Hantavirus Cardiopulmonary Syndrome

Key Features

Essentials of Diagnosis

• Influenza-like prodrome (fever, myalgia, headache, cough)

• Rapid onset of unexplained pulmonary edema and myocardiopathy

• Residence or travel in endemic area; exposure to aerosols from deer mouse droppings or secretions

General Considerations

• First native bunyavirus infection endemic in the United States

• Distinctly differs in mode of spread (no arthropod vector) and clinical picture from other bunyavirus diseases

• Has been confirmed in more than 34 states and Canada

• Epidemics occur when environmental conditions favor large increases in the rodent population and increased prevalence of virus

Clinical Findings

Symptoms and Signs

• After an incubation period of 1–3 weeks, onset is sudden, with a nonspecific virus-like prodrome

  • Fever, chills

  • Back, hip, and leg pain

  • Headache

  • Nausea and vomiting

• Abdominal pain may be present

• Sore throat, conjunctivitis, rash, and adenopathy are absent

• Respiratory symptoms are absent or limited to a dry cough

• After 1–10 days (usually 3–7), dyspnea, tachypnea, and evidence of a pulmonary capillary leak syndrome appear and progress rapidly

• Hypotension is common, not only from hypoxemia but also from myocardial dysfunction

• Copious, amber-colored, nonpurulent secretions are common

• Decreased cardiac output due to myocardiopathy and elevated systemic vascular resistance distinguish this disease from early bacterial sepsis

Differential Diagnosis

• Plague

• Tularemia

• Q fever

• Psittacosis

• Toxin exposure

• Legionellosis

• Fungal infections

Diagnosis

Laboratory Findings

• A serum IgM ELISA test is positive early in the illness

• Leukocytosis with a prominent left shift and immunoblasts, thrombocytopenia, and hemoconcentration

• Lactate dehydrogenase is increased

• Liver function tests are elevated

• Serum albumin is low

• Creatinine is elevated in some patients

• Proteinuria is common

• Lactic acidosis and low venous bicarbonate are poor prognostic signs

Imaging

• Radiography

  • Initially normal

  • Bilateral interstitial infiltrates with the typical butterfly pattern of acute pulmonary edema, bibasilar airspace disease, or both seen later

  • Significant pleural effusions are often present

Treatment

• Supportive with oxygen therapy and mechanical ventilation as required

• Venoarterial extracorporeal membrane oxygenation can provide short-term support for selected patients

• Because of capillary leakage, Swan-Ganz catheterization to monitor cardiac output and inotropic support—rather than fluid therapy—should be used to maintain perfusion

Outcome

Prognosis

• No isolation is required since transmission is not person to person

• Case fatality rate is 30–40%

References