Duret haemorrhages

Causes

Duret haemorrhages are named after Henri Duret, who discovered these brainstem lesions in dogs with increased intracranial pressure. They 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 with parahippocampal gyrus herniation through the tentorial notch. or acute hematoma, edema following trauma, abscess, or tumor.

Pathogenesis

Duret 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.

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, known as the Kernohan-Woltman syndrome. This may succeed or accompany temporal lobe (uncal) herniation and subfalcian herniation secondary to a supratentorial mass.

The pathophysiological mechanism is uncertain 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.

Diagnosis

Duret haemorrhages can be demonstrated by medical imaging techniques of CT or MRI though difficult.

Prognosis

Duret haemorrhages usually indicate a fatal outcome. However, survival has been reported.

Society and culture

George 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.

References

References

1. (2012). "Dorland's Illustrated Medical Dictionary". Elsevier.
2. Duret RL. (April 1955). "[A rare and little known hemorrhagic syndrome.]". Brux Med.
3. [https://www.ars-neurochirurgica.com/lexikon/duret-blutung Duret haemorrhage - Neurosurgical lexicon]
4. (2012). "Dorland's Illustrated Medical Dictionary". Elsevier.
5. Collier, J. The false localizing signs of intracranial tumour. ''Brain'' 27:490-508, 1904.
6. J. W. Kernohan JW, Woltman HW. Incisura of the crus due to contralateral brain tumor. ''Archives of Neurology and Psychiatry'', Chicago, 1929, 21: 274–287.
7. Fisher CM. (May 1995). "Brain herniation: a revision of classical concepts". Can J Neurol Sci.
8. (April 2008). "Atypical Duret haemorrhages seen on computed tomography". Emergency Medicine Australasia.
9. (January 2002). "Brainstem hemorrhage in descending transtentorial herniation (Duret hemorrhage)". Intensive Care Med.
10. (October 2000). "Recovery from Duret hemorrhage: a rare complication after craniotomy--case report". Neurol. Med. Chir. (Tokyo).
11. (November 2005). "Duret hemorrhage is not always suggestive of poor prognosis: a case of acute severe hyponatremia". Am J Emerg Med.
12. Takahiro Mezaki, [https://dx.doi.org/10.1016/S0140-6736(17)31623-9George Gershwin's death and Duret haemorrhage] NEJM, 12 August 2017