Temporal arteritis: improving patient evaluation with a new protocol

Abstract

Context: The process of diagnosing temporal arteritis remains controversial. Although temporal artery biopsy has long been the standard tool of evaluation, its poor sensitivity has prompted investigation of other methods to aid in diagnosis. Improved clinical evaluation and various imaging techniques have been suggested as ways to establish the diagnosis through noninvasive means and to improve biopsy yield.

Objective: To retrospectively report and evaluate the process and experience of the Kaiser Permanente Northwest Region in implementing a new protocol that includes an enhanced clinical evaluation as well as the incorporation of color duplex ultrasonography in addition to biopsy when appropriate for temporal arteritis evaluation.

Results: A 38% reduction in the number of temporal artery biopsies performed was achieved through the new protocol, which was created by a multidisciplinary process, including stakeholders from all departments involved. The percentage of abnormal biopsy results rose from 8.5% at baseline to 24%. No cases of the disease were missed after careful evaluation of clinical and medical-legal records.

Conclusions: Adding specialist clinical evaluation and color duplex ultrasonography to the standard diagnostic workup for temporal arteritis creates a rapid, noninvasive, resource-sensible means to diagnose giant cell arteritis, to improve temporal artery biopsy yield, and to decrease the total number of biopsies done. The diagnosis can be made in some cases by clinical evaluation and color duplex ultrasonography alone, thereby saving the patient an unnecessary surgical procedure. Protocols such as this can be implemented by multidisciplinary cooperation in a patient-centered, integrated system.

Figure 1

Histologic specimen of giant cell arteritis. Arrow points to giant cell in arterial wall. Reprinted with permission from: Mansoor O, Majeed T. A 90 year old woman with painless vision loss. Digital Journal of Ophthalmology [serial on the Internet] 2005 Feb 10 [cited 2012 Oct 31];11(7): Figure 2. Available from: www.djo.harvard.edu/site.php?url=/physicians/gr/728&page=GR_TT.

Figure 2

Initial protocol revision. GCA = giant cell arteritis; Duplex = duplex ultrasound imaging.

Figure 3

Current algorithm that includes clinical risk stratification. CRP = C-reactive protein; ESR = erythrocyte sedimentation rate; po = orally; PCP = primary care provider; Recs = recommendations; Rheum = rheumatology; US = ultrasound image; w/u = workup; +/− = with or without.

Figure 4

Total number of temporal artery biopsies done for first 3 years after starting new protocol (August 2008–July 2011).