Multiple myeloma presenting with bilateral ankle pain (microangiopathy) and complicated by streptococcal meningitis and Pneumocystis carinii pneumonia.

Multiple myeloma is characterised by the neoplastic proliferation of a single clone of plasma cells producing a monoclonal immunoglobulin. This clone of plasma cells proliferates in the bone marrow, resulting in extensive skeletal destruction with osteolytic lesions, osteopenia and pathological fractures. Additional disease-related complications include hypercalcaemia, renal insufficiency, anaemia and infection. We present the case of a 64-year-old woman presenting with rapid onset, painful distal symmetrical lower limb weakness and an acute kidney injury. Owing to her IgG κ paraprotein (kappa light chain 4620, kappa:lambda ratio 826), she was diagnosed with probable plasma cell myeloma. This diagnosis was confirmed following a trephine biopsy. She required renal replacement therapy, inotropic support and a percutaneous tracheostomy. She became acutely confused with a Glasgow Coma Scale score of 10/15 and a CT head showed no acute pathology. Further investigation with a lumbar puncture confirmed the diagnosis of streptococcal meningitis. She was treated with intravenous acyclovir, ceftriaxone and fluconazole. Her non-bronchoalveolar lavage revealed a diagnosis of Pneumocystis carinii pneumonia and she required treatment with co-trimoxazole. This case report discusses the clinical presentation, diagnostic algorithm and treatment of myeloma. This manuscript offers an important clinical reminder to consider myeloma in the differential diagnosis in patients presenting with bone pain and acute kidney injury.