Bret Stetka, MD; José G. Merino, MD, MPhil


April 24, 2013

Editor's Note:
At the 2013 Annual Meeting of the American Academy of Neurology (AAN) in San Diego, California, Medscape sat down with José G. Merino, MD, MPhil, to discuss 4 intriguing areas of research presented at the Hot Topics Plenary Session,[1] of which he served as moderator. Dr. Merino is a neurologist at Johns Hopkins Community Physicians in Bethesda, Maryland, and a member of the AAN Science Committee.

Medscape: This year, the AAN Science Committee chose 4 presentations to include in the Hot Topics session. Can you walk us through your selections and discuss why they're potentially so important to clinical neurology?

Dr. Merino: Every year, the AAN Science Committee identifies exciting topics that have an impact on neurology and selects speakers to share their experience with neurologists attending the meeting. This year, we had some very interesting talks.

One of the talks dealt with an important current public health issue. Dr. David Clifford, chair of the Neuroinfectious Disease Section of the AAN and a professor at Washington University in St. Louis, spoke about the recent outbreak of meningitis linked to fungal contamination of steroids used to treat back pain. There have been over 700 reports (and 53 deaths) linked to these injections. The infection can present as a local epidural abscess, arachnoiditis, discitis, vertebral osteomyelitis, central nervous system abscess, meningitis, or stroke. It is caused by a brown-black mold, Exserohilum rostratum. The confirmation of the fungus has occurred in around 30% of cases, but the disease is suspected in anyone who has the relevant symptoms and was treated with steroids compounded at the implicated pharmacy (New England Compounding Pharmacy).

Treatment should be initiated promptly with intravenous voriconazole and, in some instances, liposomal amphotericin B. The Website of the Centers for Disease Control and Prevention (CDC) has information about the diagnosis and treatment of this mold.

Medscape: Is the outbreak behind us, or are new cases still presenting?

Dr. Merino: The steroid lots have been recalled, but there were a lot of people who could have been infected and fungus can take a long time to grow. So we may still be seeing new cases this year. Over 700 cases and 53 deaths have been reported to the CDC, and the CDC continues to receive reports of spinal and paraspinal infections, some with meningitis.

Medscape: What can you tell us about the other presentations?

Dr. Merino: Dr. Michelle Monje from Stanford School of Medicine gave a very interesting talk about the effect of neck radiation (for cancer) on hippocampal neurogenesis. Patients who undergo radiation sometimes have memory dysfunction, and impairment of hippocampal neurogenesis may be an important mechanism underlying this memory dysfunction. Radiation leads to inflammatory changes that affect the survival and differentiation of neural stem cells in the hippocampus.

These findings are very interesting because they highlight the role of neural stem cells throughout life on memory formation. These findings may have implications for understanding the pathophysiology of dementia and for the development of new therapies.

Medscape: How did she assess neuronal replication, or a lack thereof?

Dr. Merino: She used immunohistochemical markers of neurogenesis, cell division, gliogenesis, and inflammation. For the human studies, she compared the brains of patients who had received neck radiation with those of age- and sex-matched controls.