Differential Diagnosis

The patient's presentation of fatigue, generalized bone pain, high calcium levels, anemia (Hb: 8), and elevated creatinine (210) suggests a systemic disorder affecting bone and renal function. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Multiple Myeloma: This is the most likely diagnosis given the combination of high calcium levels (hypercalcemia), anemia, renal impairment (elevated creatinine), and bone pain. Multiple myeloma is a plasma cell dyscrasia characterized by these findings due to bone marrow infiltration by malignant plasma cells, which can lead to bone destruction, renal failure, and anemia.

• Other Likely Diagnoses

  • Paget Disease: While Paget disease can cause bone pain and elevated calcium levels, it typically presents with more localized bone involvement and less frequently with significant renal impairment or anemia to this degree. However, it remains a consideration.
  • Chronic Myeloid Leukemia (CML): CML can cause anemia and bone pain due to marrow infiltration, but it less commonly presents with hypercalcemia and significant renal impairment as primary features.

• Do Not Miss Diagnoses

  • Metastatic Cancer: Although not as directly suggested by the lab findings, metastatic cancer (e.g., breast, lung, or prostate cancer) can cause hypercalcemia, bone pain, and renal impairment. Missing this diagnosis could be catastrophic, so it's essential to consider and rule out with appropriate imaging and tumor marker studies.
  • Primary Hyperparathyroidism: This condition can cause hypercalcemia and, less commonly, renal impairment. While it's less likely given the full picture, especially with significant anemia and bone pain, it's a diagnosis that should not be missed due to its potential for significant morbidity if untreated.

• Rare Diagnoses

  • Systemic Lupus Erythematosus (SLE): SLE can cause a wide range of systemic symptoms, including renal impairment and anemia. However, it is less commonly associated with significant hypercalcemia and bone pain as primary presenting features. SLE would be an unusual diagnosis given the specific combination of findings in this patient.
  • Other rare plasma cell dyscrasias or lymphoproliferative disorders: These could potentially present with similar findings but are less common than multiple myeloma and would require specific diagnostic testing for identification.