Acquired platelet dysfunction induced by infection in an older patient: Severe hemorrhage despite normal platelet count

We report a rare case of acquired, transient platelet dysfunction induced by infection in an older patient. An 84-year-old female with persistent pneumonia presented with severe mucocutaneous bleeding and anemia (nadir hemoglobin: 38 g/L) despite normal platelet count and coagulation parameters. Platelet function tests showed absent or reduced aggregation to all standard agonists. Treatment included platelet transfusion support, targeted anti-infection therapy, and adjunctive agents (ulinastatin and sulodexide) to address inflammation and endothelial dysfunction. The patient’s platelet function normalized with the resolution of infection. This case highlights infection as an underrecognized etiology of acquired platelet dysfunction, particularly in older patients, where normal platelet counts may obscure the diagnosis of major platelet functional impairment.