Babesiosis: An Atypical Cause of Respiratory Failure.

Babesiosis is a parasitic infection of the protozoa, which has been increasing in incidence in endemic areas of the United States. Symptoms of babesiosis can occur on a wide spectrum, from a mild flu-like illness to a fulminant disease course. Known complications of severe cases include intravascular hemolytic anemia and may involve the coagulation system, heart, spleen, kidneys, and in some cases, the lungs. This case report describes an 81-year-old, asplenic female in northern Wisconsin who presented to a hospital with shortness of breath and a non-productive cough. Definitive diagnosis of babesiosis, which was made through both a nucleic acid panel and blood smear, was initially delayed given the rare pulmonary manifestation of babesiosis. When the lungs are involved in the disease course, non-cardiogenic pulmonary edema leading to acute respiratory distress syndrome is among the most commonly seen complications. The pathophysiology of pulmonary involvement has not been made entirely clear but is most likely multifactorial, including the sequelae of changes to both the patient's red blood cells and pulmonary vasculature. This report highlights that atypical tick-borne illnesses like babesiosis should be considered as a cause of acute respiratory failure, particularly in the setting of sepsis and fever. The threshold for parasitic testing should be low in patients in endemic regions with risk factors, including increased age and history of asplenia, as babesiosis frequently has no localizing symptoms to suggest a protozoan infection. As babesiosis incidence continues to rise, prompt diagnosis and proper treatment can prevent severe complications and death in patients.