What Complications Can Arise From a Concussion?
Neurological DisordersConcussion

What Complications Can Arise From a Concussion?

What Complications Can Arise From a Concussion?
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Updated on February 23, 2024
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A concussion is a traumatic brain injury (TBI) that is caused by a blow to the head or body that can lead to a range of symptoms, including persistent headache, dizziness, and problems with memory or thinking.

Symptoms of concussions and other mild TBIs usually resolve on their own within one to six weeks. But for some people, symptoms last longer and can result in further complications.

Here are some of the more common complications of a concussion.

Post-Concussion Syndrome

Headache and dizziness are common symptoms of a concussion, but in most cases, they will go away in a couple of days or a few weeks with adequate rest. In certain people who have suffered a head injury, however, these symptoms persist and can lead to a concussion complication known as post-concussion syndrome.

In addition to headaches, dizziness, and imbalance, symptoms of post-concussion syndrome can include fatigue, changes in mood, irritability, anxiety, blurred vision, tinnitus (ringing in the ears), insomnia, loss of concentration and memory, and sensitivity to noise and light.

The severity of headache can vary from tension headache to full-blown migraine.

Researchers have yet to determine why some people with a concussion develop a complication like post-concussion syndrome and others do not.

Your doctor can help you monitor symptoms and track your recovery progress, and you should follow up with your doctor if the symptoms persist longer than anticipated.

Post-Traumatic Vertigo

Post-traumatic vertigo is another possible concussion complication. It is characterized by the dizziness that follows a head or neck injury, such as a concussion. There are several types of post-traumatic vertigo.

The first is called benign paroxysmal positional vertigo (BPPV). This is a pattern of dizziness that is brought on only when the head is placed in certain positions or when there’s a change in position. Turning your head quickly or rolling over in bed are common movements that will bring on dizziness. With BPPV, the vertigo effect is typically a spinning sensation that comes on quickly and only lasts seconds to minutes. But it can be so severe that it may also be accompanied by nausea.

After a head injury, scarring of the drainage pathways of the brain may cause fluid to build up and lead to post-traumatic Ménière’s disease, sometimes called hydrops. In this case, episodes of dizziness are accompanied by noises in the ear or hearing changes. The onset of symptoms can be immediate or take as long as one year after the initial trauma.

Following a concussion or other head injury, people may also get vertigo when they strain or blow their nose, when they get headache or migraine, or when there is a change in their psychological state, such as with depression or anxiety.

Doctors can diagnose post-traumatic vertigo through an exam and tests that evaluate dizziness, balance, and hearing.

Post-traumatic vertigo should be treated by a doctor, and treatment often includes a physical therapist as well. The first line of treatment is typically an approach known as vestibular therapy. Medications may be considered, but they should be used with caution, since some of the medications for vertigo can cause rebound vertigo if used chronically. In rare cases, surgery may be recommended.


Second Impact Syndrome

Second impact syndrome is a rare concussion complication that occurs when a second concussion happens before the first one has completely healed. This can lead to rapid and severe brain swelling, which can turn fatal.

Second impact syndrome can occur from even a very mild trauma that takes place within days or even weeks after the initial concussion.

The condition is most common in young athletes, especially those who participate in sports like football, hockey, boxing, or soccer. In this population, concussions can sometimes go undetected, putting players at risk for second impact syndrome.

It’s vital that athletes and coaches are aware of the signs of concussion to ensure that athletes get adequate time for their brains to heal.

People with a concussion need to rest in order to properly heal and should limit any activity that is physically or mentally demanding. They should not return to play until they have been cleared by their doctor, and when regular activity is resumed, it should be done so gradually.


Predisposition to Degenerative Brain Diseases

Over the past few decades, research has linked moderate to severe brain trauma with an increased risk of Alzheimer’s disease and other types of dementia.

One study concluded that a history of just one prior head injury was associated with a 1.25 higher risk of dementia than in those who never experienced one. Two or more prior head injuries were associated with a more than 2 times increased risk of dementia.

Another study found that in adults ages 50 and older, the risk of dementia was increased by 4 to 6 times the first year after traumatic brain injury. After the first year, the risk decreased rapidly but was still there more than 30 years after the initial trauma.

Other studies have shown mixed results, and more research is needed to better understand the link.

Emerging research indicates that people who have experienced repeated traumatic brain injuries or multiple blows to the head without loss of consciousness are at an increased risk of developing a brain disease called chronic traumatic encephalopathy, or CTE. Professional athletes, including former NFL players, and combat veterans appear to be at a higher risk for CTE.

It remains unclear how often CTE occurs, but it is believed to be relatively rare. Complicating the picture is that CTE can only be fully diagnosed after someone dies, and autopsy findings do not necessarily correlate with clinical symptoms that may have been occurring before death.

Much more research around CTE is needed, and a few studies have started to shed some light.

In one study, researchers from the Department of Veterans Affairs and Boston University reported that 87 of the 91 deceased former NFL players they studied tested positive for CTE.

Another study, of 202 deceased former football players (a combination of high school, college, and professional athletes), identified CTE in 177 of the participants. Of the 111 former NFL players, CTE was diagnosed in 110.

While most studies on CTE have been conducted only on athletes, research suggests those who do not play contact sports can also be affected. In a study, researchers examined the brains of 300 deceased former athletes and 450 deceased non-athletes. CTE was found in 27 athletes and 15 non-athletes.

A case study also found evidence of CTE in a young female victim of domestic violence, prompting calls for more research in this population.

Additionally, the majority of research on CTE has been done in men. The Boston University CTE Research Center has been enrolling female former soccer players for a first all-women CTE study.

Other research underway, such as the Late Effects of TBI project (LETBI), is exploring the long-term effects of TBI in the general population.

Such studies will help researchers better understand the relationship between head trauma and CTE, how to identify it early, and potential treatments.

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Michael R. Yochelson, MD, MBA

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Michael R. Yochelson, MD, MBA, is the chief medical officer at the Shepherd Center in Atlanta, where he was instrumental in starting its first fellowship in brain injury medicine. ...

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