Today, we had an interesting case of an elderly female who presented with lethargy, constipation and generalized weakness found to have hypercalcemia. Hypercalcemia workup starts with PTH dependent vs PTH independent etiologies.
PTH dependent hypercalcemia
- If elveated urinary calcium, think primary hyperparathyroidism
- If normal or low urinary calcium, think FHH
PTH independent hypercalcemia
- If PTHrP elevated, think cancer
- If high 25 Vit D and high 1,25 Vit D, think excessive PO intake
- If high 1 25 Vit D, think granulomatous disease
- If normal, think medications, immobilization, hyperthyroidism or adrenal insufficiency
Given the hypercalcemia, protein gap, and pancytopenia, the suspicion for multiple myeloma (MM) was high. Subsequent SPEP with immunofixation and bone marrow biopsy confirmed the diagnosis of IgG kappa Multiple Myeloma. Remember that multiple myeloma is a clonal proliferation of plasma cells and bone marrow biopsy with more than 10% plasma cells confirms diagnosis. The monoclonal protein produced by these plasma cells is an abnormal immunoglobulin (immunoglobulin G [IgG], IgM, or IgA, or, rarely, IgE or IgD) and/or light chain protein (kappa or lambda), either of which causes hyperviscosity and/or end-organ damage.