A previously healthy 46-year-old man presented with constant and awakening dorsal pain and fever for 5 days. There was no other pain, digestive disorder or sign of infection preceding the symptoms. Clinical examination revealed stiffness and pain on mobilisation of the dorsal spine in all planes. Temperature was of 38.7°C and no other sign of infectious disease was present. Standard laboratory examinations showed an elevation of serum C reactive protein level at 81 mg/L (normal rate <5 mg/L). Procalcitonin serum level was normal and repeated blood cultures were negative.

Thoracic spine X-rays showed T7–T8 …