Primary Hypoparathyroidism Mimicking Ankylosing Spondylitis in a Young Man with Fahr's Syndrome: A Case Report.

Patients with chronic idiopathic hypoparathyroidism may develop neurological complications, including calcification of the basal ganglia and other areas of the brain. In Fahr's syndrome, intracranial calcification is associated with an underlying disorder such as hypo or hyperparathyroidism. We report the case of a 37-year-old gentleman, with a history of bilateral cataract surgery and seizures, who presented with a new episode of seizure and was found to have severe hypocalcemia and bilateral symmetric intracranial calcification due to previously diagnosed primary hypoparathyroidism. He had symptoms and signs mimicking ankylosing spondylitis (AS), but with negative radiological and serological findings, not fitting into the diagnosis of axial spondyloarthropathies (SpA), as per standard criteria. Patients with long-standing idiopathic hypoparathyroidism can have severe calcification of soft tissues and bones, including vertebrae and paravertebral soft tissues, causing inflammatory back pain and stiffness. It is vital to report such cases as their occurrence is rare, and physicians should be aware of the possibility while evaluating patients with inflammatory back pain. Treatment in these cases is directed towards hypocalcemia and underlying primary pathology rather than spondyloarthropathy.