Sacroiliac joint involvement in ochronotic spondylosis.

The musculoskeletal involvement can be seen in alkaptonuria, which is an autosomal recessive disease. Homogentisic acid levels elevate during the disease. The accumulation of homogentisic acid in the body tissues and the formation of pigment is termed ochronosis. We present a 51-year-old male patient with intraoperative ochronotic arthropathy of the knees and bilateral punctate brown pigmentation on the sclera. Spine movements in the lumbar and cervical movements were limited. Movements of both hips were limited and painful in all directions. On the sacroiliac joint graphy, severe narrowing, irregularity, and erosions were detected in the bilateral coxofemoral areas, especially on the right, which might suggest grade 3 sacroiliitis. When the patient's urine was mixed with sodium hydroxide, the urine became alkaline and its color turned black. [ABSTRACT FROM AUTHOR]