A woman with a bamboo spine in the thoracic vertebra and normal sacroiliac joint;a 5-years undiagnosed ankylosing spondylitis: Case report and literature review

Ankylosing spondylitis (AS) is a chronic inflammatory disease that causes deterioration in the function of the spine and peripheral joints. In addition to history and examination, imaging is important in diagnosing this disease. Pelvic X-rays in particular may show pseudowidening, erosion, and sclerosis sacroiliac joint. Spinal X-rays may also identify syndesmophytes. In more advanced stages, the spine may also be involved, forming a specific type of disease called “bamboo spine”. The New York criteria, which includes radiologic and clinical criteria, are used to diagnose AS. The distribution of involvement in joints and bones in AS varies, but classically, it is ascending from the sacroiliac joint, lumbar, and thoracic region. Herein, we report a case of AS that was undiagnosed for 5 years. Despite the normal appearance of the sacroiliac joint, severe involvement of the spinal column in the thoracic region known as “bamboo spine” was observed. The time order of bone involvement in this patient is contrary to what is usually seen. Based on the New York criteria for AS, the case under discussion is not included in the AS definition; however, the patient had clinical symptoms of AS, bamboo spine, and showed a dramatic response to treatment of AS. Heeding the course of the AS as well as the clinical signs and imaging results of various areas (heart, lumbar spine, and sacroiliac joint) will help physicians diagnose AS accurately and in a timely manner. Also, the radiologic manifestation of a rheumatologic disease may occur without any predictable order.