Case Presentation: A 65 year old female with a history of type one diabetes presented to an outside hospital with malaise, fatigue, and fever for two weeks. Her social history was notable for frequently participating in the interactive game of Geocaching in the outdoors of southeastern PA. On arrival she had severe sepsis with a fever to 102.1F of an unclear source. Her admission labs revealed direct hyperbilirubinemia with an associated mixed transaminitis, thrombocytopenia, anemia, and hyponatremia. A blood parasite stain was positive for Babesia species and Babesia microti DNA was detected via PCR. Despite initiation of atovaquone and azithromycin, the patient developed worsening hyperbilirubinemia, hemolytic anemia with thrombocytopenia and parasitemia (11%), as well as acute hypoxic respiratory failure concerning for severe babesiosis with multiple organ involvement. She was subsequently transferred to our center for further management. Doxycycline and clindamycin were added to her regimen. Nonetheless, the patient rapidly worsened with an acute encephalopathy and progressive hyperbilirubinemia (peak Tbili of 18.7) and thrombocytopenia (nadir of 18). Therefore on hospital day seven the patient underwent RBCE. The following day the patient’s clinical picture had markedly improved, with near complete normalization of her prior laboratory derangements as well as resolution of her respiratory failure and encephalopathy. There were no parasites detected on her parasite smear the following day and she was discharged on hospital day 13.
Discussion: Babesia is an emerging zoonotic tick-borne parasitic disease which is likely underreported but cases are rising in Pennsylvania (PA). This case presents a patient with severe babesisos with high levels of parasitemia and multi-organ involvement who rapidly deteriorated despite appropriate anti-microbial therapy, but then showed a robust response to red blood cell exchange transfusion (RBCE). As of 2020 the IDSA weakly recommends RBCE for “selected patients with severe babesiosis” based on low-quality evidence. There is a general consensus that RBCE should be considered in cases with parasite levels >10% although strong empiric evidence supporting this is lacking.
Conclusions: There currently are no universally accepted guidelines regarding when to initiate exchange transfusion in Babesia infections and there are only limited case reports and studies documenting the effectiveness of RBCE in severe babesiosis. As it stands, the risks of exchange should be weighed against the benefit of prompt and brisk reduction in parasitemia for individual patients. Our cases highlights the importance of prompt recognition of babesiosis in order to implement the appropriate therapy expeditiously. This case also adds to the paucity of literature on appropriate use of RBCE in severe babesiosis, urging hospitalists to consider this life-saving intervention when patients have severe infection or high parasite levels. Clinician recognition of the wide spectrum of clinical manifestations of babesiosis is vital as is the necessity to understand the risk factors associated with severe disease and the available management options.