SHM Converge Scientific Abstract ePoster Gallery-An Unexpected Case of Non-Endemic Tick-Borne Relapsing Fever

Pdf Summary

A 65-year-old woman with mild asthma and migraines developed two days of fever and altered mental status after a five-week trip to Colorado, then presented to a Wisconsin emergency department. She reported subjective fevers, urinary incontinence, confusion, apathy, forgetfulness, difficulty completing tasks, and multiple insect bites. On exam, she was febrile, mildly tachycardic, and hypotensive, with a small erythematous thigh lesion. Labs showed thrombocytopenia, elevated liver enzymes, mild hyponatremia, hypokalemia, and elevated procalcitonin. CT head, chest X-ray, and CT abdomen/pelvis were unrevealing.<br /><br />She was initially treated with cefepime and vancomycin, then doxycycline was added because of concern for a tick-borne illness. Her condition worsened overnight with persistent hypotension and tachycardia, but she did not require ICU vasopressors. A peripheral blood smear revealed spirochetes within 10 hours, strongly suggesting tick-borne relapsing fever (TBRF). She improved rapidly after ceftriaxone and doxycycline, and was discharged after one day with a 10-day doxycycline course. At discharge, liver tests and platelet count had improved. Follow-up showed near-complete recovery, with mild lingering balance and cognitive issues that improved with time and physical therapy. Later PCR testing was positive for relapsing fever Borrelia species.<br /><br />The case highlights that TBRF can present with nonspecific flu-like symptoms, neurologic changes, and thrombocytopenia, even outside classically endemic regions. Travel to the southwestern United States, cabin exposure, or tick exposure should raise suspicion. Peripheral blood smear is an inexpensive, rapid diagnostic tool, while PCR is most sensitive but slower and more costly. Early empiric doxycycline is appropriate when clinical suspicion is high, with monitoring for Jarisch-Herxheimer reaction after treatment initiation.

Asset Subtitle

Manlu Liu

Meta Tag

Author List Caitlin S. Pepperell, Daniel J. Robbins, Eduard Matkovic, Jordan Kenik, Manlu Liu, Michael E. Rockman, Michael Scolarici, Rylee Doucette, Zaynab Almothafer

Category Clinical Vignettes

Concept Tick-Borne Relapsing Fever

Concept Peripheral Blood Smear

Concept Doxycycline

Concept Borrelia

Concept Soft Tick

Distinguished Non-Finalist

Presenter Organization University of Wisconsin School of Medicine and Public Health

Presenting Author Manlu Liu

Track Adult

Keywords

tick-borne relapsing fever

Borrelia

spirochetes

doxycycline

fever

altered mental status

thrombocytopenia

Colorado travel

peripheral blood smear

Jarisch-Herxheimer reaction

Tick-Borne Relapsing Fever

Peripheral Blood Smear

Doxycycline

Borrelia

Soft Tick