Know Your Pathology: Diffuse Idiopathic Skeletal Hyperostosis

Diffuse idiopathic skeletal hyperostosis (DISH), also known as Forestier’s disease, is primarily a disease of the spine, but individuals suffering from this condition exhibit characteristic bony abormalities elsewhere in the body that distinguish it from ankylosing spondylitis. DISH is not a true arthropathy because it does not affect cartilage or synovium (Roberts and Manchester, 2005: 159). Instead, there is gradual and complete fusion of the spine, particularly in the thoracic region, with retention of the integtrity of vertebral articular surfaces and joint spaces (Roberts and Manchester, 2005: 159). The anterior longitudinal ligament of the spine and paraspinal tissues ossify, the osteophytes that are produced being large and flowing like ‘candlewax’ (Roberts and Manchester, 2005: 159-160). In addition, there are enthesopathies at tendon and ligament insertions and cartilage, especially in the neck and ribs, ossifies (Roberts and Manchester, 2005: 160).

Its specific cause is unknown, but it appears to be associated with obesity and Type 2 diabetes (Roberts and Manchester, 2005: 159). Males are slightly more affected than females and the age of onset is usually over 50 years of age (Roberts and Manchester, 2005: 159). DISH is found more in Northern European people (Roberts and Manchester, 2005: 160).

A disease of some antiquity, the earliest known case is that of a Neanderthal skeleton from Iraq, dated between 40,000 and 73,000 years BP (Roberts and Manchester, 2005: 159). It is also increasingly being seen in both monastic and non-monastic cemetery groups in the archaeological record (Roberts and Manchester, 2005: 160). It has been suggested that a rich diet and lack of exercise predisposed medieval monks to obesity and late onset diabetes. Such high status people may also have lived longer to develop the condition (Roberts and Manchester, 2005: 160).

DISH has also been reported in an Alaskan bear, as well as in extinct Mammut, Teleoceras, Menoceras, Equus, Bison bison, Canis diris, Ovibos, Smilodon, megatheridae, Thinocetus arthritis and Pelocetus, and in contemporary Papio, Cercopithecus, Macaca, Erythrocebus, and Gorilla gorilla gorilla (Rothschild and Martin, 1993: 236). Ossified tendons are also present in most dinosaurs (including ceratopsians, hadrosaurs, iguanodonts, and pachycephalosaurs). This includes a juvenile Pinacosaurus grangeri and Pachyrhinosaurus and has even been observed in an embryonic duckbill (Hypacrosaurus ?) (Rothschild and Martin, 1993: 235-236). Whilst these non-pathologic phenomenon are considered simply as extensions of presygophases by some researchers, they are considered by others to be indistinguishable from the tendon ossification seen in DISH (Rothschild and Martin, 1993: 236). Analogous tendon ossification has also been noted in c. 50% of sauropods, resulting in the fusion of two to four cervical vertebrae, something considered non-traumatic in origin as CT scans reveal the zygoapophyseal facets are unaffected (Rothschild and Martin, 1993: 236).

References:

Roberts, C. and Manchester, K. 2005. The Archaeology of Disease. 3rd Edition. Stroud: Alan Sutton Publishing Ltd.

Rothschild, B.M. and Martin, L.D. 1993. Paleopathology: Disease in the Fossil Record. CRC Press: London.

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