AN UNUSUAL CASE OF SYMPTOMATIC HYPERCALCEMIA FROM GRAVES' DISEASE IN A YOUNG FILIPINO FEMALE

Abstract

INTRODUCTION
Hypercalcemia in hyperthyroidism is usually asymptomatic, and related to a concurrent primary hyperparathyroidism. In this report, we describe a case of symptomatic hypercalcemia secondary to Graves’ disease alone.

CASE
Her ECG showed sinus tachycardia. The complete blood count and electrolytes were normal however, ionized calcium was high at 1.6 mmol/L (NV 1-1.3). Renal function was normal. Hydration with saline and furosemide 20 mg once daily was started though calcium levels remained elevated. Other causes of hypercalcemia were excluded as PTH was appropriately suppressed (8.8 ng/L; NV 14-72), vitamin D was also low (15.29 nmol/LNV: >30). CT scan of chest and abdomen together with bone scan did not point to any underlying malignancy nor metabolic bone disease. Medication history was also unremarkable. She was hyperthyroid with a suppressed thyroid stimulating hormone level of 0.004 pmol/L (NV: 0.55-4.78), elevated free T3 of >20 pmol/L (NV: 2.3-4.2), and elevated free T4 of 8.4 pmol/L (NV: 0.89-1.76). TSH receptor antibody levels were raised at 41.07 (NV: <1 kU/L) supporting the diagnosis of Graves’disease. She was started on propylthiouracil 50 mg four times daily, along with propranolol 40 mg three times daily. She was subsequently seen after two weeks with normal repeat calcium level and thyroid function tests.

CONCLUSION
This report highlights thyroid disease as a cause of hypercalcemia. The definitive treatment for the hypercalcemia is correction of thyroid function.