Lessons can be learnt from US fungal meningitis outbreak

By Helen Albert, Senior medwireNews Reporter

As the current outbreak of fungal meningitis caused by contaminated methylprednisolone acetate injections continues to spread across the USA, past experience suggests that lessons can be learnt, says a US researcher.

Writing in the Annals of Internal Medicine, John Perfect (Duke University, Durham, North Carolina) describes a very similar outbreak that occurred in 2002 when five patients contracted Exophiala (Wangiella) dermatitidis meningitis or arthritis from contaminated methylprednisolone acetate.

He says that the 2002 outbreak and the current much larger outbreak show "that compounding of preservative-free corticosteroids requires meticulous sterility to ensure lack of fungal contamination," as "in the absence of that level of sterility and in an environment of highly concentrated steroids, fungi grow aggressively."

Perfect also notes that although many people were exposed in 2002, the number of actual symptomatic infections was relatively small. This may give some hope to the 14,000 people estimated to have been exposed in the current epidemic, which has, to date, led to 294 patients being infected with fungal meningitis, developing stroke due to presumed fungal meningitis, or contracting other central nervous system-related infections, and claimed 23 lives.

In the 2002 outbreak, voriconazole was successfully used to treat all the people with iatrogenic fungal meningitis except for one patient who died. In the current outbreak, voriconazole has also been used as the drug of choice either alone for milder cases or in combination with amphotericin B in patients with more serious disease.

However, treatment with voriconazole can be problematic with many drug-drug interactions and side effects, such as hallucinations, visual distortion, nausea, elevation of hepatic enzymes, and photosensitivity, occurring frequently, especially at the higher doses needed to treat meningitis.

Perfect notes that a feature of the infections observed in 2002 was that some patients did not develop symptoms of infection until as long as 6 months after exposure. It remains to be seen whether this will also be the case in the current outbreak.

The 2012 outbreak has been isolated to preservative-free methylprednisolone acetate contaminated with the fungus Exserohilum rostratum, although interestingly, as reported in a case study and review published in the New England Journal of Medicine, the index patient in the outbreak was infected with Aspergillus fumigatus. However, no further cases of infection with this mold have been recorded so far.

The US Food and Drug Administration, in conjunction with the Centers for Disease Control and Prevention, are currently carrying out a rigorous investigation into the outbreak, which has been isolated to the New England Compounding Center (NECC) in Framingham, Massachusetts.

The NECC center has been shut down and a voluntary recall of all products produced there is currently underway.

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