Osteomyelitis of the Spine
Osteomyelitis of the spine, also known as vertebral osteomyelitis, is an infection involving the bone of one or more vertebrae. It is closely related to discitis (disc infection) and often occurs together with it, a combination called spondylodiscitis. Spinal osteomyelitis is uncommon but serious because it can destroy bone, destabilize the spine, and, in advanced cases, compress nearby nerves or the spinal cord. Prompt diagnosis with MRI and targeted antimicrobial treatment are essential to prevent long-term complications.
What is it?
Vertebral osteomyelitis is an infection of the bone of one or more vertebrae. The infection most often starts in the bone marrow next to a disc and can then spread to involve the disc itself (discitis) and the vertebra above or below, producing the combined picture of spondylodiscitis. In some cases, infection can extend further to form an epidural abscess in the spinal canal or paraspinal abscess in the surrounding soft tissues. Because the infection takes place inside the vertebra, conventional X-rays may appear normal in the early stages, and MRI is generally needed to make the diagnosis.
Most cases of spinal osteomyelitis are caused by bacteria reaching the spine through the bloodstream from another infection elsewhere in the body. Staphylococcus aureus is the most common organism, but other bacteria, mycobacteria (such as tuberculosis), and fungi can also be responsible. Infection may also occur after spinal procedures, surgery, or, less commonly, by direct spread from nearby infection. Risk factors include older age, diabetes, intravenous drug use, immune suppression, chronic kidney disease, cancer, recent spinal injections or surgery, and prolonged use of indwelling catheters. The lumbar spine is most commonly affected, followed by the thoracic and cervical spine.
Symptoms typically develop gradually over weeks. The most common is persistent, focal back or neck pain that may be present at rest, often worsens at night, and is different from typical mechanical back pain that improves with rest. Fever and chills may be present but are not always seen, particularly in older adults. Localized tenderness over the affected vertebra is common on examination. If the infection extends into the spinal canal or causes vertebral collapse, neurological symptoms such as numbness, tingling, weakness, gait or balance difficulty, or bowel or bladder dysfunction can develop. Spinal epidural abscess, in particular, is a medical emergency.
MRI of the spine with contrast is the preferred imaging test for evaluating suspected spinal osteomyelitis because it can detect early bone marrow changes, disc involvement, soft-tissue spread, and any associated abscess. Typical findings include bone marrow edema in the affected vertebrae, abnormal disc signal, contrast enhancement of the bone and disc, endplate destruction, and sometimes paraspinal or epidural fluid collections. CT is useful for assessing bony destruction and may be used when MRI is not possible. Blood tests for inflammatory markers (such as CRP, ESR, and white blood cell count) and blood cultures support the diagnosis. Image-guided needle biopsy or surgical sampling is often necessary to identify the specific organism and guide treatment.
Important to Know
Spinal osteomyelitis is a serious condition that requires prompt evaluation and treatment, usually in coordination with a multidisciplinary team that may include infectious disease, spine surgery, interventional radiology, and primary care. The mainstay of treatment is a prolonged course of targeted antibiotics or antifungal medications—typically several weeks—guided by results from blood cultures or biopsy. Supportive care, pain management, and bracing are often used as well. Image-guided drainage or surgery may be needed for abscesses, severe instability, neurological compromise, or when medical treatment alone is not enough.
Because symptoms can be subtle and overlap with more common causes of back pain, a high index of suspicion is important, especially in patients with risk factors. Early diagnosis greatly improves outcomes and reduces the risk of long-term complications such as chronic pain, spinal deformity, and permanent neurological injury.
Red flag symptoms include severe or progressively worsening back or neck pain (especially at rest or at night), fever or chills with back pain, progressive weakness or numbness, gait or balance difficulty, loss of bowel or bladder control, or unexplained weight loss in a patient with risk factors. These warrant urgent medical evaluation.