domingo, 10 de febrero de 2013

Palaeopathology: Two recent case studies

by Katy Meyers
Palaeopathology, the study of ancient diseases in human or animal remains usually means analysis of the skeletal material to examine the diseases effect on the bone. However, palaeopathology is not a straightforward science with many diseases not even appearing on the bone, and when they do, they present very similar manifestations but with very different causes.
Radiograph of knees revealing new bone formation (arrows) of periostitis along the femur and tibia.
Radiograph of knees revealing new bone formation (arrows) of periostitis along the femur and tibia.
Periostitis, for example, is a non-specific infection of the bone that causes extra bony growth in long small layers across the bone. It can appear from any number of infections or diseases, and therefore is not indicative of a single cause. In order to diagnose pathology in bones, it takes a careful inspection of all the possible pathological signs and careful analysis of all the potential diseases within the historical context.
In most cases we are left not with a single correct diagnosis, but with a differential diagnosis of the most likely pathology and others that are also possible. Here are two case studies in paleopathology: ovarian teratoma, and osteogenesis imperfecta.

Ovarian Teratoma: La Fogonussa (Lleida, Catalonia)

The individual investigated by Armentano et al. (2012) was an adult female, aged 30-40 years, who was recovered from a 5th century Roman necropolis in the Iberian Peninsula. She was found complete, well preserved, and lying in supine position in a tegulae (tile) covered grave.
Burial of individual 87 from the late Roman site of La Fogonussa (Catalonia, Spain). The structure of the grave was made of tegulae placed to form a gabled roof., via Armentano et al 2012
Burial of individual 87 from the late Roman site of La Fogonussa (Catalonia, Spain). The structure of the grave was made of tegulae placed to form a gabled roof., via Armentano et al 2012
Initial analysis found that she had a number of degenerative changes, primarily osteoarthritis, that comes with ageing. There was also a round calcified mass in the pelvic region.
In order to determine it’s nature, they conducted macroscopic analysis and CT scans. The mass measured 43 by 44 mm and had a rugose (wrinkled) texture. Internal investigation of the tumour found it had two small deformed teeth within the sediment and two small teeth embedded in the bone itself.
Ovarian Teratoma, via Armentano et al 2012
Ovarian Teratoma, via Armentano et al 2012
The localization of the protuberance to one side, the overall shape, and the presence of bony structures and teeth within are pathognomonic (diagnostically unique) of ovarian teratoma.
An ovarian teratoma is a benign tumor of varying shape that is usually characterized as being ‘bizarre’. They often occur on one side of the pelvis, and are found mainly in women of child-bearing age. They contain germ layers which can lead to development of hair, teeth, thyroid glands, or bone in the tumour. It can be cause of death as it may result in anaemia or interruptions in neighbouring organs.
What is unique about this case is that it is the first documented example of an ancient ovarian teratoma. While other types of teratomas and calcifications have been found, even these are quite rare. It is only because the tumour contained bone and teeth that an exact diagnosis was possible, since any soft tissue structures do not preserve. It is not that they did not happen, it is that unless the evidence is present (as in this case) it is nearly ‘invisible’ in the record.

Osteogenesis imperfecta: Dakhleh Oasis, Egypt

This investigation by Cope and Dupras (2011) is based on the skeletal remains of a foetus from the Romano-Byzantine period Kellis 2 cemetery (circa A.D. 50–A.D. 450), in the Dakhleh Oasis, Egypt.
Typically in this period and region, sub-adult burials are found oriented east-west in a supine extended position. However, the individual under investigation was recovered from a shallow grave, partially on its right side and back in a semi-flexed position. All of the skeletal elements were recovered, though most of the cranium was fragmented due to taphonomic processes.
The bones were very brittle with a light beige colour, which was not normal for skeletons excavated from Kellis 2. Most of the bones had an abnormal curvature, including a ribcage that was barrel shaped, and a number of bones were partially or completely fractured. There was also abnormal bone growth at the metaphyses (the ends of the long bones where growth occurs).
Infant's skeleton with osteogenesis imperfecta next to coffin and larger image of skull. From Speos Artemidos, Egypt 22nd Dynasty, around 850 BC (not the individual discussed in article)  {c} Trustees of the British Museum
Infant’s skeleton with osteogenesis imperfecta next to coffin and larger image of skull. From Speos Artemidos, Egypt 22nd Dynasty, around 850 BC (not the individual discussed in article) {c} Trustees of the British Museum
Given the appearance of the bones, bending, fractures, and a lack of other pathological indicators, they diagnose this individual as having osteogenesis imperfecta.
It is a genetic disorder that causes problems with the production of collagen to strengthen bones. Individuals with this condition have extremely fragile bones, are prone to fractures, and many die prior to or at birth. Other individuals have been found in the archaeological literature with this condition, but this is the youngest.
Other individuals from the Dakhleh Oasis have been found with the condition. The findings from these archaeological studies shows that it is highly likely that this foetus has osteogenesis imperfecta.
Foetal skeletons are very rarely recovered from excavation sites and it is extremely unusual to find ones with recognisable pathological conditions. The finding of a foetus with osteogenesis imperfecta suggests the disorder had some prevalence in the population, and is the youngest documented case of this disorder to date.


 http://www.pasthorizonspr.com/index.php/archives/02/2013/palaeopathology-two-recent-case-studies

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