TERSON'S SYNDROME

Signs and Symptoms

Superior and nasal subretinal hemorrhage with disc edema.

Intraocular hemorrhage is seen in approximately 20% of patients with acute intracranial bleeding.¹ Significant vitreous hemorrhage occurs in a smaller percentage of these patients.^1,4 Although the intraocular bleeding may consist of subretinal and deep intraretinal hemorrhage, they may also lie superficially, being just under the internal limiting membrane or su bhyaloid. Significant vitreous hemorrhage will occur if the blood breaks through the internal limiting membrane or the posterior hyaloid face and moves into the vitreous gel.^1,3

Visual acuity is often diminished and in some cases is the first sign of trouble.³ The amount of acute vision loss is related to the extent of the bleeding.^3,4 Late complications include epiretinal membrane formation and, rarely, tractional or rhegmatogenous retinal detachments.⁵ It is important to note that some patients suffering from ruptured intracranial aneurysms may exhibit vision loss secondary to the associated vitreous hemorrhage while not demonstrating any headache, neurological deficits or signs of meningeal irritation.² Terson's syndrome seems to be an anomaly of adults, with at least one study documenting that the maximal incidence of intraretinal hemorrhage in children with non-abuse intracranial hemorrhage (intracranial hemorrhage not associated with shaken baby syndrome) is 8%.⁴

Pathophysiology

The etiopathology of Terson's syndrome has been controversial since its inception.¹ Early investigators believed that the resulting intraocular hemorrhage emanated from the direct dissection of subarachnoid hemorrhage down the optic nerve sheath.¹ However, poor anatomical communication between the subarachnoid space of the optic nerve and the vitreous humor makes this mechanism unlikely. Currently, sudden spiking of intracranial pressure occurring at the time of an intracranial bleed is recognized as the primary event that precipitates the intraocular bleeding.¹ Frequently, the amount of ocular hemorrhage correlates directly with the rapidity and magnitude of intracranial pressure elevation. Why this type of increased intracranial pressure translates into intraocular bleeding remains unclear.¹ Regillo postulates that increased orbital venous pressure, which translates directly through the cavernous sinus, or compression of both the ophthalmic veins and adjacent retinochoroidal anastamoses secondary to rapid effusion of cerebrospinal fluid or blood into the optic nerve sheath could explain the phenomenon.¹ Either way, it appears that an acute obstruction of the retinal venous circulation results in the rupture of superficial retinal vessels.¹

Management

Since patients with this entity have suffered some catastrophic intracranial event and have already presented to a general or emergency physician with other significant systemic symptoms and signs, the diagnosis of Terson's syndrome is generally straightforward.^1­5 Some suggest that the presence of Terson's syndrome may be associated with a higher rate of mortality.¹ In suspected cases that do not have an established traumatic source of intracranial hemorrhage, emergency neuroimaging with either tomography or magnetic resonance imaging is indicated, as a ruptured intracranial aneurysm is the likely cause.¹

Clinical Pearls

• In Terson's syndrome, in general when the blood clears, visual acuity returns. When the vision remains decreased, it is typically secondary to persistent vitreous hemorrhage or retinal pigment epithelial disturbances and/or epiretinal membrane formation.
• Even in cases without these significant complications, occasionally some degree of visual acuity loss may persist indefinitely because the subretinal hemorrhage or the injurious event itself disrupted the optic nerve, retinal pigment epithelium or the retinal tissue. In these cases, electrodiagnostic testing may be useful in providing definitive diagnosis.
• In cases of acute painful CN III palsy, always examine within the eye for retinal or vitreous hemorrhage due to the high incidence of intracranial aneurysm causing CN III palsy. However, do this through an undilated pupil, as pupil dilation is contraindicated in CN III palsy due to the necessity of following the pupillary responses.