A 39-year-old outdoor enthusiast presented after backcountry camping in the southeastern United States and subsequent adventure travel in Costa Rica. He developed persistent high fevers and systemic illness consistent with sepsis. The patient's recent activities included wilderness exposures that raised concern for environmental and zoonotic pathogens. The case emphasizes the importance of capturing both local and international exposure histories in patients with febrile illness following outdoor recreation.
On initial evaluation the patient had cytopenias and hepatic involvement: specifically, leukopenia, thrombocytopenia, and transaminitis, findings reported together as pancytopenia with associated liver enzyme elevations. Despite the severity of illness and an extensive infectious workup, initial diagnostic testing did not identify a causative agent. The published abstract notes that infectious testing was initially negative but does not provide details on the exact tests performed, timing, or individual numeric laboratory values.
Because initial testing was unrevealing, clinicians pursued further serologic evaluation. Convalescent serology subsequently confirmed leptospirosis as the etiology of the patient's sepsis and cytopenias. The source reports that the convalescent serology established the diagnosis but does not specify the serologic method, titers, or precise timing of sample collection relative to symptom onset in the abstract.
This case illustrates common diagnostic challenges when patients present with febrile illness after wilderness or travel exposures. Several factors complicate recognition and diagnosis:
Overlapping syndromic presentations: leptospirosis can mimic viral and more common bacterial illnesses, producing nonspecific features such as fever, cytopenias, and hepatic enzyme elevations.
Multiplicity of exposures: travel that spans different ecological regions (in this case, the southeastern United States and Costa Rica) broadens the differential diagnosis and may reduce the pretest probability for any single pathogen.
Limitations of acute testing: serologic assays for zoonotic infections may be negative early in the course of illness; convalescent samples can be required to demonstrate seroconversion and confirm a diagnosis.
Underrecognition of zoonoses: leptospirosis is described in the report as an underrecognized cause of febrile illness among wilderness travelers and outdoor athletes, which can lead to delays in targeted diagnosis and management.
The abstract does not provide granular diagnostic timelines, imaging results, or the full list of pathogens that were excluded during the initial workup. Those details were not reported in the source abstract.
Key clinical lessons from this report for providers in critical care, emergency, infectious disease, and wilderness medicine settings include:
Maintain a broad differential for febrile patients with recent outdoor or travel exposures, including leptospirosis when there is potential freshwater exposure or contact with environments where zoonotic transmission is possible.
Recognize that pancytopenia and transaminitis can accompany severe presentations of zoonotic infections and sepsis, and initial routine testing may be nondiagnostic.
Consider serial testing strategies: when acute diagnostics are negative but clinical suspicion remains, obtain convalescent serology to document seroconversion and confirm infections like leptospirosis.
Obtain a detailed exposure history, including specific activities (for example, freshwater recreation, camping, or travel to endemic regions), which can guide targeted testing and empiric management.
Increased awareness and suspicion for underrecognized zoonoses can shorten time to diagnosis and appropriate treatment in critically ill travelers and outdoor athletes.
Overall, this case report demonstrates that leptospirosis can present as severe sepsis with pancytopenia and transaminitis in an outdoor enthusiast and that diagnosis may require convalescent serology after initial testing is unrevealing. The abstract highlights the diagnostic challenge when exposures span both local and tropical environments and underscores the importance of including zoonotic pathogens in the differential diagnosis of febrile wilderness travelers.
(Notes: the abstract reports the demographic, clinical syndrome, exposure locations, initial laboratory abnormalities, and convalescent serologic confirmation of leptospirosis. Specific laboratory values, management details, serologic assay type, and timelines were not provided in the source abstract.)