Infant of a diabetic mother Infant with erythroblastosis fetalis Persistent hyperinsulinemic hypoglycemia
Glucose-6-phosphatase deficiency Amylo-1,6-glucosidase deficiency Liver phosphorylase deficiency Glycogen synthase deficiency
Fructose-1,6-diphosphatase deficiency Pyruvate carboxylase deficiency Phosphoenolpyruvate carboxykinase deficiency
Long-, medium-, or short-chain fatty acid acyl-CoA dehydrogenase deficiency Carnitine deficiency (primary or secondary) Carnitine palmitoyltransferase deficiency
Global hepatic dysfunction Reye syndrome Hepatitis Heart failure Sepsis, shock
ACTH, Adrenocorticotropic hormone; acyl-CoA, acyl coenzyme A; IGF-2, insulin-like growth factor-2.
as nesidioblastosis, or persistent hyperinsulinemic hypoglycemia of the newborn. In these infants, hyperplasia ofthe pancreatic islet cells develops in the absence of excessstimulation by maternal diabetes. Some of these patients havegenetic abnormalities of the islet cell sulfonylurea receptoror other genetic defects that alter the function of the adenosine triphosphate−sensitive potassium channel that regulatesinsulin secretion. Hyperinsulinism also can occur in Beckwith-Wiedemann syndrome, a condition characterized by neonatal somatic gigantism: macrosomia, macroglossia,omphalocele, visceromegaly, and earlobe creases.
Regardless of the cause, neonates with hyperinsulinism arecharacteristically large for gestational age (see Chapter 60). Hypoglycemia is severe and frequently occurs within 1 to 3 hours of a feeding. Glucose requirements are increased, oftentwo to three times the normal basal glucose requirement of 6to 8 mg/kg/min. The diagnosis of hyperinsulinism is confirmedby the detection of serum insulin concentrations greater than
Headache Palpitation (tachycardia) Mental confusion Pallor Somnolence Paresthesia Dysarthria Trembling Personality changes Anxiety Inability to concentrate Weakness Staring Nausea Hunger Vomiting Convulsions *These features and perceptions of the features may be blunted if the patient is receiving β-blocking agents.
5 μU/mL during an episode of hypoglycemia. The absence ofserum and urine ketones at the time of hypoglycemia is animportant diagnostic feature, distinguishing hyperinsulinismfrom defects in counterregulatory hormone secretion.
Treatment initially involves the infusion of intravenous (IV) glucose at high rates and of diazoxide to suppress insulin secretion. If diazoxide therapy is unsuccessful, long-acting somatostatin analogs can be tried. Often medical therapy for persistent hyperinsulinemic hypoglycemia of the newborn is unsuccessful, and subtotal (90%) pancreatectomy is required to prevent long-term neurologic sequelae of hypoglycemia.
In children hyperinsulinemia is a rare condition characterized by a voracious appetite, obesity, and accelerated linear growth and usually results from an islet cell adenoma. Computed tomography, magnetic resonance imaging, or radioisotope imaging of the pancreas should be attempted, but visualization of an adenoma is usually difficult. Surgical removal of the adenoma is curative.
In rare cases insulin or a hypoglycemic medication is administered by a parent or caregiver to a child as a form of child abuse, which is a condition referred to as Munchausen syndrome by proxy. This diagnosis should be suspected if extremely high insulin concentrations are detected (>100 μU/mL). C-peptide concentrations are low or undetectable, which confirms that the insulin is from an exogenous source.