A head injury involves any trauma to the scalp, skull, or brain. This article focuses on closed head injuries, a significant category of head trauma where the skull remains intact.
What Defines a Closed Head Injury?
A closed head injury occurs when the brain is damaged without any break or penetration of the skull. The outer protective layers of the brain remain intact. This distinguishes it from an open or penetrating head injury, where an object pierces the skull and enters the brain tissue. Most head injuries are classified as closed.
Despite the skull remaining unbroken, the force of impact can cause the brain to move violently within the cranial cavity, leading to various types of internal damage. Common forms of closed head injuries include concussions, which are temporary disturbances of brain function. Brain contusions are bruises to the brain tissue, often occurring at the impact site or on the opposite side as the brain shifts.
Diffuse axonal injury (DAI) involves the shearing and tearing of the brain’s long nerve fibers due to rotational forces, leading to widespread damage. Intracranial hematomas, which are collections of blood clots within the skull, also represent a serious type of closed head injury. These can compress brain tissue.
Common Causes and Injury Mechanisms
Closed head injuries often result from everyday incidents and high-impact events. Falls are a leading cause, particularly among young children and older adults. Motor vehicle accidents, including car and bicycle crashes, also frequently lead to these injuries due to sudden stops or impacts. Sports-related incidents and assaults are additional common scenarios.
The mechanisms of injury involve the brain moving inside the skull. A direct impact can cause the brain to strike the inside of the skull at the point of impact and then rebound to hit the opposite side. Rapid acceleration-deceleration forces can cause the brain to violently shift back and forth. Rotational forces, where the head twists suddenly, can lead to the tearing of nerve fibers and blood vessels within the brain. These movements can result in bruising, swelling, or bleeding.
Recognizing the Signs and Symptoms
Symptoms of a closed head injury vary depending on severity and location. Physical signs often include headache, nausea, vomiting, or dizziness. Individuals might also experience blurred vision, sensitivity to light or sound, and problems with balance.
Cognitive changes are common following a closed head injury. These can manifest as confusion, memory problems, difficulty concentrating, or a general feeling of mental fogginess. Emotional and behavioral symptoms can emerge, such as increased irritability, anxiety, mood swings, or disturbances in sleep patterns.
Certain “red flag” symptoms indicate a severe injury and require immediate medical attention. These include loss of consciousness, seizures, or a headache that worsens persistently. Weakness or numbness on one side of the body, slurred speech, or clear fluid draining from the nose or ears are also serious indicators.
Diagnosis and Management
Diagnosing a closed head injury begins with a medical evaluation. This assessment includes a review of the injury event and symptoms. A neurological exam assesses reflexes, coordination, balance, and cognitive function.
Imaging studies identify internal damage. A computed tomography (CT) scan is often the initial choice due to its speed and ability to detect fractures, bleeding, and swelling. Magnetic resonance imaging (MRI) offers more detailed views of brain tissue.
Initial management focuses on stabilizing the patient and preventing further damage. Physical and cognitive rest is important, meaning limiting activities that require significant mental or physical exertion. Monitoring for any worsening symptoms is also essential. Pain management is addressed. Avoiding activities that could exacerbate the injury, such as strenuous exercise or contact sports, is important during the initial recovery phase.