Determining the exact path of tainted steroids that already have led to 23 deaths could present challenges for physicians performing autopsies and trying to pin down exactly who is responsible for the deaths, medical experts say.
On Sunday, federal officials reported only one new case of a person being diagnosed with fungal meningitis. That was in Indiana, pushing the national illness total to 285. Tennessee's total remains at 69, with nine deaths.
Though nearly all of the lawsuits filed by victims and their next of kin have named only the Massachusetts drug compounder, the New England Compounding Center, as a defendant, a suit filed in Virginia also named the pain clinic where the victim was treated.
Dr. Michael Baden, a high-profile forensic physician in New York, said it was possible that in at least some of the fatal cases the person administering the epidural steroid may inadvertently have pierced the spinal dura, the protective coating around the spinal canal.
If that occurred, the fatal fungus would have a direct path to the victim's brain, he said.
That also could explain why some victims died much more quickly than others, Baden said. Health officials with the U.S. Centers for Disease Control and Prevention have said that while some patients became ill with fungal meningitis within a week, others did not show symptoms for six weeks.
But Baden and others say that determining whether that protective coating was breached could be difficult.
"Any perforation of the dura will heal after a few days," he said. "The chances of finding that puncture are remote."
He said it also was possible that the fungus could penetrate the dura even if there were no puncture.
'It's a horror story'
Dr. Natalie Strand, an anesthesiologist at the Keck School of Medicine at the University of Southern California, said physicians use contrast dyes and a fluoroscope when they treat back pain patients with steroids in order to avoid puncturing the dura.
She and Baden noted that the correct administration of a spinal steroid requires placing the drug in a very small space.
Strand said the meningitis outbreak has caused concerns among some of her patients because the symptoms of meningitis, such as nausea and back pain, are common and can result from many other causes.
"It's a horror story," she said, adding that officials at USC were relieved when they determined that none of the tainted medicine was used on their patients.
"I've had a lot of patients expressing concerns," she said.
Doctors could face trouble
Dr. Cyril Wecht, a Pittsburgh pathologist, said piercing the dura "is something that should not happen."
But he added that he would not be surprised if it did happen in some of the meningitis cases being studied by state and federal health experts.
Wecht agreed that detecting whether the spinal cord's protective coating was breached would be difficult.
"After a few days the white blood cells would obfuscate and obscure the needle hole. It would be pretty hard to isolate the infectious process," he said.
Wecht also noted that treatment with steroids, such as the methylprednisolone acetate that caused the current outbreak, also leaves patients more vulnerable to infections by lessening the response of the immune system.
Fred Pritzker, a Minnesota attorney who has filed a suit against New England Compounding, said the physicians who administered the tainted steroid "absolutely" could be held liable for their involvement.
He said they could be found at fault for the way the drug was administered and for failing to ensure that the drugs they injected came from a safe and reliable source.
In what is apparently the first nationwide class action, filed Friday in U.S. District Court in Dallas, attorneys for Lori Cavanaugh charged that she was treated with tainted methylprednisolone and subsequently suffered headaches, nausea, dizziness and stiffness in the neck.
Though Cavanaugh was treated in Michigan, the complaint contends that Texas is the most appropriate location to pursue all the claims stemming from the outbreak because more than 100 Texas residents were injected with the steroid at just one Texas facility.
Edward Jazlowiecki, one of Cavanaugh's lawyers, said he had no doubt New England Compounding would file for bankruptcy in the near future.
"There'll never be enough money to compensate everyone," he said. "They are going to go bankrupt. You can bet on it."