Oct. 10, 2012 at 3:47 PM ET
An outbreak of fungal meningitis linked to steroid shots for back pain has now killed 12 people, with 137 confirmed cases, according to the latest numbers from the Centers for Disease Control and Prevention. And most of the cases so far have been caused by a mold that's never been known to cause meningitis before.
Cases have been identified in 10 states: Florida, Indiana, Maryland, Michigan, Minnesota, New Jersey, North Carolina, Ohio, Tennessee and Virginia. Ten of the people infected have been infected with a black mold called Exserohilum rostratum, CDC officials told doctors in a conference call on Wednesday. While at first the outbreak was linked to another mold called Aspergillus, just one of 11 patients whose tests have come back so far has been infected with that particular fungus.
Exserophilum has not been linked to meningitis before, Dr. Tom Chiller of the CDC's Division of Foodborne, Waterborne and Environmental Diseases said. This makes it tricky to treat. So the CDC is recommending a strong intravenous cocktail of two antifungal drugs called voriconazole and lipsomal amphotericin B for as long as patients can tolerate it. "We realize these are two antifungal medicines that are toxic," Chiller said. He said CDC is still trying to figure out the best dose and the best length of time to treat patients.
Both of the molds are found commonly in nature - in soil and on plants. Aspergillus can cause lung infections and has in rare cases caused meningitis. Exserophilum can cause skin infections and can infect the heart, but had not been found in spinal fluid before.
Because the drugs can damage the kidneys and have other toxic side-effects, the CDC doesn't recommend treating anyone who isn't showing symptoms. Most of the patients who have tested positive for signs of fungal meningitis have a headache, neck pain or nausea, Chiller said. A few patients also have reported dizziness or sensitivity to light. Most of the patients who have died had strokes, Chiller said.
It is possible the fungus is escaping into the bloodstream and brain and is causing the strokes, he said. CDC says as many as 13,000 people may have been given injections with steroids from the three lots clearly linked with contamination. The New England Compounding Center, a pharmacy in Framingham, Mass., made all the contamninated lots of drugs and has recalled all of its products. But only patients who received back or neck injections of a steroid called methylprednilosone from NECC are at risk, the CDC stresses.
And only patients with symptoms should get the risky spinal tap to see if they might have meningitis.
Meningitis is an inflammation of the spinal cord and brain fluid, and it's usually caused by bacteria or viruses. Fungal meningitis is rare, and it caused more subtle symptoms than the other types. Dr. Paul Been of Riverside Methodist Hospital in Columbus, Ohio, said even testing for meningitis can be dangerous.
"Patients can't just come in and demand a test," Been told NBCNews.com in a telephone interview. "It's definitely an invasive procedure," he added.
A needle must be used to puncture the spine and take out fluid.
"Patients have to understand," he said.
He said his emergency room had seen three or four worried patients in the past day, all of them without any symptoms.
Making matters worse, said Chiller, most of the patients will never test positive for fungus in the cerebrospinal fluid. Fungus doesn't grow well in tests, he told doctors on the call.
So the CDC's guidelines are to look for signs of inflammation in the fluid instead. If it's there, then the patients should be treated with the antifungal drugs. And because the fungi grow so slowly, it's not clear how long the incubation period may be.
"I don't know how far out to tell you to think," Chiller told the doctors.
Right now, anyone who got a spinal or neck injection of the steroid from NECC between May 21 and September of this year needs to keep an eye out for symptoms.
In the meantime, the Food and Drug Administration is testing drugs from NECC to see just how many were contaminated and with what fungi. It's possible there are even more types of fungus growing in the contaminated vials, experts say. FDA scientists spotted fungus in at least one sealed vial.