Msk Dermatology · Year 2 · from Msk Dermatology

Case 2: Vertebral Osteomyelitis

Patient Presentation

Demographics: 64-year-old man

Chief Complaint: "I've had terrible back pain for 6 weeks that's getting worse."

History of Present Illness: The patient describes progressive lower back pain that began insidiously approximately 6 weeks ago without any clear precipitant. The pain is constant, worse at night, and disturbs his sleep. It is not relieved by rest and is aggravated by movement. He has lost 12 pounds over this period. He had a urinary tract infection treated with oral antibiotics about 2 months ago. Over the past week, he has developed subjective fevers and night sweats.

Past Medical History:

• Type 2 diabetes mellitus
• Benign prostatic hyperplasia
• Recent urinary tract infection (E. coli, treated with ciprofloxacin x 7 days)

Medications:

• Metformin 1000 mg twice daily
• Tamsulosin 0.4 mg daily
• Ibuprofen 400 mg TID (self-prescribed for back pain)

Social History:

• Retired plumber
• Non-smoker
• Occasional alcohol

Physical Examination

• Vital Signs: BP 128/78 mmHg, HR 88 bpm, Temp 38.1C, BMI 28 kg/m2
• General: Uncomfortable, difficulty finding comfortable position
• Spine:
• Paraspinal muscle tenderness L3-L5 region
• Percussion tenderness over L4 spinous process
• Limited range of motion due to pain
• No midline step-off
• Neurologic:
• Strength 5/5 bilateral lower extremities
• Sensation intact
• Reflexes 2+ and symmetric
• Negative straight leg raise
• Rectal exam: Prostate mildly enlarged, non-tender

Workup and Results

Laboratory Studies:

Imaging:

• Lumbar spine X-ray: Subtle endplate irregularity at L4-L5, disc space narrowing
• MRI lumbar spine (with contrast):
• L4-L5 discitis with involvement of adjacent vertebral endplates
• Enhancing inflammatory tissue in disc space
• Pre-vertebral and epidural phlegmon without frank abscess
• No spinal cord compression or significant canal stenosis

CT-guided Biopsy:

• L4-L5 disc space biopsy performed
• Culture: Escherichia coli (same susceptibility pattern as prior UTI)
• Histopathology: Acute and chronic inflammation consistent with osteomyelitis

Clinical Image

Radiograph demonstrating chronic osteomyelitis with cortical destruction, periosteal reaction, and sequestrum formation. While this image shows extremity osteomyelitis, similar destructive changes occur in vertebral osteomyelitis. Source: Wikimedia Commons, Public Domain.

Diagnosis

Vertebral Osteomyelitis (L4-L5 Discitis) with Epidural Phlegmon - E. coli

Pathogenesis:

• Hematogenous seeding from urinary tract infection 2 months prior
• E. coli from UTI established vertebral infection
• Diabetes as predisposing factor

Treatment Plan

Antibiotic Therapy:

1. IV ceftriaxone 2g daily based on E. coli susceptibilities
2. Duration: 6 weeks IV therapy for vertebral osteomyelitis
3. May consider oral step-down to fluoroquinolone after 2-4 weeks if good response

Monitoring:

• Weekly CRP to track response (should decline within 1-2 weeks)
• Repeat MRI at 4-6 weeks if inadequate clinical response
• Serial neurologic exams for any new deficits

Activity:

• Bed rest initially, then mobilization with lumbar brace
• Avoid heavy lifting and bending

Surgical Considerations:

• Currently no surgery indicated (no abscess, no neurologic deficit, no instability)
• Would require surgery if:
• Epidural abscess with compression
• Neurologic deterioration
• Failed medical therapy
• Spinal instability

Follow-up:

• Infectious disease consultation for antibiotic management
• Repeat imaging if not improving
• Address diabetes control (uncontrolled diabetes impairs infection response)

Teaching Points

1. Vertebral osteomyelitis presentation: Insidious back pain, worse at night, with systemic symptoms; average delay to diagnosis is 6-12 weeks
2. Common sources: Urinary tract (especially gram-negatives), skin infections, endocarditis, dental procedures
3. MRI is imaging of choice: Shows disc space infection, vertebral endplate involvement, and epidural extension before radiographic changes appear
4. Tissue diagnosis important: Blood cultures positive in ~50%; CT-guided biopsy provides organism identification if cultures negative
5. Duration: 6 weeks of appropriate antibiotic therapy; epidural abscess or other complications may require longer courses or surgery

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