E. Coli Urinary Tract Infection Causing Vertebral Osteomyelitis Followed by Epidural Abscess

Abstract

INTRODUCTION: Vertebral osteomyelitis (OM) is a rare bone infection of the spine commonly caused by Staphylococcus aureus (S. aureus). OM usually affects the long bones. Although hematogenous spread with extension into the epidural space is rare and is associated with high mortality rates and complications. We describe a case of Escherichia coli (E. coli) urosepsis and pneumonia complicated with vertebral OM and epidural abscess in the absence of predisposing risk factors. CASE PRESENTATION:A 68 year old man with past medical history of hypertension presented with progressive dyspnea on exertion for 5 days, productive cough, fever and chills and pleuritic chest pain radiating to the back. He denied any history of intravenous (IV) drug use. Vitals showed a blood pressure of 185/102, heart rate of 102 beats per minute and a temperature of 39.1 C. On physical exam, he had increased breath sounds in the right lower lung, diffuse bilateral wheezing and thoracic vertebral tenderness. Laboratory studies were significant for a white cell count of 18.4k x10^3/mcl and creatinine of 1.6 mg/dl. Chest X-ray showed right basilar opacity. Urine analysis indicated signs of infection. He was started on broad-spectrum antibiotics after obtaining blood cultures which grew E.coli. CT scan of the chest and abdomen showed right sided pleural effusion, pneumonia, and acute OM at T7-T8. MRI of the spine showed epidural abscess & incidental finding of left kidney mass concerning renal cell carcinoma (RCC). Despite appropriate antibiotic coverage, his condition worsened which prompted drainage of the epidural abscess with T6-T9 laminectomy. Intraoperative findings were consistent with an epidural phlegmon and he was discharged to complete 6 weeks of Piperacillin/Tazobactam. DISCUSSION: Vertebral OM in adults is usually caused by hematogenous spread of infection with S. aureus being the most often prevailing pathogen for OM. Cases of epidural abscess secondary to E.coli have been described in literature and most often they have been associated with genitourinaryconditions or have been seen in patients with preexisting risk factors such as diabetes, alcoholism, or trauma. Our case described a scenario of very rapid clinical manifestation of OM secondary to E.coli in an immunocompromised patient with likely undiagnosed RCC. It was accompanied with local spread of the infection to the adjacent epidural space causing epidural abscess.CONCLUSIONS: Vertebral OM is a rare infection usually caused by S. aureus and most often occurs in IV drug users with lumbar spine being the most frequent site of infection. However, it can be associated with urinary tract infection caused by E. Coli with the involvement of thoracic spine. It is therefore important to have strong suspicions, start antibiotics and obtain neurosurgical evaluation for epidural abscess and OM in patients who present with E.coli urosepsis and complaints of back pain.