spondylodiscitis

Spondylodiscitis is an infection of the intervertebral disc and the adjacent vertebral endplates. It is most often caused by bacterial hematogenous spread, though it can arise after spinal procedures, surgery, or direct inoculation. In some cases, the infection is tuberculous or fungal, and the term can describe any infectious process that involves both the disc space and adjacent vertebrae.

The most common form is pyogenic spondylodiscitis, with Staphylococcus aureus and Streptococcus species among the typical pathogens. Risk factors include advanced age, diabetes, immunosuppression, intravenous drug use, recent bacteremia, or recent spinal instrumentation or surgery. Pediatric cases occur but have different etiologies and patterns compared with adults.

Clinical features typically include acute or subacute back pain, focal spinal tenderness, and fever; systemic symptoms may be mild. Neurologic deficits can occur if there is an epidural abscess or spinal instability. Laboratory studies usually show elevated inflammatory markers such as CRP and ESR, and blood cultures may identify the organism in many cases.

Diagnosis relies primarily on magnetic resonance imaging, which can visualize discitis, endplate destruction, and any associated abscess. Blood cultures are obtained, and CT-guided biopsy or tissue culture is often needed to identify the causative organism and tailor therapy, especially in culture-negative cases.

Treatment consists of prolonged antimicrobial therapy, typically intravenous antibiotics for several weeks followed by oral therapy to complete 6 weeks or more, depending on the pathogen and clinical response. Surgical intervention is considered for spinal instability, persistent infection, large abscesses, or neurologic compromise. Early diagnosis and targeted treatment improve outcomes and reduce complications such as vertebral collapse or chronic pain.