Definition of post-concussion syndrome

Post-concussion syndrome is a complex disorder in which concussion symptoms — such as headaches and dizziness — last for weeks and sometimes months after the impact that caused the concussion.

Concussion is a type of mild traumatic brain injury, usually occurring after a blow to the head. Loss of consciousness isn't required for a diagnosis of concussion. In some cases, only a brief lapse of memory or a feeling of being dazed is experienced. Between 30 percent and 80 percent of the people who have a mild to moderate brain injury will also experience at least some of the symptoms of post-concussion syndrome.

Concussion has recently been in the public eye because it is often one of the injuries caused by improvised explosive devices in Iraq. In most people, concussion symptoms occur within the first seven to 10 days and go away within three months. Up to 15 percent have symptoms that persist a year or more.

Symptoms of post-concussion syndrome

Post-concussion symptoms include:

• Headaches
• Dizziness
• Fatigue
• Irritability
• Anxiety
• Insomnia
• Loss of concentration and memory
• Noise and light sensitivity

Headaches can feel like tension or migraine, and may contain qualities of both. In some cases, people experience behavior or emotional changes after a mild traumatic brain injury. Family members may notice that the person has become more irritable, argumentative, stubborn, opinionated or suspicious.

Causes of post-concussion syndrome

Some experts believe post-concussion syndrome is caused by structural damage to the brain or disruption of neurotransmitter systems, resulting from the impact that caused the concussion. Others believe it is related to psychological factors, especially since the most common symptoms — headache, dizziness and sleep problems — are similar to those often experienced by people diagnosed with depression, anxiety or post-traumatic stress disorder. In many cases, both physiological effects of brain trauma and emotional reactions to these effects may play a role in the development of symptoms.

Researchers have not determined why some people who have had concussions develop post-concussion syndrome while others do not. There has been no proven correlation between the severity of the injury and the likelihood of developing post-concussion syndrome.

Risk factors for post-concussion syndrome

The risk of developing post-concussion syndrome increases with age. It also is more likely to happen to women rather than men. To some degree this may simply be because women are generally more likely to seek medical attention when they have symptoms.

Some studies indicate that the disorder occurs more often after concussions associated with car accidents, falls or assaults. Sports-related concussions are less likely to result in post-concussion syndrome. However, this may reflect the fact that athletes are generally more fit than the average person and that they're also often motivated to conceal postconcussive symptoms to avoid being removed from play.

Tests and diagnosis of post-concussion syndrome

There is no single test that will prove you have post-concussion syndrome. Your doctor may want to order a scan of your brain, to check for other potential problems that could be causing your symptoms. Magnetic resonance imaging (MRI) scans are more sensitive than are computerized tomography (CT). In fact, MRI can detect brain abnormalities in about 30 percent of people who have had normal CT scans.

If you are experiencing a lot of dizziness, you may be referred to a doctor who specializes in ear, nose and throat complaints. A referral to a psychologist or psychiatrist may be in order if your symptoms include anxiety or depression.

Treatments and drugs for post-concussion syndrome

There is no specific treatment for post-concussion syndrome. Instead, most doctors treat the individual symptoms you are experiencing.

Headaches
Medications commonly used for migraine or tension headaches, including some antidepressants, appear to be effective when these types of headaches are associated with post-concussion syndrome.

The overuse of over-the-counter and prescription pain relievers may contribute to post-concussion syndrome headaches. Withdrawal from the offending painkiller may result in improvement of these headaches; however, the headaches usually need additional treatment.

Memory and thinking problems
There are no medications that are currently recommended specifically for the treatment of cognitive problems after mild traumatic brain injury. Brief, focused rehabilitation that provides individualized training in how to use a pocket calendar, electronic organizer or other techniques to work around memory deficits is often helpful.

Depression and anxiety
If you are experiencing depression or anxiety in connection with post-concussion syndrome, it may be helpful to discuss this with a psychologist or psychiatrist who has experience in working with people with brain injury. Medications to combat anxiety or depression also may be prescribed. The symptoms of post-concussion syndrome often improve after the affected person learns that there is a cause for his or her symptoms. Education about the disorder can ease a person's fears and help provide peace of mind.

Prognosis for those with post-concussion syndrome

The true prognosis is difficult to define given that many patients with minor symptoms may not enter the health care system and those that participate in research appear to have more significant symptoms at baseline. In addition, a wide heterogeneity exists in patients enrolled in studies.

Most patients recover fully in less than 3 months, although some small studies suggest persistence of minor cognitive defects for asymptomatic minor traumatic brain injury patients.  Approximately 15% of patients complain of problems more than 12 months after injury. This group is likely to experience persistent and intrusive symptoms that may be refractory to treatment and impose a lifelong disability.