Endocrine Abstracts

A 17-year-old woman was hospitalized emergently after suffering sudden palpitations and losing consciousness. On admittance she was in a state of shock, with a pulse rate of 140/min and systolic blood pressure of 70 mmHg. Echocardiography revealed a diffuse wall hypokinesis with decreased left ventricular ejection fraction. Acute heart failure was diagnosed. Coronary angiography, LV imaging, and myocardial biopsy suggested fulminant Takotsubo cardiomyopathy due to catecholamine hypersecretion, with urine normetanephrine 1350 ng/mg/Cr and urine noradrenaline 728 µg/day (noradrenaline dominant). Other endocrine hormones were in the normal ranges. Paraganglioma (PPGL) was suggested by an abdominal-CT showing a well-defined 33 × 22 mm tumor in the right retroperitoneum and by MRI showing hypointensity on T1-weighted image and a high intensity on T2-weighted image. Scintigraphic and PET-CT evidence of accumulated MIBG confirmed solitary PPGL in the right retroperitoneum. The tumor was surgically removed, and clear evidence of the SDHB mutation was confirmed. The 75 g OGTT test was performed before and after the surgery. Blood glucose (mg/dl) was normal high before resection, and improved after resection. The patient’s IRI value, an all rose sharply at 15 minutes after the preoperative glucose loading. Improvements over the initial secretion expressed by the insulinogenic index (I.I.), the secretion expressed by HOMR-β (significant), and the resistance expressed by the HOMA-IR and Matsuda index were observed.[Discussion] This case has been presented as acute catecholamine cardiomyopathy, Takotsubo cardiomyopathy due to PPGL. Among the various genetic mutations that influence PPGL, those in genes encoding subunits of succinate dehydrogenase are the most relevant. As a mechanism of impaired glucose tolerance in catecholamine-producing tumors, noradrenaline dominance has been reported to lower insulin sensitivity and promote hepatic gluconeogenesis. In our case, hypersecretion of insulin was observed 15 minutes after the glucose loading before resection of the catecholamine-producing tumor, and improvements in the hypersecretion of insulin and insulin resistance were obtained after the tumor was excised. The catecholamine-producing tumor did not appear to impair early insulin secretion in our case. In this case exhibiting insulin hypersecretion at 15 minutes after glucose loading before tumor resection, the insulin secretion seemed to increase in a blood glucose-dependent manner.