Understanding the Post-Concussion Syndrome

Post Concussion Syndrome

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Once the diagnosis of a concussion is confirmed through baseline and other testing, it is usually a matter of few days before symptoms resolve and one can resume their routine activities. This is true in about 90% of cases that are diagnosed with a concussion. Not true for Post-Concussion Syndrome, which accounts for 10% of cases amongst high school athletes and 5% to 30% amongst other populations.

These are cases where increased swelling in the brain can lead to neurocognitive and other symptoms to persist longer.

If symptoms persist, get worse and do not resolve within 10 to 14 days after the injury, then the athlete is carrying a probable diagnosis of a Post-Concussion Syndrome (PCS).

It is a definitive diagnosis, if after about one or two months, the athlete upon evaluation is still experiencing concussion like symptoms.

The patients might experience these symptoms under circumstances of rest or upon physical or mental exertion, which indirectly puts them under cognitive overload. The cognitive overload in turn leads to symptom prolongation and difficulty with activities of daily living (ADL), thus leaving them feeling disabled with their professional and social lives.

Diagnosing / Recognizing a PCS patient:

Since PCS is not associated with a broken leg or a broken arm and is not visually relevant, it seems to be the most underdiagnosed problem amongst others, in athletes involved in high impact sports or other

recreational activities. Though, in depth evaluation and treatment can and should only be provided by a specialist, the caretakers and family members also form an integral part of the team. As the symptoms manifest in many different ways for different patients, it is the responsibility of caretakers and close associates to closely monitor the patient with PCS and report any worsening / exacerbation of symptoms if any, to a specialist.

Some of the most common symptoms to look out for are the ones typical of any head injury and include:

  • Headaches and Migraines
  • Dizziness and Vertigo
  • Slow / Delayed Thinking
  • Anxiety
  • Depression
  • Sleep Disturbances
  • Fatigue
  • Sensitivity to Light
  • Blurred Vision
  • Noise Sensitivity
  • Difficulty Concentrating
  • Memory Loss

Some of the risk factors for developing a post-concussion syndrome are as follows:

  • Age. Studies have found increasing age to be a probable risk factor for post-concussion syndrome. This could be attributed prolong recovery time from a previous concussion.
  • Sex. Women carry a higher probability to be diagnosed with post-concussion syndrome. This is mostly attributed to them seeking more medical attention and hence making more doctor visits.
  • Previous concussions: If this is not your first injury, then chances of symptom prolongation i.e. PCS are pretty high.
  • History of ADHD, migraine, seizures or any other mood and anxiety related disorder again puts you at a higher chance for PCS secondary to prolong recovery and other psychological disorders.
  • A few of the less common reasons would include, lack of coping skills, poor support system and lack of knowledge i.e. being ignorant and negligent can further lead to symptom prolongation.

It won’t be fun to only know what these symptoms are, it is equally important to know why they occur.

For that, let’s look into the pathophysiology of a concussion/PCS.

Pathophysiology: This is defined as studying how the brain and its structures function under normal and abnormal circumstances. For the sake of our current discussion, we will look into the following sub topics to understand its relation to the symptoms of PCS.

Membrane Permeability: Any concussive injury immediately initiates a cascade of abnormal events at the microscopic level, which disrupt the normal functioning of the brain cells.

Studies have shown that a concussive injury causes the abnormal movement of several substances across neuronal cell membranes. The neurotransmitters glutamate and N-acetylaspartylglutamic acid (NAA) are leaked out causing massive depolarizations, with the movement of potassium ions out of the cell and calcium ions into the cell.

These abnormal movements of ions interfere with the neuron’s ability to re-polarize and therefore to send and receive signals, and unless the polarization can be re-established, the neuron cannot function properly. This accounts for our brief loss of consciousness, dazed behavior, confusion and memory loss immediately after an injury. Our brain cells just couldn’t work properly.

Pumping all these ions back to where they belong requires a lot of energy, mainly glucose delivered to the brain in the blood. The brain therefore requires more blood and fuel than usual as it tries to repair itself in the minutes and hours following the injury.

Furthermore, the influx of calcium into the neurons triggers an enzyme to attack and breakdown the proteins that make up the cells’ cytoskeleton – the structural backbone of the cell that allows it to keep its precise shape and facilitates transport of substances throughout the cell. The damage to the cytoskeleton causes swelling of the axon, thereby disrupting the overall connectivity of the brain.

In short, the circuits in our brain are simply not working properly. Interestingly although the brain is good at overcoming some types of mild damage by restructuring its circuits, in more severe injuries, these axonal problems can persist for years.

Free Radicals:

In addition to this energy crisis, there’s also reason to believe that a concussive injury results in a higher production of what are called free radicals in the brain. These are highly reactive molecules that damage surrounding proteins, lipids (like those that make up cell membranes), and even DNA.

Studies have shown that brain injuries cause much higher levels of these free radicals, that may add yet another insult to an already struggling brain.

Pituitary gland and hormones:

The pituitary gland, found at the base of the brain secretes several vitally important hormones into the blood stream, and can be thought of as the conductor to the orchestra of wide-ranging bodily functions

Recent studies have shown that the function of this vitally important gland can be impaired by concussive injuries, causing lower levels of some of these hormones being produced. This pituitary dysfunction can last months, years and even decades in severe head injuries in adults.

Hypothyroidism, cortisol deficiency, uncontrolled urination and kidney dysfunction are just some of the consequences seen in children. It is also thought that some of these hormonal changes, even if undetected when tested, may have an effect on memory, attention, higher cognitive functions, mood, and sleep.

Autonomic Nervous system dysfunction: 

Studies have shown that disruption of the ANS does occur following a concussive head injury. The most common outcome result is poor regulation of blood pressure with respect to change in positions. Hence. A lot of times, the delay in blood pressure regulation leads to patients feeling light headed and dizzy, most specifically when sitting up from a laying position.

Vestibular-Ocular system dysfunction:

In order to control our balance, gait and posture, the brain relies on a complex system of neural networks involving many parts of the brain. The eyes, the balance organs of the inner ear and receptors that sense movements in joints all play a role. This system is vulnerable to damage from head injuries. This affects our ability to walk normally, and clarity of vision. It also explains the symptoms of dizziness and occasional feelings that the room is spinning (vertigo), not to mention the general fogginess, difficulty in concentrating, and sensitivity to bright light.


For more information about Post-Concussion Syndrome I.e. treatment, recent advancements, get your copy of the book Concussion and Sports: What every parent needs to know.

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