Most common tumor of pancreas is
a. Insulinoma is the most common functioning tumor of the pancreas, and affected patients have a tableau of symptoms referable to hypoglycemia (symptoms of catecholamine release), mental confusion and obtundation, or both.
a. The diagnostic hallmark of the syndrome is the so-called Whipple triad, namely, symptoms of hypoglycemia (catecholamine release) and low blood glucose (40-50 mg/dL) and relief of symptoms after the IV administration of glucose.
b. The triad is not entirely diagnostic because it may be emulated by factitious administration of hypoglycemic agents, by rare soft tissue tumors, or occasionally by reactive hypoglycemia.
c. The clinical syndrome of hyperinsulinism may follow one of two patterns or sometimes a combination of both.
d. The symptom complex may be due to autonomic nervous overactivity, as expressed by fatigue, weakness, fearfulness, hunger, tremor, sweating, and tachycardia, or alternatively, a central nervous system disturbance with apathy (or irritability or anxiety), confusion, excitement, loss of orientation, blurring of vision, delirium, stupor, coma, or convulsions.
e. The pathognomonic finding is an inappropriately high (>5 mU/mL) level of serum insulin during symptomatic hypoglycemia.
f. A possible mechanism for this high level of insulin in the face of hypoglycemia may be overexpression of the insulin splice variant.
g. A diagnostic ratio of blood insulin (in microunits per milliliter) to glucose (in milligrams per deciliter) of greater than 0.4 or C peptide levels higher than 2 nmol/L have proved valuable in diagnosis.
h. The best way to induce hypoglycemia is with fasting: two thirds of patients will experience hypoglycemic symptoms in 24 hours, and nearly all other patients experience symptoms by 72 hours of fasting.
i. Provocative tests, usually involving tolbutamide or glucagon, have been used, but they may cause dangerously profound hypoglycemia and are not generally necessary.
j. Most important, preoperative fasting orders must be accompanied by IV administration of glucose