Accumulation of homogentisic acid (HGA), and its metabolites in tissues causes ochronosis. The word ochronosis refers to the dark bluish-black discoloration of connective tissues including the sclera, cornea, auricular cartilage, heart valves, articular cartilage, tendons, and ligaments.
Alkaptonuria frequently occurs in association with lumbar disc disease. In patients with no other signs of alkaptonuria or ochronosis, early detection of the disease is important to treat involvement of other systems (e.g., cardiovascular and urinary) 1).
Neurogenic claudication resulting from focal ligamentum flavum hypertrophy in the lumbar spine due to ochronotic deposits has only been previously reported once in the literature. In a article, Yucetas and Ucler from Adiyaman present a 71-year-old male patient with alkaptonuria-associated degenerative L3-L4-L5 stenosis, diagnosed after lumbar decompressive laminectomy 2).
A rare case of ochronosis presenting with cervical compressive myelopathy 3).
A 45-year-old previously healthy female patient who was operated on for prolapsed lumbar disc herniation, and in whom the nucleus pulposus was discovered to be black intraoperatively. The alkaptonuria was diagnosed after histopathological examination of the black disc material. Elevated urinary concentration of homogentisic acid confirmed the diagnosis 4).
A 58-year-old woman with back pain. Radiographs and magnetic resonance imaging (MRI) revealed characteristic features of ochronotic spondyloarthropathy 5).
Kalevski et al. published a case of a 33-year old patient with alcaptonuria and lumbar disc herniation. After the surgical treatment the patient’s complaints were alleviated and almost no complaints were registered, during the next follow-up.
The most common symptoms seen in alkaptonuria are complaints of pain in large joints and back pain. They are usually associated with the main disease. This case demonstrates that even there is a small likelihood for a prolapsed lumbar disk, it should be sought in such patients as the surgical treatment is able to yields a positive results 6).
In 1994 Koh et al published a case of alkaptonuria with root canal stenosis 7).
Kaufmann et al. reported a patient with alkaptonuric ochronosis and multiple intracranial aneurysms presenting with subarachnoid hemorrhage. The ruptured aneurysm was surgically treated, with a satisfactory outcome. In view of the well-known association of other connective tissuedisorders with intracranial aneurysms, a potentially causal relationship is suggested between cerebral aneurysms and alkaptonuric ochronosis 8).