In a letter to the editor published Wednesday in the New England Journal of Medicine Mayo Clinic physicians wrote some patients sickened with a mysterious lung illness linked to e-cigarettes and vaping have shown airway and lung damage resembling a chemical burn.
Background: Cases of a mysterious vaping illness top 1,000, CDC says
CDC data updated Thursday shows the number of reported cases of the lung illness has risen to 1,080, with 18 reported deaths. Cases of the illness have been reported in 46 states and one U.S. territory, with deaths reported in 15 states.
Anne Schuchat—CDC's principal deputy director, who is overseeing the agency's investigation into the matter—said she expects the number of cases to increase further as state officials report new cases in the ongoing outbreak. She added that the number of reported cases is rising at a "brisk case," and the cases typically involve "really serious injuries." She said, "[W]e don't know how well people will recover from them, whether lung damage may be permanent."
CDC a majority of patients with the illness have reported using products containing the compound tetrahydrocannabinol (THC), the high-inducing chemical found in marijuana. However, investigators said they are not yet narrowing the scope of their probe.
Schuchat said CDC recommends that people abstain from vaping products, and particularly products that use THC. "We really have the feeling right now that there might be a lot of different, nasty things in e-cigarette or vaping products," she said.
Lung damage among some patients with illness resembles chemical burns, researchers find
While federal and state investigators continue to search for a common cause among patients with the lung illness, physicians at Mayo Clinic noted that "few reports of vaping-associated lung injury have included histopathological findings."
To fill that void, the providers examined the lung biopsies of 17 patients with probable or confirmed cases of the vaping-associated lung illness, including two who died. All of the patients reported a history of vaping, and 71% reported vaping marijuana or cannabis oils. The patients ranged in age from 19 to 67.
The physicians found all of the biopsies showed signs of lung inflammation—or pneumonitis—and damage to airway and lung tissue, similar to individuals who have been exposed to chemical spills or harmful gases. According to the physicians, the findings suggest the illness might be caused by "one or more inhaled toxic substances," though they noted that the biopsies did not offer any clues as to which chemicals may have caused the damage.
The researchers also noted that the biopsies did not show evidence of lipoid pneumonia, which happens when fat enters the lungs. The researchers found the biopsies showed some evidence of lipids in macrophages, which are a type of immune cell, but did not support any of the previous hypotheses suggesting lipids inhaled through vaping devices might be the culprit behind the lung illness, because the symptoms the 17 patients experienced were not consistent with lipoid pneumonia.
Brandon Larsen, a senior author of the study and a pathologist at Mayo Clinic Arizona, said, "All 17 of our cases show a pattern of injury in the lung that looks like a toxic chemical exposure, a toxic chemical fume exposure, or a chemical burn injury." He added, "To be honest, they look like the kind of change you would expect to see in an unfortunate worker in an industrial accident where a big barrel of toxic chemicals spills, and that person is exposed to toxic fumes and there is a chemical burn in the airways."
How the data can improve public health officials' response
Researchers have said finding a way to diagnosis the lung illnesses might help determine the source of the condition, but it would also help them address the emerging public health crisis by clarifying the messaging surrounding the illness.
Sean Callahan, a University of Utah pulmonologist involved in a separate study on the vaping illness released last month, said, "We still don't know 100% what's causing this, but if you're saying it's because a bunch of people are inhaling oil, then young people might say, 'Oh we just shouldn't inhale oil. We need to have a good message around this."
Larsen recommended that future studies "look more closely at the chemical compounds, and not just oils, … to figure out which ones are injurious" (Joseph, STAT News, 10/2; Lee Hotz, Wall Street Journal, 10/2; Bowden, The Hill, 10/1; Grady, New York Times, 10/3; Butt et al., New England Journal of Medicine, 10/2; Stanglin, USA Today, 10/3; Sun, Washington Post, 10/3).