Diagnosing Spinal Gout: A Rare Case of Back Pain and Fever

Abstract

Gout is a common inflammatory arthritis that has a high prevalence worldwide. It is characterized by monosodium urate deposition, usually affecting the joints and soft tissue of the lower extremities. Urate deposition in the axial skeleton resulting in spinal gout is rare. However, it seems to be more prevalent than usually thought, largely because it is underdiagnosed. Imaging findings are, for the most part, nonspecific and often mimic infectious etiologies. Definitive diagnosis requires pathological examination. Thus, it can be easily missed. We present a 41-year-old male with a seven-year history of untreated gout who came in with severe back pain, fevers, and radiculopathy. He was initially diagnosed with vertebral osteomyelitis. However, after a biopsy, spinal gout was confirmed. Spinal gout can be misdiagnosed as vertebral osteomyelitis given the similarities in presentation and imaging findings. This case report highlights the importance of keeping spinal gout as a differential of vertebral osteomyelitis, especially in patients with long-standing or uncontrolled gout with tophi.

Figure 1

(a) T2 weighted axial image at L5-S1 level; (b) T2 weighted sagittal image. There is moderate diffuse circumferential disc bulging, severe right facet arthropathy, marked inflammatory changes involving the right facet joint at L5-S1, and significant edema in the posterior right paraspinous musculature near the lumbosacral junction.

Figure 2

(a) Tophi involving the right elbow; (b) white, chalky deposit from aspirate; (c) monosodium urate monohydrate (MSU) crystals from a gouty tophus viewed under polarized light. Strong birefringence was noted along with the needle-shaped morphology classic for MSU.

Figure 3

CT of the lumbar spine showing erosive degenerative changes of the right L5-S1 facet joint (arrow), with mild soft tissue prominence surrounding this region. Narrowing of the right L5-S1 neural foramina is also appreciated.

Figure 4

(a, b) Biopsy from right L5-S1 facet joint demonstrating large amorphous deposits (arrows) surrounded by granulomatous inflammation and foreign body giant cells, consistent with spinal gout.