[Involvement of the tympanic membrane and ear ossicle system in ochronotic alkaptonuria].
Ochronotic alcaptonuria is a rare hereditary disease in which the metabolism of phenylalanine and tyrosine is disturbed, leading to accumulation and urinary excretion of homogentisic acid. Its affinity towards bradytroph tissues makes e.g. cartilage, tendons, sclera etc. become stained dark, hard and inflexible, leading to early arthrosis or ruptures of tendons. In the ENT literature mostly signs like darkening of the conchas, the septum or the larynx are mentioned, whereas involvements of the middle ear are rarely described. Such changes were seen in a 60-year old patient, who showed dark discolourations of his thickened tympanic membranes. He had a combined high-frequency hearing loss, the conductive component of which we explain as an increase of mass and changed elasticity. It may also be due to alterations of the ossicular chain. The case was demonstrated to direct the ENT specialist's attention to findings suspicious of ochronotic alcaptonuria and - on the other hand - to present photos of involved tympanic membranes, which in this kind we did not see in the literature.