Concussions: The Hard Facts

Due to the widespread and serious nature of concussions, it’s vital for healthcare professionals to develop the skills to treat.

Conservative estimates suggest that up to 3.8 million concussions, or mild traumatic brain injuries (mTBIs), occur annually in the U.S. Common in adolescents, concussions can have long-term consequences. They may affect a person’s ability to function physically, cognitively, and psychologically.

Though often associated with contact sports like American football or ice hockey, concussions are not exclusive to sports. They may also occur during falls, in motor vehicle accidents, or through intentional self-harm.

Due to the widespread and serious nature of concussions, it’s vital for healthcare professionals to develop the skills necessary to screen, examine, treat, and provide anticipatory guidance in cases of this complex and multifaceted diagnosis.

What is a concussion?

Derived from the Latin verb concutere, meaning “to shake violently,” healthcare professionals often use the word concussion interchangeably with mTBI or minor head injury.

The World Health Organization (WHO) defines an mTBI as “an acute brain injury resulting from mechanical energy to the head from external physical forces.” Symptoms can include one or more of the following:

• Confusion or disorientation
• Loss of consciousness for 30 minutes or less
• Post-traumatic amnesia for less than 24 hours
• Other transient neurological abnormalities include: focal signs, symptoms, or seizure, as well as a score on the Glasgow Coma Scale between 13 to 15 a half hour after an injury (or later upon presentation for healthcare)

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SRCSs: An important subset

Sport-related concussions, or SRCs, are a significant subset of mTBIs and involve subtle but important differences. The following designations are included in the definition of SRCs, according to The International Consensus Conference on Concussion in Sport:

• A direct blow to the head, face, neck or elsewhere on the body with an impulsive force transmitted to the head may cause an SRC.
• SRC usually results in the rapid onset of short-lived impairment of neurological function that resolves spontaneously. However, in some cases, signs and symptoms may evolve over a number of minutes to hours.
• SRC may result in neuropathological changes. The acute clinical signs and symptoms largely reflect a functional disturbance rather than a structural injury and, as such, no abnormality is seen on standard structural neuroimaging studies.
• SRC results in a range of clinical signs and symptoms that may or may not involve loss of consciousness. Resolution of the signs and symptoms typically follows a sequential course, but in some cases, symptoms may be prolonged.

With more than 44 million U.S. adolescents regularly participating in sports, the risk of SRCs for those athletes under 18 is significant. Experts estimate this group suffers between 1.1 million and 1.9 million concussions annually.

The sports with the highest incidence of concussions are soccer, American football, basketball, lacrosse, cheerleading, ice hockey, and softball, with concussions occurring more frequently during gameplay than in practice.

Types of concussions

Critical to the diagnosis and treatment of mTBIs is understanding what type of concussion the patient suffered.

Acceleration/deceleration injuries typically result in a shearing strain of underlying neural elements in the brain. Though a blow to the head may be the source of the initial acceleration, direct contact is not required.

In a neuronal depolarization injury, the mechanical disruption of cell membranes and axonal shearing and stretching forces can cause molecular alterations in cell function, including unregulated ionic depolarization and abnormal glutamate release. This process ultimately results in a depolarization of neurons, causing diffuse neuronal depression.

In cases of an energy crisis — caused by a disruption of ionic homeostasis — there is an elevated energy demand as the body attempts to restore normal cellular function. This results in a metabolic crisis that includes oxidative stress, local lactic acid accumulation, impaired axonal transport, and altered neurotransmission.

Blast-related injuries are rare among athletes but common among military personnel. The pressure wave from a blast may cause a primary injury to the brain tissue. This is similar to the dysfunction sustained in an acceleration/deceleration injury. Debris related to the blast or any impact may also cause secondary and tertiary injuries.

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Symptoms and warning signs

A concussion patient may present with symptoms in one or more of these five categories: symptom presentation, physical signs, behavioral changes, cognitive deficits, and sleep alterations. Early identification of these signs and symptoms is a critical first step in the examination process.

• Physical symptoms may include headache, loss of consciousness, amnesia, dizziness, or blurred vision. It may also include light and sound sensitivity, balance problems, slow or incoherent speech, blank stares, or a stunned appearance.
• Behavioral changes may include irritability, sadness, anxiety, depression, or emotional lability.
• Cognitive deficits may include impaired memory, poor concentration, inattentiveness, or cognitive fatigue.
• Sleep alterations may include difficulty falling asleep, drowsiness, excessive sleep, or fragmented sleep.

Evaluating concussions

Regardless of the cause, multiple variables influence the complexity of a concussion. By assessing the patient’s symptoms, a healthcare professional can individualize the examination to determine the cause of the symptom — and the best course of care.

This article was adapted from our sister site, Elite Learning.