Pathophysiology
1) cause is infection by a hantavirus member of the Bunyaviridae 2) specific viruses are Sin Nombre virus, Black Creek virus, and Bayou virus
Signs and Symptoms
1) 3-4 day prodrome of fever, nausea and vomiting, abdominal pain, myalgias, malaise, and dizziness 2) followed by shock, tachycardia, hypoxemia, and late-developing cough 3) 48 hours after onset of pulmonary symptoms patients either dramatically improve or dramatically worsen and die if not treated
Characteristic Test Findings
Laboratory – 1) thrombocytopenia 2) “left shift” of WBC differential 3) hemoconcentration 4) increased PTT 5) metabolic acidosis 6) proteinuria 7) decreased serum albumin 8) increased serum lactate 9) increased creatinine 10) positive IgM for hantavirus Radiology – 11) pulmonary edema with a central distribution
Inheritance/Epidemiology
1) mostly affects rural residents, particularly after cleaning out barns or sheds 2) animal reservoir are rodents, especially in the Sigmodontinae family (rice rat, white-footed mouse, and deer mouse)
Treatment
1) supportive care with aggressive use of early supplemental oxygen (intubation if required) and aggressive fluid resuscitation 2) ribavirin has been used with mixed results 3) New Mexico University Hospital is the center with the most experience world-wide caring for these patients and they are extremely aggressive about using early ECMO
Tips for USMLE
1) in hantavirus pulmonary syndrome skin and conjunctiva are not involved 2) thrombocytopenia is always present, so if there is a normal platelet count it is not hantavirus
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