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

Case Presentation

We report the case of a 42-year-old Chinese man with a history of chronic tophaceous gout who presented with back pain 2 years ago. The pain was sudden, located at his lower back, radiated to his left lower limb, persisted for a few days, and was subsequently relieved with non-steroidal anti-inflammatory drugs (NSAIDs). There were no neurological abnormalities at that time and further investigations were not performed. He continued to experience episodes of the same back pain over the next 18 months. Two months prior to hospitalization, he had another episode of severe back pain which radiated down to his left lower limb with weakness of his left lower limb. There was no history of trauma, prolonged fever, cough, hemoptysis, loss of appetite, loss of weight, or incontinence.

His past medical history included gout which was diagnosed 4 years ago. He had monthly recurrent gouty arthritis, which affected his first metatarsophalangeal joints, ankles, knees, and shoulders. He noted multiple swellings over his limbs for the past 3 years. During this period, he self-medicated with NSAIDs which terminated the gouty arthritis episodes. He did not seek any medical treatment for urate-lowering therapy.

A physical examination showed normal cardiovascular, respiratory, and abdominal systems. There were multiple tophi seen over the dorsum of bilateral hands, bilateral elbows, bilateral ankles, and toes. A neurological examination showed normal tone in his bilateral lower limbs. Power was reduced for left thigh flexion and extension (3/5) and knee flexion (4/5). His left knee jerk reflex and left ankle jerk reflex were reduced. Sensation was reduced at left L4 and L5 dermatomes. There was no sensory level. His anal tone was normal. Neurology of his upper limbs was normal.

Full blood count: total white cell, 18 × 103/μL (3.99–10); hemoglobin, 11 g/dL (12.1–18.1); platelets, 526 × 103/μL (142–424). Creatinine was 165 μmol/L (60–120). Creatinine clearance was 58 ml/minute. Sodium was 130 mmol/L (135–145), potassium was 3.2 mmol/L (3.3–5.1), and urea was 7.6 mmol/L (1.7–8.3). Uric acid was 524 μmol/L (202–420). C-reactive protein (CRP) positive was 96 mg/L. An echocardiogram showed no vegetations. A chest radiograph was normal. Lumbosacral radiographs showed irregularities of the L4, L5, and S1 endplate with reduction in L4/L5 and L5/S1 intervertebral discs space and L5 vertebral body (Figure 1). MRI of his spine showed hyperintensity within the intervertebral discs spaces of L4/L5 and L5/S1 on T2-weighted imaging (T2WI) in keeping with fluid within (Figure 2). There was also irregular endplate erosion manifested as hypointensity on T1-weighted imaging (T1WI; Figure 3) which demonstrated heterogenous enhancement of the involved vertebral endplate and epidural components post contrast (Figure 4). The initial diagnosis was epidural abscess with spondylodiscitis. Staphylococcus aureus or Mycobacterium tuberculosis infection was suspected. He was started on intravenously administered cloxacillin. Investigations for tuberculosis were negative. Blood cultures were negative. A percutaneous biopsy was not performed as the clinical suspicion for epidural abscess and spondylodiscitis was high and the differential diagnoses of tumor and spinal tophi were not suspected. He underwent surgery to drain the abscess and laminectomy and posterolateral fusion.

Figure 1.

Lumbosacral radiograph showing irregularities of the L4, L5, and S1 endplate with reduction in L4/L5 and L5/S1 intervertebral discs space and L5 vertebral body

Figure 2.

Hyperintensity within the intervertebral discs spaces of L4/L5 and L5/S1 on T2-weighted imaging in keeping with fluid within. Fluid within the L4/L5 and L5/S1 intervertebral discs spaces (arrows) on T2-weighted imaging

Figure 3.

Irregular endplate erosion manifested as hypointensity on T1-weighted imaging

Figure 4.

T1-weighted imaging post contrast showing enhancement of the irregular endplate (red arrows) with enhancing epidural mass-like lesion (yellow arrows)

Operative findings showed chalky white non-adherent material over the facet joints resembling gouty tophi. A small mass lesion with bony erosion was noted over the left L4/L5 facet joint extending and causing a small bony defect on the left side of the L4 lamina. There was no pus or slough seen at the operative site. Pedicle screws were inserted at the desired lumbar and sacral levels, mainly from L3 to S1. Laminectomy was performed at the L4 and L5 levels. Pre-contoured rods were inserted on both sides followed by posterolateral fusion. He was treated for spinal tophi with colchicine.

The vertebral disc was sent for histopathological examination but yielded necrotic tissue only. Tissue cultures were negative, acid-fast bacilli smears were negative, and tuberculosis culture was negative.

During the admission, he had a flare of gouty arthritis of his right wrist and metacarpophalangeal joints. He was started on colchicine and a course of steroids and the gouty arthritis subsequently resolved. During follow up, his back pain improved and he was started on allopurinol for urate-lowering therapy.

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....