What is it?
Trauma to the head can cause several types of head and brain injuries, also called traumatic brain injury (TBI). Problems from head injury include:
- Skull fracture — A skull fracture is a crack or break in one of the skull's bones. In some cases, the skull is dented inward so that fragments of shattered bone are pressed against the surface of the brain. This is called a depressed skull fracture. In most cases, a skull fracture causes a bruise (contusion) on the surface of the brain under the fracture.
- Epidural hematoma — This is a very serious form of bleeding that happens when one of the blood vessels under the skull is torn during an injury. Usually the skull is fractured as well. As the injured vessel bleeds, blood collects in the space between the skull and the dura, the outermost of the three membranes that cover the brain. This collection of blood is called a hematoma. The hematoma can expand within the skull and press on the brain, causing death.
- Acute subdural hematoma — In this injury, a blood vessel tears, and blood collects between the dura and the surface of the brain. This can happen when the head is hit or when a sudden stop causes the head to move violently forward and back (whiplash). Acute subdural hematoma develops rapidly, most commonly after serious head trauma caused by an assault, car accident, or fall. It is a very severe brain injury that typically causes unconsciousness, and it is fatal in about 50% of cases.
- Chronic subdural hematoma — Unlike the acute form, this type of subdural hematoma usually develops gradually because the bleeding inside the skull is less dramatic, and the hematoma can accumulate in several small, separate episodes of bleeding. A chronic subdural hematoma typically follows a fairly minor head injury in a person who is elderly, who is taking blood-thinning medications, or whose brain has shrunk as a result of alcoholism or dementia. Symptoms develop gradually over one to six weeks. The most common symptoms are drowsiness, inattentiveness or confusion, headaches, changes in personality, seizures, and mild paralysis.
- Intraparenchymal hemorrhages and contusions— "Intraparenchymal" means "in the tissue." Intraparenchymal hemorrhage is pooling of blood that occurs within the brain tissue. A contusion is bruising in the brain— in a contusion, a bruise or an area of swelling can be seen on a CT scan but blood does not pool. The force of an impact on one side of the brain can cause the brain to bounce or ricochet within the skull. This can cause harm in two places — one directly beneath the "hit," and a second area of damage on the opposite side of the brain.
- Concussion — If there are any symptoms of confusion, memory impairment, or loss of consciousness after traumatic brain injury, the injury is called a "concussion." Symptoms of a concussion can include not having memory of the minutes immediately before the injury, temporarily losing consciousness, or having vomiting, dizziness, coordination problems, confusion, ringing in the ears, sleepiness, or seizures. Head trauma can cause swelling inside the brain and a potentially deadly increase in pressure inside the skull.
In the United States, the most common causes of head injuries are motor vehicle accidents, falls, and violent assaults.
Traumatic brain injury can also be caused by exposure to blast explosives in military combat, even if there is no direct contact with shrapnel. This is sometimes called "shell shock." Explosions cause a wave of changed atmospheric pressure, and brain movement within the skull can occur as a soldier recoils from a blast.
Up to 75% of people with severe head injuries also suffer serious damage to the neck bones or other parts of the body during the same injury.
Head injuries can cause a wide variety of symptoms, depending on the type of injury, its severity, and its location. Some doctors classify head injuries into three categories, based on symptoms:
- Mild head injury — There is minimal injury to the outside of the head, with no loss of consciousness. The injured person may vomit once or twice and complain of a headache.
- Moderate head injury — There is a more obvious injury to the outside of the head, and the person may have lost consciousness briefly. Other symptoms can include memory loss (amnesia), headache, dizziness, drowsiness, nausea and vomiting, confusion, a bruise-like discoloration around the eyes or behind the ear, or a clear fluid oozing from the nose. This fluid is not mucus, but fluid from around the brain (cerebrospinal fluid) that has leaked through a skull fracture near the nose.
- Severe head injury — There is serious damage to the outside of the head, often together with injuries involving the neck, arms, legs, or major body organs. In most cases, the person is either unconscious or barely responsive. However, some people become agitated or physically aggressive. About 10% of people with severe head injury have seizures.
All head injuries should be evaluated promptly by a doctor, so either call for emergency help or have a friend or family member drive you to an emergency department. Once you arrive at the emergency department, the doctor will want to know:
- how you hurt your head, including the height of your fall or your position (front seat, back seat, driver) in a car accident
- your immediate reaction to the injury, especially any loss of consciousness or memory loss. If you are with a person who has a head injury on a sports field, ask the player if he or she remembers the play that happened right before the injury. If memory is not perfect, this injury should be counted as a concussion, even if the person did not lose consciousness.
- any symptoms that occurred soon after the injury, such as vomiting, headache, confusion, sleepiness, or seizures
- your current medications, including nonprescription drugs
- your past medical history, especially any neurological problems (stroke, epilepsy, etc.), any prior episodes of head injury, and your recent alcohol use if you are a heavy drinker
- whether you are having pain in your neck, chest, abdomen, arms, or legs.
If you are not able to answer these questions, the information can be provided by a family member, friend, or the emergency medical personnel who brought you to the hospital.
The doctor will do a physical and neurological examination, including assessments of your pupil size, reflexes, sensation, and muscle strength. If the results of these exams are normal, you may not need further tests. However, the doctor may decide to monitor your condition in the hospital.
If you have more severe head injuries, emergency personnel will try to stabilize your condition as much as possible before arrival at the hospital. To do this, they may pass a tube down your throat and windpipe (trachea) to help breathing with a mechanical ventilator, control any bleeding from open wounds, give medication intravenously (injected into a vein) to maintain blood pressure, and immobilize the neck in case of a cervical fracture.
Once you arrive at the hospital and are stabilized, the doctor will do a brief physical and neurological evaluation. This will be followed by a computed tomography (CT) scan of the head and spinal x-rays, if necessary. In most cases, a CT scan is the best way to detect skull fractures, brain injury, or bleeding inside the head.
Even if your head injury is only mild, you may have difficulty concentrating temporarily and may experience occasional headaches, dizziness, and fatigue. This collection of symptoms is caused by a concussion. When symptoms are long-lasting, they are called post-concussion syndrome. A concussion usually improves within three months.
You should not play contact sports until you have healed fully from a concussion and have received clearance to return from a medical professional who is certified to perform this function.
The goal is to prevent two serious problems – repeat concussion and brain hemorrhage. Both of these are more likely to occur if the brain is still recovering from a first concussion.
A severe head injury can be fatal, or can require an extended hospital stay with prolonged rehabilitation. In some cases, disability is permanent.
To help prevent head injuries, try the following suggestions:
- If you drink alcohol, drink in moderation. Never drink and drive.
- Wear a seat belt or helmet.
- If you play sports, wear appropriate protective headgear.
- If your job involves working high above the ground, use approved safety equipment to prevent accidental falls. Never work in a high place if you feel dizzy or light-headed, have been drinking alcohol, or are taking medication that can make you dizzy or affect your balance.
- Get periodic vision checks. Poor vision can increase your risk of falls and other types of accidents. This is especially true if you are elderly or if you work in high places.
If you have minor head trauma, your doctor may decide to monitor your condition in the emergency department for a short period of time or to admit you to the hospital for a brief period of observation. While you are in the emergency department or in a hospital room, medical personnel will ask you periodically about your symptoms, check your vital signs, and confirm that you are awake and can respond.
Once your doctor is satisfied that you can be sent home safely, he or she will allow you to leave on the condition that a responsible adult will stay with you at home for a day or two to help monitor your condition. This person will be given specific instructions about possible danger signs to watch for.
If you are troubled by headaches after your head injury, your doctor may suggest that you try acetaminophen (Tylenol) first. If this does not work, your doctor probably will prescribe a stronger pain reliever. It's safest to avoid aspirin, ibuprofen (Advil, Motrin), and naproxen (Aleve, Naprosyn) unless your doctor recommends it, since these drugs might increase the risk of bleeding inside the head.
In people with more extensive head injuries, treatment depends on the type of injury, its severity, and its location. For example, the person may need treatment in an intensive care unit for close monitoring of brain function and blood pressure, as well as seizure prevention. Surgery may be performed to repair a depressed skull fracture, drain an epidural or subdural hematoma, or treat a brain hemorrhage or contusion.
When to call a professional
Call for emergency help immediately if you find someone unconscious at an accident scene. Also call for emergency help if someone with a serious head injury experiences any of the following symptoms:
- nausea and vomiting
- difficulty walking
- slurred speech
- memory loss
- poor coordination
- irrational behavior
- aggressive behavior
- numbness or paralysis in any part of the body.
Even if your head injury appears to be less severe, and your symptoms are mild, it may be possible that you have had significant damage to the brain or its surrounding structures. This is especially true if you:
- are elderly
- take medication to thin the blood
- have a bleeding disorder
- have a history of heavy alcohol use.
If you have one or more of the risk factors listed above, call a doctor or go to an emergency department immediately if you have a head injury.
The outlook depends on the severity of the injury:
- Mild head injuries — The prognosis is usually very good. Although some people experience post-concussion syndrome, this typically goes away after about three months. In most cases, there is no long-term damage, although improvement may be gradual.
- Moderate head injuries — The most dramatic improvement usually occurs within the first one to six weeks. After that time, there may be some remaining problems with memory or attention, but these may not be permanent.
- Severe head injuries — Up to 50% of severe head injuries are fatal. Among people who survive these injuries, about 20% suffer severe disabilities.
National Institute of Neurological Disorders and Stroke
National Rehabilitation Information Center (NARIC)
Brain Injury Association of America
Brain Trauma Foundation