Tick-Borne Relapsing Fever in Southwest Colorado: A Case Report.

BACKGROUND: Tick-borne relapsing fever (TBRF) is a zoonosis caused by spirochetes of the genus Borrelia. The zoonosis is endemic in higher-elevation coniferous forests of the western United States. CASE REPORT: We discuss the case of a 44-year-old male residing in the San Juan Mountains of Western Colorado who presented with fever, myalgia, vomiting, and "violent chills" to an emergency department. Laboratory studies were notable for bandemia and thrombocytopenia with mild hyperbilirubinemia. Peripheral smear demonstrated multiple Borrelia spirochetes. The patient was treated with parenteral ceftriaxone and discharged with oral doxycycline therapy and recovered uneventfully. We discuss the clinical and epidemiological features of TBRF and the salient points for clinical diagnosis and management of this rare but important disease entity. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: TBRF is a rare and potentially life-threatening infectious process, which presents with nonspecific findings and often poses a diagnostic challenge. TBRF should be considered in the differential diagnosis for patients residing or vacationing in high-altitude forested areas in the western United States.