Alkaptonuria and Cervical Disc Herniation: Case Report.

backgroundAlkaptonuria is a rare metabolic disorder, an autosomal recessive disease caused by the deficiency of an enzyme, homogentisate 1,2-dioxygenase. As a consequence, there is an accumulation of homogentisic acid, which deposits in connective tissues, leading to ochronotic arthropathy. CASE PRESENTATION: In this case, a 35-year-old man who was diagnosed as having alkaptonuria in 2023 at the National Institutes of Health, underwent urine analysis that showed a peak homogentisic acid level of 3383 mmol/mol creatinine. He reported that 20 days prior to admission, he woke up at night due to sudden and intense cervical pain (visual analog scale 10), with shock-like pain radiating to the lateral sides of the arms and dorsoradial areas of the forearms, which was associated with weakness in elbow flexion and signs of pyramidal release. He underwent magnetic resonance imaging of the cervical spine, which revealed an acute extruded C5 to C6 disc herniation. He subsequently underwent a C5 to C6 discectomy and anterior arthrodesis, where an ochronotic-pigmented disc was observed intraoperatively. On the first postoperative day, an improvement in elbow flexion strength was noted, and he was discharged 5 days later. DISCUSSION: There is currently no effective and proven treatment for alkaptonuria; nitisinone has shown potential as the first effective treatment but may lead to corneal issues due to triggered tyrosinemia. The treatment for ochronotic arthropathy is primarily symptomatic, with surgical procedures reserved for more advanced degenerative cases.

conclusionThis study aims to enhance understanding of the pathophysiology of the spinal column in alkaptonuria and to explore the best surgical therapy strategies for this disease.