7 What investigations are performed to make a diagnosis of multiple myeloma?Įvaluating a patient with suspected multiple myeloma involves establishing evidence of a monoclonal paraprotein with serum electrophoresis (EPG) and immunofixation, together with an FLC analysis. Smouldering multiple myeloma requires closer follow up because of a higher risk of progression (10% per year compared to 1% per year). These patients may ultimately progress to symptomatic myeloma and require careful monitoring. The condition may become apparent when routine blood tests reveal an elevated total protein and globulin, and subsequent serum electrophoresis demonstrates a monoclonal paraprotein. Smouldering myeloma and MGUSīy definition, patients with MGUS and smouldering multiple myeloma are asymptomatic. Less conventional presentations with myeloma include recurrent bacterial infections (defined as >2 episodes in 12 months), often due to an associated hypogammaglobulinaemia, or symptomatic hyperviscosity with confusion, visual changes, headaches and vertigo.

Thoracic spine x-ray demonstrating multiple wedge compression insufficiency fractures typical of myeloma 6 In regions where MRI is unavailable, computed tomography (CT) may have a role in further investigating suspicious, but non-diagnostic, bony lesions seen on plain film.įigure 2.

Magnetic resonance imaging (MRI) short-tau inversion recovery (STIR) is a more sensitive investigation, and may be used to identify lytic lesions in suspicious cases when the skeletal survey fails to yield a diagnosis. A skeletal survey, or whole body X-ray survey, is typically employed to detect osteolytic lesions.

5 Those with more advanced disease may present with a pathological fracture from minimal trauma ( Figure 2). Lytic lesions are detectable in almost 80% of patients at diagnosis. 4 It is most commonly detected as an asymptomatic elevation in serum creatinine, but patients may rarely present with oliguria or uraemia.īony pain is a relatively common symptom, particularly back pain, occurring in up to 58% of patients. Renal impairment occurs in 20–40% of newly diagnosed patients with myeloma, and is typically due to light chain deposition within the distal and collecting renal tubules or hypercalcaemia. If PTH levels are appropriately suppressed, an alternative explanation such as myeloma must be considered. Some laboratories also offer PTH related peptide assays to exclude paraneoplastic hypercalcaemia. 3 Alternative aetiologies should be excluded with a laboratory assay for intact parathyroid hormone (PTH), which should be suppressed in response to the hypercalcaemia, and vitamin D levels. Profound elevations in serum calcium can rarely lead to coma or cardiac arrhythmia. Symptomatic hypercalcaemia may present in a dramatic fashion with confusion, disorientation, muscle weakness, constipation, anorexia, polyuria and polydipsia. 2 The serum calcium level should always be interpreted after correction for albumin. Hypercalcaemia is a less frequent manifestation of myeloma at diagnosis, occurring in approximately 13% of patients. Routine haematinics are normal and rouleaux may be noted on the blood film. The anaemia of multiple myeloma is typically normochromic and normocytic, but mild macrocytosis can also be seen. Alternatively, an asymptomatic, but persistent, anaemia may be detected on routine bloods. 1 Patients with significant anaemia may present with fatigue, dyspnoea on exertion or angina. A combination of these symptoms should heighten diagnostic suspicion for myeloma.Īnaemia is found in approximately 70% of those with newly diagnosed myeloma. The classical complications are often abbreviated into the acronym ‘CRAB’: consisting of hypercalcaemia, renal impairment, anaemia and bony lesions. The clinical presentation of multiple myeloma can be extremely varied. How can multiple myeloma and MGUS present? Multiple myeloma Usually required to confirm a diagnosis of multiple myelomaĪ small proportion of cases may be non-secretory with undetectable paraprotein No clear explanation including pre-renal causes, primary renal disorders or obstructive conditions No history of malignancy, sarcoidosis or use of medications such as thiazides Parathyroid hormone appropriately suppressed No clear alternative explanation such as renal impairment or anaemia of chronic disease Vitamin B12, folate and iron studies normal When should a diagnosis of myeloma be considered? Finding

Monoclonal gammopathy of undetermined significance is defined as a serum paraprotein of 30 g/L or a bone marrow plasmacytosis of >10% ( Table 1). MGUS and smouldering myeloma are asymptomatic with no evidence of end organ damage. Trephine showing infiltration with malignant plasma cells

Multiple myeloma lab findings usmle