In adults, endogenous hyperinsulinemic hypoglycemia is almost
invariably due to insulinoma. In these patients with insulinoma,
neuroglycopenic episodes exclusively after meal ingestion and negative
...72-h fasts are extraordinarily rare. We describe five adults with
neuroglycopenic episodes from hyperinsulinemic hypoglycemia within
4 h of meal ingestion and negative 72-h fasts. Each had negative
transabdominal ultrasonography, spiral computed tomographic scanning,
and celiac axis angiography of the pancreas. However, all showed
positive selective arterial calcium stimulation tests indicative of
pancreatic β-cell hyperfunction. At pancreatic exploration, no
insulinoma was detected by intraoperative ultrasonography and complete
mobilization and palpation of the pancreas. Moreover, the resected
pancreata showed islet hypertrophy and nesidioblastosis, but no
insulinoma. No definite disease-causing mutation was detected in Kir6.2
and SUR1 genes, which encode the subunits of the pancreatic
ATP-sensitive potassium channel responsible for glucose-induced insulin
secretion. Four patients who underwent gradient-guided partial
pancreatectomy have been free of hypoglycemic symptoms for up to 3 yr
follow-up; the other, who underwent a limited distal pancreatectomy,
has had brief recurrence of symptoms. The unique clinical features and
responses to dynamic testing in these adults with hyperinsulinemic
hypoglycemia in the absence of insulinoma may constitute a new syndrome
of postprandial hypoglycemia from diffuse β-cell hyperfunction.
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