Author: Leah Farquharson


A concussion is a form of traumatic brain injury caused by the rapid acceleration or deceleration of the brain (Stillman et al., 2017). A common mechanism to concussion is head trauma, often experienced in athletes who participate in contact sports (Stillman et al., 2017). There are many different symptoms associated with concussion, and each individual presents concussion differently (Stillman et al., 2017). Due to the differences between individuals, treatment plans must be personalized and specific to the patient (Stillman et al., 2017). A general recommendation for patients recovering from concussions is both cognitive and physical rest (Stillman et al., 2017). 



A concussion is caused by the rapid acceleration or deceleration of the brain (Stillman et al., 2017). A common mechanism for rapid acceleration or deceleration is trauma to the head (Stillman et al., 2017). Trauma to other parts of the body may indirectly cause rapid acceleration or deceleration of the brain, although this is less common (Stillman et al., 2017).

Rotation of the brain may induce shear strain to the parenchyma (Stillman et al., 2017). Shear may deform axonal membranes and many sodium-potassium channels open (Stillman et al., 2017). The opening of these channels leads to a wave of depolarization and a spreading depression-like phenomenon (Stillman et al., 2017). As a result, the brain’s glucose requirement increases but the cerebral blood flow decreases, leading to an energy mismatch (Stillman et al., 2017). 



Athletes in contact or collision sports are most likely to have concussions (Stillman et al., 2017). Young children also have higher rates of concussion than adults (Ropper & Gorson, 2007). Military personnel is also at increased risk of concussion with over 20% of military personnel acquiring at least one concussion (Mullally, 2017). In adults, the most common cause of head trauma leading to concussion is a motor vehicle accident (Mullally, 2017).



Patients may experience some or all of the following symptoms

  • Headaches
  • Dizziness
  • Sleep disturbance
  • Psychiatric symptoms 
  • Cognitive issues
  • Loss of consciousness
  • Post traumatic amnesia
  • Confusion
  • Poor balance
  • Drowsiness
  • Slowed verbal output
  • Unsteadiness
  • Light sensitivity
  • Vision changes
  • Nausea
  • Sensitivity to noise
  • Tinnitus
  • Irritability
  • Feeling slowed down or in a fog
  • Difficulty concentrating
  • Difficulty remembering
  • Low energy
  • Increased emotionality
  • Disorientation
  • Appearing dazed
  • Eye movement abnormalities
  • Physical incoordination
  • Seizure (Stillman et al., 2017).


Risk Factors

  • Participating in contact or collision sports (Stillman et al., 2017).
  • Age: young children have higher rates of concussions (Ropper & Gorson, 2007).
  • Combat: military personnel is at an increased risk of concussion (Mullally, 2017).
  • Motor vehicles: a common cause of concussion is motor vehicle accidents (Mullally, 2017).



A healthcare practitioner may perform multiple assessments to diagnose concussion (McCrory et al., 2013). Clinical symptoms, sleep disturbance, physical signs, cognitive impairment, and neurobehavioural features may be assessed (McCrory et al., 2013). Patients history, especially detailed concussion history may be assessed  (McCrory et al., 2013). A commonly used tool for diagnosing a concussion is called the SCAT3, a tool providing guidelines for a detailed clinical assessment for concussion (McCrory et al., 2013). If a patient displays clinical symptoms, sleep disturbance, physical signs, cognitive impairment, or deficits in neurobehavioural features, the physician may suspect and diagnose the concussion (McCrory et al., 2013).

Clinical features

Patients with concussions present differently depending on the individual, some may display symptoms that others do not (Stillman et al., 2017). Patients with concussions may have any or all of the symptoms listed above (Stillman et al., 2017). 


Pathological features

Patients with concussions may have diffuse axonal injury (Johnson et al., 2013). Diffuse axonal injury is most commonly seen in the white matter of the brain, due to mechanical loading of the brain during trauma as well as selective vulnerability of the white matter (Johnson et al., 2013). Diffuse axonal injury can include breaking of the axonal cytoskeletons which may result in transport interruption, swelling, and proteolysis (Johnson et al., 2013). Axonal degeneration, both short-term and long-term, may be present in concussion patients (Johnson et al., 2013). Long-term axonal degradation may result in Alzheimer’s disease-like pathological changes in some individuals (Johnson et al., 2013).  


Treatment protocol

There is no single treatment for concussion (Stillman et al., 2017). Treatment is generally symptom-based, and most effective if started as early as possible (Stillman et al., 2017).

Generally, patients will be advised physical and cognitive rest (Stillman et al., 2017). Length of rest and type of rest may vary between individuals (Stillman et al., 2017). Recommended rest time is around 3-5 days depending on the individual (Stillman et al., 2017). However, excessive rest may result in fatigue, diurnal sleep disruption, reactive depression, anxiety, and psychological deconditioning (Stillman et al., 2017). Following the period of rest, a return to sport progression is recommended (Stillman et al., 2017).

Patients should start with light exercises, such as stationary biking or walking, then increase the intensity of exercise and add resistance exercises as the patient recovers (Stillman et al., 2017). As physical activities increase, especially for athletes, patients should avoid additional head trauma (Stillman et al., 2017). Non-contact activities are introduced once aerobic training is symptom-free, and contact training can be introduced after that (Stillman et al., 2017). 

Cognitive rest includes avoiding electronic activities, such as texting, playing video games, and using the computer (Stillman et al., 2017). Patients should also avoid activities that require concentration, such as reading and doing homework (Stillman et al., 2017). Patients should work with parents, teachers, and other people to determine an appropriate return to school schedule if necessary (Stillman et al., 2017). 

Pharmacological treatment may include analgesics, antidepressants, narcotic analgesics, and triptans for headaches and migraines (McCrory et al., 2013; Mullally, 2017). Analgesics, such as non-steroidal, anti-inflammatory drugs like ibuprofen, are generally given as a first choice for headache relief (Mullally, 2017). Antidepressants in low doses may help for headache relief and in cases of insomnia (Mullally, 2017). Narcotic analgesics are given if other pharmaceuticals do not help as overuse is common (Mullally, 2017).

Articles on misdiagnosis


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