מתוך medicontext.co.il

By Peggy Peck

CHICAGO (Reuters Health) – Computed tomography is a fast and easy way to confirm a diagnosis in patients with suspected inhalation anthrax, according to Dr. James Earls, radiologist at INOVA Fairfax Hospital, Fairfax, Virginia.

Dr. Earls is one of the radiologists who evaluated two postal workers treated for inhalation anthrax at Fairfax Hospital. "CT scans show abnormally large lymph nodes, unlike anything I've ever seen on chest CT," said Dr. Earls. He was one of three radiologists who discussed radiologists' role in diagnosing anthrax at the 87th Scientific Assembly and Annual Meeting of the Radiological Society of North America.

Dr. Earls said that both postal workers were started on antibiotic treatment "on the basis of presumptive diagnosis by CT." Both men survived anthrax and were discharged earlier this month. They worked at the Brentwood post office, which processed an anthrax-filled letter sent to Senator Tom Daschle (D-SD).

Dr. Earls said that based on the Fairfax experience, "the CDC [Centers for Disease Control and Prevention] changed its anthrax algorithm to include CT scans." He explained that patients infected with anthrax show a slight thickening in the mediastinum on chest x-ray. That finding should be followed up with CT, which will reveal "enlarged lymph nodes, pleural, pericardial and mediastinal fluids and airway edema."

Dr. Earls, who is now a consultant to the CDC, is working with Dr. Jeffrey Galvin of the Armed Forces Institute of Pathology (AFIP) in Washington, DC to set up a registry of inhalation anthrax cases, including both x-ray and CT images. Dr. Galvin said that the AFIP has set up a Web site (http://anthrax.radpath.org) where "radiologists and particularly front-line doctors can view images of how anthrax looks."

Dr. Galvin said, for example, that many doctors expect anthrax to look like pneumonia, but it doesn't. "This isn't pneumonia. The lungs are just the means by which the bacteria enters the body."

The lung images were especially striking in the case of 61-year-old hospital worker Kathy Nguyen, who died at New York's Lenox Hill Hospital last month. Dr. Christopher Krol, a radiology resident at Lenox Hill Hospital, said Nguyen's enlarged lymph nodes actually pressed against her heart.

Dr. Krol said CT scans give the clearest picture of advanced anthrax, but he warned that it is unclear how soon after exposure to anthrax spores a CT scan can pin down the diagnosis. That is a crucial point, Dr. Galvin told Reuters Health, because the faster the disease is diagnosed, the more likely it is that antibiotic treatment will work.

While the radiologists are enthusiastic about the ability of CT to aid in diagnosis of inhalation anthrax, they all cautioned about the possibility of overuse of this readily available technology. Dr. Earls said that since "every US hospital has a CT scan" there is a clear potential for unnecessary studies.

In an interview with Reuters Health, Dr. Earls said that as soon as news about the Brentwood postal workers was made public, worried residents of the community flooded his hospital.

"We had about 200 to 300 patients. About 100 of them had somewhat suspicious symptoms, so we did chest x-rays and in 50 patients the chest x-rays indicated a possibility of infection so they had CT scans." All of the CT scans were negative for anthrax, he said, and "the good news is that none of those patients went on to develop infection."