Axial Gout Is Frequently Associated With the Presence of Current Tophi, Although Not With Spinal Symptoms

STUDY DESIGN: Prospective cross-sectional study. OBJECTIVE: To analyze the association of tomographically identified axial gouty lesions with clinical and laboratory characteristics. SUMMARY OF BACKGROUND DATA: Axial gout might be more common than previously thought. The true relationship of these lesions to symptoms or other gout-associated features is poorly understood. METHODS: Forty-two patients with gout underwent thoracic and lumbar spine computed tomographic (CT) scans. CT scans were read by an experienced radiologist blinded to the features of the patients. Axial gout was defined as the presence of bony erosions, facet joints, or disc calcification and tophi in the axial skeleton. Epidemiological and clinical data were collected from medical records. At study entry, patients were evaluated for axial symptoms (back pain or neurological complaints) and subcutaneous tophi. The Fisher exact test and the Student t test were performed for statistical analyses of data. RESULTS: Twelve (29%) of the 42 patients had CT evidence of axial gout. Axial tophi were identified in 5 patients (12%), interapophyseal joints erosions or calcifications in 7 patients (17%), and discal abnormalities in 9 patients (21%). Lumbar spine involvement was a universal finding. Five patients (42%) had thoracic spine involvement and 2 patients (18%) had sacroiliac lesions. No association was found between symptoms and axial gout (P = 0.62). Duration of gout, mechanism of disease (overproduction vs. underexcretion), and metabolic comorbidities were not related to axial involvement. A higher prevalence of axial gout was found between patients with current peripheral tophi (67% vs. 30%; P = 0.03); however, no association was found in patients with a past history of tophi (P = 0.72). CONCLUSION: Our study demonstrated a high prevalence of axial gout not associated with spine symptoms. This finding introduces a differential diagnosis in axial lesions in patients with gout. In addition, the unique association with a current but not previous history of peripheral tophi suggests that gout treatment might be effective in preventing or solving gout axial lesions. LEVEL OF EVIDENCE: 3.