Gouty sacroiliitis: A case report of often-overlooked cause of inflammatory back pain

Gout is a chronic disease caused by monosodium urate crystal deposition, typically affecting the big toe, midfoot, and ankle. As it rarely involves the sacroiliac joints, it could be easily misdiagnosed as spondylarthritis.

Qi-Hong Guo et al reported the case of a patient with a long history of gout with recurrent low back pain. Computed tomography of the sacroiliac joint suggested sacroiliac arthritis, puncture biopsy indicated gout granuloma, and polarized light microscopy confirmed monosodium urate crystal deposits.

A 34-year-old man with recurrent pain and swelling of the large joints of the feet for the last 5 years, diagnosed with gout and erratically taking febuxostat tablets presented with recurrent attacks of low back pain for 1 year, especially at night and aggravated by activity, limited movement of lower limbs, and difficulty walking during episodes that were not completely relieved by nonsteroidal anti-inflammatory drugs. He denied any history of ophthalmia, inflammatory bowel disease, or psoriasis rash manifestation. He had a family history of gout but not of ankylosing spondylitis. The authors found no visible tophi on him, and the lumbar and thoracic spine mobility was normal.

Laboratory investigation showed elevated serum creatinine (126.2 μmol/L; normal up to 104 μmol/L), uric acid (708.8 μmol/L), C-reactive protein (13.5 mg/L; normal up to 10 mg/L), and ESR (3 mm/h, normal up to 20 mm/h), and the HLA-B27, antinuclear antibodies, rheumatoid factor, and anti-cyclic citrullinated peptide antibodies were all negative. A computed tomography (CT) scan found “edge of uvula”-like change at the left sacroiliac joint. Dual-energy CT (DECT) revealed urate deposits at the sacroiliac joints. Ultrasound identified MSU crystal deposits at the right big toe.

A CT-guided percutaneous needle aspiration of the sacroiliac joint was performed, and pathological investigation showed hyaline fibrous and gout granuloma, with strong negative bi-refringent needle-shaped crystals on polarized light microscopy, confirming the presence of MSU. The clinical symptoms were relieved after colchicine and febuxostat treatment, with uric acid levels at 403 μmol/L and C-reactive protein at 0.34 mg/L.

The authors commented that “Gout is the most common inflammatory arthritis affecting adults, which can co-exist with other forms of arthritis. Gouty sacroiliitis is an often-overlooked cause of inflammatory back pain. This case description aims to raise awareness of the disease and reduce misdiagnosis and underdiagnosis.”

Further reading:

Gouty sacroiliitis: A case report of an often-overlooked cause of inflammatory back pain

Qi-Hong Guo, Jun-Guang Lu et al

Int J Rheum Dis. 2023;26:151–153.

DOI: 10.1111/1756-185X.14438