MON-842 - Refractory Hypercalcemia from Parathyroid Adenoma Despite Medical Therapy and Alcohol Ablation

Introduction 
Primary hyperparathyroidism is the most common cause of hypercalcemia. When indicated, parathyroidectomy is the most effective treatment, though medical therapy or minimally invasive approaches such as alcohol ablation are considered in patients who are poor surgical candidates or decline surgery.  We report a case of longstanding primary hyperparathyroidism complicated by recurrent, severe hypercalcemia refractory to medical management and alcohol ablation.    
 
Case report  
A 71-year-old woman with persistent longstanding primary hyperparathyroidism was hospitalized with confusion, lethargy and reduced appetite. In addition to primary hyperparathyroidism, her medical history included schizoaffective disorder, coronary artery disease, and sick sinus syndrome status post pacemaker placement.  On admission, laboratory findings were notable for severe hypercalcemia (total calcium 16.8 mg/dL, ionized calcium 2.01 mmol/L), markedly elevated intact parathyroid hormone (PTH 1322 pg/mL) and acute kidney injury with creatinine 3.47 mg/dL from a baseline of ~1.8 mg/dL.  
She has had multiple hospitalizations over a three-year period for hypercalcemic crisis with serum calcium levels reaching as high as 17.3 mg/dl in the past requiring aggressive intravenous fluids and medical therapy with pamidronate, calcitonin and denosumab, in addition to the maintenance dose of cinacalcet. Despite localization of left inferior parathyroid adenoma on imaging, she had declined surgical intervention necessitating medical therapy. Hypercalcemia persisted despite maximal medical therapy. Ten months prior to her current admission, an alcohol ablation of the culprit lesion resulted in downtrending serum calcium levels.  However, she subsequently experienced recurrent hypercalcemic crises with progressive end-organ dysfunction, resulting in two additional hospitalizations prior to the current admission. Given the recurrent hospitalization for severe hypercalcemia, she ultimately agreed to surgical intervention, and underwent successful inferior parathyroidectomy resulting in normalization of serum calcium and PTH levels. Her postoperative course was notable for transient hypocalcemia requiring calcium supplementation.  

Conclusion 
This case underscores that parathyroidectomy is the definitive and most durable treatment for primary hyperparathyroidism, particularly in patients with recurrent hypercalcemic crises and end-organ dysfunction. Although hypercalcemic crisis is rare (1-2%) in non-malignant primary hyperparathyroidism, delayed definitive management can result in recurrent hospitalization and morbidity. Medical therapy and alcohol ablation may offer temporary biochemical improvement, but long-term control is limited. Shared decision making and ongoing counseling are critical, as patient preference may change with disease progression.

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