Head Injury
Even the mildest bump on the head is capable of damaging the brain. More than a million of these head injuries every year are sustained by children, 30,000 of whom will suffer permanent disabilities. In fact, 60 percent of patients who sustain a mild brain injury continue to have a range of symptoms called “post concussion syndrome” as long as six months after the injury. These symptoms can result in a puzzling interplay of behavioral, cognitive, and emotional complaints that can be difficult to diagnose and that can cause ongoing discomfort and destroy personal lives.
Boys are twice as likely to be injured as girls, especially between the ages of 14 and 24. Children are more likely to incur traumatic brain injury during the spring and summer. Traffic accidents account for almost half of the injuries in school-age children and teens; about 34 percent occur at home and the rest in recreation areas. In young children, abuse is the primary cause of head injury; 64 percent of babies under age one who are physically abused have brain injuries, usually caused by shaking. In children under age five, half of all head injuries are related to falls.
The kind of injury the brain receives in a closed head injury is determined by the type of accident: whether or not the head was restrained on impact, and the direction, force, and velocity of the blow. If the head is resting upon impact, the maximum damage will be found at the impact site; a moving head will experience damage on the side opposite the point of impact. A closed head injury can cause widespread damage as the force of impact causes the brain to smash against the opposite side of the skull, tearing nerve fibers and blood vessels. This type of injury may affect the brain stem, causing physical, intellectual, emotional, and social problems. The entire personality of the child may be forever changed.
Symptoms
The signs following head injury may be elusive, but it is important to understand that symptoms tend to get worse over time. If a child begins to play or run immediately after getting a bump on the head, for example, serious injury is unlikely, but the child should still be closely watched for 24 hours.
Symptoms after a head injury may be caused both from the direct physical damage to the brain and from secondary factors such as lack of oxygen, swelling, and blood flow disturbances.
Both kinds of injuries can cause swirling movements throughout the brain, tearing nerve fibers and causing widespread vascular damage. There may be bleeding in the brain, and swelling may raise pressure inside the skull and block oxygen to the brain.
After a head injury, there may be a period of impaired consciousness followed by a period of confusion and poor memory with disorientation, and problems with the ability to store and retrieve new information. The physical and emotional shock of the accident interrupts the transfer of all short-term memory information just before the accident. This is why some children can remember information several days before and after an accident but not information right before the accident occurred. Indeed, brain scan research indicates that contusions and diffuse injuries associated with mild head injury are likely to affect those parts of the brain that relate to memory, concentration, information processing, and problem solving.
There may be a temporary amnesia following head injury that often begins with memory loss over a period of weeks, months, or years before the injury, diminishing as recovery proceeds. Permanent amnesia, however, may extend for just a few seconds or minutes before the accident; in very severe head injuries, however, the permanent amnesia may cover weeks or months before the accident.
A small minority of children are plagued by symptoms, including headache, dizziness, confusion, and memory loss, which may continue for months. Obvious warning signs include:
- lethargy
- confusion
- irritability
- severe headaches
- changes in speech, vision, or movement
- bleeding
- vomiting
- seizure
- coma
More subtle signs of head injury may also appear gradually, and may include:
- long- and short-term memory problems
- slowed thinking
- distorted perception
- concentration problems
- attention deficits
- communication problems (oral or written)
- poor planning and sequencing
- poor judgment
- changes in mood or personality
Sometimes, certain behavior may appear long after the traumatic brain injury occurs. These behaviors may include overeating or drinking, excessive talking, restlessness, disorientation, or seizure disorders.
Diagnosis
In the past, diagnostic tests were not sensitive enough to detect the subtle structural changes that can occur and persist after a mild head injury. While computerized axial tomography (CAT) scans are widely available in emergency rooms to help diagnose brain bruises, many experts believe these scans may not pick up the subtle damage after a mild head injury. Magnetic resonance imaging (MRI) and PET scan are more sensitive in pinpointing many brain lesions and may be more sensitive in detecting the diffuse shearing and contusions as well.
In many children, however, brain scans cannot detect the microscopic damage that occurs when fibers are stretched in a mild, diffuse injury, as brain axons lose some of their covering and become less efficient. This mild injury to the white matter of the brain reduces the quality of communication between different parts of the brain. In this case, a quantitative electroencephalogram (EEG)—that measures the time delay between two regions of the brain and the amount of time it takes for information to be sent from one region to another—may help to reveal damage. Evoked potential brain tests are not generally used in children with mild head injury because they are not sensitive enough to document physiological abnormalities unless testing is done within a day or two of injury.
Treatment
Only a small percentage of children with mild head injury are hospitalized overnight, and instructions upon leaving the emergency room usually do not address behavioral, cognitive, and emotional symptoms that can occur after such an injury. Patients who do experience symptoms should be seen by a specialist. Unless doctors are thoroughly familiar with medical literature in this new field, experts warn that there is a good chance that patient complaints will be ignored. Parents of children with continuing symptoms after a mild head injury should call the local office of the Brain Injury Association for a referral to a specialist.
Prevention
Head injuries can be prevented by taking appropriate safety precautions, such as insisting that children wear helmets when biking, riding a scooter, skating, sledding, or skiing. Children also should wear seat belts and ride in the backseats of cars.
