Multiple Myeloma. Diagnostic challenges and standard therapy.

In the diagnosis of multiple myeloma (MM), the clinician must exclude other disorders in which a plasma cell reaction may occur such as rheumatoid arthritis and connective tissue disorders, or metastatic carcinoma where the patient may have osteolytic lesions associated with bone metastases. Patients with smoldering multiple myeloma (SMM) or monoclonal gammopathy of undetermined significance (MGUS) have none of the complicating features of MM and do not require treatment with potentially toxic agents. The plasma cell labeling index can help make a differential diagnosis of MM from SMM. Patients with a high labeling index have a high risk of complications and should be monitored carefully. However, the labeling index can be low in active MM. In addition, SMM or MGUS patients have few or no circulating plasma cells. High-dose chemotherapy and stem cell support prolong overall survival in contrast to conventional therapy. If stem cell transplantation is considered, it is important to harvest the cells before using alkylating agents to obtain a sufficient number of cells. Supportive treatment consists of the occasional use of erythropoietin to maintain adequate hemoglobin levels and adequate hydration to protect renal function. Vaccination against pneumococcal infections and the prophylactic use of antibiotic therapy during the first 2 months of treatment can be beneficial. Recognizing the symptoms of spinal cord compression and initiating dexamethasone therapy promptly to prevent paraplegia are critical.