Duret haemorrhages

Brainstem

Duret haemorrhages are small lineal areas of bleeding in the midbrain and upper pons of the brainstem. They are caused by a traumatic downward displacement of the brainstem.[1]

It is named for Henri Duret.[2]

Pathogenesis

They are secondary to raised intracranial pressure with the 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 that may be caused by this displacement of the brainstem against the tentorial incisure. The resulting ipsilateral hemiparesis is a false localising sign,[3] known as the Kernohan-Woltman syndrome.[4] This may succeed or accompany temporal lobe (uncal) herniation and subfalcian herniation secondary to a supratentorial mass.

Causes

The common causes include hippocampal gyrus herniation through the tentorial notch, acute hematoma, edema following trauma, abscess, or tumor.

Imaging can be difficult.[5]

Diagnosis

Duret haemorrhages are demonstrated by medical imaging techniques of CT or MRI.

Prognosis

It usually indicates a fatal outcome.[6] However, survival has been reported.[7][8]

Pathophysiology

The mechanism is uncertain[9] 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.

References

  1. ↑ Dorland's (2012). Dorland's Illustrated Medical Dictionary (32nd ed.). Elsevier. p. 824. ISBN 978-1-4160-6257-8.
  2. ↑ Duret RL (April 1955). "[A rare and little known hemorrhagic syndrome.]". Brux Med (in French) 35 (16): 797–800. PMID 14378705.
  3. ↑ Collier, J. The false localizing signs of intracranial tumour. Brain 27:490-508, 1904.
  4. ↑ 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.
  5. ↑ Marupaka SK, Sood B (April 2008). "Atypical Duret haemorrhages seen on computed tomography". Emerg Med Australas 20 (2): 180–2. doi:10.1111/j.1742-6723.2008.01072.x. PMID 18377408.
  6. ↑ Parizel PM, Makkat S, Jorens PG; et al. (January 2002). "Brainstem hemorrhage in descending transtentorial herniation (Duret hemorrhage)". Intensive Care Med 28 (1): 85–8. doi:10.1007/s00134-001-1160-y. PMID 11819006.
  7. ↑ Fujimoto Y, Aguiar PH, Freitas AB, de Andrade AF, Marino Júnior R (October 2000). "Recovery from Duret hemorrhage: a rare complication after craniotomy--case report". Neurol. Med. Chir. (Tokyo) 40 (10): 508–10. doi:10.2176/nmc.40.508. PMID 11098635.
  8. ↑ Kamijo Y, Soma K, Kishita R, Hamanaka S (November 2005). "Duret hemorrhage is not always suggestive of poor prognosis: a case of acute severe hyponatremia". Am J Emerg Med 23 (7): 908–10. doi:10.1016/j.ajem.2005.07.014. PMID 16291454.
  9. ↑ Fisher CM (May 1995). "Brain herniation: a revision of classical concepts". Can J Neurol Sci 22 (2): 83–91. PMID 7627921.

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