Ochronosis in alkaptonuria is associated with a widespread arthropathy.
Classic triad:
(1) discoloration of the urine
(2) arthritis
(3) ochronotic pigmentation
Musculoskeletal findings:
(1) widespread degenerative arthritis of major joints (hips, knees)
(2) alterations of the spine with low back pain
Changes that can be seen on ultrasonography:
(1) exudative or proliferative tenosynovitis
(2) synovial hypertrophy
(3) tendon or ligament calcifications
(4) enthesophytes
(5) chondrocalcinosis
Imaging studies of the spine may show:
(1) relative sparing of the sacroiliac joint
(2) dense, wafer-like disk calcifications
(3) vacuum disks
(4) broad syndesmophytes
(5) osteopenia
If surgery is performed, then affected joints and tissues may show dark pigmentation.
