Neglected Alkaptonuric Patients Presented with Symptomatic Degenerative Disc Disorders: Report of Two Cases and Review of Literature

Alkaptonuria (AKU) is a rare autosomal disorder characterized by the accumulation of excess homogentisic acid (HGA) in connective tissues. Herein, we report the uncommon presentation of degenerative lumbar disc disease occurring in two patients with AKU warranting spinal surgery. We report two cases of symptomatic disc herniation and vertebral canal stenosis, presented with radiculopathy and progressive neurogenic claudication, respectively. During spinal surgery, blackened ligamentum flavum and intervertebral disc raised the suspicion of a metabolic disorder. Re-examination of patients revealed nose and ear cartilage discoloration in only one of them, however, histopathological findings and urinalysis were confirmatory for AKU in both. Notwithstanding the rarity of AKU, spine surgeons must be vigilant in their examination and diagnosis, and should not exclude any possible diagnosis without thorough consideration.