Several pathogenetic theories have been proposed for explaining the development of Terson hemorrhage since its original description2-6,8,9,11,13,14,18)
. The most widely accepted pathogenetic mechanism suggests that a suddenly increased intracranial pressure (IICP) is propagated from the intracranial compartment to the orbit through a rapid effusion of cerebrospinal fluid via the optic nerve sheath2,5,13,14,16,18)
. The venous obstruction causes venous stasis, which results in distention and rupture of the fine retinal capillaries5,14)
. This pathogenetic mechanism explains the association of Terson hemorrhage with pathological conditions other than SAH.
The occurrence of Terson hemorrhage has been described in cases of moyamoya disease1)
, severe closed-head injuries5,11,18)
, intracerebral hemorrhage11)
, carotid artery occlusion11)
, cranial subdural hematoma17)
, lumbosacral myelomeningocele19)
, and as a complication associated with intraarterial angiography6)
The present case shows that IVH secondary to moyamoya disease can induce an abrupt increase in ICP resulting in Terson hemorrhage. If the only reason of Terson syndrome is venous congestion due to IICP, equal incidence of Terson hemorrhage as seen in SAH should be present in the other IICP conditions. But, the other IICP conditions do not show the same incidence of SAH associated Terson hrmorrhage. Therefore, the other factors may be associated with the development of Terson hemorrhage14,15,20)
Patients with moyamoya disease can exhibit various ocular symptoms which are mainly caused by stenotic and occulsive lesions in the occipital visual cortex or optic pathways or tract, but have relatively normal intraocular findings10,12)
Careful ophthalmological examination including meticulous fundoscopic evaluation remains the method of choice for detecting Terson hemorrhage. The ideal timing for performing an ophthalmological examination remains to be defined. Manschot8)
reported that all Terson hemorrhages were present within one hour from the ictal event. However, delayed Terson hemorrhage might occur up to 47 days after the ictus.
Swallow et al.17)
evaluated the potential of CT scans of the orbits for detecting Terson hemorrhages. They found that in the majority (66.7%) of patients with Terson hemorrhage, characteristic retinal nodularity and retinal crescentic hyperdensities were evident on their CT scans17)
. However, in our case we could not see the evidence of retinal or orbital hemorrhage on initial CT scans.
The visual outcome was excellent in the majority of cases of Terson hemorrhage. In rare instances, however, Terson hemorrhage can be associated with the development of proliferative retinopathy, retinal breaks, retinal detachment, and cataract20)
. Surgical intervention is reserved for those cases in which there is no visual acuity improvement within 6 months from the ictal event5,18)
. The surgical treatment of choice, when indicated, is pars plana vitrectomy7)