Rogue one: a story of tophaceous gout in the spine

Abstract

A 26-year-old man with history of extensive tophaceous gout presented to the referring facility with decreased bilateral lower extremity sensation and motor function that began acutely 1 week prior to admission and had progressed to urinary incontinence. The patient was admitted to the intensive care unit due to concern for sepsis secondary to epidural abscess. The patient was started on empiric vancomycin and cefepime. Neurosurgery did not recommend acute neurosurgical intervention given the lack of a compressive lesion. Aspiration of the paraspinal collection by interventional radiology subsequently showed crystals consistent with tophaceous gout. Given the high initial suspicion for gout and results of the paraspinal aspiration, the patient was started on prolonged steroid taper as well as allopurinol and colchicine. The patient eventually had partial neurological recovery with discharge to an inpatient rehabilitation facility for further physical therapy rehabilitation.

Background

Gout is a metabolic disorder caused by hyperuricaemia, with uric acid crystal deposition leading to joint inflammation. Tophaceous gout is a more severe form of the disease that occurs when nodular masses of uric acid manifest in the joints of patients with chronic gout. The total prevalence of gout in the USA is estimated at 3.9% (8.3 million individuals) comprising 5.9% of men (6.1 million) and 2.0% of women (2.2 million).¹ Since the average age of gout diagnosis in males is 30, it is very unusual to see a patient with extensive disease at an earlier age. Furthermore, gouty arthritis is usually confined to the first metatarsophalangeal joint of the first toe, the tarsals, ankles, knees or finger joints. It is also important to note the broad diagnosis of transverse myelitis, an inflammatory process of the spinal cord, which presents as subacute onset of weakness, sensory alterations and bowel/bladder dysfunction. We report a case of tophaceous gout leading to substantial neurological deficits in a 26-year-old man.

Case presentation

A 26-year-old man with medical history significant for hypertension, extensive tophaceous gout and lumbar spine degenerative changes was transferred to our facility for emergency neurosurgical evaluation. Notably, he had previously been admitted to our institution 4 months prior to his current presentation for treatment of presumed paraspinal abscess. CT-guided drainage of paraspinal fluid at the time yielded a ‘crunchy white material’ which was felt consistent with tophaceous gout. While culture of the aspirated material and blood cultures were negative, an infectious cause was unable to be completely ruled out and thus patient was started on empiric antibiotics (vancomycin and ceftriaxone) and continued for 6 weeks. At the time of his hospital discharge, the patient was prescribed colchicine 0.6 mg and prednisone 20 mg for 5 days with tapering to 10 mg daily. Outpatient follow-up with rheumatology was scheduled, but the patient missed this appointment.

During the current presentation, he initially presented to the referring facility with decreased bilateral lower extremity sensation and motor function that began acutely a week prior to admission at the outside facility and had progressed to urinary incontinence.

He had been taking colchicine 0.6 mg daily having completed the prednisone taper from his prior admission, but notably was not on urate-lowering therapy. On transfer, he was admitted to the intensive care unit due to concern for sepsis secondary to epidural abscess. Physical examination revealed temperature of 102°F, heart rate of 138, respiratory rate of 17 and blood pressure of 99/49 mm Hg. The patient was found to have 5/5 symmetric muscle strength in his upper extremities with 2+ reflexes. However, he had 0/5 muscle strength with decreased tone and was areflexic throughout his lower extremities. His rectal tone was decreased as well. Sensation was decreased to all modalities below T10 sensory level (patient was found to have no sensation below T10 in a matter of hours).

Investigations

MRI of the patient’s spine showed L3–S1 peripherally enhancing paraspinal soft tissue foci adjacent to facets; L4–L5 enhancing epidural soft tissue on the left in conjunction with degenerative change causing advanced canal stenosis with completely effacing cerebrospinal fluid; L3–L4 enhancing epidural soft tissue on the right causing moderate canal stenosis; T8–T9 abnormal increased T2 signal within the central conus medullaris secondary to cord infarct (figures 1 and 2). While it was unclear why the patient had thoracic level infarct, the soft tissue-enhancing lesions were favoured to be gout given patient’s history.

Figure 1.

T1 postcontrast MRI of L3–L4 disc space showing enhancement within the paraspinal soft tissues with extension through the right neural foramen into the epidural space.

Figure 2.

(A) Axial MRI at the level of T8–T9 showing central cord T2 hyperintensity (red arrow). (B) Diffusion weighted imaging shows bright signal from T8 through the conus medularis consistent with cord infarct (red arrows). (C) Apparent diffusion coefficient shows dark signal from T8 through the conus confirming infarct (red arrow).

Reversible causes of myelitis such as vitamin B12 deficiency, folate deficiency, syphilis, vitamin E deficiency, copper deficiency, lyme and serum neuromyelitis optica were ruled out. Interventional radiology was consulted to perform biopsy for confirmation of the diagnosis. While the epidural fluid collection could not be accessed, successful aspiration of the paraspinal fluid collection was obtained.

Differential diagnosis

The initial differential diagnosis included tophaceous gout, spinal infarction and epidural abscess.

Treatment

The patient was started on empiric vancomycin and cefepime. Neurosurgery was consulted and did not recommend acute neurosurgical intervention given the lack of a compressive lesion and plegia for greater than 24 hours. Neurology was consulted for further recommendations regarding spinal infarct and recommended systolic blood pressure of greater than 100 and aspirin 81 mg daily. While his plegia and sensory level deficits were felt likely in setting of spinal infarct, given his subacute progression of neurological deficits prior to presentation an inflammatory response to the epidural lesions was felt to be another possible aetiology of his symptoms that could possibly reverse or improve with treatment of these lesions. Ultimately, pathology examination of the aspirated material from the paraspinal fluid collection showed crystals consistent with tophaceous gout.

Given the results of the paraspinal biopsy, the patient was started on 1 g of solumedrol daily for 5 days per neurology and rheumatology. He was also started on allopurinol 100 mg daily and colchicine 0.6 mg daily. The patient’s prednisone taper after 1 g solumedrol for 5 days was the following: prednisone 60 mg for 4 days, 50 mg for 4 days, 40 mg for 4 days, 30 mg for 4 days, 20 mg for 4 days, 10 mg for 4 days, 5 mg until outpatient follow-up. Ultimately, while an inflammatory process due to tophaceous gout was most likely given the pathology results, infectious process could not be ruled out, and per infectious disease recommendations, vancomycin and cefepime were continued for a total of 6 weeks. Of note, blood cultures remained no growth to date and after his initial presentation to the intensive care unit, the patient remained afebrile.

Outcome and follow-up

Per recommendations from neurology and neurosurgery, the patient was started on physical therapy. He was deemed to be a candidate for inpatient rehabilitation services. By the time of discharge, the patient was able to feel light touch/vibration in lower extremities. However, he remained plegic and areflexic in his lower extremities.

Discussion

While the incidence of gout has steadily increased since the 1970s, the prevalence of gout in individuals between the ages of 18 and 44 remains uncommon, affecting less than 3 per 1000 persons in this age range.^{2 3} Despite numerous publications, tophaceous gout of the spine remains an even more rare finding. Gout can affect the entire spine and has been shown to have many different presentations.^4–16 The male to female ratio is estimated to be 3:1 with the average age of individuals with spinal gout being 57 years.¹⁷ Cases date as far back as the 1950s and yet despite this long history, there is currently no consensus on diagnosis and treatment.^9–17

Tophaceous gout of the spine may be easily confused with other disease processes such as infection or malignancy. In this setting, the broad diagnosis of transverse myelitis versus compressive disease should be a part of the differential diagnosis, allowing for the diagnosis of tophaceous spinal gout to remain a part of the differential. This is especially true if the patient has a previous history of tophi in other areas of the body. Draganescu et al found that only 30% of the individuals in their review had no previous history of gout.¹⁵ This observation is supported by many other cases in which paraspinal tophi were preceded by tophi in other areas of the body.5–8 13 15 17–19 Furthermore, only one of the individuals with no history of gout was less than 40 years of age. This is important to highlight since it is unlikely for younger individuals to have paraspinal gout as their first presentation. While febrility and leucocytosis have classically been thought of as secondary to an infectious case, many documented cases of spinal gout also have these as part of their presentation.

In their review, Lumezanu et al recommend that if spinal gout is on the differential, CT imaging is more valuable than MRI. Purported advantages of CT include better visualisation of erosions and/or tophi which can then be correlated to those seen in the hands and feet of the patient (figure 3). While MRI imaging may reveal tophi, it usually does so with less specific characteristics, which could lead to misdiagnosis and inappropriate spinal decompression procedures.5–8 10 13 16 Once tophi of the spine have been visualised, CT-guided biopsy can allow for crystalline particles to be extracted leading to a definitive diagnosis of spinal gout.¹⁴ Of note, dual energy CT is a newer imaging modality that is a more specific and sensitive at diagnosing monosodium urate deposits; however, this scanner is not currently available at all institutions and is not financially viable at this time.²⁰

Figure 3.

CT abdomen pelvis without contrast of L3–L4; note increased attenuation of material near the right neural foramen. When compared with MRI, findings are not consistent with infection; the tophaceous material is intrinsically hyperdense on non-contrast CT.

Treatment of spinal gout remains a relatively controversial issue. Labao et al state that cases of tophaceous spinal gout, specifically those with spinal cord compression, should be managed with decompressive surgery.²¹ This was also echoed more recently by Ribiero da et al where a chalky white mass lesion was found to be firmly adherent and compressing the dural sac.¹⁵ Yet, the question of what to do in non-compressive situations remains. In the case presented by Barrett et al, the patient was found to have non-compressive spinal gout, yet still underwent a laminectomy for treatment. However, they do state that if they had made the diagnosis of non-compressive spinal gout preoperatively, there could have been a possibility for medical management rather than a need for an open procedure.⁵ With an open procedure, not only is there an increase in costs and length of hospital stay but also the procedure itself has its own inherent risks. Jacobs et al showcase that aggressive medical management with corticosteroids and uric acid-lowering therapy including allopurinol/colchicine can lead to symptomatic treatment and neurological recovery.²² To our knowledge, no studies comparing the efficacy of surgical decompression and medical management exists.

Learning points.

• Keep tophaceous gout on the differential in cases of possible epidural infections or surgical emergency due to either spinal cord compression or transverse myelitis.

• If spinal gout is suspected, CT of the spine should be the initial choice of imaging to both visualise tophi and allow for better comparison with other tophi in the body.

• In the setting of compressive lesion, patient should be immediately taken to the operating room for an open procedure.

• In the setting of a non-compressive aetiology, CT-guided biopsy of the lesion can help confirm the diagnosis; once the diagnosis of spinal gout is confirmed, treatment with high-dose steroids and allopurinol/colchicine can be confidently initiated.

• With this systematic approach, the need for unnecessary testing and treatment can be avoided, cutting down both hospital cost and length of stay.