Terson syndrome in reverse: intraventricular haemorrhage following primary intraocular haemorrhage.

Terson syndrome (TS) describes the presence of intraocular haemorrhage in patients with intracranial haemorrhage or traumatic brain injury. The aetiology of TS is controversial as an anatomical conduit between the vitreous humour and subarachnoid space remains contested. We herewith present a case of primary vitreous haemorrhage with secondary intracranial extension into the ventricles. Cranial CT demonstrates blood within the left optic nerve and chiasm but not within the subarachnoid space. This unusual phenomenon, which has not been reported before, may be described as 'Terson syndrome in reverse'. We explore mechanisms by which blood within the globe may track into the ventricular system, contextualising recent advances in the understanding of ocular-intracranial fluid transport.