Ochronosis in differential diagnosis of patients with chronic backache: a review of the literature.

A 50-year-old man presented with a complaint of low-back pain and widespread joint pain for the previous 20 years. Conventional radiography revealed wide areas of calcification in the intervertebral discs and degenerative changes in the peripheral joints. A diagnosis of ochronosis was made by the observation of bluish-brown pigmentation in the nose and ears, dark urine colors following alkalization, and high levels of homogentisic acid in the urine. Ochronosis should be considered in the differential diagnosis of patients with chronic low-back pain regarding features of widespread calcification in the intervertebral discs at radiography and bluish-brown pigmentation in the nose and ears.