WEDNESDAY, May 21 (HealthDay News) -- U.S. soldiers exposed to a blazing sulfur mine fire near Mosul, Iraq, in 2003 returned home with a debilitating breathing disorder that affects the small airways of the lung.

But doctors were only able to diagnose the condition, bronchiolitis, with a lung biopsy. Conventional, non-invasive tests weren't able to reliably identify the problem, said the authors of a study expected to be presented Wednesday at the American Thoracic Society's International Conference, in Toronto.

"In my view, if someone returns from service in Iraq and is short of breath, and we don't have an explanation, this needs to be considered," said Dr. Robert Miller, senior author of the study and assistant professor of pulmonary and critical care medicine at Vanderbilt University School of Medicine in Nashville, Tenn. "The other thing is that routine screening probably is ineffective in this case."

Knowing this should also help returning soldiers receive needed medical benefits. "It's important to make this diagnosis by biopsy, because it is the only way soldiers can get any type of disability," Miller said.

The sulfur mine fire near Mosul set off the largest man-made release of sulfur dioxide in history, 100 times greater than that from the eruption of Mount Saint Helens in Washington state in 1980, according to background information for the study.

Dr. Jeffrey Bernstein, director of the Florida Poison Information Center at the University of Miami/Jackson Memorial Hospital, said sulfur dioxide is a known irritant, a byproduct of combustion, and a component of air pollution. "At high concentrations and prolonged exposure, it makes its way into the lower lungs and causes inflammation," he explained.

Although results of standard pulmonary function tests performed on the soldiers were unremarkable, the severity of their symptoms led doctors to perform the first biopsies, said Dr. Matthew King, lead author of the study and a fellow in pulmonary and critical care medicine at Vanderbilt.

"We were dealing with elite, trained people. They could run two miles in 12-and-a-half or 13 minutes before they were deployed," Miller said. "When we got them, at best they could walk-run two miles."

One soldier's pulmonary function was 115 percent at the time of deployment. Upon his return, that had declined to the low 80s -- although the low 80s is considered normal, the study authors said.

In all, 31 returning soldiers underwent biopsies in addition to chest X-rays, pulmonary function tests and high-resolution computed tomography. Of these, 29 were diagnosed with bronchiolitis. And, of these 29, 21 had been exposed to the sulfur mine fire in Mosul while five had "unknown exposures." In other words, some soldiers who were not deployed near the fire experienced similar problems.

"The speculation on [the five individuals with "unknown exposure"] is that when you're fighting a war in Iraq that you're exposed to a lot of fires that subject you to inhalation," Miller said. "They burn everything over there, all their trash, all their human waste, not to mention things like weapons caches and explosives."

Bernstein said: "It makes rational sense that sulfur dioxide could cause this disease in soldiers who had a pretty large known exposure. It's a very good study of this type, but there are some questions that they will need to address. What [the study] doesn't say is how many people were dispatched to that area and were exposed and didn't get bronchiolitis."

There is no good treatment for bronchiolitis, Miller said, and most of the soldiers studied have been medically discharged from the military. The good news is that the soldiers followed in this study have not seen any deterioration of their condition in the past two or two-and-a-half years.

All study participants were from the 101st Airborne Battalion based at Fort Campbell, Ky. But these troops weren't the only ones exposed to the Mosul fire. Other battalions also assisted in controlling the fire, King said, and may have been affected as well.

More information

The U.S. Army has more on the health effects of the Mosul fire.

SOURCES: Matthew King, M.D., fellow in pulmonary and critical care medicine, Vanderbilt University School of Medicine, Nashville, Tenn.; Robert Miller, M.D., assistant professor of pulmonary and critical care medicine, Vanderbilt University School of Medicine, Nashville, Tenn.; Jeffrey Bernstein, M.D., medical director, Florida Poison Information Center at the University of Miami/Jackson Memorial Hospital; May 21, 2008, presentation, American Thoracic Society's International Conference, Toronto

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