Traumatic brain injury

Traumatic brain injury
Name	Traumatic brain injury
Caption	A computed tomography scan showing a traumatic brain injury.
Field	Neurology, Neurosurgery, Emergency medicine
Symptoms	Headache, confusion, vomiting, seizures, loss of consciousness
Complications	Post-traumatic epilepsy, hydrocephalus, chronic traumatic encephalopathy
Causes	Falls, motor vehicle collisions, violence, sports injury
Risks	Alcohol use, military service, contact sports
Diagnosis	Based on neurological exam, Glasgow Coma Scale, neuroimaging
Treatment	Supportive care, surgery, rehabilitation
Medication	Anticonvulsants, diuretics
Prognosis	Varies from full recovery to permanent disability or death
Frequency	~69 million globally per year
Deaths	~5-10% of cases

Traumatic brain injury. It is a disruption in the normal function of the brain caused by an external mechanical force, such as a blow or jolt to the head. This condition represents a major global cause of death and disability, affecting individuals across all demographics. The clinical presentation and long-term consequences can vary dramatically, from a brief alteration in mental status to prolonged unconsciousness and permanent neurological deficits.

Definition and classification

Traumatic brain injury is formally defined as an alteration in brain function or other evidence of brain pathology caused by an external force. The severity is primarily classified using the Glasgow Coma Scale, a tool developed at the University of Glasgow, which scores eye, verbal, and motor responses. Injuries are categorized as mild, moderate, or severe, with mild often referred to as a concussion. Further classification is based on the mechanism, such as closed or penetrating head injury, and the specific pathological features observed, like diffuse axonal injury or the presence of an intracranial hemorrhage.

Causes and mechanisms

The leading causes globally include falls, motor vehicle collisions, and acts of violence, with significant contributions from sports injury in athletic populations and blast injury in military contexts, such as during the War in Afghanistan. The primary mechanisms involve the brain undergoing rapid acceleration or deceleration, colliding with the inner skull, or being penetrated by an object. This can result in focal damage, like contusions and lacerations, or widespread cellular dysfunction, as seen in diffuse axonal injury, a hallmark of severe cases.

Signs and symptoms

Immediate physical symptoms may include headache, vomiting, loss of consciousness, and post-traumatic amnesia. Neurological signs can involve pupillary abnormality, weakness, or sensory deficits. Following the initial injury, individuals may experience a wide array of cognitive, somatic, and emotional symptoms, such as difficulties with memory, attention, sleep disturbances, and irritability. Severe injuries can lead to coma or a persistent vegetative state.

Diagnosis

Initial assessment in the emergency department relies heavily on the Glasgow Coma Scale and a thorough neurological examination. Neuroimaging is a cornerstone of diagnosis; computed tomography scans, pioneered by Godfrey Hounsfield, are the first-line modality for detecting acute bleeding and skull fractures. For detecting more subtle injuries, magnetic resonance imaging, technology advanced by Paul Lauterbur and Peter Mansfield, is often employed. Tools like the Sport Concussion Assessment Tool are used in athletic settings.

Treatment and management

Acute management focuses on preventing secondary injury by ensuring adequate oxygenation, cerebral perfusion pressure, and controlling intracranial pressure. This often occurs in an intensive care unit and may involve medications like mannitol or hypertonic saline. Surgical intervention by a neurosurgeon may be necessary to evacuate a hematoma or decompress the brain. Long-term care involves multidisciplinary rehabilitation with specialists from physical therapy, occupational therapy, and spe-language pathology.

Prognosis and outcomes

Outcomes range from complete recovery to severe permanent disability or death. Prognostic models like the International Mission for Prognosis and Analysis of Clinical Trials in TBI (IMPACT) use factors such as age, pupillary response, and Glasgow Coma Scale score to predict mortality and functional outcomes at six months, often measured by the Glasgow Outcome Scale. Long-term sequelae can include post-traumatic epilepsy, hydrocephalus, and neuropsychiatric conditions. Repetitive mild injuries are associated with chronic traumatic encephalopathy, a condition notably studied in athletes from the National Football League.

Prevention

Preventive measures are multifaceted and context-specific. In automotive safety, legislation mandating seat belt use and the development of airbags by companies like Volvo have reduced injuries. In sports, organizations like FIFA and the International Ice Hockey Federation have implemented concussion protocols and rule changes. For the military, advancements in Kevlar helmet design by the United States Army aim to mitigate blast injury. Public health campaigns, such as those by the Centers for Disease Control and Prevention, promote fall prevention in the elderly.

Category:Neurological disorders Category:Emergency medicine Category:Trauma