What is a head injury?
Head injuries are one of the most common causes of disability and death in adults. The injury can be as mild as a bump, bruise (contusion), or cut on the head, or can be moderate to severe in nature due to a concussion, deep cut or open wound, fractured skull bone(s), or from internal bleeding and damage to the brain.
A head injury is a broad term that describes a vast array of injuries that occur to the scalp, skull, brain, and underlying tissue and blood vessels in the head. Head injuries are also commonly referred to as brain injury, or traumatic brain injury (TBI), depending on the extent of the head trauma.
Head injuries are rising dramatically, with about 1.4 million people injured each year - and more than 50,000 of those dying. Five million Americans are alive today who have had a head injury and now need help with the activities of daily living, costing the country more than $56 billion per year.
What are the different types of head injury?
The following are some of the different types of head injuries:
A concussion is an injury to the head area that may cause instant loss of awareness or alertness for a few minutes up to a few hours after the traumatic event.
A skull fracture is a break in the skull bone. There are four major types of skull fractures, including the following:
Linear skull fractures
This is the most common type of skull fracture. In a linear fracture, there is a break in the bone, but it does not move the bone. These patients may be observed in the hospital for a brief amount of time, and can usually resume normal activities in a few days. Usually, no interventions are necessary.
Depressed skull fractures
This type of fracture may be seen with or without a cut in the scalp. In this fracture, part of the skull is actually sunken in from the trauma. This type of skull fracture may require surgical intervention, depending on the severity, to help correct the deformity.
Diastatic skull fractures
These are fractures that occur along the suture lines in the skull. The sutures are the areas between the bones in the head that fuse when we are children. In this type of fracture, the normal suture lines are widened. These fractures are more often seen in newborns and older infants.
Basilar skull fracture
This is the most serious type of skull fracture, and involves a break in the bone at the base of the skull. Patients with this type of fracture frequently have bruises around their eyes and a bruise behind their ear. They may also have clear fluid draining from their nose or ears due to a tear in part of the covering of the brain. These patients usually require close observation in the hospital.
Intracranial hematoma (ICH)
There are several types of ICH, or blood clots, in or around the brain. The different types are classified by their location in the brain. These can range from mild head injuries to quite serious and potentially life-threatening injuries. The different types of ICH include the following:
Epidural hematomas occur when a blood clot forms underneath the skull, but on top of the dura, the tough covering that surrounds the brain. They usually come from a tear in an artery that runs just under the skull called the middle meningeal artery. Epidural hematomas are usually associated with a skull fracture.
Subdural hematomas occur when a blood clot forms underneath the skull and underneath the dura, but outside of the brain. These can form from a tear in the veins that go from the brain to the dura, or from a cut on the brain itself. They are sometimes, but not always, associated with a skull fracture.
Contusion or intracerebral hematoma
A contusion is a bruise to the brain itself. A contusion causes bleeding and swelling inside of the brain around the area where the head was struck. Contusions may occur with skull fractures or other blood clots such as a subdural or epidural hematoma. When bleeding occurs inside the brain itself (also called "intraparenchymal hemorrhage"), this can sometimes occur spontaneously. When trauma is not the cause, the most common causes are long-standing high blood pressure in older adults, bleeding disorders in either children or adults, or the use of medications that cause blood thinning or certain drugs of abuse.
Diffuse axonal injury (DAI)
These injuries are fairly common and are usually caused by shaking of the brain back and forth, which can happen in car accidents, from falls or shaken baby syndrome. Diffuse injuries can be mild, such as with a concussion, or may be very severe, as in diffuse axonal injury (DAI). In DAI, the patient is usually in a coma for a prolonged period of time, with injury to many different parts of the brain.