Endocrine Abstracts

Nonislet cell tumor hypoglycemia (NICTH) is a rare complication of malignancy characterized by overproduction of incompletely processed IGF-2 and subsequent stimulation of insulin receptors and increased glucose utilization. We report a patient with pancreatic adenocarcinoma with neuroendocrine differentiation who presented with NICTH and paraneoplastic hypercalcemia. A 51 year-old male was admitted to the ER for altered mental status and confusion. His blood glucose was 27 mg/dl and serum potassium was 3.1 mmol/l; other investigations showed increased transaminase levels and normal thyroid function. His vital signs were normal and he was taking no medication. He was treated with a 30 ml bolus of 33% dextrose solution, intravenous KCl and continuous infusion of 10% dextrose solution at 100 ml/h, achieving normoglycemia. After stopping the dextrose infusion for 2 hours, his blood glucose levels dropped again to 22 mg/dl and blood samples were taken; insulin and c-peptide levels were undetectable, cortisol was 18.5 mcg/dl and IGF-1 was 48 ng/ml (53-201). A 1 mg glucagon stimulation test was performed and blood glucose raised to 63 mg/dl at 20 minutes. Whole body CT scan revealed a pancreatic mass measuring 14x12 cm with cystic component, pathological abdominal lymphnodes and numerous liver metastases; tumor biopsy revealed a poorly differentiated adenocarcinoma with neuroendocrine differentiation (synaptophysin +, CD56 -). A diagnosis of NICTH was made and he was started on 30 mg methylprednisolone BID, hyperglucidic diet and 10% dextrose infusion was continued. Despite these therapeutic measures, other severe hypoglycemic episodes occurred and he was started on 8 mg dexamethasone BID, because of its longer duration of action, with discrete benefit. On the fourth day, he experienced a hypercalcemic crisis (blood calcium levels 14.9 mg/dl); other exams showed phosphorus 1.8 mg/dl, normal 25 (OH)vitamin D and magnesium with suppressed PTHi 15.3 pg/ml (14-65). Treatment of paraneoplastic hypercalcemia consisted of i.v. bisphosphonate infusion (zoledronic acid 4 mg) in addition to saline rehydration. In the next three days, calcium levels normalized and remained stable. A trial of octreotide was started in attempt to further reduce hypoglycemic events with no benefit. Unfortunately, the patient was not eligible for tumor debulking or chemotherapy and after seven days, he died due to multiorgan failure. This case report has shown that hypoglycemia in the setting of NICTH is difficult to manage and can be accompanied by other hormone secretory syndromes; longer acting glucocorticoids and increased carbohydrate intake may help reducing severity and frequency of hypoglycemic episodes.