Terson Syndrome 

In 1881, Litten first described an intraretinal hemorrhage associated with subarachnoid hemorrhage in the German literature.^[1] However, Terson's description of vitreous hemorrhage following subarachnoid hemorrhage in 1900 is now associated with this syndrome.

Terson syndrome originally was defined by the occurrence of vitreous hemorrhage in association with subarachnoid hemorrhage. Terson syndrome now encompasses any intraocular hemorrhage associated with intracranial hemorrhage and elevated intracranial pressures. Intraocular hemorrhage includes the development of subretinal, retinal, preretinal, subhyaloidal, or vitreal blood. The classic presentation is in the subhyaloidal space.

Frequency

Reports have shown an incidence of 10-50% of intraocular hemorrhage with subarachnoid hemorrhage. This association is statistically associated with the severity of the subarachnoid hemorrhage based on the Hunt-Hess classification system of subarachnoid hemorrhages. The incidence of vitreous hemorrhage is much lower (3-13%). Papilledema and unconsciousness are both positively correlated with Terson syndrome.

Terson syndrome has been described most commonly in subarachnoid hemorrhages due to ruptured cerebral aneurysms. Although early studies attempted to link this syndrome with aneurysms of the anterior communicating artery, statistical analysis has not correlated it with a specific aneurysmal location. Other reports include such causes as strangulation, trauma, tumor, perioperative, and postoperative intracranial bleeding.

The pathogenesis of Terson syndrome has been controversial. The earliest reports assumed that the intracerebral blood directly connected with the intraocular space through the lamina cribrosa. While electron microscopy of the optic nerve anatomy has not demonstrated a communication between the 2 spaces, one case report has demonstrated bilateral optic nerve sheath hemorrhages following rupture of an anterior choroidal artery aneurysm resulting in a Terson syndrome.^[2] Pathological specimens have not shown any blood in the optic nerve sheath within 3 mm of the globe.

Another mechanism suggests that a sudden rise in the venous pressure caused by the intracerebral bleeding is transmitted to the eye and results in intraocular bleeding. However, experimental studies have shown that the intravenous pressures are not high enough to create an intraocular hemorrhage.

The sudden rise in intracranial pressure is probably the primary inciting event in Terson syndrome. Intracranial pressure is transmitted through the optic nerve sheath to the swollen optic nerve head, which occludes the retinal and choroidal anastomoses at the level of the lamina cribrosa. The elevated venous pressure generated in the retinal venous system is assumed to rupture the superficial retinal vessels, resulting in intraocular hemorrhages.

A case report supports this theory by demonstrating peripapillary fluorescein leakage in a patient with vitreous hemorrhage secondary to a subarachnoid hemorrhage.^[3] Because of these assumptions regarding the pathogenesis of the syndrome, the definition of Terson syndrome now includes any intraocular hemorrhage associated with intracranial bleeding and acutely increased intracranial pressure. Attempts have been made to correlate Terson syndrome with the intraocular hemorrhages seen in shaken baby syndrome because of the similarity in clinical findings in the eye and the brain, but acute tractional forces may be an additional factor contributing to the intraocular hemorrhage in the latter.

The neurologic symptoms are related to intracranial bleeding. Reported visual acuities range from 20/20 to light perception, but they often are difficult to obtain secondary to the impaired neurologic status of the patient. The degree of visual loss is related to the degree and extent of the intraocular hemorrhage.

The intraocular hemorrhage is usually bilateral and superficial to the retina. Intraretinal or subretinal hemorrhages have been reported but are less frequent. Preretinal hemorrhage can develop into vitreous hemorrhage weeks after the initial inciting event. The intraocular hemorrhage may be difficult to diagnose immediately because the ophthalmologist is restricted from dilating the patient for neurologic monitoring. A decreased red reflex is helpful in evaluating a patient who is comatose, and B-scan ultrasound can further establish the extent of vitreous hemorrhage.

Strict guidelines for treatment have not been established by clinical studies. Patients usually have responded well to observation.

Indications for a vitrectomy include the following:

• Nonclearing vitreous hemorrhage in patient who is monocular
• Subfoveal hemorrhage
• Retinal detachment with vitreous hemorrhage
• Prevention of amblyopia in pediatric patients
• Late complications of intraocular hemorrhage, such as epiretinal membrane formation (macular pucker)
• Occupational necessity for rapidly cleared vision

The relevant anatomy in Terson syndrome includes the inner retinal vasculature, choroidal vasculature, chorioretinal anastomoses near the optic nerve head, and subarachnoid space surrounding the optic nerve.

Contraindications for a vitrectomy include a small intraocular hemorrhage with a high likelihood of spontaneous clearing and an intraocular hemorrhage that is spontaneously clearing.