Persistently raised inflammatory markers in a patient with resolved lower respiratory tract infection: a diagnostic challenge

We present the case of a woman in her early nineties who was admitted after recurrent falls and a short history of respiratory symptoms. She was diagnosed with influenza A lower respiratory tract infection (LRTI) complicated by hospital-acquired pneumonia (HAP). Despite clinical and radiological recovery, inflammatory markers remained persistently elevated, including neutrophilic leucocytosis, thrombocytosis, and elevated C-reactive protein (CRP), without residual symptoms or objective evidence of infection. Extensive investigation and multidisciplinary input failed to identify an infective, autoimmune, or malignant cause. This case illustrates the challenge of interpreting persistent biochemical abnormalities in older adults, highlights the importance of clinical context, and cautions against over-investigation and unnecessary antibiotic use in asymptomatic patients.