. It is typically defined by a Glasgow Coma Scale score of 13 or higher 2.
- Moderate Traumatic Brain Injury: This type of injury is more severe than mild TBI and can result in significant morbidity and mortality 3, 4.
- Severe Traumatic Brain Injury: This is the most severe type of brain injury, often resulting in significant neurologic morbidity and high probability of mortality 3, 4.
- Chronic Traumatic Encephalopathy (CTE): This is a long-term debilitating condition that can result from repetitive mild traumatic brain injuries, often associated with behavioral changes, executive dysfunction, memory loss, and cognitive impairments 5.
- Concussion and Subconcussion: These are types of mild TBI that can be difficult to diagnose and may have persistent and sometimes progressive long-term effects 5.
Classification and Diagnosis
The classification and diagnosis of brain injuries from trauma can be challenging due to the lack of clearly defined definitions and criteria 2. The Glasgow Coma Scale is often used to assess the severity of brain injury, but it has its limitations 2. Recent efforts have focused on developing new terminology and classification systems, as well as biomarkers and imaging technologies to improve diagnosis and management of brain injuries 2, 6.
Clinical Consequences
The clinical consequences of brain injuries from trauma can be significant and long-lasting. Mild TBI can result in acute symptoms such as headache, dizziness, and fatigue, which typically resolve in days to weeks 6. However, some individuals may experience a later set of symptoms, known as late phase post-traumatic disorder, which can be more prolonged and influenced by psychosocial factors 6. Moderate and severe TBI can result in significant neurologic morbidity and mortality, and require structured and evidence-based management 3, 4.