Vertebral Osteomyelitis (Spondylodiscitis)

Most commonly, bacteria travel to the spine through the bloodstream from an infection elsewhere — the skin, the urinary tract, the chest, the heart valves, or an infected intravenous line — and settle in the vertebral bone, which has a rich blood supply. The most frequent organism is Staphylococcus aureus. Less often, infection is introduced directly during spinal surgery or a procedure. Risk factors include diabetes, a weakened immune system, kidney failure requiring dialysis, injecting drug use, and increasing age.

The dominant symptom is back or neck pain that is usually persistent, often severe, and characteristically present at night and at rest — a pattern that distinguishes it from ordinary mechanical back pain. Tenderness over the affected part of the spine is common. Fever is a useful clue when present but is absent in many patients. If an abscess forms and presses on the spinal cord or nerves, there can be weakness, numbness, or disturbance of bladder or bowel control.

Persistent back pain that is worse at night and at rest, especially with fever, unexplained weight loss, or in someone with diabetes, a weakened immune system, dialysis, or a recent bloodstream infection, should be assessed promptly. New weakness or numbness in the limbs, or any loss of bladder or bowel control, is a spinal emergency requiring immediate attention, as it may signal an epidural abscess compressing the spinal cord.

An MRI scan is the investigation of choice, showing infection in the bone and disc and revealing any abscess in or around the spinal canal. Blood tests show raised inflammatory markers (ESR and CRP) in almost all cases, and two sets of blood cultures are taken to identify the organism. When the blood cultures are negative, an image-guided needle biopsy of the affected bone or disc is recommended, because identifying the exact germ allows precisely targeted antibiotics. Where MRI cannot be performed, other scans such as CT or nuclear medicine studies may be used.

The foundation of treatment is a prolonged course of antibiotics, ideally targeted to the specific organism. Treatment usually begins intravenously and commonly lasts around six weeks in total, though the exact regimen and duration depend on the organism, any abscess, and the individual. High-quality evidence supports a six-week course for most uncomplicated cases. Pain relief and a period of rest or bracing support recovery, and inflammatory markers are tracked to confirm the infection is responding.

Antibiotics alone cure most cases. Surgery is considered where there is a neurological deficit from cord or nerve compression, a significant epidural or paravertebral abscess, spinal instability or a developing deformity, intractable pain, or a failure to respond to appropriate antibiotics. Surgery aims to drain the infection, decompress the nerves and stabilise the spine, and is guided by the pattern of the disease.

The most serious complication is a spinal epidural abscess pressing on the spinal cord, which can cause paralysis if not treated promptly. Others include spread of infection to the bloodstream, destruction of the vertebra leading to collapse and deformity, and, uncommonly, recurrence. Prompt diagnosis and adequate treatment greatly reduce these risks, which is why persistent, unusual back pain in an at-risk person is taken seriously.

With timely diagnosis and the correct, adequate course of antibiotics, most people are cured, although residual back pain and stiffness are common and can take months to improve. The outlook is less favourable where diagnosis has been delayed, where there is significant bone destruction or neurological injury, or where the immune system is compromised. Long-term follow-up ensures the infection is fully cleared.

Myth: "Back pain is never a sign of infection." Fact: Persistent back pain that is worse at night and at rest can be a warning sign of spinal infection, especially in at-risk people.

Myth: "If blood cultures are negative, there's no infection." Fact: Blood cultures are often negative, which is exactly why an image-guided biopsy is used to identify the organism.

Myth: "Spinal infection always leads to paralysis." Fact: With prompt diagnosis and adequate antibiotics, most people are cured; serious complications are the exception, not the rule.

This page is for general education and does not replace an individual assessment. Treatment depends on a person's specific symptoms, examination findings, imaging findings and overall health, and should always be discussed with a suitably qualified healthcare professional.

Vertebral osteomyelitis means an infection of the vertebral bone. Because the infection usually spreads to include the adjacent disc, the combined condition is called spondylodiscitis, and in adults the disc and bone are typically affected together. It is an uncommon but serious infection whose incidence is rising, partly because the population is ageing and more people live with conditions that weaken the immune system. Its danger lies in how easily it is mistaken for ordinary back pain, and in its potential to form an abscess that presses on the spinal cord. This page explains how vertebral osteomyelitis develops, how it is recognised and diagnosed, and how it is treated. Our related pages cover discitis and Pott disease (spinal tuberculosis).

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• —Guideline note (place near references): The IDSA 2015 guideline on native vertebral osteomyelitis was the principal guideline source. No separate NICE or AAOS clinical practice guideline specific to pyogenic vertebral osteomyelitis was identified at the time of writing.

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.