PS-R03-5: HYPOTENSIVE AND HYPERGLYCEMIC EFFECTS OF DIAZOXIDE IN A CASE OF INSULINOMA

Abstract

Case report: We report the case of sporadic insulinoma in a 70-year-old female with breast cancer and hypertension treated by irbesartan 100 mg and benidipine 8 mg, who presented with a 1-month history of episodic tremulousness, diaphoresis, increased hunger, confusion and fainting. Initial laboratory investigations showed low blood glucose (21 mg/dL) and high blood insulin (107 μU/mL) levels. The hypoglycemic symptoms were relieved greatly by glucose administration and Whipple's triad for insulinoma was met. An abdominal contrast-enhanced computed tomography scan showed a 12 mm, small, well demarcated, heterogeneously enhancing lesion within the tail of pancreas without dilatation of pancreatic duct. The site also showed a well-defined accumulation of boundaries on PET-CT. Patient was diagnosed with insulinoma. Since Patient did not initially wish to undergo surgery, blood glucose control was performed by taking diazoxide 225 mg, gradually reduced to 50 mg. Before and after taking diazoxide, blood glucose increased from 75 ± 40 mg/dL to 124 ± 35 mg/dL significantly (p < 0.05). On the other hand, blood pressure was significantly reduced from 141 ± 3/78 ± 3 mmHg to 126 ± 3/75 ± 3 mmHg. Benidipine was withdrawn to about 130/80 mmHg. Then, Patient changed her mind and underwent laparoscopic caudal pancreatic resection. Histopathological examination of the pancreatic mass confirmed neuroendocrine tumor (insulinoma). Patient had an uneventful recovery. Blood pressure re-increased above 140/90 mmHg and benidipine was resumed. Although diazoxide suppresses insulin secretion in the pancreas due to its KATP channel opening action and improves hypoglycemic attacks with insulinoma, it also acts on the KATP channel of vascular smooth muscle and show a hypotensive effect. It is important to pay close attention not only to blood glucose but also to blood pressure fluctuations when using diazoxide.