Rapidly evolving bilateral diffuse infiltrates usually develop in a patient with normal heart size within 48 hours. Focal lobar infiltrates suggest bacterial pneumonia. Specific diagnosis is made by serology, immunohistochemical staining of tissues, or reverse transcriptase-polymerase chain reaction for hantaviral RNA in blood or tissues. Progressive pulmonary edema and respiratory failure occur in 80 to 90 percent of patients within one to two days of hospitalization. Low cardiac output and normal to elevated systemic vascular resistance contrast with findings in patients with bacterial sepsis.
Management is based on correction of hypoxemia and hypotension.
Early use of inotropic agents and vasopressors is preferable to fluid administration for maintaining tissue perfusion. The mortality is about 50 percent, and most deaths have been caused by intractable hypotension and associated dysrhythmia. In survivors, recovery is often very rapid and apparently complete.