Question

A 70-year-old man with a history of hypertension presents with complaints of fatigue and worsening lower back and pelvic pain. He denies a history of trauma or fever. On examination, he is pale with diffuse tenderness to palpation of his lumbar spine and pelvis. Neurological examination is nonfocal. Laboratory studies show a normocytic anemia and a creatinine of 1.9 mg/dL. His X-ray is shown above. What is the most likely diagnosis?

a) Cauda equina syndrome
b) Lymphoma
c) Metastatic prostate cancer
d) Multiple myeloma

Answer 1

The most likely diagnosis for the described 70-year-old man with back pain, anemia, and renal dysfunction is multiple myeloma. This condition can cause both the skeletal symptoms and the renal dysfunction presented in the case.

Step-by-step explanation:

Given the presentation of a 70-year-old man with a history of hypertension, complaints of fatigue, worsening lower back and pelvic pain without a history of trauma or fever, paleness, diffuse tenderness to palpation of his lumbar spine and pelvis, nonfocal neurological examination, normocytic anemia, and a creatinine of 1.9 mg/dL, one of the differential diagnoses to consider is multiple myeloma. The laboratory findings of anemia and renal impairment, along with the described symptoms and age of the patient, are consistent with this diagnosis. The presence of bone pain in the absence of trauma also points towards a diagnosis involving the bone marrow, such as multiple myeloma, which can lead to bone lesions and increased fracture risk. Furthermore, multiple myeloma may result in renal dysfunction due to factors like hypercalcemia or "cast nephropathy", a condition where high amounts of proteins from cancerous plasma cells clog the kidneys.