Disease & Conditions >>> Headache Articles & News
Head Injury And Chronic Headaches
By: William G. Speed III, MD
In the United States 1.5 to 3 million people are treated for mild head injuries each year. This figure underestimates the total number of head injuries, since some people do not seek medical help and would not be counted in these statistics. Most or all head trauma victims will have head pain for hours to days following the injury. About 30% will continue to experience headaches for more than 2 months. It is these patients who are classified as having chronic post-traumatic headache. Post-concussion headache and closed head injury headache are other terms referring to the same thing. The term post-traumatic syndrome is used if there are symptoms in addition to the headache. Using these statistics, it is estimated that there are over 450,000 new cases of chronic post-traumatic headache in the United States each year. It may be of little comfort, but for those of you with this problem, you have plenty of company.
Inside the Injured Brain
Most head injuries result from car accidents (particularly rear-end collisions) or falls. The remainder are caused by recreational activities (for example, football, wrestling or boxing) and industrial accidents. Like migraine, when the existence of chronic post-traumatic headaches was first recognized, they were considered, in large part, to be the result of psychological problems or malingering. Over the past few decades, there is an increasing body of evidence supporting the concept that chronic post-traumatic headaches and post-traumatic syndrome are the result of injury to the brain.
The brain itself contains about 100 billion nerve cells or neurons. These are the cells that permit the brain to do all the things it does. They are linked together by microscopic thread-like structures called axons. There may be only one axon from some neurons and up to many thousands from others. Axons allow neurons to communicate with each other by chemical and electrical signals, which allows us to think, dream, rationalize, walk, see hear, talk, calculate, and remember. Injuring this complex network will disrupt some function or functions of the brain. Some of the symptoms resulting from brain injury may be so subtle that they are recognized only under special testing, while others are blatantly obvious.
Our knowledge of brain injury resulting from minor head trauma comes from clinical observations of hundreds to thousands of patients with post-traumatic syndrome, as well as studies in animals. Axon shearing (tearing) occurs in animals subjected to mild head injury. Similar damage to axons has been found in humans with a history of mild head injury who later died of other causes and were autopsied. The evidence to show that real injury to the brain can result from mild head trauma is very strong.
The head itself does not have to strike or be struck by anything for a brain injury to occur. Suspicion that the symptoms are out of proportion to the intensity of the injury is often expressed, because many more severe injuries such as fractured skulls, bullet wounds, or brain surgery seldom lead to headaches which last more than a few days. Actually, basic physics explains this quite well. When a force is delivered to the head and nothing happens to the skull, then the energy from that force is transmitted directly to the brain. If the force causes the skull to fracture, then the fracture itself absorbs much of the force before it reaches the brain. Therefore, so-called "minor head injury" or "closed head injury," meaning there was no fracture, actually delivers significant force to the brain. This, combined with free movement of the head during whiplash, is more than enough to account for injury to the brain.
Headache and Other Symptoms
The headache resulting from a mild head injury usually begins immediately or shortly after the injury. Most of these headaches are generalized, meaning they are felt all over the head and frequently include the neck, but some are more localized. They are aching, throbbing, pounding, pressure, squeezing, stabbing, or expanding. Some patients feel all of these painful sensations and some just a few. Often the headaches are very intense and at times reach incapacitating levels. The degree of intensity may fluctuate throughout the day. The headaches are likely to be worsened by mental or physical activity.
In addition to the chronic headache, the following symptoms are frequent following a closed head injury: personality change, impaired memory, impaired concentration, reduced attention span, easy distractibility, fatigue, apathy, poor sleep (insomnia), decreased sexual desire (libido), dizziness or lightheadedness, irritability, anger outbursts (short fuse syndrome), mood swings, depression, and frustration. These symptoms can range in severity from being quite subtle to being very obvious to both the patient and others.
The subtle symptoms may be the most frustrating of all. Some patients are aware that they can function as they did before the injury as long as what they are doing is simple and uncomplicated. But when they increase the degree of effort required or the complexity of the task, then the ability to respond is clearly not the same as it was prior to injury. There is no doubt that the mild head injury experienced by these patients affects how much and how rapidly information can be processed by the brain. These subtle but devastating changes are poorly detected by standard tests of mental functioning, and almost always brain imaging (MRI and CT scans) will also be normal.
These patients may then be told that everything is normal. The suggestion may be made that their symptoms are due to psychological problems, or that they are looking for a reason not to return to work, or that they are trying to get money from the insurance company. Such comments have no basis in fact. Studies have not demonstrated any evidence that winning lawsuits will cause the headaches to disappear, nor do psychiatrists have a good track record for treating post-traumatic headache. The combination of chronic headache plus any of the other symptoms seen in the chronic post-traumatic syndrome may have an overwhelming and destructive negative impact on marriage, career, social life and financial stability. Psychological problems may develop as the result of post-traumatic syndrome, but they are rarely or never the cause.
Medical and Surgical Treatment
With appropriate medical management about 80% to 85% of patients with chronic post-traumatic headache can be given reasonable control of these headaches within 6 to 12 months. Some may be totally free of headaches and some may still experience a few headaches which have become tolerable. That leaves 15% to 20% who are likely to continue with these headaches for the rest of their lives.
There are many medications which in various combinations may be useful in managing chronic post-traumatic headaches such as beta blockers, antidepressants, calcium channel blockers, MAO inhibitors, anti-seizure drugs, serotonin antagonists, and intravenous DHE (usually a hospital procedure). If all else fails, a trial of controlled-release opiates can be considered. The use of other pain medication, including over-the-counter pain relievers, is best avoided because of the potential for producing rebound headache.
At the back of the head near its juncture with the neck, there are two nerves called occipital nerves, one on the right and one on the left. These nerves are commonly involved with head injury headaches. Blocking the occipital nerve with a local anesthetic (usually lidocaine) combined with a corticosteroid (such as dexamethasone) may provide short-term pain relief. Some patients have good long-term results from occipital nerve blocks. If a good response is obtained but the pain later returns, this procedure may be repeated. Some neurosurgeons are adept at cutting these nerves where they leave the cervical spine, resulting in more long-term control for some patients who do not respond to other measures. Yet a smaller number may have sufficient neck injury problems to consider a spinal fusion surgery. Such problems are quite complex and require the involvement of doctors who are very experienced in evaluating and treating them.
The impairment in memory and concentration experienced by head injury patients limits the potential benefit of biofeedback. Physical therapy is sometimes useful for a limited time. Psychotherapy may be suggested for those having great difficulty in coping with their symptoms.
For the many non-headache symptoms that may accompany the chronic post-traumatic syndrome, there are no clearly established uniform management procedures. A variety of techniques have been used--including memory and concentration practice and the use of electronic memory aids--but no specific approach has a proven advantage over another.
--William G. Speed III, MD, FACP. Baltimore, MD