Cerebral amyloid angiopathy: a long-term consequence of traumatic brain injury?

Excerpt

In this issue of Acta Neurochirurgica, Dr. Nakayama and coworkers present an interesting case report describing a 32-year-old man who presented with lobar intracerebral hemorrhages where a tissue biopsy obtained at surgery confirmed the diagnosis of cerebral amyloid angiopathy (CAA). CAA is a consequence of β-amyloid deposition in the media and adventitia of small cerebral vessels, is predominately observed in elderly patients > 55 years, and commonly leads to multiple lobar intracerebral hemorrhages as well as cognitive impairment [1]. In fact, this case in Acta is the youngest CAA patient ever reported and only the third confirmed CAA case in a patient less than 40 years old. The common denominator of each of these three young CAA cases is that they all had sustained a previous traumatic brain injury (TBI), in the case presented by Dr. Nakayama at a very young age. Although there should be much caution when interpreting a causative role for TBI in these rare CAA patients, this report adds to numerous others implying that TBI may have chronic, life-long consequences. At the time of the initial traumatic impact, there is a loss of neuronal and glial cells and a complex secondary injury cascade is elicited [2]. Thus far, most TBI research has focused on these early post-injury events and a magnitude of therapies aiming at neuroprotection have been evaluated of which a subset reached the clinical trial stage. However, these compounds invariably failed to increase the rate of favorable outcomes in clinical TBI [3] and other treatment targets are needed. It is becoming increasingly clear that ongoing injury mechanisms contribute to a gradual worsening of the initial brain injury and an increased risk of developing neurodegenerative disorders. The mortality following TBI is increased many years following the initial event [4] and post-traumatic epilepsy is another common life-long condition observed particularly in severe TBI patients [5]. In addition, some degree of chronic cognitive impairment is a feature of virtually every patient surviving severe TBI [6] and when using longitudinal radiological evaluations, a generalized and progressive brain atrophy can be observed post-TBI [7]. Finally, epidemiological evidence suggests that TBI is associated with an increased risk of Parkinson’s disease, Lewy body accumulation, and an accelerated onset as well as a fourfold increase of risk of Alzheimer’s disease (AD) [8, 9]. …