Answer:
Alkaptonuric ( ochronotic ) arthropathy.
Discussion:
Ochronosis is a rare autosomal recessive metabolic disorder of amino acid metabolism characterized by an absence of homogentisic acid oxidase. This results in homogentisic acid being excreted in the urine (alkaptonuria) and deposited in tissues (ochronosis), causing joint disease (ochronotic arthropathy).
Radiologic manifestations of ochronosis are most characteristic in the spine. These changes are especially apparent in the lumbar and thoracic spines and to a lesser extent in the cervical spine. The most distinctive abnormality is at the intervertebral disc, where loss of disc height, vacuum phenomenon, and thin, horizontal, wafer-like calcifications are seen parallel to the body endplates.
These discal alterations are seen at multiple levels simultaneously. There is notably a low level of marginal bony proliferation, with osteophytes visible. As the disease progresses eventual osseous ankylosis across the disc space may occur, similar to ankylosing spondylitis, except the disc spaces are markedly diminished. There is no syndesmophyte formation, and the sacroiliac joints are unfused.
Osteoporosis is usually prominent, as is the loss of lumbar lordosis and increased thoracic kyphosis. Ligamentous ossification may be apparent.
References:
Essentials of skeletal Radiology- Yochum and Rowe- third edition.
Dr. Karunakaran M. Kalathi MD, Dr. Arun Chelladurai MD
Consultant Radiologists, Aarthi Scans, Thirunelveli, Tamilnadu, India
Alkaptonuric ( ochronotic ) arthropathy.
Discussion:
Ochronosis is a rare autosomal recessive metabolic disorder of amino acid metabolism characterized by an absence of homogentisic acid oxidase. This results in homogentisic acid being excreted in the urine (alkaptonuria) and deposited in tissues (ochronosis), causing joint disease (ochronotic arthropathy).
Radiologic manifestations of ochronosis are most characteristic in the spine. These changes are especially apparent in the lumbar and thoracic spines and to a lesser extent in the cervical spine. The most distinctive abnormality is at the intervertebral disc, where loss of disc height, vacuum phenomenon, and thin, horizontal, wafer-like calcifications are seen parallel to the body endplates.
These discal alterations are seen at multiple levels simultaneously. There is notably a low level of marginal bony proliferation, with osteophytes visible. As the disease progresses eventual osseous ankylosis across the disc space may occur, similar to ankylosing spondylitis, except the disc spaces are markedly diminished. There is no syndesmophyte formation, and the sacroiliac joints are unfused.
Osteoporosis is usually prominent, as is the loss of lumbar lordosis and increased thoracic kyphosis. Ligamentous ossification may be apparent.
References:
Essentials of skeletal Radiology- Yochum and Rowe- third edition.
Dr. Karunakaran M. Kalathi MD, Dr. Arun Chelladurai MD
Consultant Radiologists, Aarthi Scans, Thirunelveli, Tamilnadu, India