DISCITIS

Discitis is an infection or inflammatory condition of the intervertebral disc space, often with involvement of adjacent vertebral endplates and vertebral bodies. It includes pyogenic discitis as well as tuberculous discitis and other infectious etiologies. In children, discitis is more commonly hematogenous in origin; in adults, risk factors include diabetes, intravenous drug use, spinal procedures, and immunosuppression.

Pathophysiology typically begins with bacteremia seeding the disc space and adjacent endplates. The relatively limited blood supply of the adult disc allows infection to spread and cause inflammation, disc destruction, and, in some cases, vertebral osteomyelitis, epidural abscess, or spinal instability.

Clinical features usually involve acute focal back or neck pain and tenderness at the affected level, often with fever. Movement is painful and range of motion is limited. In young children, irritability and refusing to walk or hold the neck still are common. Neurologic deficits are uncommon early but may occur with abscess formation or severe vertebral destruction.

Diagnosis relies on imaging and laboratory tests. Magnetic resonance imaging is the modality of choice for early detection and characterization. Laboratory tests typically show elevated inflammatory markers such as ESR and CRP; white blood cell count may be normal or elevated. Blood cultures are positive in a portion of cases. CT-guided biopsy or aspiration may be necessary to identify the organism when blood cultures are negative or to tailor antibiotics.

Treatment involves targeted antibiotic therapy, usually initiated intravenously and continued for six to twelve weeks, with the regimen adjusted based on culture results. Surgical intervention is considered for epidural abscess, spinal instability, neurological deficits, or failure to improve with medical therapy.

Complications can include epidural abscess, vertebral deformity, chronic back pain, and, rarely, sepsis. With timely treatment, the prognosis is generally favorable.