Recurrent Pneumococcemia

A 61-year-old woman is admitted with fever, cough, and purulent sputum. Chest radiography shows right lower lobe consolidation, and blood cultures obtained on presentation grow penicillin-susceptible Streptococcus pneumoniae. Review of the chart shows that she also had a previous episode of pneumococcal bacteremia about 1 year earlier.

Laboratory evaluation shows a white blood cell count of 0.9 x 10^3/uL, hemoglobin 10.4 g/dL, platelets 196 x 10^3/uL, total protein 10.3 g/dL, albumin 2.8 g/dL, creatinine 1.0 mg/dL, and calcium 9.1 mg/dL. A peripheral blood smear demonstrates prominent rouleaux formation. She has no known history of splenectomy, cirrhosis, or advanced HIV infection.

Given the recurrence of invasive pneumococcal disease and the abnormal laboratory pattern, the team begins to consider whether there is any immunodeficiency that could be predisposing her to recurrent infection.