Institute of Neurology and Neurosurgery, Havana, Cuba.
Neurol India. 2022 Mar-Apr;70(2):670-675. doi: 10.4103/0028-3886.344634.
New controversies have raised on brain death (BD) diagnosis when lesions are localized in the posterior fossa.
The aim of this study was to discuss the particularities of BD diagnosis in patients with posterior fossa lesions.
The author made a systematic review of literature on this topic.
A supratentorial brain lesion usually produces a rostrocaudal transtentorial brain herniation, resulting in forebrain and brainstem loss of function. In secondary brain lesions (i.e., cerebral hypoxia), the brainstem is also affected like the forebrain. Nevertheless, some cases complaining posterior fossa lesions (i.e., basilar artery thrombotic infarcts, or hemorrhages of the brainstem and/or cerebellum) may retain intracranial blood flow and EEG activity. In this article, I discuss that if a posterior fossa lesion does not produce an enormous increment of intracranial pressure, a complete intracranial circulatory arrest does not occur, explaining the preservation of EEG activity, evoked potentials, and autonomic function. I also addressed Jahi McMath, who was declared braindead, but ancillary tests, performed 9 months after initial brain insult, showed conservation of intracranial structures, EEG activity, and autonomic reactivity to "Mother Talks" stimulus, rejecting the diagnosis of BD. Jahi McMath's MRI study demonstrated a huge lesion in the pons. Some authors have argued that in patients with primary brainstem lesions it might be possible to find in some cases partial recovery of consciousness, even fulfilling clinical BD criteria. This was the case in Jahi McMath.
当病变局限于后颅窝时，脑死亡（BD）的诊断引发了新的争议。
本研究旨在讨论后颅窝病变患者 BD 诊断的特殊性。
作者对该主题的文献进行了系统回顾。
幕上脑损伤通常会导致前后向的脑穿通疝，导致前脑和脑干功能丧失。在继发性脑损伤（如脑缺氧）中，脑干也会像前脑一样受到影响。然而，一些抱怨后颅窝病变的病例（如基底动脉血栓性梗死，或脑干和/或小脑出血）可能会保留颅内血流和 EEG 活动。在本文中，我讨论了如果后颅窝病变不会导致颅内压显著增加，就不会发生完全的颅内循环停止，从而解释了 EEG 活动、诱发电位和自主功能的保留。我还提到了 Jahi McMath，她被宣布脑死亡，但在最初的脑损伤后 9 个月进行的辅助检查显示，颅内结构、EEG 活动和对“母亲说话”刺激的自主反应得到了保留，从而否定了 BD 的诊断。Jahi McMath 的 MRI 研究显示脑桥有巨大病变。一些作者认为，在原发性脑干病变患者中，即使满足临床 BD 标准，也有可能在某些情况下出现部分意识恢复。Jahi McMath 就是这种情况。
