У Браунвальда про Cardiac Ochronosis всего одна строчка: "Ochronosis with alkaptonuria is another rare cause of AS".
ALKAPTONURIA
Alkaptonuria is a rare (frequency 1:200,000) disorder of tyrosine catabolism in which deficiency of homogentisate 1,2-dioxygenase (also known as homogentisic acid oxidase) leads to excretion of large amounts of homogentisic acid in urine and accumulation of oxidized homogentisic acid pigment in connective tissues
(ochronosis). Alkaptonuria may go unrecognized until middle life, when degenerative joint disease develops. Prior to this time, about half of patients might be diagnosed for the presence of dark urine. Foci of gray-brown scleral pigment and generalized darkening of the concha, anthelix, and, finally, helix of the ear usually develop after age 30. Low back pain usually starts between 30 and 40 years of age. Ochronotic arthritis is heralded by pain, stiffness, and some limitation of motion of the hips, knees, and shoulders. Acute arthritis may resemble rheumatoid arthritis, but small joints are usually spared.
Pigmentation of heart valves, larynx, tympanic membranes, and skin occurs, and occasional patients develop pigmented renal or prostatic calculi.
Degenerative cardiovascular disease is increased in older patients.The diagnosis should be suspected in a patient whose urine darkens to blackness. Homogentistic acid in urine is identified by urine organic acid analysis or by a specific colorimetric test. Ochronotic arthritis is treated symptomatically. Ascorbic acid and protein restriction are not effective in reducing homogentisic acid production. By contrast, nitisone [2-(2-nitro-4 trifluoromethylbenzoyl)-1,3-cyclohexanedione], a drug used in tyrosinemia type I, reduces urinary excretion of homogentisic acid and, in conjunction with a low-protein diet, might prevent the long-term complications of alkaptonuria.
Harrison’s Principles of Internal Medicine 17th edition 2008
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