Case Presentation: A healthy 65-year-old male was admitted to the hospital for presumed COPD exacerbation and despite treatment developed hypoxic respiratory failure and shock, transferring to the intensive care unit (ICU) for further management.On arrival, he was tachycardic (120 BPM), BP 74/47 mmHg, febrile (39.0℃) and mechanically ventilated (RR 14) concerning for septic shock. Examination revealed pallor, distant heart sounds and coarse ventilated breath sounds. Exposure history revealed that he was an avid outdoorsman and lives in a heavily wooded area in northern Minnesota.An ECG revealed sinus tachycardia. Chest X-ray revealed minimal atelectasis and confirmed placement of invasive lines. Laboratory workup revealed anemia (hemoglobin 5.2 g/dL) and thrombocytopenia (platelets 31 x109/L), moderate hyponatremia (128 mmol/L), hyperglycemia (657 mg/dL), uremia (118 mg/dL), hypochloremia (87 mmol/L), severe acidosis (pH 7.16, anion gap 29 mmol/L, lactate 6.7 mmol/L) and acute kidney injury (creatinine of 5.2 mg/dL). Additional workup was concerning for hemolysis (haptoglobin 10 mg/dL, LDH 1313 U/L, indirect hyperbilirubinemia with a total bilirubin of 3.1 mg/dL and direct bilirubin of 0.4 mg/dL, alkaline phosphatase 124 U/L and AST (76 U/L) and normal ALT. Disseminated intravascular coagulation (DIC) was ruled out following normal coagulation studies, fibrinogen, and D-dimer. While negative for schistocytes, peripheral blood smear revealed numerous intra-erythrocytic rings and Maltese cross formations with an estimated parasitic burden of 11.8%. Subsequent real-time PCR confirmed Babesia microti parasitemia without evidence of coinfection. Blood cultures were otherwise negative. Following a diagnosis of babesiosis, emergent exchange transfusion in addition to treatment with clindamycin and quinidine was initiated with significant improvement in clinical status and parasitic burden. His complicated ICU course included continuous venovenous hemodialysis followed by intermittent hemodialysis and following stabilization, was transferred to the hospital floor on oral antibiotics for further management.

Discussion: Hospital admissions for non-specific respiratory symptoms in otherwise healthy patients require further investigation. This case of severe Babesia microti parasitemia resulting in multi-organ failure highlights the importance of carefully reviewing a patient’s exposure history to further elucidate a unifying diagnosis. Babesiosis is a protozoan infection, with Babesia microti being the most common species causing infection in humans (1). Cases are seasonal, affecting individuals in heavily-wooded areas in the Midwest and northeastern U.S. Symptoms are largely non-specific and include fatigue and intermittent fevers, similar to this patient’s presentation (2-4).

Conclusions: The appropriate clinical context and laboratory work revealing a triad of hemolytic anemia, thrombocytopenia, and liver enzyme abnormalities should heighten suspicion for babesiosis. Diagnosis in the appropriate host can be demonstrated with microscopy or PCR testing (1-4). Careful consideration of coinfection with Borellia, Ehrlichia, and Anaplasma species should be investigated in overlapping endemic areas (3,4). Treatment options include regimens of azithromycin/atovaqone or clindamycin/quinine for a total of 7-10 days with similar regimens for relapse in addition to exchange transfusions for levels of parasitemia of greater than 10% (4).