Pseudo-subarachnoid hemorrhage and gadolinium encephalopathy following lumbar epidural steroid injection

The safety of magnetic resonance imaging contrast agents

Gadolinium-based contrast agents are increasingly used in clinical practice. While these pharmaceuticals are verified causal agents in nephrogenic systemic fibrosis, there is a growing body of literature supporting their role as causal agents in symptoms associated with gadolinium exposure after intravenous use and encephalopathy following intrathecal administration. Gadolinium-based contrast agents are multidentate organic ligands that strongly bind the metal ion to reduce the toxicity of the metal. The notion that cationic gadolinium dissociates from these chelates and causes the disease is prevalent among patients and providers. We hypothesize that non-ligand-bound (soluble) gadolinium will be exceedingly low in patients. Soluble, ionic gadolinium is not likely to be the initial step in mediating any disease. The Kidney Institute of New Mexico was the first to identify gadolinium-rich nanoparticles in skin and kidney tissues from magnetic resonance imaging contrast agents in rodents. In 2023, they found similar nanoparticles in the kidney cells of humans with normal renal function, likely from contrast agents. We suspect these nanoparticles are the mediators of chronic toxicity from magnetic resonance imaging contrast agents. This article explores associations between gadolinium contrast and adverse health outcomes supported by clinical reports and rodent models.

Hidden risk of gadolinium-based contrast agents during interventional pain medicine procedures: a retrospective chart review

INTRODUCTION

Epidural steroid injections and epidural blood patches commonly involve the injection of a small amount of radiocontrast media under fluoroscopy to properly identify the target tissue or anatomic space and prevent off-target or intravascular delivery of therapeutic or diagnostic drugs. Iodinated low osmolar non-ionic contrast media is the standard preparation used as it is considered safe and cost-effective, but gadolinium-based preparations have been used as an alternative for patients with an 'iodine'-related or radiocontrast media allergy label to prevent hypersensitivity reactions. The risk of neurotoxic events when gadolinium is inadvertently injected into the intrathecal space has been reported in recent years, raising concerns when gadolinium-based contrast media is used in lieu of iodinated low osmolar non-ionic contrast media.

METHODS

A retrospective review was conducted of patients who received gadolinium-based contrast media for procedures with risk of inadvertent intrathecal access from January 1, 2019 to May 1, 2022. Information on patient demographics, allergy label information, and procedure description was documented for all patients who received gadolinium-based contrast media for axial spine procedures (including epidural steroid injections, epidural blood patch procedures, and selective nerve root blocks), and all side effects reported within 1 month of the procedure were recorded. Saved fluoroscopy images of all procedures for which there was concern for possible gadolinium-based contrast media-related side effect were reviewed for evidence of inadvertent intrathecal gadolinium-based contrast media administration. Descriptive statistical analysis was performed using REDCap and IBM SPSS Statistics V.28.

RESULTS

We identified 508 patients who received gadolinium-based contrast media during a fluoroscopically guided axial spine procedure. These patients underwent 697 epidural procedures and 23 patients were identified as experiencing an adverse event that could be consistent with possible, probable, or clear signs of exposure to intrathecal gadolinium. Our calculated adverse event rate was 3.3%. Ten patients required additional medical evaluation or treatment.

DISCUSSION

Almost all patients in our cohort had an allergy label on their chart that guided the provider to switch to gadolinium-based contrast media, but most were incomplete, ill-defined, or related to allergy to iodine but not iodinated contrast media. Such practice is not recommended based on current guidelines. The current study raises concern regarding the use of gadolinium-based contrast media in axial spine procedures, with the risk of potential severe adverse events, without evidence-based need for avoiding iodinated contrast media.

American Society of Regional Anesthesia and Pain Medicine contrast shortage position statement

The medical field has been experiencing numerous drug shortages in recent years. The most recent shortage to impact the field of interventional pain medicine is that of iodinated contrast medium. Pain physicians must adapt to these changes while maintaining quality of care. This position statement offers guidance on adapting to the shortage.