Recurrent acute low back pain secondary to lumbar epidural calcification

Epidural calcification is a rare cause of back pain, and spontaneous epidural calcification has not been reported previously. We describe a patient with acute low back pain and signs of lumbar nerve root compression due to epidural calcification, as demonstrated by CT-scan and MRI. Radiological signs of spondylodiscitis led to a search for an infectious cause, which was negative, and her symptoms responded rapidly to NSAID treatment alone. Her symptoms recurred 18 months later, and further imaging studies again revealed epidural calcification, but with a changed distribution. Her symptoms were relieved once more by NSAID treatment alone. We propose that epidural calcification secondary to aseptic spondylodiscitis is the main cause of acute back pain in this patient. A possible mechanism may be the pro-inflammatory effects of calcium pyrophosphate or hydroxyapatite crystal deposition within the epidural space.