A Case Report of Hantavirus Capillary Leak Syndrome in the Southwestern United States

Hantavirus cardiopulmonary syndrome (HCPS) is a rare but frequently fatal viral disease endemic to the Americas, transmitted primarily through inhalation of aerosolized rodent excreta. Early symptoms are nonspecific, but the disease can rapidly progress to severe respiratory compromise and shock due to profound capillary leak. We report the case of a previously healthy 20‐year‐old man who initially presented with abdominal pain, nausea, vomiting, diarrhea, and progressive weakness after occupational exposure on a ranch in southwestern Arizona. He quickly developed hemoconcentration (hematocrit 58%), thrombocytopenia (17,000 cells/μL), septic shock, and noncardiogenic pulmonary edema. The initial infectious workup was negative. His clinical course was complicated by respiratory failure requiring intubation and vasopressor support. Computed tomography of his chest showed pulmonary edema and large bilateral pleural effusions despite aggressive diuresis, requiring bilateral chest tubes. He gradually improved with supportive care, was successfully extubated, weaned off oxygen, and discharged home with outpatient rehabilitation. His diagnosis was later confirmed with a serum ELISA test which was positive for hantavirus IgM and IgG. This case highlights the diagnostic complexity of HCPS, particularly when gastrointestinal symptoms predominate early in the illness. In endemic areas with rodent exposure history, hemoconcentration and thrombocytopenia, along with signs of volume overload and rapidly progressive acute respiratory failure, should raise suspicion for hantavirus infection. Identification and supportive care are the mainstay of treatment. Although this patient did not require ECMO, transfer to an ECMO center may be beneficial to support recovery during the cardiopulmonary phase, as recommended by the Centers for Disease Control.