Читать книгу Concussion - Kester J Nedd DO - Страница 8

CHAPTER 3

“A Silent Epidemic” – Traumatic Brain Injury (TBI) and Concussion

ACCORDING TO THE Brain Injury Association of America, “every 21 seconds, a person gets a traumatic brain injury (TBI) in the United States”. World Health Organization (WHO) predicts that by 2020, TBI will be among the top three conditions that cause death and disability (Hyder 2017).

A comprehensive review of TBI published in The Lancet Neurology estimated that more than 50 million cases are annually recorded worldwide. The review further stated that half of the world’s population will experience one or more TBI over their lifetime (Feign 2013, Maas 2017). Humphreys (2013) provided lower estimates of 10 million TBI worldwide on an annual basis.

There is a wide range of annual incidence reports in the USA for the number of people with TBI/concussion, with a significant amount of underreporting noted. The number of incidence reports ranges from 1.7 million to 3.8 million persons annually (Bazarian 2005, Ropper 2007, Halsted 2010, Arbogast 2016, CDC 2016, Faul 2010). By comparison, 2% of the population are living with disabilities resulting from TBI (CDC, 2011).

TBI is one of the most-often overlooked conditions, even though it constitutes a major economic burden on the healthcare system. It is the leading cause of injury-related death and disability worldwide (WHO 2006, Majdan 2016, Faul 2010, CDC 2010). In 2003, over 2.8 million persons with TBI/concussion visited the emergency departments of American hospitals. Mild TBI accounts for around 80% of the cases, moderate TBI for about 10%, and severe TBI for approximately 10% of the cases (Faul 2010). A similar breakdown of incidences based on the severity has been noted worldwide.

In our industry, we commonly utilize the Glasgow Coma Scale (GCS) score, developed by Teasdale and Jennett in Glasgow, UK (Teasdale 1974). The GCS measures the level of consciousness as a tool to classify patients based on the initial severity at the time of presentation. This scale, widely used in the field of brain injury, is highly predictive about who with moderate to severe TBI will survive (Steyerber 2008, Saatman 2008). According to Laskowski, “it (GCS) does not necessarily reflect the underlying cerebral pathology because different structural abnormalities can produce a similar clinical picture” (Laskowski 2015).

For persons with milder forms of TBI that are generally classified as concussion, utilizing this scale as a predictor of long-term outcomes can be misleading. So, don’t be fooled by a high GCS score. Despite having a GCS of 13–15 (a high score is associated with mild injury) patients with concussions can experience more dire consequences from their injury. We have a saying in our industry: “Not all mild brain injury is considered mild”.

The scale utilizes 3 variables, each with the elements presented with a weighted score. A final score is provided after each element is tabulated.

The three variables are as follows:

Table #1 -- GCS Score

Variables	Weighted Score Range	Severity Based upon Total Scores
One’s ability to talk (vocalize)	1–4	Mild	13–15
One’s ability to open the eyes (visual system)	1–5	Moderate	9–12
One’s ability to mobilize the extremities (motor response)	1–6	Severe	Less than 8
Maximum Total Score	15	Minimum Score	3

Based on the compiled tabulated score, the lowest and worse score is a 3, where the patient is totally comatose. The best score is 15, where the patient may be symptomatic but fully awake and functioning or can be completely normal. Mild TBI/concussion is generally attributed to a score of 13–15, moderate between 9–12, and severe is 8 and below.

Around 52% of severe brain injury survivors are moderately to severely disabled at 1 year after the injury, and around 43% of the patients hospitalized and discharged develop long-term disabilities (Thornhill 2000, Selassie 2008).

Defining the severity of a TBI/concussion is complex and involves assessing the disability measures, community and psychosocial functioning, neurological impairments, and quality of life measures. Having a severe TBI in the acute phase of the injury, as defined by the GCS, is predictive of negative long-term consequences, however, this is not necessarily the case in all patients.

With regard to mild TBI (concussion), approximately 15% of the patients with cerebral concussions have persistent symptoms for more than 3 months, demonstrate increased rates of disability, and need to use the healthcare system (McCrory 2017, Mechtler 2014, Bigler 2008).

TBI affects the young disproportionately and accounts for as much as 30% of the deaths caused by injury to young people under 45 years of age. This makes it the single most common cause of death and disability for individuals under the age of 45 (Faul 2015).

The most common causes of TBI/concussion include road traffic incidents or accidents (RTI), falls, sporting injuries, and interpersonal violence.

What is interesting about TBI/concussion is that the causes have evolved over time in keeping with our changing lifestyles, human interactions, world order, and technology. A major study on the incidence and occurrence of TBI worldwide reported on the Global Burden of Disease Study in 2016 revealed that the two leading causes of TBI were road traffic accidents and falls. The increase in the incidence of TBI between 1990 and 2016 can be attributed to the increase in population density, population aging, and the increased use of motor vehicles, motorcycles, and bicycles (GBD 2016).

Road traffic accidents increasingly affect the youth in low–middle-income countries, and this ties in with the male preponderance of the condition (Maas 2008). Developing nations are more significantly affected by this condition due to defective roads, the lack of or limited enforcement of laws that promote safety, and defective equipment.

Alcohol and substance abuse also play an important role in such cases. The highest rates of TBI in Latin America and the Caribbean result from road traffic incidents (RTI) and violence (Murry 1996). RTIs are the most significant contributor to the economic costs associated with TBI in Latin America (Hijar 1999). Further, violence is the second largest cause of intracranial injury in the Latin American region as well as a principal cause of death in Brazil, Columbia, Venezuela, El Salvador, and Mexico (Briceno-Leon 2005).

A study covering a quarter of a million people in Ontario, Canada, showed that the long-term risk of individuals who have a concussion committing suicide is three times the general incidence. When the concussion occurs over a weekend, the risk is even higher (Frallick 2016).

While motor vehicle accidents remain the major cause of TBI in high-income countries (HICs), there has been a relative increase in age-related TBI due to falls in HICs. This has been evidenced by the growth in the oldest segment of the elderly population and in the pediatric age group. Falls in the elderly are the major cause of TBI due to aging factors resulting in the loss of balance and motor control and the medical conditions of the elderly (Brazinova 2016, CDC 2015, Peters 2015, CDC 2010).

The increased incidence of injury related to sports has been noted and this in part is due to better education and higher self-reporting (CDC 2011, Hootman 2007, Lincoln 2011).

Military conflicts being a major cause of injuries have placed war-torn Syria as the country with the highest incidence of TBI in recent times (GBD 2018).

The direct costs incurred due to TBI in the USA have been estimated at $13.1 billion per year. An additional $64.7 billion is lost because of missed work and lost productivity. The total medical costs range from $63.4 to $79.1 billion (Salassie 2008, Coronado 2011).

These cost estimates mostly cover direct costs, such as that spent on acute care, hospitalization, acute, and sub-acute rehabilitation. However, these numbers are believed to be an underestimation because they do not cover certain indirect long-term costs such as neurobehavioral management and the impact on families and social order. Worldwide, direct and indirect costs related to TBI borne by the global economy are estimated at approximately $400 billion per year.