Cardiovascular Complications of Anaplasmosis: A Case of Acute Pulmonary Embolism and Literature Review

Background: Anaplasmosis is an emerging tick-borne infection that typically presents as a non-specific febrile illness, with variable degrees of cytopenias and liver tests abnormalities. Severe complications remain atypical and uncommon. Case Report: We report a case of acute pulmonary embolism (PE) occurring during confirmed anaplasmosis in a 73-year-old male with no traditional thromboembolic risk factors. The patient presented with fever, constitutional symptoms, thrombocytopenia, leukopenia, and abnormal liver tests, raising suspicion for a tick-borne illness. Despite early clinical improvement on doxycycline, persistent tachycardia triggered further evaluation and uncovered an acute PE. Comprehensive workup at admission and repeated 14 months later excluded inherited and acquired thrombophilias, malignancies, autoimmune diseases, and alternative infectious etiologies. The patient was treated with doxycycline 100 mg orally twice daily for 10 days and anticoagulation with unfractionated heparin followed by 6 months of apixaban for a first episode of provoked PE. He attained complete clinical recovery without recurrence of thrombosis at the two-year follow-up. Discussion: Infectious diseases are increasingly recognized as contributors to thrombosis through inflammation-mediated hypercoagulability and endothelial dysfunction. Pulmonary involvement in anaplasmosis typically manifests as pneumonitis, pneumonia or acute respiratory distress syndrome, but thrombotic complications such as PE are exceedingly rare. This case highlights a rare but clinically significant vascular complication of anaplasmosis and underscores the importance of considering thromboembolic events in patients with persistent or unexplained tachycardia. Conclusions: As the incidence of anaplasmosis continues to rise, greater awareness of its potential cardiovascular manifestations is essential. Early recognition and prompt treatment with doxycycline remain critical, while further studies are needed to better define the thrombotic risk associated with this infection.