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.

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