A 66-year-old man comes to the office due to increasing pain in his left arm. The patient works as a furniture transporter and initially attributed the pain to a muscular strain, but it has slowly worsened and stopped responding to over-the-counter pain medications. The pain started 3 months ago and is mainly near the left elbow. He also notes back pain. He has not had fever or chills. His other medical problems include hypertension and hypercholesterolemia. The patient has never smoked. Temperature is 36.8 C (98.2 F), blood pressure is 132/86 mm Hg, pulse is 88/min, and respirations are 14/min. He appears comfortable. His mucous membranes are pale. There is no lymphadenopathy. Cardiopulmonary examination is normal. The abdomen is soft without organomegaly. The prostate is smooth, nontender, and moderately enlarged. Neurologic examination is unremarkable. Laboratory results are as follows: X-ray of the left arm is shown in the exhibit.

Which of the following tests would be the most useful next step in the management of this patient?

Question

A 66-year-old man comes to the office due to increasing pain in his left arm. The patient works as a furniture transporter and initially attributed the pain to a muscular strain, but it has slowly worsened and stopped responding to over-the-counter pain medications. The pain started 3 months ago and is mainly near the left elbow. He also notes back pain. He has not had fever or chills. His other medical problems include hypertension and hypercholesterolemia. The patient has never smoked. Temperature is 36.8 C (98.2 F) , blood pressure is 132/86 mm Hg, pulse is 88/min, and respirations are 14/min. He appears comfortable. His mucous membranes are pale. There is no lymphadenopathy. Cardiopulmonary examination is normal. The abdomen is soft without organomegaly. The prostate is smooth, nontender, and moderately enlarged. Neurologic examination is unremarkable. Laboratory results are as follows:

X-ray of the left arm is shown in the exhibit.

Which of the following tests would be the most useful next step in the management of this patient?

Quizplus · Accepted Answer

11ec25c8_d131_2ad2_bc81_7b6de0239410_MD0003_00 This patient has back pain, normocytic anemia, and arm pain with an x-ray showing multiple osteolytic (lucent) lesions. In an elderly patient, this raises suspicion for multiple myeloma (MM). MM is a plasma cell neoplasm. Pathology stems from bone marrow infiltration (fractures, hypercalcemia, anemia) and monoclonal protein production (renal insufficiency). Serum protein electrophoresis (SPEP) is a common screening test for MM that detects elevated serum monoclonal protein (M-spike). Bone marrow biopsy, a more invasive procedure, can then confirm diagnosis (>10% clonal plasma cells). (Choice A) Blood cultures are useful for diagnosing infections. This patient has symptoms of bone pain and evidence of osteolytic lesions. He has not had fevers, chills, or other systemic symptoms. Infection is much less likely than malignancy. (Choice B) Bone marrow biopsy is an invasive test and performed only after gathering more information with peripheral smear (rouleaux), serum free light chain analysis, SPEP, and urine protein electrophoresis. (Choice C) Bone scans are not useful in the diagnosis of MM as they detect only osteoblastic activity (as is often seen in metastatic solid tumors). In MM, the lesions are osteoclastic (lytic), so whole body cross-sectional bone imaging (eg, low dose CT scan), is needed to identify bone involvement. (Choice D) Prostate cancer can cause bone lesions, but they tend to be osteoblastic (sclerotic) not osteolytic. In a patient with osteolytic lesions alone, MM is far more likely. (Choice E) Hyperparathyroidism can cause osteopenia with subsequent fractures but is unlikely to cause osteolytic lesions. Osteitis fibrosa cystica (eg, brown tumors of the long bones) is associated with hyperparathyroidism; however, it is very rare in the United States, lesions are typically well-defined (vs moth-eaten appearance), and other radiographic abnormalities are common (eg, subperiosteal bone resorption of the middle phalanx, highly specific for hyperparathyroidism). MM is far more common and more likely. Educational objective: Bone pain is a common presenting symptom in multiple myeloma (MM). In an elderly patient with evidence of osteolytic lesions on x-ray, MM should always be suspected. The screening tests of choice for MM are serum protein electrophoresis, urine protein electrophoresis, and free light chain analysis. Diagnosis can be confirmed with bone marrow biopsy.

A 66-Year-Old Man Comes to the Office Due to Increasing