BACKGROUND: Infective endocarditis (IE) typically presents with fever, a heart murmur, or constitutional symptoms, making diagnosis challenging when neurological manifestations predominate. We report an atypical case of IE in which disturbance of consciousness was the initial manifestation.

CASE REPORT: A man in his 50s was admitted to our hospital with isolated disturbance of consciousness and no history of fever; a temperature of 38°C was recorded on admission. Investigations confirmed an extensive acute right hemispheric watershed (border-zone) infarction involving the right temporoparietal lobe, without evidence of hemorrhagic transformation or intracranial hemorrhage. Subsequent workup identified Staphylococcus aureus bacteremia, mitral valve vegetation, and multiple organ dysfunction syndrome. The absence of classic IE risk factors contributed to a delayed diagnosis. Guideline-concordant clinical management was implemented. Long-term outcome data were unavailable because of patient transfer; only in-hospital mortality (after transfer) was confirmed. We discuss the application of the 2023 Duke criteria to this case and examine factors contributing to the delayed diagnosis of IE. Disturbance of consciousness as the predominant initial manifestation of S. aureus IE is rare and frequently results in diagnostic delay. This case underscores the importance of maintaining a high index of suspicion for IE in patients with sepsis complicated by acute cerebral infarction, particularly among critical care and neurology clinicians.

CONCLUSIONS: This case highlights isolated disturbance of consciousness as an atypical initial presentation of IE. Although IE is frequently complicated by acute cerebral infarction, clinicians may not routinely consider IE in the differential diagnosis of patients presenting with disturbed consciousness.

Keywords: Cardiology, Case Reports, Consciousness Disorders, Diagnosis, Endocarditis, literature review