Acute paraparesis and sensory loss following intravenous corticosteroid administration in a case of longitudinally extensive transverse myelitis caused by spinal dural arteriovenous fistula: case report and review of literature.

INTRODUCTION: The underlying causes of longitudinally extensive transverse myelitis (LETM) are broad and include inflammatory processes, compression and spinal dural arteriovenous fistula (SDAVF). Presenting symptoms of SDAVF are nonspecific and often go misdiagnosed. Acute clinical deterioration from SDAVF has been described following exertion or valsalva. However, deterioration has been recently recognized following steroid administration and may contribute to increased morbidity.

CASE PRESENTATION: We describe a 63-year-old woman with a 2-year history of intermittent lower extremity numbness and back pain, lumbar stenosis, who presented with subacute worsening of symptoms following a course of oral steroids for an upper respiratory infection. Initial whole-spine imaging was concerning for LETM and lumbar puncture was concerning for an inflammatory process. The patient was treated with intravenous (IV) methylprednisolone, after which she developed acute onset bilateral lower extremity paraparesis with a sensory level. Angiogram confirmed the diagnosis of SDAVF and the patient was treated surgically. Post-operative course was complicated and subsequent clinical improvement has been slow with incomplete recovery to date.

DISCUSSION: This case illustrates the nonspecific presentation of SDAVF and the difficulty of differentiating it from other causes of LETM. It demonstrates acute clinical deterioration of SDAVF following steroid administration, a recently recognized clinical entity. The most likely mechanism is hydrostatic steroid effect coupled with iatrogenic fluid co-administration causing increased venous congestion. Previous cases have demonstrated this effect to be transient and resolves after discontinuation of steroids. This case highlights a recent association of increased morbidity following steroid administration despite definitive treatment.