Case Presentation: A 44-year-old female with a history of SLE and chronic diarrhea presented with a one-day history of fever and lethargy. On admission, she was septic with a pancytopenia and a neutropenia with an ANC of 1.6. CT of chest, abdomen and pelvis showed non-specific enteritis, concordant with the chronic diarrhea history, but no other conclusive evidence of a septic source was found. She was started empirically on Vancomycin, Piperacillin-Tazobactam and Meropenem. Further workup, including blood cultures, urinalysis, viral respiratory and GI PCR panels were unremarkable. She continued to decompensate clinically with high fevers, hypotensive episodes and worsening fatigue. She developed elevated liver enzymes, her platelets dropped to 36 and ANC to 0.6. Further questioning revealed that she recently experienced a tick bite. This prompted a decision to empirically start doxycycline and send for a comprehensive tick-borne panel. On day 2 of empiric treatment with doxycycline, she became afebrile and all bloodwork trended toward normal. She was discharged with resolution of her symptoms and lab abnormalities. Results for the tickborne panel returned positive for Ehrlichia Chaffeensis and Babesia Duncani WA1.

Discussion: This case demonstrates the need for early empiric initiation of doxycycline in patients with a high clinical suspicion for tick-borne illnesses; especially for those at risk for decompensation (eg immunosuppression from SLE) in tick-borne illness endemic areas, like Delaware. The CDC describes the presentation of Babesiosis to range from mild flu-like symptoms to being fatal. Common labs include thrombocytopenia, elevated aminotransferases and a low hematocrit. Early empiric treatment has demonstrated a 49% decrease in ICU admission rates, a decrease in ARDS occurrence and multiorgan failure with a 43% reduction in need for mechanical ventilation. Although current practice recommends treatment of Babesiosis with Quinine or atovaquone with Clindamycin or Azithromycin, not enough evidence exists for the use of Doxycycline monotherapy. Moreover, there is limited clinical experience when treating the relatively uncommon, Babesia Duncani WA1. This patient’s great clinical response suggests that Doxycycline may be used as an alternative agent.

Conclusions: Babesia Duncani is an uncommon tick-borne illness transmitted by the winter tick, Dermacentor albipictus, and can be fatal if not treated early. With the increasing incidence of tick-borne illnesses worldwide, we emphasize the importance of placing tick-borne illnesses as a differential diagnosis for septic patients in endemic areas with an unclear infectious source. The patient described here presented with typical symptoms and lab findings for a relatively uncommon tickborne illness, Babesia Duncani WA1 with an Ehrlicia co-infection, but by identifying her symptoms and lab derangements early in the disease course, coupled with a detailed history, early empiric treatment with doxycycline resulted in an excellent clinical outcome.