Diagnostic Approach in Patients Presenting with Inflammatory Back Pain

ABSTRACT

OBJECTIVE: To investigate the etiologic diseases of inflammatory back pain (IBP) and to propose a diagnostic algorithm for approaching the patients with IBP. METHOD: One-hundred-and-forty patients with IBP visiting the clinic for spinal disorders were involved. Clinical features of spondyloarthropathy (SpA) through medical records, presence of intervertebral disc disease, sacroiliitis and degenerative spondylosis through plain radiography and magnetic resonance image (MRI) of spine and pelvis, HLA B27 positivity, and quantitative laboratory results of acute phase reactant were retrospectively reviewed. RESULTS: Diverse spinal disorders were indentified as etiologic diseases for IBP that were SpA (44 patients), diffuse idiopathic skeletal hyperostosis (DISH) (15 patients), degenerative spondylosis (15 patients), HLA B27 associated IBP (14 patients), lumbosacral radiculopathy (4 patients), and others (48 patients). When onset age was less than 45 years, the most frequent cause was SpA. When onset age was more than 45 years, DISH and degenerative spondylosis were the most frequent causes. Onset age (p=0.002), age at presenting to clinic (p=0.001), number of items satisfying IBP criteria (p=0.001), HLA B27 positivity (p=0.000), and elevated acute phase reactant (p=0.002) were statistically associated with SpA. CONCLUSION: The relative frequency among various etiologic disease of IPB is different depending on the onset age of IPB. Onset age of IBP, numbers of items satisfying IBP criteria, and laboratory test for HLA B27 and acute phase reactant can be useful factors for determining the causes of IBP, especially for diagnosing SpA. Diagnostic algorithm for approaching the patients with IBP is proposed according to the sensitivity and specificity of the factors which have statistically meaningful relationship with diagnosis of SpA.