Tick Borne Disease Induced Pancytopenia

One of the uncommon and often missed causes of acute pancytopenia is tick-borne illnesses, mainly Human Monocytic Ehrlichiosis (HME) / Human Granulocytic Anaplasmosis (HGA) and Babesiosis, though the specific mechanism of the former is still unknown. The challenges in such diagnosis are that the tests for many tick-borne diseases have poor validity, and also that these diseases can co-exist, making the exact etiology of the hematopoietic defect more difficult to identify. This report demonstrates a case of acute pancytopenia secondary to tick-borne illness, which is a rare presentation. This was based on the exposure history, exclusion of other causes, Erythema Migrans lesion, response to doxycycline, and the known limitations of testing. A 60-year-old Caucasian female with Rheumatoid arthritis, presented in Rochester, New York during summer, with a six-day history of vague symptoms including fatigue, headache, poor appetite, and nausea. She was frequently visiting her husband who lives in a cabin in a near wooded area. Records showed she had a history of Lyme disease that got successfully treated one year prior, but did not recall any tick bites lately. She was found to have fever, acute pancytopenia, and transaminitis. Her initial labs also showed high LDH and CRP. Otherwise, Reticulocytes, Vitamin B12, Folate, Lactic acid, have all been normal, as well as her imaging including chest X-ray, head CT, and abdominal ultrasound. A bone marrow aspirate showed nonspecific reactive changes. Infectious diseases team later noted a circular skin lesion with pale center suggesting Erythema Migrans, with a thorough workup only positive for Lyme IgG and EBV IgG, but negative for Legionella antigen, Leptospirosis antibody, HIV, Parvovirus B19, Hepatitis panel, HME/HGA testing, blood smear, and blood cultures. She was started on a Doxycycline trial on Day 4 for probable tick-borne illness with rapid improvement in her symptoms and lab results