New patterns in H1N1 deaths

SAO PAULO, Dec. 23 (UPI) -- In a Brazilian study, 76 percent of the patients who died of H1N1 had underlying medical conditions such as heart disease or cancer, researchers say.

However, lead author Dr. Thais Mauad of Sao Paulo University in Brazil said there was no clear complicating medical condition in the remaining one-quarter.

Mauad and colleagues examined 21 patients who had died in Sao Paulo with confirmed H1N1 infection in July and August. Most were 30 to 59.

While previous data has shown most patients with a non-fatal infection have fever, cough and achiness, but "most patients with a fatal form of the disease presented with difficulty breathing, fever and achiness being less frequently present."

All patients died of severe acute lung injury, but there were three distinct patterns of the damage to their lungs, indicating that the infection killed in distinct ways.

"All patients have a picture of acute lung injury," Mauad says in a statement. "In some patients this is the predominant pattern, in others, acute lung injury is associated with necrotizing bronchiolitis, and in others there is a hemorrhagic pattern."

Patients with necrotizing bronchiolitis are more likely to have a bacterial co-infection, patients with heart disease and cancer are more likely to have a hemorrhagic condition in their lungs, Mauad says.