Comparative study on low back pain misdiagnosed as spondyloarthropathy.

This study aims to investigate features of different diseases with low back pain misdiagnosed as spondyloarthropathy so as to improve the accuracy of diagnosis for spondyloarthropathy. The clinical and laboratory data of 24 cases misdiagnosed as spondyloarthropathy in recent 3 years were comparatively and retrospectively analyzed. The diagnostic accuracy of the European Spondyloarthropathy Study Group (ESSG) criteria, Amor criteria, and the combination of them in these misdiagnosed cases was also analyzed. The final diagnoses of these 24 cases were listed below: four malignant tumors (retroperitoneal adipose sarcoma, advanced gastric carcinoma, ovarian papillary epithelioma, acute lymphocytic leukemia), six benign tumors (two parathyroid adenoma with hyperparathyroidism, one intraspinal lipoma, intraspinal ependymomas, sacral tubulocyst, and intraspinal schwannoglioma, respectively). The other 14 cases included fibromyalgia syndrome (3), osteitis condensans (3), diffuse idiopathic skeletal hyperostosis (2), lumbar intervertebral disk protrusion (1), congenital scoliosis (1), Wilson's disease (1), ochronosis (1), Fanconi syndrome (1) and hypophosphatemic rachiopathy (1). Among patients with tumor, all except three patients had persistent low back pain without morning stiffness, which aggravated at night and could not be relieved by rest or exercise. The symptoms could not be relieved by administration of multiple nonsteroidal anti-inflammatory drugs. Eleven patients had inflammatory low back pain defined by Calin. Of the total misdiagnosed cases, 54.17-83.33% could be prevented by application of ESSG criteria or Amor criteria, or a combination of them. From the data, we could see that the clinical features of different diseases with low back pain were different from each other and from those of spondyloarthropathy. The various criteria for spondyloarthropathy may be more effective in combination, along with other clinical information like these clinical features.