A 58 years old woman, who had backache and recurrent chest infections for 6 months, develops sudden weakness of the legs and urinary retention. His investigations show a hemoglobin of 7.3 gm/dl, serum calcium 12.6 mg/dl, phosphate-2.5 mg/dl, alkaline phosphatase-100 u/1, serum albumin-3 gm/dl, globulin-7.1 gm/dl and urea-178 mg/d. What is the most likely diagnosis?
A 58 years old woman, who had backache and recurrent chest infections for 6 months, develops sudden weakness of the legs and urinary retention. His investigations show a hemoglobin of 7.3 gm/dl, serum calcium 12.6 mg/dl, phosphate-2.5 mg/dl, alkaline phosphatase-100 u/1, serum albumin-3 gm/dl, globulin-7.1 gm/dl and urea-178 mg/d. What is the most likely diagnosis?
💡 Explanation
**Core Concept**
Hypercalcemia of malignancy is a condition where an elevated serum calcium level is caused by the presence of a cancer. This can occur through various mechanisms, including bone destruction, increased osteoclast activity, or the production of parathyroid hormone-related protein (PTHrP) by tumor cells.
**Why the Correct Answer is Right**
The patient's presentation of hypercalcemia, anemia, renal impairment, and elevated alkaline phosphatase suggests a diagnosis of multiple myeloma. Multiple myeloma is a type of plasma cell dyscrasia characterized by the clonal proliferation of malignant plasma cells in the bone marrow. The elevated calcium level is due to the breakdown of bone by osteoclasts, which is stimulated by the production of RANKL (receptor activator of NF-kB ligand) by myeloma cells. The anemia is due to the replacement of normal bone marrow by malignant plasma cells, while the renal impairment is caused by the hypercalcemia.
**Why Each Wrong Option is Incorrect**
**Option A:** While hyperparathyroidism can cause hypercalcemia, the patient's elevated globulin level and anemia suggest a malignancy rather than a parathyroid disorder.
**Option B:** Osteomalacia is a condition characterized by softening of the bones due to impaired mineralization, which is not consistent with the patient's elevated alkaline phosphatase level.
**Option C:** Paget's disease is a localized bone disorder that can cause hypercalcemia, but it typically presents with localized bone pain and deformity, rather than systemic symptoms.
**Clinical Pearl / High-Yield Fact**
Multiple myeloma is often associated with a "CRAB" syndrome, which stands for Calcium (hypercalcemia), Renal (renal impairment), Anemia, and Bone lesions (lytic bone lesions).
**Correct Answer:** C.
✓ Correct Answer: C. Multiple myeloma
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