Overview
Discitis is the inflammation of an intervertebral disc or disc space due to infection, which can lead to abscess formation, sepsis, and disc erosion. The most commonly affected region is the lumbar spine.
Discitis usually occurs secondary to the haematogenous spread of infection from other sites (e.g. infective endocarditis), but can also occur due to direct inoculation.
The most common causative organism is Staphylococcus aureus. It can also occur due to tuberculosis, or viral infections, and can be aseptic.
Risk Factors
- Immunocompromised states – such as HIV and immunosuppressant drugs
- Diabetes mellitus
- Intravenous drug use
Presentation
Features of discitis can present insidiously and include:
- Back pain, localised tenderness and restricted movement
- Pain that is worse on movement
- Constitutional symptoms – these include fever, anorexia, and weight loss
- Neurological deficits may be seen, particularly if a spinal epidural abscess develops
Investigations
Overview
Some investigations and their findings include:
- Full blood count (FBC): may show leukocytosis
- C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR): may be elevated
- Cultures of suspected infection sites: blood cultures and sputum cultures, urine etc.
- MRI – usually used for diagnosis
- CT-guided biopsy – can confirm the diagnosis and allow culture
Management
Overview
Intravenous antibiotics are prescribed for 6-8 weeks. These are adjusted depending on culture results. For discitis due to Staphylococcus aureus, a transthoracic echocardiogram should be done to look for infective endocarditis.
Complications
Sepsis and epidural abscess – an epidural abscess may present with focal neurological deficits according to the spinal cord segment affected.
