Back to basics: MRI reveals spinal infection
- Published: Jul 1, 2013
- Author: David Bradley
- Channels: MRI Spectroscopy
Steroids are often injected into sites along the spinal column in treating back pain, but if a batch is contaminated serious infection can arise. Researchers have demonstrated that magnetic resonance imaging (MRI) at the site of injection could be used to identify fungal spinal or paraspinal infection, allowing early pharmacological or surgical intervention to reduce the risk of serious complications.
During the autumn of 2012, there was an unprecedented outbreak of meningitis in numerous US states. The problem was identified as allegedly being associated with fungal contamination - with Exserohilum rostratum - of injectable doses of the steroid methylprednisolone prepared by a compounding pharmacy. Meningitis was the first problem to arise but within six weeks of the outbreak, the frequency of that condition subsided only to be superseded by localized spinal and paraspinal infections. Healthcare workers reported that the period in which meningitis was frequent was brief but there was a steady stream of the spinal infections long after the initial administering of the steroid injections. Medics suggest that because most of the patients involved were receiving steroid injections to treat back pain or neuropathic symptoms, the inflammation and pain arising because of subsequent infection was obfuscated by the symptoms from which they were suffering prior to that. "The clinical findings are often subtle and similar to those that led the patient to undergo the methylprednisolone injection," a team writing in JAMA state.
Anurag Malani of St Joseph Mercy Hospital, in Ann Arbor, Michigan and colleagues - David Vandenberg, Bonita Singal, Michael Kasotakis, Spencer Koch, Varsha Moudgal, Rajasekhar Jagarlamudi, Anupama Neelakanta, Michael Otto, Lakshmi Halasyamani, Rami Kaakaji and Carol Kauffman - have now carried out a study using contrast-enhanced MRI screening to investigate whether patients who did not present with obvious infection were nevertheless suffering from the effects of receiving an injection of contaminated methylprednisolone. The researchers scanned 172 patients in this category during the period November 2012 to April 2013.
The researchers found that of those patients, 36 (21 percent) showed an abnormality in their scan. Almost all of them (35) had probable or subsequently confirmed fungal spinal or paraspinal infection as defined by the Centers for Disease Control and Prevention (CDC) case definition. 17 were probable and 18 confirmed. All of those 35 patients with an infection were treated with antifungal drugs and 24 required surgical intervention. "At the time of surgery, 17 of 24 patients (71 percent), including 5 patients who denied having symptoms, had laboratory evidence of fungal infection," the authors write. The team further adds that data on 115 patients reporting on new or worsening back or neck pain, radiculopathy, or lower-extremity weakness suggested that 30 percent had at least one of those symptoms.
"Our findings support obtaining contrast-enhanced MRI of the injection site in patients with persistent back pain even when their pain disorder has not worsened," the researchers write. "A proactive outreach to patients receiving injections from a highly contaminated lot, especially lot No. 06292012@26, is needed." MRI could be used in future incidence of worsening pain in patients that have received injected drugs and could allow infection to be spotted much earlier and so treated to improve outcomes significantly.
In an editorial to accompany the research paper George Thompson of the University of California, Davis and colleagues, suggest that for patients who received spinal injections with steroids from an unknown lot number, MRI-based screening may be appropriate in this evolving outbreak.
J Am Med Assoc 2013, 309, 2465-2472: "Magnetic Resonance Imaging Screening to Identify Spinal and Paraspinal Infections Associated With Injections of Contaminated Methylprednisolone Acetate"
Article by David Bradley
The views represented in this article are solely those of the author and do not necessarily represent those of John Wiley and Sons, Ltd.