Initial Negative MRI Spine and Persistent Staphylococcus aureus Bacteraemia Lead to Delayed Diagnosis of Lumbar Spondylodiscitis and Epidural Abscess: A Case Report.

Vertebral osteomyelitis and spondylodiscitis are uncommon but potentially life-threatening infections that may present with non-specific symptoms, resulting in delayed diagnosis. We report the case of a 65-year-old man who presented with acute low back pain, high-grade fever, confusion, and transient neurological symptoms. Initial investigations demonstrated markedly elevated inflammatory markers and persistent methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia. A CT of the head and thorax/abdomen/pelvis, transthoracic echocardiography, and an early whole-spine MRI study failed to identify the source of infection. Despite appropriate intravenous antimicrobial therapy, the patient remained bacteraemic with persistent back pain, prompting repeat MRI, which demonstrated L5-S1 spondylodiscitis complicated by an anterior epidural abscess causing cauda equina compression and an associated prevertebral collection. As the patient remained neurologically intact, a multidisciplinary team involving microbiology, radiology, cardiology, and spinal surgery agreed on conservative management with prolonged intravenous flucloxacillin. The patient demonstrated progressive clinical improvement with resolution of fever, declining inflammatory markers, preserved neurological function, and successful discharge to complete outpatient parenteral antimicrobial therapy. This case highlights the importance of maintaining a high index of suspicion for vertebral infection in patients with persistent S. aureus bacteremia (SAB) and ongoing back pain despite initially negative imaging. It also emphasises the value of repeat MRI when clinical suspicion persists and demonstrates that carefully selected patients with spinal epidural abscess may be successfully managed without surgery through a multidisciplinary approach.