Objective: Characterize patients with negative temporal artery biopsies in regard to their eventual diagnoses, and to find features that would differentiate biopsy-negative GCA from non-GCA patients.
Methods: 58 patients with negative biopsies were included. Patients' data and final diagnoses were obtained from medical records. Biopsy-negative GCA was diagnosed when the American College of Rheumatology classification criteria were met, symptoms improved within 3 days of corticosteroid therapy, and no other condition relevant to the patient's symptoms diagnosed during a follow up of 6 months.
Results: Biopsy negative GCA was diagnosed in 11 cases (19%). "Isolated" polymyalgia rheumatica was eventually diagnosed in 5 patients (9%). Altogether, rheumatologic conditions were diagnosed in 23 cases (40%). Other patients (60%) had various hematologic, neurologic-ophthalmic, infectious and malignant disorders. Patients with biopsy-negative GCA were older than non-GCA cases, 81.7+/-6.2 and 74.8+/-8 years, respectively (p=0.05). Headaches were more common in biopsy-negative GCA patients: 91% of them presented with headaches, compared to only 40% of non-GCA patients (p=0.005). Thrombo-cytosis was more common in patients with biopsy-negative GCA compared to non-GCA patients (73% and 19%, respectively, p=0.001). Other clinical and laboratory parameters did not differ significantly between the two groups.
Conclusions: 19% of patients with negative temporal artery biopsies were eventually diagnosed as GCA. Older age, headache and thrombocytosis were more common in that group. These features may help in the diagnostic approach in cases with negative biopsies.