Cerebral venous sinus thrombosis (CVST)—a blood clot in the dural venous sinuses—can result in papilledema, but the optic nerve condition may not set in for some time, researchers warn. A new study published in the American Journal of Ophthalmology indicates the importance of serial ophthalmic evaluation following all cases of CVST. Clinicians should perform funduscopy at the time of the initial CVST diagnosis and for weeks later, since a subset of cases can show delayed onset or worsening of papilledema.

The researchers performed a study of 65 CVST patients across seven tertiary care neuro-ophthalmology clinics. The team reviewed the times from CVST diagnosis to papilledema documentation, progression, times to resolution, treatment interventions and final visual outcomes.

They found papilledema present in 54% of patients on initial documentation. But, later during the course of the disease, an additional 46% of patients developed the complication. On average, papilledema was first documented 29 days after CVST diagnosis. In 21.5% of cases, it took approximately 55 days for papilledema to progress and six months to clear up. While these patients were sometimes able to achieve 20/20 vision, 40% ended up with residual visual field defects and some were left with nothing but light perception. Cases where the papilledema worsened had more permanent visual field deficits.