Spinal infections: diagnostic tests and imaging studies.

UNLABELLED: Clinical signs and symptoms caused by spinal infections often are subtle and insidious; therefore, clinical suspicion in patients with nonmechanical pain is important in making the correct diagnosis in the early stage of disease. Serologic tests such as erythrocyte sedimentation rate and C-reactive protein are quite sensitive, but specificity is relatively low. Imaging tests include plain radiographs, radionuclide studies, computed tomography scan, and magnetic resonance imaging. Changes on plain radiographs appear at least 3 to 4 weeks after the onset of disease. Bone scan is a sensitive but not a specific test. Computed tomography provides structural details in the bone and intervertebral disc but magnetic resonance imaging is a superior imaging test for diagnosing infections earlier and more accurately. In many patients, percutaneous or open biopsy is required to make the definitive diagnosis of discitis or osteomyelitis and the organism responsible for the infection. Early and accurate diagnosis of spinal infections will lead to less invasive treatment for the patient. LEVEL OF EVIDENCE: Level V (Expert Opinion). Please see the Guidelines for Authors for a complete description of levels of evidence.