Ochronosis

Abstract

Alkaptonuria is a disorder characterized by a metabolic alteration of the amino acids phenylalanine and tyrosine, which causes the accumulation of benzoquinone homogentisic acid and acetic acid in various tissues, including articular cartilage. Its deposit leads to cartilage and joint injury, triggering peripheral arthropathy, known as ochronosis. This disease has a low prevalence worldwide. Among the clinical findings to consider for diagnosis is the presence of black spots in the diaper as a sign at an early age. With the development of the disease, patients present low back pain, arthralgia, as well as pigmentation of the sclera or the auricle as late signs. It is important to carry out a detailed medical history, a meticulous physical examination, and complementary tests such as skin biopsy and histological study to reach the diagnosis. Clinical management is controversial so far, however, favorable results have been reported with nitisinone as a therapeutic option. This article reports the clinical case of a patient with a picture of left knee pain of one year evolution, the tests and interventions performed, as well as the detail of the reported histopathological study. Being a disease with few detected cases, it is necessary to emphasize the importance of knowing it in order to diagnose it properly.