What are the typical presentation and treatment of vertebral discitis in patients of all ages?

Presentation of Vertebral Discitis

Vertebral discitis (spondylodiscitis) typically presents with recalcitrant back or neck pain unresponsive to conservative measures, often accompanied by elevated inflammatory markers (ESR/CRP), with or without fever. 1, 2

Clinical Presentation

Cardinal Features

• Back or neck pain is the most common presenting symptom, characteristically persistent and unresponsive to conservative treatment 1, 2
• Fever is present in only 45% of adult cases, making its absence unreliable for excluding the diagnosis 1
• Elevated inflammatory markers (ESR and CRP) are typically present and should raise suspicion when combined with spinal pain 1, 2

Age-Specific Presentations

• Adults: Present with localized spinal pain, fever (when present), and elevated inflammatory markers; infection begins at the vertebral endplate via hematogenous seeding 1, 2
• Young children (1-3 years): Most difficult to diagnose; present with refusal to walk (63%), inability to flex the lower back (50%), loss of lumbar lordosis (40%), and only 27% report back pain directly 3, 4
• Older children: More likely to present with back pain and fever, with mean age of 7.5 years for vertebral osteomyelitis versus 2.8 years for isolated discitis 4

Neurologic Manifestations

• Neurologic symptoms may occur with epidural extension, including radiculopathy or myelopathy 1, 2
• Progressive neurologic deficits indicate need for urgent surgical evaluation 2, 5
• Paraplegia is a recognized but uncommon complication 6

Key Risk Factors to Elicit

High-Risk Populations

• Recent Staphylococcus aureus bacteremia within the preceding 3 months is a critical risk factor 1, 2
• Infective endocarditis is among the most significant risk factors 1, 2
• Intravenous drug use increases risk and may present with multilevel involvement 1

Medical Comorbidities

• Diabetes mellitus, immunosuppression, long-term steroid use 1, 2
• Hepatic or renal failure 1, 2
• Recent spinal instrumentation or procedures 1

Diagnostic Delay and Pitfalls

The diagnosis is frequently delayed by 2-4 months and initially misdiagnosed as degenerative disc disease in up to 34% of cases. 1, 2 This occurs because:

• Back pain is extremely common in the general population 1
• The clinical presentation is often indolent and nonspecific 1
• Fever may be absent in more than half of patients 1
• Plain radiographs are insensitive for early diagnosis 1, 7

Physical Examination Findings

Specific Examination Maneuvers

• Percussion tenderness over the affected spine segment 1
• Paravertebral muscle spasm 1, 7
• Restricted spinal movements with loss of normal range of motion 6
• Loss of lumbar lordosis (particularly in children) 3
• Complete motor and sensory neurologic examination to assess for cord or nerve root compression 1

Laboratory Findings

Essential Initial Testing

• Two sets of blood cultures (aerobic and anaerobic) should be obtained before antibiotics 1, 2
• Baseline ESR and CRP are recommended in all suspected cases 1, 2
• White blood cell count with differential 1

Monitoring Parameters

• ESR values >50 mm/hour and CRP values >2.75 mg/dL after 4 weeks of treatment indicate higher risk of treatment failure 2

Imaging Characteristics

MRI Findings (Preferred Modality)

• MRI is the imaging modality of choice with 97% sensitivity, 93% specificity, and 94% accuracy 2
• Characteristic findings include inability to distinguish margins between disc space and adjacent vertebral marrow on T1-weighted images 2
• Increased signal intensity on T2-weighted images in the disc and adjacent vertebrae 2
• May demonstrate paravertebral inflammatory mass (75% in children) 3

PET/CT Considerations

• [18F]FDG PET/CT shows 95% sensitivity and 91% specificity for spondylodiscitis 1
• May be the modality of choice for detection within 14 days of symptom onset 1
• Particularly useful in patients with spinal hardware or when MRI is contraindicated 1
• Changed management in 52% of patients, including antibiotic modifications or guiding surgical interventions 1

Microbiologic Considerations

Common Pathogens

• Staphylococcus aureus is the most frequent causative organism 1, 2, 7
• Infection is commonly monomicrobial 1, 2
• Brucella species should be considered in endemic areas 1, 2
• Mycobacterium tuberculosis in high-endemicity regions 1

Diagnostic Sampling

• Image-guided aspiration biopsy is recommended to establish microbiologic diagnosis 2
• Empiric antibiotics should be withheld until microbiologic diagnosis is confirmed, except in septic patients or those with neurologic compromise 1, 2
• The concomitant presence of S. aureus bloodstream infection within 3 months and compatible MRI changes may preclude need for disc space aspiration 1

Treatment Principles

Medical Management

• Definitive therapy should be based on culture results and susceptibility testing 1, 2
• Majority of patients are cured with 6-week antimicrobial course 1
• Spinal immobilization with external bracing may reduce pain during treatment 1, 7

Surgical Indications

• Progressive neurologic deficits 2, 5
• Spinal instability with or without pain despite adequate antimicrobial therapy 2, 5
• Progressive deformity 2
• Failure of prolonged antibiotic treatment (63% of surgical cases) 5
• Epidural abscess with mass effect 2, 5

Surgical Approaches

• Posterior long-segment fixation without formal debridement combined with antibiotics is effective, with resolution of infection in 95% of cases at long-term follow-up 5
• Aggressive debridement may not be necessary and may contribute to morbidity 5

Prognosis

• Mortality has improved from 25% in pre-antibiotic era to 0-11% in contemporary cohorts 2
• Factors associated with worse outcomes include multidisc disease, concomitant epidural abscess, S. aureus infection, and significant comorbidities 2
• Residual back pain, limited spinal mobility, and neurologic deficits may occur despite treatment 7
• In children, radiological fusion occurs in 20% and is predictable after 2 years; MRI changes typically resolve by 24 months for vertebral body and 34 months for disc 3