A Rare Cause of Back Pain and Radiculopathy – Spinal Tophi

A Case Report

S. A. Wan; C. L. The; A. T. Jobli; Y. K. Cheong; W. V. Chin; B. B. Tan

Disclosures

J Med Case Reports. 2019;13(8) 

In This Article

Discussion

Our case demonstrated the difficulty of diagnosis of spinal gouty tophi due to the rarity of the condition. The initial diagnosis was epidural abscess with spondylodiscitis. In this part of the world, tuberculosis of the spine must be considered as well. Staphylococcus aureus is the predominant organism causing spondylodiscitis, accounting for half of non-tuberculous cases.[2] Another possible differential diagnosis is neoplasm. The history, physical examination, and spine imaging were pointing toward an infective process, especially with the vertebral destruction seen on the spine radiograph and the MR images. The diagnosis of spinal tophi was not suspected despite our patient having multiple peripheral tophi and having acute polyarticular gout at the time of presentation. Similar case reports have been published in which initial suspected epidural abscess and spondylodiscitis were later found to be spinal tophi after surgery was performed.[3–8]

The various clinical presentations of spinal gout were described by Elgafy et al. in a review of 68 cases of spinal gout.[9] The most common clinical presentation was back pain, followed by spinal cord compression, spinal nerve root compression, fever, cranial nerve palsy, and atlantoaxial subluxation. The most common location of spinal gout involvement was the lumbar region (38 patients), followed by the thoracic region in 15 patients, and the cervical region in 15 patients. Clinicians usually suspected other conditions such as infections (epidural abscess, spondylodiscitis) or neoplasm before the diagnosis of spinal tophi was established either by fine-needle aspiration or biopsy or during surgery.[10–16]

Although spinal gout was thought of as rare, it may be underdiagnosed. Only those with neurological symptoms and back pain will present and be investigated with or without surgical intervention. Other patients who are asymptomatic may not be diagnosed. Konatalapalli et al.[17] reviewed 92 patients with gout and 64 had undergone computed tomography (CT) of the spine for various reasons. Out of the 64 patients, nine had features of spinal gout. Spinal gout was diagnosed clinically in one patient. The same group later performed a cross-sectional study to determine the prevalence of spinal gout in patients with gouty arthritis and found that among the 48 patients, 35% had spinal erosions and/or tophi,[18] and 15% had spinal tophi. All patients with spinal tophi had abnormal hand or feet radiographs. Konatalapalli et al.[18] found that extremity radiographs characteristic of gouty arthropathy correlated strongly with CT evidence of spinal gout. Duration of gout, presence of back pain, and level of serum uric acid level did not correlate with axial gout. Multiple sites may be affected in spinal gout: epidural space, intradural space, ligamentum flavum, discovertebral junction, the pedicles, facet joints, spinous processes, filum terminale, and neural foramina.

Looking back at the spine radiograph of this patient, the L2 did show erosion with overhanging edge which could represent gouty arthropathy. There are no specific MR features of gouty arthritis or tophi. The commonly described MRI features of tophi are hypointense on T1WI, hyperintense on T2WI, and heterogeneously enhanced post contrast.[19,20] Gouty arthritis can affect any part of the vertebrae[21] with various imaging features including spondylodiscitis, destructive arthritis, or even an epidural mass.[22] The enhancing epidural components mimic an epidural mass, which was also described by Wendling et al.[22] and Hou et al..[5] Our patient demonstrated hypointensity on T1W1 which correlates with endplate sclerosis on the radiograph (Figure 3) and heterogenous enhancement post contrast (Figure 4). These findings are similar to an infective cause of spondylodiscitis.

Treatment for spinal tophi depends on the clinical presentation. The presence of neurological impairment warrants surgical intervention. In many cases, the diagnosis of spinal tophi was not suspected and surgery was performed for presumed epidural abscess/spondylodiscitis/spinal mass. In some cases, a fine-needle aspiration or biopsy was performed and once the diagnosis of spinal tophi was obtained, medical treatment was started.[9,19,23] Medical treatments for gout include colchicine, NSAIDs, and steroids for acute gout attack, followed by urate-lowering therapies such as allopurinol, febuxostat, or probenecid.

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