Spine

A spinal infection should be considered when a person has significant spinal pain along with other warning signs. These warning signs include fever without an obvious cause, a history of intravenous drug use, abnormal blood tests suggesting infection, or medical treatment that weakens the immune system, such as steroids, chemotherapy, or other immunosuppressive drugs. X-ray examination may also raise concern if it shows narrowing of the disc space together with damage to nearby bone or swelling in the surrounding soft tissue.

If the patient is stable and has no new or major neurological deficit, doctors usually try to identify the microorganisms before starting antibiotics. This is important because the most effective treatment depends on the exact organism causing the infection. Initial tests commonly include a full blood count, renal and liver function tests, inflammatory markers such as C-reactive protein and erythrocyte sedimentation rate, blood cultures, and urine testing. In patients with fever or chills, at least two sets of blood cultures should be obtained. Other samples, such as sputum or wound swabs, may be collected when clinically relevant. 

When plain X-rays or other imaging examinations clearly suggest the suspicion of spinal infection (Figure 1), a biopsy may be arranged. With a CT-or X-ray-guided biopsy, the laboratory can look for bacteria, tuberculosis, fungi, or other uncommon organisms. If blood cultures already show a likely cause, such as Staphylococcus aureus, a biopsy may not be necessary, and treatment can be guided by the culture result. 

If the infected part of the spine is not clear, magnetic resonance imaging (MRI), is usually the most helpful test. MRI can show the spine, discs, nerves, and surrounding tissues in detail and can guide whether a biopsy or drainage procedure is needed.

The first priority is to protect the patient from pain, nerve damage, and worsening infection. Pain relief, rest, and sometimes a spinal brace can help reduce discomfort and support the spine. If the patient is stable, antibiotics are often delayed until cultures, or biopsy results are available. This approach gives doctors the best chance of choosing the right drug rather than using broad treatment without differentiation. 

However, antibiotics should not be delayed if the patient is very unwell, has signs of blood infection, or develops weakness, numbness, bladder or bowel problems, or other signs of nerve involvement. In these situations, blood cultures should be taken quickly and empirical antibiotics started while pending for further results. The choice of antibiotics depends on whether the infection appears to be community-acquired, hospital-acquired, or related to a weakened immune system. Microbiologist’s advice is valuable when the infection is complex, caused by resistant bacteria, or when the correct treatment is uncertain.

Recovery is assessed by monitoring both symptoms and test results. Doctors will evaluate the level of spinal pain, any change in nerve function, blood markers of infection, and consider follow-up imaging when needed. Blood tests may be repeated regularly during treatment, and X-rays can help show whether the spine is becoming more stable or whether there is further bone damage.

Most bacterial spinal infections require at least six weeks of antibiotics. Some patients need a longer course, especially if there is a large abscess that has not been drained, extensive bone destruction, infection with resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), or a slow clinical response. Before antibiotics are stopped, the care team should review whether symptoms have improved, whether there has been any nerve deterioration, whether blood markers have settled, and whether imaging shows no further damage.

Tuberculosis (TB) can also infect the spine. Doctors may suspect spinal TB when a person has known TB in another part of the body or when imaging shows patterns typical of TB, such as spread of an abscess under the spinal ligaments over several vertebral levels or greater involvement of the spinal bones than the discs (Figure 2). Treatment should be started after the diagnosis is confirmed, and usually involves several anti-TB medicines taken for a prolonged period.

Because anti-TB medicines can affect the liver, nerves, eyes, and other body systems, education and regular monitoring are necessary. Patients should be advised to report symptoms such as loss of appetite, nausea, vomiting, fever, jaundice, numbness, or visual changes.