Inferior Vena Cava Septic Thrombophlebitis: A Severe Complication of Paraspinal Steroid Injection Leading to Methicillin-Resistant Staphylococcus aureus Dissemination.

Paraspinal steroid injections, while widely employed for the treatment of back pain, carry risks of serious complications including infection. We describe a 54-year-old immunocompetent woman who developed a disseminated methicillin-resistant Staphylococcus aureus (MRSA) infection following a lumbar paraspinal steroid injection for back pain. She presented with fever, dyspnea, and acute low back pain, progressing to hypoxic respiratory failure requiring intubation. Diagnostic workup revealed MRSA bacteremia complicated by a lumbar spinal epidural abscess, bilateral psoas and quadratus lumborum pyomyositis, inferior vena cava (IVC) septic thrombophlebitis, pulmonary septic emboli, and meningoencephalitis. The patient received intravenous vancomycin and anticoagulation therapy with apixaban. Clinical improvement was observed with resolution of bacteremia and complete radiological resolution of the IVC thrombus after completing an 8-week treatment course. This case underscores the devastating potential of MRSA to transform a localized infection into widespread metastatic disease, driven by its potent virulence factors. It points out the importance of early recognition of systemic complications, including vascular thrombosis and central nervous system involvement, following paraspinal interventions. Moreover, it demonstrates the need for prompt imaging, timely administration of targeted antibiotics, and multidisciplinary management. Given the increasing use of corticosteroid injections and rising concerns about antibiotic-resistant pathogens, this case serves as a reminder of potential iatrogenic complications and the critical importance of infection control and vigilant monitoring. Clinicians should maintain a high index of suspicion for deep-seated infections in patients presenting with systemic symptoms after steroid injection, even in the absence of overt immunosuppression.