Disseminated Septic Emboli From Aortic Valve Infective Endocarditis in an Immunocompromised Patient: A Case Report

Disseminated sepsis with septic embolic disease can present with a wide spectrum of clinical manifestations and may closely mimic metastatic malignancy or immune-related adverse events in oncology patients. We report the case of a 50-year-old woman with cervical squamous cell carcinoma receiving pembrolizumab and infliximab who presented with fever, progressive blistering skin lesions, non-pruritic rash, and new right-sided neurological deficits. Initial concerns included toxic epidermal necrolysis, immunotherapy-related toxicity, metastatic disease, and severe infection. Examination revealed haemorrhagic blisters involving the fingers and toes, truncal rash, and transient right-sided weakness. Blood investigations demonstrated markedly elevated inflammatory markers. Imaging showed a cavitating left lower lobe lung lesion with air-fluid level, bilateral pulmonary infiltrates, hepatic lesions, and ring-enhancing lesions within the left frontal and parietal lobes concerning for cerebral abscesses or metastases. MRI brain findings favoured cerebral abscesses with surrounding vasogenic oedema. Wound cultures from hand and foot lesions grew Streptococcus pyogenes (Group A Streptococcus). Multidisciplinary input from dermatology, oncology, respiratory medicine, microbiology, vascular surgery, gastroenterology, and neurosurgery guided management. The patient initially received empirical piperacillin-tazobactam and gentamicin for severe sepsis. Following multidisciplinary microbiology review, antimicrobial therapy was escalated to meropenem and teicoplanin to provide broad-spectrum coverage while the diagnostic evaluation was ongoing because of extensive cerebral, pulmonary, and soft tissue infection in an immunocompromised host. The patient demonstrated significant clinical and biochemical improvement, and pembrolizumab and infliximab were withheld. Neurosurgical intervention was not considered appropriate due to the extent of systemic disease and favourable response to medical management. This case highlights the diagnostic complexity of disseminated infection in immunocompromised oncology patients, particularly when septic emboli and cerebral abscesses mimic metastatic disease or immune-related adverse events. Early multidisciplinary assessment and prompt antimicrobial therapy were essential in achieving clinical stabilisation.