Duret haemorrhages
Duret haemorrhages are small linear areas of bleeding in the midbrain and upper pons of the brainstem. They are caused by a traumatic downward displacement of the brainstem.[1] They are named after Henri Duret. CausesDuret haemorrhages are named after Henri Duret,[2] who discovered these brainstem lesions in dogs with increased intracranial pressure.[3] They are small linear areas of bleeding in the midbrain and upper pons of the brainstem.[citation needed] They are caused by a traumatic downward displacement of the brainstem with parahippocampal gyrus herniation through the tentorial notch.[4] or acute hematoma, edema following trauma, abscess, or tumor.[citation needed] PathogenesisDuret haemorrhages are haemorrhages secondary to raised intracranial pressure with formation of a transtentorial pressure cone involving the front part of the cerebral peduncles, the cerebral crura. Increased pressure above the tentorium may also involve other midbrain structures.[citation needed] Kernohan's notch is a groove in the cerebral peduncle which may be caused by this displacement of the brainstem against the tentorial incisure. The resulting ipsilateral hemiparesis is a false localising sign,[5] known as the Kernohan-Woltman syndrome.[6] This may succeed or accompany temporal lobe (uncal) herniation and subfalcian herniation secondary to a supratentorial mass.[citation needed] The pathophysiological mechanism is uncertain[7] but is probably caused by the displacement of the brainstem stretching and tearing perforating branches of the basilar artery to the pons; venous infarction may play a role.[citation needed] DiagnosisDuret haemorrhages can be demonstrated by medical imaging techniques of CT or MRI though difficult.[8] PrognosisDuret haemorrhages usually indicate a fatal outcome.[9] However, survival has been reported.[10][11] Society and cultureGeorge Gershwin died after emergency surgery of a large brain tumour, believed to have been a glioblastoma. The fact that he had suddenly collapsed and become comatose when he stood up on his last day of life, has been interpreted as brain herniation and Duret haemorrhages.[12] References
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