Left-sided infective endocarditis driven by Pseudomonas is a rare and life-threatening condition, particularly when it occurs in patients without a history of injection drug use. According to a case report published in Cureus, clinicians managed a complex presentation involving septic shock and ischemic stroke in a patient undergoing programmed death-ligand 1 (PD-L1) inhibitor therapy.
Clinical Presentation and Emergency Findings
The patient presented with acute clinical deterioration characterized by septic shock, a systemic inflammatory response triggered by a severe bacterial infection. Medical evaluation also revealed an acute ischemic stroke, caused by septic emboli breaking off from cardiac valve vegetations and traveling to the brain. While infective endocarditis typically affects the right side of the heart in people who inject drugs, left-sided involvement introduces a high risk of systemic arterial embolization, affecting organs such as the brain, kidneys, and spleen.
Role of Immunotherapy in Infection Risk
The patient was actively receiving PD-L1 inhibitor therapy, a type of immune checkpoint inhibitor used in cancer treatment. Immune checkpoint inhibitors enhance the body’s immune response against tumors, but they can also trigger immune-related adverse events or alter infection susceptibility. According to the medical team, managing oncological therapies while addressing severe opportunistic or uncommon bacterial infections requires careful balancing of immunosuppressive and restorative strategies.
Diagnostic Challenges of Pseudomonas Endocarditis
Pseudomonas species are uncommon pathogens in native-valve infective endocarditis, accounting for a small percentage of cases outside of healthcare-associated exposures or intravenous drug use. Blood cultures remain critical for confirming bacteremia, while echocardiography—specifically transesophageal echocardiography—is essential for visualizing valvular vegetations, abscesses, or perforation. Early identification of the organism guides targeted antimicrobial therapy, which often requires prolonged courses of combination intravenous antibiotics.
Prognosis and Treatment Strategies
Treating left-sided Pseudomonas endocarditis complicated by septic shock and stroke demands a multidisciplinary approach involving cardiology, infectious disease, neurology, and critical care specialists. Surgical intervention is frequently required alongside antimicrobial therapy to remove infected valve tissue and manage persistent heart failure or recurrent embolization. Mortality rates for left-sided endocarditis remain significant, making rapid hemodynamic stabilization and prompt source control vital for patient survival.
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