The most frequent cause for such a picture is silent myocardial infarction so it is important to obtain an ECG and echocardiogram early to aid in the assessment. Infections in the immunocompetent which might present with a non-specific prodrome leading to acute cardiopulmonary deterioration as in HPS include leptospirosis, Legionnaire's disease, mycoplasma, Q fever, chlamydia, and in regions where the organisms are present, septicemic plague, tularemia, coccidioidomycosis and histoplasmosis. Non-infectious conditions such as Goodpasture's syndrome should also be considered. Lack of coryza aids the clinical distinction between HPS and Influenza A infection. It must be remembered that HPS is relatively uncommon and in the immunocompromised PCP, CMV, cryptococcus, aspergillus and graft vs. host disease are far more likely to be the cause of diffuse pulmonary infiltrates than a hantaviral infection.
Asymptomatic illness is rare.
Radiologic Findings HPS has a characteristic radiological evolution, beginning with minimal changes of interstitial pulmonary edema, progressing to alveolar edema with severe bilateral involvement. Pleural effusions are common and are often large enough to be evident radiographically. Heart size is usually normal. Cardiac silhouette size on chest radiographs is usually normal. To view large versions of these images, click directly on the image buttons.