Septic arthritis in ochronosis’ patient

Abstract

Alkaptonuria is a rare autosomal recessive metabolic disease caused by homogentisic acid oxidase enzyme deficiency. High homogentisic acid levels will eventually result in black deposits in skin, sclerae, connective tissues (ochronosis) and urine (alkaptonuria). It can lead to early degeneration of joints. The diagnosis is often delayed because of its low prevalence and non-specific early symptoms. We describe a clinical presentation of ochronotic arthropathy, on a complex patient, who developed a septic arthritis of the knee. The patient was under immunosuppressive therapy, due to a previous colon adenocarcinoma and received a knee corticosteroid infiltration, two weeks before the onset of pain. It was performed joint lavage and arthrolysis by arthrotomy. During the procedure, we found a dark pigmentation on bone. Urine tests were positive for alkaptonuria. The patient completed an antibiotic cycle and rehabilitation, with satisfying improvement in knee's range of motion. At four years follow-up the patient can walk without crutches, presents minor knee pain. High level of suspicion and awareness is needed to diagnose ochronosis. The joint destruction in a complex patient must be carefully analysed. We've chosen a non-aggressive therapeutic management, but according to the literature, other therapeutic strategies could have also been chosen, like joint arthroplasty. We've declined this option because the patient is still doing antineoplastic treatment.