Definitions

pressure cone

Duret haemorrhage

Duret haemorrhages (also spelled, Duret hemorrhages) are small areas of bleeding in the ventral and paramedian parts of the upper brainstem, (midbrain and pons).

It is named for RL Duret.

Causes

They are secondary to raised intracranial pressure with formation of a transtentorial pressure cone involving the cerebral peduncles (crus cerebri) and other midbrain structures caused by raised pressure above the tentorium.

Kernohan’s notch is a groove in the cerebral peduncle that may be caused by this displacement of the brainstem against the incisura of the tentorium. 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.

Causes

The common causes are an acute haematoma, oedema following trauma, abscess, or tumour.

Imaging can be difficult.

Diagnosis

The Duret haemorrhage is demonstrated at CT or MRI.

Prognosis

It usually indicates a fatal outcome. However, survival has been reported.

Pathophysiology

The mechanism is uncertain but is probably caused by the displacement of the brainstem stretching and lacerating pontine perforating branches of the basilar artery; venous infarction may play a role.

References

External links

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