What does Terson syndrome look like?

A 30-year-old woman with no significant medical history has been admitted to the emergency department in a coma following a sudden loss of consciousness. This episode was preceded by acute, acute-severe headaches and blurred vision earlier the same day.

After patient stabilisation, a CT scan was performed, revealing a spontaneous hyperdensity in the sulci and the cisterns, consistent with a subarachnoid haemorrhage (Figures 1a and 1b). A large haematoma was seen in the left frontal lobe (Figure 1b), causing a mass effect on adjacent structures and resulting in a contralateral midline shift. Additionally, the posterior poles of the orbits showed spontaneous hyperdensity, more pronounced in the left eye (Figure 1a).

Background

Terson syndrome was first described by Albert Terson in 1900 to refer to vitreous haemorrhage associated with subarachnoid haemorrhage. Since then, the term has been expanded to include intraocular haemorrhages caused by increasing intracranial pressure, extending beyond subarachnoid haemorrhage. There are two main hypotheses regarding the pathophysiology of Terson syndrome. The first suggests that increased intracranial pressure leads to elevated intraocular venous pressure, causing rupture of superficial vessels. The second hypothesis proposes that subarachnoid blood enters the eye via the optic nerve and the space surrounding the retinal vessels [1].

Clinical Perspective

Visual symptoms in Terson syndrome typically include a sudden decrease in vision. However, neurological symptoms typically dominate and are often the primary reason for imaging. Intraocular haemorrhage is often bilateral, and its incidence correlates with the severity of intracranial haemorrhage, with papilledema and unconsciousness being positively associated.

The most common aetiology is the rupture of an aneurysm, particularly in the anterior communicating artery, though no statistically significant correlation has been established. Other reported causes include conditions associated with increased cranial pressure, such as strangulation, trauma, hypertension, tumours, and peri or postoperative bleeding [2].

Imaging Perspective

CT scan is the gold standard to set the accurate diagnosis of this emergency. It can reveal both intracranial and intraocular haemorrhages. The ocular haemorrhage typically involves vitreous and retrohyaloid haemorrhage, often associated with retinal and subretinal bleeding, appearing as spontaneous hyperdensity at the posterior poles of the eyes, with varying severity. B-scan ultrasonography may be necessary to assess the severity and rule out a retinal detachment, particularly in cases involving trauma [3].

Outcome

Vitrectomy has been shown to be effective in restoring vision, with better outcomes observed in younger patients and those treated soon after the cranial event. The overall prognosis largely depends on survival following the subarachnoid haemorrhage. Long-term observation is a common therapeutic management strategy, as up to half of the patients experience spontaneous regression of the haemorrhage [4].

Take Home Message

• Terson syndrome involves vitreous and retrohyaloid, along with retinal and subretinal haemorrhages, associated with subarachnoid haemorrhage.
• Neurological manifestations from brain bleeding typically predominate in the clinical presentation.
• CT scan in emergency settings is key to diagnosing the syndrome, revealing both ocular and parenchymal haemorrhages. Early diagnosis is crucial for appropriate management.
• The overall prognosis depends on the severity of brain bleeding. Vitrectomy, particularly in cases of bilateral ocular haemorrhage, is a safe and effective technique commonly used.

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