TUESDAY, Dec. 21, 2004 (HealthDayNews) -- A rare and dangerous form of pneumonia, which struck 22 U.S. soldiers in 2003 and the early part of 2004, has prompted a government study to determine its origins.
This strain, known as acute eosinophilic pneumonia (AEP), is so rare that the entire medical literature contains only about 150 published accounts of it, according to lead study author Dr. Andrew F. Shorr, chief of the pulmonary clinic at Walter Reed Army Medical Center in Washington, D.C. And none of that literature has accounts of the disease striking in clusters, as it apparently did in Iraq.
There seems to be no explanation for the unusual cluster, which included two deaths, except for one salient fact -- all of the patients were smokers, and nearly all of them were new to the habit. But so far, that appears to be the only element that links the AEP cases.
"We are still in the problem-solving phase," said study senior author Dr. Bruno P. Petruccelli, director of epidemiology and disease surveillance at the U.S. Army Center for Health Promotion and Preventive Medicine. "We don't recognize all of the factors."
The study, which was sponsored by the U.S. Army Office of the Surgeon General, appears in the Dec. 22/29 issue of the Journal of the American Medical Association.
Between March and August 2003, severe pneumonia was reported in 19 U.S. military personnel. Ten of these servicemen were diagnosed with AEP. An additional eight patients were diagnosed with AEP through March 2004. Between March and June 2004, another four cases surfaced.There have been no new cases since June, despite heightened monitoring, government officials say.
All of the 18 who were diagnosed with AEP during the study period were smokers; 14 (78 percent) were recent converts. All but one reported having had significant exposure to fine airborne sand or dust. The average age of the patients was 22, and the oldest was 47.
Shorr was the first to identify the disease while serving briefly in Germany. During his tour, several otherwise healthy soldiers were admitted with respiratory failure. "They were basically happening all at the same time, and it was really very perplexing," he recalled.
Shorr was disturbed enough to order bronchoscopies, which revealed that these cases were not the more common community-onset pneumonia.
"The strongest message that comes out is the very, very, very significant association between smoking and AEP," Shorr said. Beyond that, he added, "our working hypothesis is that it's probably a multi-hit insult, where you have a susceptible host -- for whatever reason -- who then is sensitized to the environment in some way because of the amount of dust in the air or some other agent, or some other exposure on top of that."
The research ruled out several other explanations, which most will find comforting. "This does not seem to be an infectious, transmissible disease. It does not seem to be related to a vaccine, either smallpox or anthrax," Shorr said.
Despite the lack of answers, the information is still potentially lifesaving.
"From a military medicine point of view, it's important," said Dr. Norman Edelman, consultant for scientific affairs for the American Lung Association. "You have to know if you run into a strange kind of pneumonia that this is what it may be. Ordinarily we treat pneumonia with antibiotics, or occasionally with antivirals, but this gets treated with corticosteroids, which is quite different. Unless you suspect that, you would never give them corticosteroids."
The message to soldiers is not a new one: If you smoke, stop, and if you don't smoke, don't start. "New-onset smoking is an issue. This is a unique risk that is nearly uniformly avoidable," Shorr said. "Recent newspaper articles have reported that people are trying to collect cigarettes to send to service members for the holidays. I would counsel against that. There are many other things you can do to support our troops."
The Armed Forces Institute of Pathology has more on AEP.