So far, 541 cases in 19 states – including one each from Georgia and South Carolina – have been identified from the outbreak, which is tied to contaminated steroid injections.
The case presented challenges for investigators, said Dr. John Jernigan, of the clinical team for the investigation and the director of the CDC’s Office of Health Associated Infections Prevention Research and Evaluation.
The first case had an unusual cause, Jernigan said.
“There was a big question at first whether this is really fungal meningitis,” he said.
In fact, the fungus responsible did not turn out to be one that caused most of the subsequent cases, identified as Exserohilum rostratum, which had never before been reported to cause meningitis, Jernigan said.
A North Carolina case allowed them to narrow the potential drugs involved, leading back to a compounding pharmacy in Massachusetts, but it also forced them to contact 14,000 patients potentially exposed to the contaminated drugs. As more potential cases were identified, they began to notice an unusually mild set of symptoms for meningitis, with mild fever and stiff neck, Jernigan said. Spinal taps, however, showed striking signs of inflammation and the diagnosis, he said.
Part of the problem might be that the steroids helped blunt the immune response and many of the injections were into the central nervous system, where immune response can be more limited, he said.
It set up a dilemma for the CDC and clinicians treating the patients, he said.
“How do we treat this?” Jernigan said. “We didn’t know.”
After consulting with other experts, they settled on two medications, one of which is toxic to the kidneys and has caused some patients to temporarily go on dialysis, he said. The initial recommendation was for three months, but some might be kept on longer because doctors lack a good determinant of whether the infection has resolved, he said.
The investigation continues, but Jernigan is hopeful the worst of the outbreak has passed.
“It appears to have certainly tailed off,” he said.