CT Scans Explain Mysterious 9/11 Cough
By Anna Gosline
16:20 30 November 04
NewScientist.com news service
http://www.newscientist.com/news/news.jsp?id=ns99996741
Inhaling toxic dust from the World Trade Center disaster on 11 September
2001 has damaged some rescue workers' lungs more than years of smoking,
US scientists reveal. Using an unconventional chest scan for the
circumstances, researchers were able to capture visual signs of the
severe respiratory problems that doctors could not otherwise have
diagnosed.
Hundreds of people have been tested and treated for respiratory problems
- or "World Trade Center cough" - since New York City's twin towers
fell, most of them suffering from asthma-like breathing difficulties.
Some people, however, maintained persistent but unidentifiable coughs
that could not be picked up using standard chest computed tomography
(CT) scans.
"These people had symptoms that just didn't fit the typical pattern.
They weren't treated at first because there wasn't any objective
evidence of what was wrong," says lead author David Mendelson at Mount
Sinai Hospital in New York City, US.
So Mendelson's team turned to a technique called end-expiratory CT. In a
normal chest scan, patients are asked to take a deep breath and hold it.
In end-expiratory scans, patients take in a deep breath and release it
slowly. In a healthy individual, the entire chest should be seen on the
scan as an even grey colour - the CT representation of moving air.
The doctors scanned 29 rescue and recovery workers with unexplained
symptoms. In 25 of these they saw splotchy black patches deep down in
the finer, branching tubes of their airways. Black spots mean that air
is trapped and stagnating in the lungs, making it difficult for the
patients to breathe freely.
Pulverised cement
In order to gauge the severity of the air-trapping pattern, the authors
developed a visual scale that ranged from 0 to 24. Mendelson says that
smokers would probably fall somewhere between 0 to 4 on his scale. The
World Trade Center rescue workers, however, averaged 10.55.
The extent of air trapping was found to reflect the amount of time each
worker was exposed to the dust and debris of the buildings' collapse.
The most likely culprit behind this type of airway disease is pulverised
alkaline cement, says Mendelson, who presented his findings at the
Radiological Society of North America's meeting in Chicago on Tuesday.
All of the subjects are now being treated with anti-inflammatory drugs.
Richard Russell, of the British Thoracic Society in London, UK, is not
surprised by the degree of lung tissue damage caused by exposure to the
fine cement dust, which is capable of penetrating deeply into the lungs
and damaging the delicate tissues found there.
But he warns that the rescue workers' breathing problems might be
permanent: "This is a physical problem that's not going to go away with
simple anti-inflammatories," he says. "We'll just have to watch and see
if the patients get better over time and make sure they're not smoking."
|
