SHM Converge Scientific Abstract ePoster Gallery-The Cost of Confirmation Bias: Ehrlichiosis Masked by Dopamine-Agonist Effects

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This case report describes a fatal instance of ehrlichiosis that was initially mistaken for pramipexole toxicity, illustrating the dangers of confirmation bias in diagnosis.<br /><br />A patient presented to the emergency department with thirst, urinary frequency, fatigue, hypotension, nausea, chills, and confusion. Laboratory studies showed severe thrombocytopenia, falling from 38,000 to 24,000, along with lymphopenia. Three months earlier, the patient had started pramipexole for Parkinson-related symptoms and had recently increased the dose. Because the family strongly believed the medication was responsible, clinicians initially focused on pramipexole toxicity. The drug was stopped, then later restarted at a lower dose. TTP was also considered, but the peripheral smear showed no schistocytes.<br /><br />Despite worsening illness, the possibility of a tick-borne infection was not recognized early. A tickborne panel and doxycycline were started late in the course, after the patient had already progressed to shock requiring multiple vasopressors. The patient ultimately died. Post-discharge testing later returned positive for Ehrlichia DNA, confirming ehrlichiosis as the true cause.<br /><br />The key lesson is that severe ehrlichiosis can present with nonspecific systemic symptoms, thrombocytopenia, and confusion, and it can rapidly deteriorate if treatment is delayed. Clinicians should avoid anchoring on a single suspected cause, especially when a medication history seems compelling. Early consideration of tick-borne disease and prompt empiric doxycycline are critical when ehrlichiosis is in the differential, even if the exposure history is not obvious.

Asset Subtitle

Ifrah S. Khurram

Meta Tag

Author List Bradley Bullock, Ifrah S. Khurram

Category Clinical Vignettes

Concept Ehrlichiosis

Concept Doxycycline

Concept Thrombocytopenia

Concept Lymphopenia

Concept Fever

Distinguished Non-Finalist

Presenter Organization San Juan Bautista School of Medicine

Presenting Author Ifrah S. Khurram

Track Adult

Keywords

ehrlichiosis

pramipexole toxicity

confirmation bias

thrombocytopenia

tick-borne infection

doxycycline

Parkinson disease

shock

confusion

Ehrlichia DNA

Ehrlichiosis

Doxycycline

Thrombocytopenia

Lymphopenia

Fever