A 39-year-old Nigerian woman with history of sickle cell disease presented to our hospital with a chief complaint of increased swelling on her left flank for the past 2 years. She initially noticed the swelling "many years ago" as a 1 cm soft, painless mass. Over the years, the swelling progressively increased to the current size of approximately 10 cm on presentation. She reported no warmth, redness, or drainage of pus or fluid. Six months prior to presentation, the patient began experiencing a dull pain in the midline of her lower back, radiating laterally to the left lower quadrant. It fluctuated in severity but was aggravated with flexion of the back. She reported no recent fevers, fatigue, changes in weight, chills, sweats, hemoptysis, or dyspnea. She did not have any urinary or gastrointestinal symptoms nor did she experience weakness or sensory loss in her lower limbs. The patient immigrated to the United States from Nigeria one year ago. She has no known history of or exposure to TB but did receive the BCG vaccine as a child.
On examination, she was a well appearing young female. Vital signs included BP 118/60 mmHg, HR 66/min, temperature 98.8 F, O2 saturation 97% on room air, and BMI 20.3. She was noted to have icteric sclera and multiple enlarged, nontender, soft, mobile cervical lymph nodes (LNs), the largest being a 2 cm right anterior cervical LN. Inspection of her back revealed a 10 cm x 16 cm well-demarcated fluctuant area without erythema or other skin changes. The area was not tender to palpation, nor were there any areas of focal tenderness at the spine. Range of motion of her back and hips was fully intact. The remainder of the examination including cardiopulmonary, abdominal, and neurologic examination was unremarkable.
Review of her lab tests revealed hemoglobin of 94 g/L, MCV 92.5 fl, RDW 21.7%, reticulocyte count 0.08 of RBCs, leukocyte count 7.4 x 103/muL, and platelet count 317 x 103/muL. Other lab tests included blood urea nitrogen 2.86 mmol/L, serum creatinine 45 mumol/L, AST 65 U/L, ALT 29 U/L, alkaline phosphatase 19 U/L, total bilirubin of 148.8 mumol/L with indirect bilirubin 131.7 mumol/L, LDH 525 U/L, and ESR 28 mm/hr. Rapid HIV testing was negative. Blood cultures drawn at initial evaluation remained sterile after 48 hours.
A computed tomography (CT) scan of the abdomen and pelvis revealed diskitis/osteomyelitis at the L4-L5 level with adjacent paraspinal and left retroperitoneal abscesses extending to the left lower back/flank subcutaneous tissue and into the epidural space. A follow-up magnetic resonance imaging (MRI) of the lumbar spine with and without contrast confirmed these findings of diskitis and osteomyelitis at L4-L5 with an expansile abscess within substance of the disk extending into ventral epidural space with involvement of left L5-S1 and right L4-L5 neural foramina (Figures 1 and 2).
Ultrasound guided drainage of the abscess was attempted but only a small amount of thick tan fluid could be collected as the contents were extremely viscous. Fluid analysis showed glucose <10 mg/dL, protein 5 g/dL, and LDH 4872 U/L. Cell count was unable to be performed due to the fluid's viscosity but differential showed 82% neutrophils. Gram stain and acid-fast staining were negative for any organisms.
Given her history and presentation, a tuberculous cold abscess was high on our differential and the patient was empirically started on the standard anti-TB regimen of isoniazid, rifampin, pyrazinamide, and ethambutol. Though she had no neurological symptoms, given the extension of the abscess, both orthopedic and neurosurgery specialists were consulted for surgical drainage of abscess. The patient and neurosurgeons were initially reluctant to perform the procedure and she was therefore discharged on anti-TB medications and pyridoxine.
Upon follow-up at a local TB clinic, she complained of right upper quadrant pain and was found to have elevated transaminases. All of her medications were stopped and a week later she was restarted on rifampin and ethambutol. Four weeks from presentation, cultures from drained abscess revealed Mycobacterium tuberculosis. At this time, the patient was reevaluated by neurosurgery and underwent paraspinal abscess drainage through paravertebral muscles. Following the procedure, she was briefly treated with moxifloxacin as per instructions from the regional TB clinic. At her last clinic visit, six months into her treatment course, she was on isoniazid, rifampin, and pyridoxine without any complaints.