Hantavirus infection in North America: a clinical review.

The recent outbreak of hantavirus in Yosemite National Park has attracted national attention, with 10 confirmed cases of hantavirus cardiopulmonary syndrome and thousands of more people exposed. This article will review the epidemiology, presentation, workup, and treatment for this rare but potentially lethal illness. The possibility of infection with hantavirus deserves consideration in patients with severe respiratory symptoms with rodent exposure or rural/wilderness travel. Accurate diagnosis requires a high index of suspicion. Hantavirus cardiopulmonary syndrome presents as a vague prodrome of fever, cough, myalgias, chills, and nausea followed by a rapidly worsening respiratory phase. Presumptive diagnosis can be made based on pulmonary interstitial edema on chest radiographs in association with leukocytosis, thrombocytopenia, and hemoconcentration. Suspected cases should be confirmed with a reference laboratory and reported to the appropriate public health authorities. Although treatment is primarily supportive, aggressive fluid administration should be avoided due to the risk of pulmonary edema. The cardiopulmonary phase of the disease can progress rapidly with catastrophic decompensation in as little as a few hours. Patients require rapid intensive care unit admission for monitoring, mechanical ventilation, vasoactive agents, and possibly extracorporeal mechanical ventilation. Emergency physicians should be aware of outbreaks and vigilant for hantavirus exposures, especially during the summer and early fall months.