Streptococcus pneumoniae bacteraemia leading to the diagnosis of multiple myeloma.

Multiple myeloma (MM) is a malignant plasma cell disorder characterised by the neoplastic proliferation of a single clone of plasma cells producing a monoclonal immunoglobulin. Anaemia, bone pain from lytic lesions, hypercalcaemia and renal failure are the most common presentations at diagnosis; however, the presence of infection at the time of diagnosis is rarely reported. The author reports an elderly male presenting with isolated fever and initial blood cultures positive for Streptococcus pneumoniae. Investigating the patient's underlying immunodeficient state predisposing him to this infection, serum and urine immunofixation electrophoresis identified monoclonal IgG λ and bone marrow biopsy revealed diffuse plasma cell infiltration that comprised 35% of the cellular elements, which were all consistent with MM. This case report highlights the importance of considering MM in asymptomatic elderly patients who present with acute pneumococcal infection without an apparent predisposing factor.