Ankylosing spondylitis: antiquity and differential diagnosis - a case study of a Bronze Age skeleton from Norabak, southeastern Armenia.

An excavation of a burial mound at Norabak site (Southeast Armenia) unearthed four burial chambers, the central one contained a single skeleton radiocarbon dated to about 1400-1200 BCE. The skeleton was observed to have a polyarticular erosive arthropathy, primarily affecting the spine, with diagnostic features of ankylosing spondylitis. The antiquity of ankylosing spondylitis is questioned in the literature, because there are few reliable and descriptive reports from prehistoric sites. Excellent preservation of the skeleton from Norabak made it possible to perform a detailed analysis of the pathologic changes and to support the diagnosis of ankylosing spondylitis in this 3000-years-old individual. Apart from the main pathology, the skeleton had a dens axis fracture of the C2 vertebra a few days before death, as well as a likely associated fracture of the C1 vertebra. This type of fracture has a high risk of displacement into the vertebral canal with severe neurological consequences. Thus, we were presented with an opportunity to reconstruct a possibly fatal event in the life of this individual. The described case provides further evidence that ankylosing spondylitis is a disease of fairly great antiquity.