Babesiosis masquerading as ITP in a patient with CLL

Abstract Introduction: We report a case of severe thrombocytopenia, which was initially thought to be a consequence of ITP, but patient was later diagnosed with Babesiosis. This case highlights the hematological manifestations of Babesiosis, and how subtle the difference in presentation can be between Babesiosis and ITP. Case report: An 85-year-old female with a past medical history of CLL (B cell type), coronary artery disease, mild aortic stenosis, essential HTN and dyslipidemia presented to the ED with bleeding gums and hematuria. Patient denied any fever, chills, fatigue or significant bodyaches. Examination revealed diffuse petechia bilaterally on the lower extremities. Labwork on presentation revealed platelet count of less than 2000/uL, WBC 14.7 x 103/uL, RBC 4.3 x 106/uL, Hb 13.2 g/dl, AST 43 U/L, ALT 27 U/L, total bilirubin 1.0 mg/dl, BUN 28 mg/dl and Cr 0.7 mg/dl. Blood smear did not show any evidence of schistocytes, platelet clumping or blast cells. HBsAg, HCV antibody and fourth generation HIV test were all negative. Ultrasound abdomen showed a normal-sized spleen. Patient's home medications included only ramipril and metoprolol succinate. In this context, ITP was presumed as the diagnosis in this patient especially with her history of CLL. Patient was started on IVIG, pulse dose steroids and Romiplastin. However, her platelet count continued to fall, necessitating platelet transfusions. On day 2 of hospitalization, CBC started showing a drop in hemoglobin levels as well. Blood smear was reviewed again, which showed intraerythrocytic rings concerning for Babesiosis. Further blood work was ordered, which revealed elevated LDH, low haptoglobin, elevated reticulocyte count and a negative direct Coombs test, indicating non-immune mediated hemolytic anemia. Tick borne panel by PCR turned out to be positive for Babesiosis as well. Thick and thin smears also confirmed the diagnosis. Patient was started on atovaquone and azithromycin. Even after antibiotic treatment, patient continued to require platelet transfusion. In the setting of refractory thrombocytopenia, patient had to be started on plasma exchange therapy. Following plasma exchange sessions, her platelet counts eventually recovered. Of note, patient received 20 units of platelets in total during the hospitalization. Discussion: ITP and CLL have well established association, and ITP is infact seen in approximately 5 % of patients with CLL. ITP appeared to be the likely diagnosis in this patient with CLL, especially given the fact that patient did not have any symptoms concerning for infectious process including fever, chills. Additionally, absence of anemia on presentation, and no evidence of splenomegaly on imaging was also favoring the diagnosis of ITP. Nevertheless, as the hospital course progressed, patient developed anemia, and her thrombocytopenia failed to respond to IVIG and steroids. With this background, the diagnosis was revisited, and infectious etiology was investigated. And patient was diagnosed with Babesiosis. This case highlights how Babesiosis can masquerade as ITP and present as severe thrombocytopenia without any symptoms suggestive of infection.