A 63-year-old man comes to the physician because of back and neck pain for the last 2 months. He takes over-the-counter acetaminophen and ibuprofen with adequate pain relief; however, the pain has recently begun to disturb his sleep. He denies weight loss, night sweats, and joint swelling. He has no other medical problems. His father was diagnosed with prostate cancer at the age of 65 and died from metastatic disease.
His blood pressure is 112/72 mm Hg and pulse is 89/min. There is no peripheral lymphadenopathy. The liver span is 11 cm and the spleen is not palpable. There is no spinal deformity or percussion tenderness. There are no skin rashes. The prostate is mildly enlarged and rubbery.
Laboratory results are as follows:

Radiographs of the lumbar spine show multiple lytic lesions and a compression fracture of the L3 vertebra. Serum protein agar gel electrophoresis and immunofixation do not reveal an M-spike.
Which of the following is the most appropriate next step in managing this patient?

Question

A 63-year-old man comes to the physician because of back and neck pain for the last 2 months.  He takes over-the-counter acetaminophen and ibuprofen with adequate pain relief; however, the pain has recently begun to disturb his sleep.  He denies weight loss, night sweats, and joint swelling.  He has no other medical problems.  His father was diagnosed with prostate cancer at the age of 65 and died from metastatic disease.
His blood pressure is 112/72 mm Hg and pulse is 89/min.  There is no peripheral lymphadenopathy.  The liver span is 11 cm and the spleen is not palpable.  There is no spinal deformity or percussion tenderness.  There are no skin rashes.  The prostate is mildly enlarged and rubbery.
Laboratory results are as follows:

Radiographs of the lumbar spine show multiple lytic lesions and a compression fracture of the L3 vertebra.  Serum protein agar gel electrophoresis and immunofixation do not reveal an M-spike.
Which of the following is the most appropriate next step in managing this patient?

Quizplus · Accepted Answer

11ec193a_9831_7bd5_853d_1fcf09fb5b45_MD0002_00 This patient's presentation (bone pain, normocytic anemia, hypercalcemia, mild renal insufficiency, and lytic lesions on x-ray) is consistent with multiple myeloma. Diagnosis is usually confirmed by serum protein electrophoresis detecting an M-spike and urine protein electrophoresis showing light (kappa > lambda) and heavy chains. Serum immunofixation increases sensitivity > 90% for detecting the M-spike in addition to determining the type of M-spike (usually IgG). Urine immunofixation increases the sensitivity even further (~ 97%) for identifying light/heavy chains. Up to 20% of myeloma patients secrete only a urine light chain, which does not produce an M spike on serum electrophoresis. Urine immunofixation is crucial for detecting monoclonal light chains in these cases. Adding a serum free light chain assay further increases the sensitivity of detection and can be used instead of urine immunofixation. Patients without evidence of monoclonal protein after thorough investigation are labeled as having "non secretory" myeloma and represent approximately 3% of multiple myeloma cases. This patient has many diagnostic features and a negative M-spike in the serum; a urine immunofixation or serum free light chain assay should be performed next to document light chains. (Choice A) Bone marrow biopsy is performed to quantify the percentage of plasma cells; however, it is usually done after checking a serum protein electrophoresis and urine immunofixation. It would also be diagnostic in cases of true non-secretory myeloma. (Choice B) CT of the chest, abdomen, and pelvis is indicated in the work-up for metastatic disease of unknown primary origin. It can also be used to detect bony lesions in multiple myeloma patients with bone pain who have negative x-rays. However, this patient has classic symptoms of multiple myeloma with abnormal x-rays. (Choice C) ESR is generally elevated in multiple myeloma, but it is neither specific nor diagnostic. Complement levels are decreased in immune complex-mediated nephritis, but would not be helpful in this case. (Choice D) Prostate biopsy would be indicated for suspected prostate cancer, which can be associated with an elevated PSA (> 4.0 ng/dL) and/or urinary symptoms. However, this patient's normal PSA and lack of symptoms make this diagnosis less likely. Educational objective: Multiple myeloma is usually diagnosed by serum electrophoresis showing an M-spike and urine electrophoresis with immunofixation showing light/heavy chains. Urine studies can be replaced by serum free light chain assay for screening purposes. Patients with negative serum and urine studies are labelled as having non-secretory myeloma. __________ References: Review of 1027 patients with newly diagnosed multiple myeloma. (http://www.ncbi.nlm.nih.gov/pubmed/12528874) International Myeloma Working Group guidelines for serum-free light chain analysis in multiple myeloma and related disorders. (http://www.ncbi.nlm.nih.gov/pubmed/19020545) Criteria for the classification of monoclonal gammopathies, multiple myeloma and related disorders: a report of the International Myeloma Working Group. (http://www.ncbi.nlm.nih.gov/pubmed/12780789)

A 63-Year-Old Man Comes to the Physician Because of Back