Introduction: We will present the most comprehensive literature review to date of case studies describing chronic traumatic encephalopathy (CTE) and its multiple risk factors in order to identify significant risk factors for developing CTE related to mild traumatic brain injury (mTBI).
Methods: Pubmed literature review as of March 12, 2013 revealed 27 articles describing one or more unique CTE cases between 1954 and 2012.
Results: We identified 151 cases with diagnosis of CTE, involving both single and multiple mTBI; 143 athletes (mostly prize fighters 68 and football players 63) and 5 military veterans. Known causes of death; natural (n=74, 70.3%), accidental (n=18, 17.1%), or suicide (n=14, 12.6%). Age at death ranged from 17 to 91, most dying between 60-69 years (25.9%). 25 cases (16.7%) had a co-morbid neurodegenerative disease. A genetic profile was available for 79 cases. Neuropathological changes shown include atrophy, ventricular dilation, cavum septum pellucidum, tau pathology (neurofibrillary tangle(NFTs) and others. Clinical presentations included difficulties with attention, memory and language, depression, paranoia, suicide ideations, substance abuse (n=28, 18.5%) executive function and visuospatial impairments; however, 5 cases (3.3%) were asymptomatic. There is also a reported higher incidence of obesity and premorbid violence.
Conclusions: mTBI has been considered the main cause for CTE; yet, little is known about factors that increase or decrease risk for the development of CTE after mTBI, mostly because of ascertainment bias. The lack of prospective studies in well-described samples renders it impossible to even estimate CTE incidence rates. Here we will describe CTE and its relation to mTBI, and address possible precipitating risk factors for its development. Furthermore, we will discuss the hypothesis that microglial activation is a primary etiology of CTE and environmental factors,age and sub-concussive head trauma all may contribute to CTE.
Patient Care: Chronic Traumatic Encephalopathy (CTE) has become a major concern of both the public and medical community. The fear surrounding this condition is mostly related to the lack of compared trials and the fact that only mTBI has been determined to be the major risk factor to its discovery. It is important to identify other confounding factors in addition to mTBI that may predispose individuals to this condition in order to better understand those at greater risk.
Learning Objectives: Review how the histological diagnosis chronic of traumatic enchephalopathy relates to mTBI. Understand how various risk factors including underlying subject’s genetics, substance abuse, age and other factors may influence the development of this condition. Discuss the importance for randomized blinded trials to better determine the incidence of CTE in various comparative populations.
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