Discitis (Spondylodiscitis)

Most cases are caused by bacteria that travel to the spine through the bloodstream from an infection elsewhere in the body — for example a skin, urine or chest infection, or an infected intravenous line. The most common organism is Staphylococcus aureus. Infection can also be introduced during spinal procedures or surgery. Certain factors increase the risk, including diabetes, a weakened immune system, kidney disease, injecting drug use, and older age. In some parts of the world, and in certain patients, tuberculosis is an important cause, which is covered on our Pott disease page.

The hallmark symptom is back or neck pain that is often severe, constant, and — importantly — present at night and at rest, unlike most mechanical back pain, which eases with rest. The pain may build up over days to weeks. A fever is helpful when present, but many people have no fever at all, which is one reason the diagnosis is delayed. Where the infection presses on the spinal cord or nerves, there may be weakness, numbness or, rarely, problems with bladder or bowel control.

Back pain that is constant, worse at night, and not relieved by rest — particularly with fever, unexplained weight loss, or in someone with diabetes, a weakened immune system, or a recent infection — should be assessed promptly. Any new leg or arm weakness, numbness, or loss of bladder or bowel control is a spinal emergency and needs immediate medical attention, because it may indicate pressure on the spinal cord or an abscess.

An MRI scan is the key investigation and is very sensitive for spinal infection, showing changes in the disc and adjacent bone and revealing any abscess. Blood tests almost always show raised inflammatory markers (ESR and CRP), and blood cultures are taken to try to identify the organism. Where blood cultures do not identify the germ, an image-guided needle biopsy of the disc or bone is often performed, because knowing the exact organism allows the antibiotics to be targeted precisely. This structured approach follows national and international guidance for spinal infection.

The mainstay of treatment is a prolonged course of antibiotics, guided wherever possible by the specific organism identified from cultures or biopsy. Treatment usually starts intravenously and typically lasts around six weeks, though this varies with the organism and the individual. Pain relief, and a period of rest or bracing for comfort and to protect the spine, are also part of care. Inflammatory markers and symptoms are monitored to confirm the infection is responding.

Most cases of discitis are cured with antibiotics alone. Surgery is reserved for specific situations: pressure on the spinal cord or nerves causing weakness, a significant abscess that needs draining, the spine becoming unstable or deformed, severe unrelenting pain, or a failure to respond to antibiotics. When surgery is needed, it aims to drain infection, relieve pressure on the nerves and stabilise the spine.

With prompt diagnosis and an adequate course of the right antibiotics, most people recover well, although back pain and stiffness can take months to settle fully and some people are left with residual discomfort. Recovery is slower where there has been a delay in diagnosis, where the spine has been damaged, or where the immune system is weakened. Careful follow-up ensures the infection is fully cleared and any complication is caught early.

Discitis, vertebral osteomyelitis and Pott disease are closely related. In adults, disc and bone infection usually occur together as spondylodiscitis, so "discitis" and "vertebral osteomyelitis" often describe the same illness from slightly different angles. Pott disease is the specific form caused by tuberculosis, which behaves somewhat differently and is treated with anti-tuberculosis medication. Our dedicated pages cover each in more detail.

Myth: "Back pain that is worse at night is nothing to worry about." Fact: Constant pain that is worse at night and at rest can be a warning sign of spinal infection and deserves assessment.

Myth: "You always have a fever with a spinal infection." Fact: Many people with discitis have no fever, which contributes to delayed diagnosis.

Myth: "Spinal infection always needs surgery." Fact: Most cases are cured with antibiotics; surgery is reserved for specific complications.

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.

Between each pair of vertebrae sits a disc that acts as a cushion. Discitis means that one of these discs has become infected. Because the disc has a poor blood supply of its own, an infection here usually spreads from, or into, the adjacent vertebral bone, so in adults discitis and vertebral bone infection (osteomyelitis) usually occur together — a combination doctors call spondylodiscitis. The most important thing to understand about discitis is that, although it is uncommon, it is serious and is frequently missed early, because its main symptom — back pain — is so common. This page explains what causes discitis, how it is recognised and diagnosed, and how it is treated. Closely related pages cover vertebral osteomyelitis 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 discitis 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.