Category: Calcium/Bone Disorders

Monitor: 26

26 - TRANSIENT HYPOPHOSPHATEMIA: DANGEROUS EVENT IN MULTIPLE MYELOMA

Saturday, Apr 27
10:00 AM – 10:30 AM

Objective : Patient with malignancies frequently experience multiple electrolyte disturbances. In multiple myeloma, the hypercalcemia and hyperphosphatemia are common biochemical disorders. However, in rare occasions develops hypophosphatemia due to multiple factors that affects the phosphate absorption and excretion. This case describes a 56-year-old woman recently diagnosed with multiple myeloma who developed severe hypophosphatemia during the medical management.


Methods : n/a


Results : n/a


Discussion : This is the case of a 56-year-female Hispanic female who was transferred from a community medical clinic to our institution for management of acute anemia, severe hypercalcemia and renal failure. She presented to ER with fatigue and general weakness since 3 months ago. Upon examination, the vital signs showed a blood pressure 161/76 mmHg, heart rate 78 bpm and respiratory rate 18. She looks pale and acutely ill. Radiographic images showed multiple skeletal lytic lesions. The initial laboratories revealed anemia 6.7 g/dl, albumin corrected hypercalcemia 12.7 mg/dl, high total proteins 11.5g/dl, elevated creatinine 6.16 mg/dl, normal intact PTH 25 pg/ml and low-normal phosphate 2.5mg/dl. The Hematology/Oncology service was consulted, and the patient was diagnosed with IgG/Kappa multiple myeloma. Intensive hydration, dexamethasone and zoledronic acid were initiated. Renal function improved as well as the corrected calcium but developed hypophosphatemia 1.9mg/dl. Endocrinology service was consulted and on evaluation of hypophosphatemia she was found with normal vitamin D 25 OH  38.1ng/mL, high intact PTH 119 pg/ml and elevated fraction excretion of filtered phosphate (FePO4) 14%. After phosphate supplementation, patient continue therapy with cyclophosphamide, bortezomib and dexamethasone. Then, the phosphate decreased to a severe low concentration of 0.87 mg/dl with a very high intact parathyroid hormone 711 pg/mL and unexpected low ionized calcium 1.15mEq/L. In view of the poor response to phosphate supplement, and the new diagnosis of secondary hyperparathyroidism and pseudonormocalcemia, we decide to start calcitriol and electrolytes normalized.


Conclusion :

The electrolytes disturbances could be very difficult to correct in patient with cancer.  The multiple medical therapies and the pathophysiology of the disease can provoke or unmask the true disturbances. It is important to recognize that multiple myeloma can cause falsely elevated levels of calcium due to paraproteinemia. Ionized calcium should be evaluated to confirm that hypercalcemia is indeed present. Clinicians should recognize spurious electrolytes disorders and prevent intervention that could be detrimental for cancer patients.


 


 

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Paula Jeffs-Gonzalez

Fellow of Endocrinology
San Juan City Hospital, Puerto Rico

Paula Jeffs-Gonzalez was born on March 18, 1980 in Santiago, Chile. In 1985, moved with the family to San Juan, Puerto Rico. She studied a bachelor in science with a major in medical technology in Interamerican University of Puerto Rico. In 2012, graduate of school of medicine from Iberoamerican University, Dominican Republic. In 2013, she trained in Oncologic Hospital of Puerto Rico. In 2017, completed a residency in Internal Medicine in San Juan City Hospital and is board certified in internal medicine. Currently, is in the endocrinology fellowship in San Juan City Hospital. Her clinical interest include all aspect of endocrinology with special interest in calcium and bone health.

Michelle Mangual- Garcia

Program Director
San Juan City Hospital
SAN JUAN

Program Director at San Juan City Hospital

Paula Jeffs

Fellow of Endocrinology
San Juan City Hospital, Puerto Rico, Not Applicable, Puerto Rico

Alex Gonzalez-Bossolo