Convalescent pulmonary dysfunction following hantavirus pulmonary syndrome in Panama and the United States

The objective of this study was to document persistent pulmonary symptoms and pulmonary function abnormalities in adults surviving hantavirus pulmonary syndrome (HPS). Acute infection by most hantaviruses result in mortality rates of 25-35%, while in Panama the mortality rate of 10% is contrasted by an unusually high incidence. In all types of HPS, the viral prodrome, cardiopulmonary phase due to massive pulmonary capillary leak syndrome, and spontaneous diuresis are followed by a convalescent phase with exertional dyspnea for 3-4 weeks, but the frequency of persistent symptoms is not known. In this observational study of a convenience sample, 14 survivors of HPS caused by Choclo virus infection in Panama and 9 survivors of HPS caused by Sin Nombre virus infection in New Mexico completed a questionnaire and pulmonary function tests up to 8 years after infection. In both groups, exertional dyspnea persisted for 1-2 years after acute infection in 43% (Panama) and 77% (New Mexico) of survivors surveyed. Reduction in midexpiratory flows (FEF(25-75%)), increased residual volume (RV), and reduced diffusion capacity (D(L)CO/VA) also were common in both populations; but the severity of reduced expiratory flow did not correlate with exertional dyspnea. Symptoms referable to previous hantavirus infection had resolved within 3 years of acute infection in most but not all patients in the Panama group. Temporary exertional dyspnea and reduced expiratory flow are common in early convalescence after HPS but resolves in almost all patients.