Arachnoiditis following caudal epidural injections for the lumbo-sacral radicular pain

Caudal epidural steroid injection is a very common intervention in treatment of low back pain and sciatica symptoms. Although extensively used, it is not devoid of complications. A few reports of chemical and infective arachnoiditis exist following lumbar epidural anaesthesia, but none following a caudal epidural steroid injection.We report a case of arachnoiditis following caudal epidural steroid injections for lumbar radiculopathy. The patient presented with contralateral sciatica, worsening low back pain and urinary retention few days following the injection, followed by worsening motor functions in L4/L5/S1 myotomes with resultant dense foot drop. Gadolinium-enhanced magnetic resonance imaging suggested infective arachnoiditis with diffuse enhancement and clumping of the nerve roots within the lumbar and sacral thecal sac. As the number of injections in the management of back pain and lumbo-sacral radicular pain is increasing annually, it is imperative to have a thorough understanding of this potentially dangerous complication and educate the patients appropriately.