Can Baseline Computed Tomography Scans Be Used to Identify Patients at High Risk of Vision Loss due to Terson...

To determine if routinely performed computed tomographic (CT) scanning in patients with aneurysmal subarachnoid hemorrhages (aSAHs) is sufficient to identify patients at high risk of vision loss due to Terson syndrome (TS).

Consecutive patients with a diagnosis of aSAH admitted to the neurologic intensive care unit of a regional referral hospital over a 3-year period were prospectively evaluated. Head CT scans performed in the emergency department were assessed for the presence of a "crescent sign" (evidence of significant subinternal limiting membrane hemorrhage). Dilated funduscopic examinations were performed by an ophthalmologist, masked to the results of the CT scan, to identify retinal and vitreous hemorrhages consistent with TS. Retinal hemorrhages were categorized according to size-those smaller than 2 mm in diameter were deemed low risk (lrTS) for vision loss and those larger than 2 mm in diameter were deemed high risk (hrTS) for vision loss.

One hundred seventeen patients with aSAH were enrolled in the study. The overall incidence of TS was 24.9% (29 of 117 patients; 12 were bilateral). Compared to patients without TS, those with TS had a higher Fisher Hemorrhage Grade and a lower mean (±standard deviation) GCS score (8.66 ± 4.97 vs 12.09 ± 1.10; P < 0.001). The CT crescent sign was positive in 7 patients (6.0%), 6 (5.1%; 2 were bilateral) of whom were found to have hrTS. Of the 110 patients without a CT crescent sign, 88 (75.1%) patients did not have TS, 21 had lrTS, and 1 patient had hrTS in one eye. The CT crescent sign was highly sensitive (85.7%) and specific (99.1%) for diagnosing hrTS.

The CT crescent sign is a highly sensitive and specific marker for hrTS. CT scanning may replace routine ophthalmologic examinations to identify patients at risk of vision loss due to aSAH.