A 48-year-old man came to the emergency department in early August with a 3-day history of influenza-like symptoms and profound dyspnea on exertion, which had started 3 days after his return to Boston from a vacation in California. Read this latest Clinical Problem-Solving case on NEJM.org.
The hantavirus pulmonary syndrome came to national attention in 1993, after a cluster of 24 young patients with severe pneumonia (76% mortality) was identified in the Four Corners region of the southwestern United States (i.e., where the boundaries of Colorado, New Mexico, Arizona, and Utah meet). Hantaviruses were known to cause a hemorrhagic fever with renal syndrome in Europe and Asia, but this syndrome was rarely associated with respiratory symptoms. Analysis of paired serum samples suggested the existence of a new species of hantavirus. The new virus was subsequently identified and called the Sin Nombre (without a name) virus.
• How does transmission of hantavirus occur?
Hantavirus infection in humans typically occurs when urine or feces from infected rodents is aerosolized (e.g., by sweeping) and inhaled by susceptible persons. Hantaviruses are viable in the environment for 9 to 15 days.
• How does infection with coccidioides present?
Coccidioides immitis, the etiologic agent of valley fever, is a dimorphic fungus that is endemic to the San Joaquin Valley. Infection is caused by inhalation of highly infectious soil-living arthroconidia, with symptoms developing after a mean incubation period of 1 to 3 weeks. In addition to fevers and arthralgias, pulmonary involvement is typical in primary infection, with the severity of manifestations proportional to the burden of inhaled arthroconidia.
Morning Report Questions
Q: What are the clinical manifestations of the hantavirus pulmonary syndrome?
A: North American hantavirus infection causes the hantavirus pulmonary syndrome, which has been reported in both New York and California. After an incubation period of 2 to 3 weeks, an influenza-like prodrome occurs, followed by the development of noncardiogenic pulmonary edema and, in severe cases, renal failure. There is a 2:1 male predominance among reported cases, which is attributed to increased occupational exposure. A prodromal phase of fever, chills, headache, myalgias, and vomiting is typically followed within 3 to 7 days by the cardiopulmonary phase of cough and dyspnea.
Q: What are characteristic laboratory findings in hantavirus pulmonary syndrome?
A: Hematologic findings include thrombocytopenia, a left-shifted granulocyte series without toxic granulations, atypical lymphocytosis, hemoconcentration, and lymphoblasts. Other laboratory abnormalities include elevations in aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels. Hypoalbuminemia and a low total protein level are common in severe cases.