Hyperinsulinism and Functional Hypoglycemia

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The purpose of this article is to present two typical cases of hyperinsulinism associated with islet cell adenoma of the pancreas, to present four unusual cases of functional hypoglycemia, and to emphasize the differential diagnosis of these two conditions.

In this article the term “hyperinsulinism,’ is restricted to hypoglycemia due to adenoma of the islands of Langerhans, and the term “functional hypoglycemia” to hypoglycemia without clinical evidence of organic disorders commonly associated with hypoglycemia. Cases of obvious adrenal, pituitary, or liver disease are excluded. It is beyond the scope of this communication to review the etiology of hypoglycemia or cases reported in the literature.1, 2, 3, 4


Case 1Adenoma of pancreas cured by excision. A man, aged 22, was seen on March 29, 1943 because of attacks characterized by trembling, weakness, sweating, and at times unconsciousness. The attacks began two and one-half years previously, occurred three or four times weekly, and were increasing in frequency and severity. They usually appeared at night but were often induced by exertion or fasting. The patient was repeatedly relieved by drinking orange juice. His illness was accompanied by a gain of 40 pounds.

Fasting blood sugar levels were 39 and 51 mg. per 100 cc. A single dose, hundred gram, oral glucose tolerance test on March 31 produced a curve as shown in figure 1. An insulin tolerance test on April 10 in which 5 units of standard insulin was given intravenously revealed the following:

Symptoms of stupor and drowsiness during. . .



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