Discitis is a relatively rare condition defined as inflammation of the intervertebral disc space in the spine. This inflammation is most frequently caused by an infection, typically bacterial, making prompt medical attention necessary. While it can affect people of any age, discitis most commonly appears in young children under the age of ten and adults over fifty. If not treated early and aggressively, the infection can lead to significant pain and potential spinal complications.
Recognizing the Signs of Discitis
The most consistent symptom of discitis is severe, localized back pain that often does not radiate into the limbs. This pain is exacerbated by movement and provides little relief even with rest or common pain medication. Patients may also present with systemic signs of infection, such as low-grade fever, chills, and malaise. Stiffness caused by the body’s attempt to immobilize the painful area can make routine daily tasks difficult.
The presentation differs noticeably in children, who may not be able to articulate their pain. Parents might instead observe a sudden refusal to walk, an unusual limp, or a rigid posture. Increased irritability and a reluctance to sit or stand upright are common indicators in this younger population. These non-specific signs can lead to diagnostic delays.
Understanding the Causes and Risk Factors
Discitis is overwhelmingly an infectious process, most commonly caused by bacteria, followed less frequently by fungi. The bacterium Staphylococcus aureus is the organism most often identified. Because the intervertebral disc has a poor blood supply, once an infection takes hold, it is difficult for the body’s immune cells to clear the pathogens.
The infection typically travels to the disc space through the bloodstream from a remote site in the body, a process called hematogenous spread. A recent urinary tract infection, a skin infection, or a dental procedure can serve as the initial source. Several factors increase an individual’s susceptibility, including a compromised immune system from conditions like diabetes or HIV, or chronic conditions like autoimmune disorders.
Procedures that introduce pathogens directly into the spinal area are significant risk factors. This includes recent spinal surgery or invasive diagnostic procedures involving the spine. Intravenous drug use also significantly increases the risk due to the introduction of bacteria into the circulation.
Confirming the Diagnosis
Diagnosis relies on a combination of laboratory tests and advanced imaging to confirm the presence and extent of inflammation. Blood work measures inflammatory markers, specifically the Erythrocyte Sedimentation Rate (ESR) and C-Reactive Protein (CRP). These markers are significantly elevated in discitis patients and are tracked serially to monitor treatment effectiveness.
Blood cultures are collected, though they only identify the causative organism in about one-third to one-half of cases. Magnetic Resonance Imaging (MRI) is considered the gold standard for visualizing discitis pathology. The MRI provides detailed images of soft tissues, showing inflammation within the disc space and erosion of the adjacent vertebral endplates, often before changes are visible on standard X-rays.
If blood cultures are negative and a specific pathogen is needed, a needle aspiration or biopsy of the infected disc space may be performed. This procedure is often guided by a CT scan to ensure precise tissue sampling. Identifying the organism through a biopsy allows clinicians to narrow the antibiotic regimen to one precisely targeted to the infection.
Treatment and Recovery
The mainstay of treatment for discitis is a prolonged course of targeted antibiotic therapy. Because antibiotics have difficulty penetrating the disc space, treatment typically begins with intravenous (IV) antibiotics for six to eight weeks. After this initial IV phase, the patient transitions to oral antibiotics for an extended period, sometimes months, depending on the clinical and laboratory response.
Immobilization is a crucial component of management, aimed at reducing pain and preventing spinal instability while the infection clears. This involves strict bed rest, followed by the use of an external brace or corset to stabilize the affected spinal segment. The goal of immobilization is to encourage a natural fusion of the vertebrae surrounding the infected disc, which stabilizes the spine.
Surgical intervention is reserved for situations where medical management has failed or complications have developed. Indications for surgery include a large spinal abscess requiring drainage, progressive spinal instability that risks collapse, or the onset of neurological deficits. The procedure typically involves debridement to remove the infected tissue and, often, immediate stabilization of the spine with instrumentation.