(545) Severe Fatal ARDS Caused by Human Granulocytic Anaplasmosis

Introduction: Human Granulocytic Anaplasmosis (HGA) is a tick-borne illness caused by gram negative intracellular pathogen, Anaplasma Phagocytophilum. Disease is usually mild with fevers, constitutional symptoms and GI complaints. We report a case of severe fatal ARDS caused by Human Anaplasma infection.

Description: A 67 yo M, resident of rural Pennsylvania, with PMH of DM presented in May 2023 with fall from 7ft ladder, sustaining right hemopneumothorax, rib fractures and unstable T12 vertebra fracture. Right chest tube was placed, and patient underwent posterior spinal fusion surgery. Admission labs showed anemia (Hb-7.3 gm/dl), leukopenia (wbc-3.6K/L), thrombocytopenia (115K/L), mild transaminitis (AST-60U/L, ALT-79U/L). On postoperative day 3, patient developed acute respiratory failure requiring mechanical ventilation. Patient developed severe ARDS and required neuromuscular paralysis and prone positioning. He received empiric antibiotic therapy course with vancomycin and cefepime despite negative infectious workup including BAL, Covid-19, respiratory viral panel, MRSA, blood cultures, respiratory cultures. His ICU course was complicated by septic shock, AKI, atrial fibrillation. Family withdrew care on day 5 of mechanical ventilation per patient’s own wishes and he expired. Blood tests for tick borne illnesses- Babesia, Ehrlichia and Lyme were negative but PCR for Anaplasma DNR came back positive after patient expired. His peripheral smear showed morulae inside the cytoplasm of infected neutrophils.

Discussion: ARDS is a very rare manifestation of Human Anaplasmosis infection. Unclear etiology of ARDS, patients from endemic regions for tick borne illnesses, spring/summer/early fall time, unexplained leukopenia, thrombocytopenia and transaminitis on labs should raise suspicion for Human Anaplasmosis. Infectious disease should be consulted, start empiric doxycycline pending PCR results. Response to doxycycline is excellent and can be lifesaving.