December 02, 2005
Friday

Researchers have found that ordinary chest X-rays can tell doctors which patients suffering from avian flu have more severe infections that require aggressive treatment.

The study by investigators at the University of Oxford shows that distinctive patterns of clouding in the lungs showed up in a group of Vietnamese patients hospitalized after testing positive for the H5N1 influenza virus.

Humans have little or no immune protection from the avian flu when the virus makes a jump from birds to people, which has been happening sporadically in Asia since 1997, with the latest round beginning in late 2003.

So far, there is no indication that the flu can be transmitted from person to person. But the possibility that the virus might mutate to allow such spreading has prompted a worldwide effort to thwart an outbreak with vaccines, drugs and public-health measures to isolate and treat people who are infected and possibly quarantine those who are exposed.

While ordinary flu usually kills only people who have weakened immune systems by allowing secondary infections, such as bacterial pneumonia, to thrive, the H5N1 strain is powerful enough to kill by itself by attacking the nervous system and the brain as well as through viral pneumonia in the lungs.

The World Health Organization reports that 133 people in five Asian countries have been confirmed as infected with the bird flu through lab tests, with 68 of those patients dying, as of Nov. 29.

Medical investigators are trying to learn as much about how to diagnose and treat avian flu as they can in order to have doctors prepared if a new flu pandemic arises.

"The most common abnormality we found was multifocal consolidation (extreme congestion), which usually represents pus and infection in patients with fever and a cough," said Dr. Nagmi Qureshi, a chest-radiology fellow at Oxford who presented the findings Friday before the annual meeting of the Radiological Society of North America in Chicago.

"We also discovered that the severity of these findings turned out to be a good predictor of patient mortality,'' he added.

Oxford scientists have been working closely with Vietnamese doctors at the Hospital for Tropical Diseases in Ho Chi Minh City since the first bird-flu cases were detected in that country. Vietnam has seen the most human cases of avian flu reported in any country - 93, with 42 fatalities, according to the WHO.

Qureshi's team studied 98 X-rays of 14 patients who had tested positive for the flu. Nine of the patients died and five survived. Three of the five patients who survived also underwent computed tomography exams after they were discharged from the hospital.

Those images showed that even though the patients' respiratory symptoms had diminished, the abnormal appearance of the lungs persisted, suggested that scar tissue had formed that could leave the victims with diminished lung capacity.

Qureshi said the findings were similar to the X-ray appearance of the lungs of patients seen in the 2003 outbreak of severe acute respiratory syndrome (SARS). "The appearance of multiple accumulations of infections in the lung is found in both avian flu and SARS, but additional abnormalities we discovered in the flu patients - including fluid in the space surrounding the lungs, enlarged lymph nodes and cavities forming in the lung tissue - were absent from patients with SARS," the researcher said.

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