What are the guidelines for diagnosing and treating discitis (inflammation of the intervertebral disc)?

From the Guidelines

Discitis management involves prompt diagnosis and aggressive treatment to prevent complications, with the most recent guidelines recommending an initial evaluation including MRI of the affected area, blood cultures, and inflammatory markers (ESR, CRP) 1. The diagnosis of discitis can be challenging due to its nonspecific presenting signs and symptoms, such as back pain, fever, and less commonly, neurologic compromise 1. Initial evaluation should include:

• MRI of the affected area to establish the diagnosis
• Blood cultures to identify the pathogen
• Inflammatory markers (ESR, CRP) to assess the severity of the infection Empiric antibiotic therapy should begin immediately after obtaining cultures, typically with vancomycin (15-20 mg/kg IV every 12 hours) plus a third-generation cephalosporin like ceftriaxone (2g IV daily) or a fluoroquinolone 1. Once the pathogen is identified through blood cultures or image-guided biopsy, antibiotics should be tailored accordingly. Treatment duration is typically 6-8 weeks, with the first 2-4 weeks administered intravenously followed by oral antibiotics if clinical improvement occurs 1. Pain management is essential, often requiring opioid analgesics initially, followed by NSAIDs as inflammation subsides. Immobilization with bracing may be necessary for spinal stability, but early mobilization should be encouraged when appropriate. Surgical intervention is indicated for neurological deficits, spinal instability, significant abscess formation, or failure of conservative treatment 1. Regular monitoring should include weekly inflammatory markers, clinical assessment, and follow-up imaging at 4-6 weeks to evaluate treatment response. This aggressive approach is necessary because discitis can lead to serious complications including abscess formation, osteomyelitis, and permanent neurological damage if not properly treated 1.

Key considerations in the management of discitis include:

• Prompt diagnosis and treatment to prevent complications
• Individualized treatment based on the severity of the infection and the patient's underlying health status
• Close monitoring of the patient's response to treatment and adjustment of the treatment plan as needed
• Consideration of surgical intervention if conservative treatment fails or if there are signs of neurological compromise or spinal instability.

From the Research

Diagnosis of Discitis

• Discitis is a rare but important cause of spinal pain caused by intervertebral disc infection, with an incidence of 2 per 100,000 per year 2
• Patients typically present with spinal pain (96%), fever (70%), and raised inflammatory markers 2
• Blood cultures and targeted microbiological analysis, such as CT-guided sampling for culture, are essential for identifying the causative organism 2

Treatment of Discitis

• Staphylococcus aureus is the most common causative organism, and treatment often involves intravenous antibiotics such as flucloxacillin or ceftriaxone 2, 3
• The optimal duration of antibiotic therapy is unclear, but a systematic review and network meta-analysis suggest that 4-8 weeks of antibiotic treatment may provide the best balance of efficacy and treatment duration 3
• Antibiotic therapy should be individualized based on clinical response, and treatment should be guided by inflammatory markers and microbiological results 2, 3
• For methicillin-susceptible Staphylococcus aureus (MSSA) infections, antistaphylococcal antibiotics such as nafcillin, oxacillin, and cefazolin are recommended, but ceftriaxone may be a suitable alternative due to its once-daily outpatient regimen and lower risk of toxicity 4, 5, 6

Management Recommendations

• It is widely recommended to perform blood cultures and CT-guided biopsies before starting antibiotics, but the optimal timing and duration of antibiotic therapy are unclear 2
• Six weeks of intravenous followed by 6 weeks of oral therapy is often suggested as treatment, but some recommend using inflammatory markers to guide antibiotic duration 2
• Larger studies are required to provide more definitive guidance for clinical decisions, and treatment should be individualized based on clinical response and microbiological results 2, 3