Severe Thrombocytopenia Secondary to Babesiosis: A Case Report.

A 76-year-old man with a history of atrial fibrillation treated with warfarin, renal calculi with a history of lithotripsy, hypertension, anxiety, and diabetes mellitus with recent tick exposure presented with abdominal pain, fatigue, nausea, and fever with chills. Workup revealed thrombocytopenia and hemolysis. Due to the likelihood of immune thrombocytopenia (ITP) secondary to a viral etiology, the patient was initially started on steroids. The patient subsequently tested positive for babesiosis on peripheral smear and polymerase chain reaction. A peripheral smear showed giant platelets and was positive for immunoglobulin M platelet antibodies. Other etiologies of thrombocytopenia were excluded. The patient was diagnosed with ITP secondary to babesiosis. Antibiotics were initiated to treat babesiosis. The platelet count was nonresponsive to steroids and gradually improved following intravenous immunoglobulin administration and continued antibiotic treatment. This rare case highlights the importance of considering ITP secondary to babesiosis as the etiology of severe thrombocytopenia in babesiosis, as appropriate recognition and early treatment of babesiosis and ITP can prevent serious complications.