Clinical features

In addition to the discolouration of the urine, patients may present with back pain or large joint arthralgias in their post-teenage years or early 30s. Pigmentation of the sclera and pinna of the ear, although classic, is often seen later in life. The severity can be extremely variable and holds little prognostic value. (1)

Constant tendon ruptures at multiple sites, especially with minimal trauma, is also a red flag. On physical exam, thickened Achilles tendon and bursa effusions are common for those with this condition. (1)

Aortic valve murmurs are heard at a much earlier point in life as well, often without predisposing congenital anomalies such as a bicuspid aortic valve. (2)

Reference

1. Perry MB, Suwannarat P, Furst GP, Gahl WA, Gerber LH. Musculoskeletal findings and disability in alkaptonuria. J Rheumatol. 2006 Nov;33(11):2280-5
2. Shah A, Son A, Salehi P. Alkaptonuric ochronosis of the carotid artery. SAGE Open Med Case Rep. 2020;8:2050313X20915411