Alkaptonuria
Ochronosis

• Rare hereditary disorder

  • More common in males 2:1

• Insufficiency of homogentisic acid oxidase

• Results in excessive homogentisic acid excreted in urine and deposited in soft tissue

• Urine may be “black”

•  Sclera may be grey-brown or yellow

• Cartilage of nose and ears may be bluish in color

• Clinical findings are combination of spondylitis  and arthritis of major joints

  • When deposited in cartilage, synovial thickening develops

  • This results in:

    • Subchondral cysts

    • Sclerosis

    • Osteophyte production, all secondary to DJD

    • Bony ankylosis may occur in joints or spine

  • Usually affects large joints-knees, shoulders, hips

  • Chondrocalcinosis of appendicular joints may develop

• In the spine:

  • Changes of degenerative disc disease

  • Ligamentous structures mat be involved

  • Resembles ankylosis spondylitis

  • Universal disc space calcification is common

• Universal disc calcification and DJD of root joints (hips and shoulders) in younger patient are pathognomonic

  Ochronosis. There is universal disc calcification, a finding that is highly suggestive of ochronosis.

Murray and Jacobson, 2^nd ed, vol.2