Nucleus pulposus pulmonary embolism. A case report.

Abstract

This postmortem case report describes nucleus pulposus pulmonary embolism occurring in a human. Clinical, pathologic, and pathogenetic features of the case are discussed. Reference is made to warnings in the literature stressing the importance of avoiding, during radiologic procedures, any possibility of intrathecal ingress of iodinated, ionic, hyperosmolar contrast material. Various tissues have been implicated as pulmonary emboli in humans. Nucleus pulposus has been reported to embolize to spinal cord vessels in animals and humans and to embolize to the lungs in two animal species. This is the first report of nucleus pulposus pulmonary embolism in a human. A patient with refractory low back pain was admitted for lumbar discography using diatrizoate meglumine, 52%, and diatrizoate sodium, 8%. Afterward, an ultimately fatal systemic reaction began, among the symptoms of which were spasmodic extensions of the lower back and legs. Postmortem examination was performed. Nucleus pulposus pulmonary emboli were seen microscopically on random lung sections. The lumbar vertebral column grossly featured acute herniations of disc material into vertebral marrow spaces; nucleus pulposus was identified microscopically in these areas. We speculate that the spasmodic back extensions imposed compressive forces on vertebrae, causing nucleus pulposus to be extruded into vertebral marrow sinusoids (thus creating emboli) and possibly causing these emboli to flow anteriorly into the anterior external vertebral plexus, which resulted in pulmonary emboli exclusively with no spinal cord emboli.