A 56-year-old male from Upstate New York presented with a febrile illness, fatigue, body aches, and a rash, initially treated for suspected Lyme disease without improvement. His symptoms progressed to include hepatosplenomegaly and pancytopenia. Bone marrow biopsy revealed intracellular organisms, leading to the identification of Anaplasma phagocytophilum via PCR. He was diagnosed with anaplasmosis, a tick-borne disease, and successfully treated with doxycycline, showing rapid clinical improvement. This case highlights the importance of considering tick-borne illnesses in endemic areas, even with atypical presentations, and using specific diagnostic tests.
Key note: A high index of suspicion for tick-borne diseases is crucial in endemic regions, especially when initial empiric treatments fail.