A 65-year-old woman comes to the office due to a month of back pain. The pain is primarily in her lumbar and thoracic spine and is partially relieved with acetaminophen. It is worse with activity and has limited her ability to take restorative yoga classes. The patient has a history of hypertension, type 2 diabetes mellitus, and osteopenia. She takes over-the-counter calcium and vitamin D supplements in addition to prescription medications. The patient had her yearly physical examination 4 months ago; physical and laboratory examinations were normal at that time. Temperature is 36.6 C (97.8 F), blood pressure is 148/82 mm Hg, and pulse is 94/min. The patient is thin but appears well. Mucous membranes are moist. There is no lymphadenopathy in the cervical or supraclavicular chains. Cardiopulmonary and abdominal examinations are normal. There is no focal tenderness over the spine. Muscle strength is 5/5 in all 4 extremities. Laboratory results are as follows: Urine dipstick is negative and urine sediment is bland except for a few granular casts. Which of the following is the most likely cause of this patient's current condition?

Question

A 65-year-old woman comes to the office due to a month of back pain.  The pain is primarily in her lumbar and thoracic spine and is partially relieved with acetaminophen.  It is worse with activity and has limited her ability to take restorative yoga classes.  The patient has a history of hypertension, type 2 diabetes mellitus, and osteopenia.  She takes over-the-counter calcium and vitamin D supplements in addition to prescription medications.  The patient had her yearly physical examination 4 months ago; physical and laboratory examinations were normal at that time.  Temperature is 36.6 C (97.8 F), blood pressure is 148/82 mm Hg, and pulse is 94/min.  The patient is thin but appears well.  Mucous membranes are moist.  There is no lymphadenopathy in the cervical or supraclavicular chains.  Cardiopulmonary and abdominal examinations are normal.  There is no focal tenderness over the spine.  Muscle strength is 5/5 in all 4 extremities.  Laboratory results are as follows:  Urine dipstick is negative and urine sediment is bland except for a few granular casts.  Which of the following is the most likely cause of this patient's current condition?

Quizplus · Accepted Answer

Multiple myeloma (MM) is a plasma cell neoplasm. Patients with MM often present with constitutional symptoms (fatigue, weight loss) or bone pain (back, chest). MM is characterized by the proliferation of neoplastic cells in the bone marrow (bone destruction, hypercalcemia, anemia) and the excessive production of a single immunoglobulin (monoclonal protein). The latter can accumulate at high levels in the serum and deposit in the renal tubules. This can result in renal insufficiency, often with a bland urinalysis (urine dipstick protein typically detects albumin, not immunoglobulins) that may show evidence of granular casts. The monoclonal protein can also damage the glomeruli (amyloidosis, monoclonal immunoglobulin deposition disease), leading to nephrotic syndrome. (Choice A) Acetaminophen toxicity may occur at high doses. However, it typically affects the liver (hepatitis, jaundice) and would not account for this patient's hypercalcemia or anemia. (Choice B) Diabetic nephropathy usually develops over many years and is associated with albuminuria. With normal laboratory studies 4 months ago and a bland urinalysis, this patient is unlikely to have diabetic nephropathy. (Choice D) Primary hyperparathyroidism can cause hypercalcemia. However, most patients are asymptomatic or are diagnosed after developing calcium nephrolithiasis. This patient who has hypercalcemia associated with bone pain and anemia is more likely to have multiple myeloma. (Choice E) Systemic lupus erythematosus typically causes glomerular injury resulting in proteinuria and hematuria, often with an increase in creatinine. This patient has a bland urinalysis, making lupus nephritis unlikely. (Choice F) Vitamin D toxicity tends to occur only at exceedingly high doses and is associated with vomiting, confusion, polyuria, and polydipsia. Anemia and renal failure would be uncommon. Educational objective: Multiple myeloma is a plasma cell neoplasm. It is characterized by the excessive production of monoclonal protein that can accumulate in the kidneys and cause renal insufficiency. Approximately 50% of patients with multiple myeloma have renal insufficiency at diagnosis.

A 65-Year-Old Woman Comes to the Office Due to a Month