Generality
The concussion is an alteration of the state of consciousness due to a trauma to the head. Due to the brain shaking, the affected subject enters a time-limited confusional state, usually limited to a few minutes.
Causes
The three main causes of concussion are:
- Car accident;
- Accidental fall;
- Sports injury or other recreational activities.
A concussion can also occur when the head and upper body are shaken violently.
At the base of the condition there is a functional disturbance of a part of the brain, known as the reticular activation system (RAS). RAS is a complex of brain cells that belongs to the central nervous system and contributes to:
- Adjust the sense of consciousness and awareness;
- Check the waking state and the circadian rhythm.
Furthermore, the lattice activation system acts as a filter: it allows ignoring irrelevant information, to focus on necessary details.
During a head injury severe enough to cause a concussion, the brain is moved from its normal position for a short period of time. This rotation interrupts the electrical activity of the neurons that make up the RAS, which, in turn, triggers the symptoms associated with the trauma, such as:
- Memory loss;
- Short period of unconsciousness;
- Mental confusion.
Who is at risk?
Studies show that children and adolescents are more vulnerable to concussions than other age groups, and need more time to recover.
If a child returns to practice a sport before complete recovery, a second head injury could have far more serious consequences.
In elderly patients, accidental falls and motor vehicle accidents are the most common causes of concussion.
Sports activities that expose subjects to a higher risk of getting a concussion include: football, rugby, cycling, boxing and martial arts, such as karate or judo.
A number of factors make some people more vulnerable to the effects of a head injury:
- The patient is 65 years of age or older;
- Previous brain surgery;
- Conditions that involve an abnormality in blood coagulation, such as haemophilia (easier bleeding) or thrombophilia (which makes the blood more prone to coagulation);
- Therapy with anticoagulant drugs, such as warfarin or low-dose aspirin.
Signs and symptoms
After suffering a concussion, the patient may experience one or more of these symptoms:
Cognitive symptoms
- Amnesia (memory loss), such as not being able to remember events that occurred before (retrograde amnesia) or after concussion (anterograde amnesia);
- Decreased reflexes;
- Confusion and difficulty with concentration.
Physical symptoms
- Headache;
- Vision disorders, blurred or double vision;
- Perception of ringing in the ears (tinnitus);
- Nausea or vomiting;
- Dizziness;
- Sensitivity to noise or light;
- Alterations in taste or smell;
- Loss of balance and coordination problems;
- Fatigue and lack of energy;
- Sleep disorders: insomnia or excessive sleepiness.
Psychological symptoms
- Personality changes or psychological adaptation problems: irritability, distraction, inappropriate emotional responses (example: suddenly burst out laughing or crying);
- Mood disorders: nervousness, anxiety or depression.
The signs of a concussion can be mild and not immediately obvious. Some individuals may notify them after days or months of injury.
The concussion can occur with or without loss of consciousness.
Alarm signals. When any of the following warning signs occur, it is particularly important to seek immediate medical attention:
- The patient remains unconscious after the initial injury;
- The patient manifests problems of understanding and difficulty in remaining awake;
- The patient is confused, agitated and exhibits unusual behavior.
Other signs of emergency include:
- Extreme drowsiness, which persists for over an hour from injury;
- Muscle weakness on one or both sides of the body;
- Persistent vision problems, unusual eye movements and eye pupils of different sizes;
- Loss of consciousness;
- Difficulty speaking;
- Persistent vomiting or nausea;
- Convulsions or seizures;
- Bleeding from one or both ears;
- Sudden deafness in one or both ears;
- Leakage of fluid from the nose or ears (could be the cerebrospinal fluid that surrounds the brain);
- Persistent and intense headache;
- Weakness, numbness, loss of balance, coordination difficulties or walking problems;
- Persistent unconsciousness (coma).
Diagnosis and clinical management
Physicians play a key role in identifying and managing traumatic brain injuries. The person making the diagnosis subjects the patient to a careful physical examination to assess any signs of more serious damage, such as bleeding from the ears or dyspnea. If the subject is conscious, the doctor can ask questions, in order to measure the ability to pay attention, learning and memory. Some neuropsychological tests can evaluate strength, balance, coordination, reflexes and perception of sensations.
The most widely used diagnostic investigation to confirm a suspected brain injury is computed tomography (CT). This allows the extent of the head injury to be assessed and ensures that there are no hematomas or cerebral haemorrhages. Brain imaging is not always necessary after a traumatic brain injury but is usually recommended in adults who:
- They have lost consciousness;
- They manifest persistent problems with short-term memory and have difficulty speaking or opening their eyes;
- They have signs and symptoms that suggest a fracture at the base of the skull, such as the clear fluid coming out of the nose or ears or the appearance of dark spots above and below the eyes ("black eye");
- Other neurological symptoms are confused or manifest, such as loss of sensation in some parts of the body, problems with balance and walking, and persistent changes in vision (eg, blurred or double vision).
Alternatively, the damage can be assessed with an MRI or X-ray, especially if the patient is believed to have suffered injury to the bones of the neck.
Treatment
After a concussion, it is necessary to subject the patient to a careful monitoring which, depending on the severity of the head injury, can last several days or weeks. The symptoms could, in fact, be the basis of a more serious condition, as in the case of a subdural hematoma or a subarachnoid hemorrhage.
Rest is the best way to recover from a mild concussion. In addition, a series of measures can be used to alleviate symptoms:
- Avoid stressful situations and physically or mentally demanding activities (including housework, exercise, school or computer use).
- Do not practice activities that can cause further head injury;
- Apply an ice pack to the affected area to reduce swelling;
- Avoid drinking alcohol or taking drugs;
- Avoid exposure to very intense lights and sounds;
- Take the medications prescribed by your doctor to control pain (example: paracetamol);
- Do not drive or do contact sports without first consulting your doctor;
- Fasten your seat belt when driving and wear a helmet during cycling, skiing, snowboarding, skateboarding, motorcycling or any other similar activity.
Recovery
The concussion can cause a wide range of short-term or long-term complications, affecting thought, feelings, language or emotions. These changes can bring memory, communication and personality problems, as well as depression, mild cognitive impairment (MCI) and early onset dementia.
Following are other potential complications of a concussion:
- Post-concussion syndrome : it is a little known condition, in which the symptoms of concussion are persistent and can last for weeks or months after the injury.
- Post-traumatic seizures: occur days or months after concussion and may require seizure management with anticonvulsant therapy.
- Epilepsy: the risk of developing epilepsy doubles within the first five years after the concussion.
- Second impact syndrome : it can occur when a subject is still symptomatic and, before complete recovery from the concussion, suffers another head injury. A second brain injury (or cumulative trauma) may be more dangerous than the previous one. In fact, vascular congestion leads to a sudden and massive increase in intracranial pressure, which can be difficult to control and can cause severe brain damage or death.
- Chronic traumatic encephalopathy (CTE) : an example of cumulative damage. Chronic traumatic encephalopathy, also called boxer encephalopathy, is a progressive neurodegenerative disease, caused by repeated episodes of concussion. Typical signs and symptoms include a loss of memory, cognitive and physical deficits and behavioral disorders (especially depression, impulsiveness, aggression, anger, irritability and suicidal behavior).
- Chronic traumatic encephalomyopathy (CTEM) : a small subgroup of individuals with CTE develops a progressive disease characterized by profound weakness, atrophy and spasticity, similar to amyotrophic lateral sclerosis (ALS).
Post-concussion syndrome
Post-concussion syndrome (PCS) is the term used to describe a set of symptoms that may persist for weeks or months after the concussion. These include:
- Changes in the ability to think, concentrate or remember;
- Mood swings and personality changes;
- Headaches and migraines (excruciating pain on one side or on the front of the head);
- Fatigue;
- Dizziness;
- Sensitivity to lights and loud noises;
- Sleep disorders.
The exact cause of PCS is not yet clear. One theory hypothesizes that the post-concussion syndrome represents the result of a chemical imbalance in the brain, triggered by the initial damage. Another theory suggests that it may be an emotional and psychological response to concussion, perhaps a milder form of post-traumatic stress disorder (PTSD).
There is no specific treatment for symptoms of post-concussion syndrome, although many medications used to treat migraines have also been shown to be effective in treating head pain. Antidepressants and psychotherapy can help control psychological symptoms, such as depression and anxiety. Most cases of post-concussion syndrome tend to resolve within 3-6 months and only one person in 10 will still have symptoms after a year.
