X-rays are not as sophisticated a form of imaging as CT scans.
Researchers suggest that what was originally believed to be ankylosing spondylitis is a different condition altogether - a degenerative spinal condition known as diffuse idiopathic skeletal hyperostosis (DISH).
The mummified remains of the pharaohs are often well-preserved and provide an excellent resource for people that study ancient diseases. The Egyptian Museum in Cairo, Egypt, contains several mummified bodies that have been subject to multiple forensic and radiological investigations over the years.
Previous X-ray studies suggested that at least three Pharaohs - Amenhotep II, Ramesses II and his son Merenptah - had developed ankylosing spondylitis, an inflammatory disease causing pain and stiffness in the back which can lead to arthritis and the fusion of bones in the spine.
Ankylosing spondylitis belongs to a group of inflammatory conditions known as the spondyloarthropathies. The American College of Rheumatology (ACR) states that this group affects up to 2.4 million Americans aged over 15. Other research suggests that around 1% of the population of the US has ankylosing spondylitis.
A re-study of the mummy X-rays suggested that, rather than ankylosing spondylitis, the Pharaohs may have instead suffered from DISH. Although it can appear similar to ankylosing spondylitis, also producing bone proliferation in the spine, DISH is a degenerative disease rather than an inflammatory one and tends to affect people aged 60 years and over.
CT scans for mummies
The authors of a new study, published in the ACR's journal Arthritis & Rheumatology, write that the original diagnosis of ankylosing spondylitis in the mummies was limited by several factors, such as the presence of embalming fluids obscuring the spine and the sacroiliac joints.
Computerized tomography (CT) is a more sophisticated form of imaging, able to produce both two- and three-dimensional images, and the authors decided to assess the CT scans of 13 mummies to see whether ankylosing spondylitis or DISH was present.
Using the scans, the authors ruled out a diagnosis of ankylosing spondylitis on account of a lack of both joint erosion in the lower back and pelvic area, and fusion in the sacroiliac and facet joints of the spine.
Four mummified Pharaohs displayed signs of DISH: Amenhotep III, Ramesses II, Merenptah and Ramesses III.
Ankylosing spondylitis was originally believed to be a disease of antiquity, partly depending on the belief that mummified remains exhibited signs of the condition. The authors of the study believe that the antiquity of the disease will now need a critical reappraisal as the disease could, in fact, have a more recent origin.
Findings could 'impact modern populations'
"The process of mummification could induce spinal changes, which should be considered when investigating diseases in ancient remains," cautions co-author Dr. Sahar Saleem, from the Kasr Al Ainy Faculty of Medicine in Cairo.
The authors also write that the scope of further research will need to be widened in order to find out precisely when these two rheumatic diseases originated:
"Future studies are thus needed to correlate CT findings in royal mummies with non-royal ancient Egyptians, as well as with subjects from other ancient and modern nations for a better understanding of the origin and natural history of DISH disease and ankylosing spondylitis."
Although interesting from a historical perspective, the authors are keen to emphasize the role that studies such as this can also play within today's medical world. "In studying these ancient remains we may be able to uncover the pathway of diseases," they say, "and how they might impact modern populations."
Earlier in the year, Medical News Today reported on a group of scientists that discovered viruses in 700-year-old human feces with antibiotic resistance genes, providing evidence that the human gut has remained unchanged after centuries.