“Diagnostic Algorithm for Patients With Suspected Giant Cell Arteritis” Useful, but No Substitute for Thorough Histopathology: Response

We want to thank Dr. George et al for their interest in our study titled “Diagnostic Algorithm for Patients With Suspected Giant Cell Arteritis” (¹). Unfortunately, none of us were able to attend the September 2015 Neuro-Ophthalmology Society of Australia meeting to comment specifically on their data and conclusions; but we have no reservations in stating that a temporal artery biopsy (TAB) is the gold standard for diagnosing giant cell arteritis (GCA). To be clear, the goal of our study was to improve the diagnostic yield of a positive TAB with a relatively simple diagnostic algorithm to serve as a guide to help clinicians decide which patient needs a TAB. In no way did we intend or state in our article that the algorithm was a substitute for a TAB. In contrast, it would not be feasible or reasonable to perform a TAB on every patient with any one of the 39 signs and symptoms as listed by Dr. George et al. As part of their proforma, they mention “a high clinical suspicion” of GCA, but it is not stated what constitutes a “high clinical suspicion.” Our algorithm allows for a simple stratification (very low, moderate, and high clinical suspicion) based on 7 signs and symptoms (in addition to accounting for comorbid conditions that can mimic GCA) to improve on the possibility of obtaining a positive TAB. Ultimately, however, to confirm or refute the diagnosis of GCA requires a TAB.