1256 - Proteus mirabilis Vertebral Osteomyelitis and Spinal Cord Injury Secondary to Staghorn Calculus: A Case Report

Case Diagnosis: A presentation of pyogenic spinal cord injury due to Proteus mirabilis osteomyelitis originating from a staghorn calculus.

Case Description: A 75-year-old female with a known staghorn calculus, pending nephrolithotomy, presented with progressive bilateral lower extremity weakness and recurrent falls over several months, with worsening symptoms over the past two days. After her latest fall, she developed acute bilateral paraplegia with sensory loss extending to her upper abdomen. Thoracic spine MRI revealed T8-T9 discitis/osteomyelitis with severe central canal stenosis and cord compression, exacerbated by extensive epidural lipomatosis. Emergent decompression was performed with T8-T9 laminectomies and partial T7 laminectomy, revealing a contused dural sac, but she retained a T9 incomplete Asia B spinal cord injury. Surgical, blood, and urine cultures grew Proteus mirabilis, linking her staghorn calculus as the source bacteremia and spinal seeding. Neurosurgery concluded that chronic myelopathy from epidural lipomatosis, coupled with acute pyogenic spinal cord infection, was further complicated by traumatic cord contusion after her fall.

Discussions: Pyogenic vertebral osteomyelitis (PVO) is uncommon, with an incidence of 2.2 to 5.8 cases per 100,000 annually, and residual neurologic deficits in less than 7% of cases. PVO is linked to disseminated urinary tract infections or surgical manipulation, yet PVO caused by Proteus mirabilis is exceptionally rare, especially in association with staghorn calculus. Our literature review found no documented cases of Proteus-related pyogenic spinal cord injury originating from staghorn calculus with lasting neurological impairment post-surgery. This case is further unique due to the patient's concurrent symptomatic epidural lipomatosis and subsequent traumatic spinal cord injury.

Conclusions: In patients with staghorn calculus and progressive neurological symptoms, clinicians should maintain a high index of suspicion for Proteus mirabilis-related vertebral osteomyelitis with potential spinal cord injury. While early diagnosis has a favorable prognosis, the presence of additional spinal pathologies significantly heightens the risk of persistent neurologic deficits.