Reactivation of Spinal Tuberculosis in a Patient with Rheumatoid Arthritis on Low-dose Methotrexate

42 year old Hispanic woman with rheumatoid arthritis who has been taking methotrexate for 24 weeks was admitted for severe, sharp lumbar back pain for 3 weeks. The pain radiated to both legs, worsened with walking or standing and improved at rest. It was accompanied by low grade fevers, anorexia and generalized fatigue. The patient denied cough or shortness of breath. MRI of the spine showed an L4 pathologic deformity with abnormal marrow infiltration and a ring-enhancing lesion within the left psoas muscle suspicious for abscess. CT-guided biopsy of the psoas showed necrotic debris and neutrophilic infiltrates. PPD test was reported negative. Bacterial and fungal cultures were negative after 5 days. She was discharged with an empiric 30-day regimen of intravenous ceftriaxone and oral linezolid due to high suspicion for a bacterial etiology. Twenty-six days later, the patient returned due to worsening of her back pain, she was unable to ambulate, and had a 15 pound interval weight loss. Previous biopsy cultures were positive for acid-fast bacilli and repeat MRI showed pathologic collapse of L4 with a retropulsive fracture, superimposed phlegmons bilaterally, severe spinal stenosis, and compression of the cauda equina. Three sputum specimens for AFB smears were negative. The patient recalled having had a BCG vaccine and a negative PPD in 1995; she denied exposure to TB or international travel for the past 21 years. The patient was placed on a 6 months regimen of isoniazid, rifampin, pyrazinamide, ethambutol, and pyridoxine. Two months after her presentation, she required an L4 corpectomy with a vertebral replacement cage, an L2-L4 laminectomy, and L3-L5 fusion due severe back pain and spine instability.