Silent, or masked, giant cell arteritis is associated with a strong inflammatory response and a benign short term course.

OBJECTIVE

To determine the frequency, characteristics, and short term outcome of patients who have biopsy-proven giant cell arteritis (GCA) but no local symptoms that can be attributed to vasculitis inflammation [silent temporal arteritis (TA)] throughout the pretreatment course of the disease or an observational period lasting at least 2 months.

METHODS

Of 175 consecutive patients with biopsy-proven GCA, 130 had typical cranial arteritis, 21 had silent vasculitis, and the remaining 24 had either discrete cranial symptoms (19 cases) or isolated extracranial vasculitis (5 cases). We sought to determine which of 15 pretreatment characteristics were associated with silent TA, as compared with typical cranial arteritis, and assessed the short term outcome in these patients.

RESULTS

Of 21 patients with silent GCA, 14 met criteria for fever of unknown origin. Aside from their different clinical presentation, this population was characterized by a longer delay in diagnosis (p = 0.003), a higher mean erythrocyte sedimentation rate (p = 0.002), higher C-reactive protein (p = 0.002), and lower levels of albumin (p = 0.01) and hemoglobin (p < 0.0001). Permanent visual loss, which occurred in 24 patients (13.7%), exclusively involved those presenting with symptoms and/or signs suggesting cranial arteritis, especially those with frank cranial arteritis. This complication was associated negatively with the delay in diagnosis (p = 0.01), and marginally with the number of symptoms and/or signs suggesting cranial arteritis recorded in each patient (p = 0.07). Oral prednisone at a mean daily dose of 0.7 mg/kg resulted in satisfactory control of silent TA within 4 weeks in all patients but one, and could subsequently be safely tapered by half in a mean delay of 38 +/- 23 days. No differences were observed between patients with silent TA and other forms of the disease regarding the mean prednisone dose at 3 month followup (18.2 +/- 4.5 vs 20.9 +/- 5.9 mg/day) and 6 month followup (14 +/- 4.4 vs 15.6 +/- 6 mg/day ).

CONCLUSIONS

Silent TA may represent a distinct subset of giant cell arteritis, marked by a protracted inflammatory response and a relatively benign short term outcome, excellent response to corticosteroids, and no visual ischemic events, despite the long period of exposure to this complication before appropriate treatment.