The retrobulbar spot sign in sudden blindness – Sufficient to rule out vasculitis?

SummaryIntroductionSudden retinal blindness is a common complication of temporal arteritis (TA). Another common cause is embolic occlusion of the central retinal artery (CRA). The aim of this prospective study was to examine the diagnostic value of hyperechoic material in the CRA for exclusion of vasculitis as a cause. The authors used orbital color-coded sonography (OCCS) for the detection of hyperechoic material.Materials and methodsTwenty-four patients with sudden visual loss were included in the study after opthalmoscopic exclusion of other causes (e.g. vitreous bleeding, retinal detachment). Parallel to routine diagnostic workup OCCS was performed in all patients.Results7 patients with the diagnosis of TA presented with different degrees of hypoperfusion in the CRA without hyperechoic material (referred to as a “spot sign”) detected by OCCS.Diagnostic workup in the remaining 17 patients did not reveal any signs of TA. The hyperechoic spot sign was visible in 10 of 12 patients (83%) with embolic CRA occlusion. Altogether the frequency of the spot sign in this group was 59%.Detection of embolic CRAO using the spot sign had a sensitivity of 83% and a specificity of 100%. The missing spot sign in patients with TA was a highly specific finding (p-value 0.01).ConclusionsThe “spot sign” is a highly specific finding, and its detection excludes the diagnosis of temporal arteritis in patients with sudden blindness. The finding of a spot sign helps prevent patients from receiving long-term steroid treatment, or an invasive temporal artery biopsy, with its immanent risks.